Lead V1 Research Articles

The Significance of rS Change in the V2 Lead for Diagnosing Ventricular Tachycardia Deserves Attention: A Case Report

Abstract Occasionally, incessant ventricular tachycardia (VT) exhibits a narrow QRS complex pattern that could be misdiagnosed as supraventricular tachycardia. In this case, a 66-year-old woman was referred to the emergency department due to the worsen hemodynamic and incessant VT manifesting as a narrow QRS complex pattern that was initially misdiagnosed as supraventricular tachycardia (SVT), which was unresponsive to antiarrhythmic drugs. The electrocardiogram manifestation of VT was characterized by an rS configuration in lead V2 with Rs pattern in leads V1 and V3, and the R-wave amplitude of lead V1 and V3 was greater than that of lead V2, which was different from the typical electrocardiogram features of right bundle branch block. The patient was subsequently found to have suspected acute myocarditis when the cause of the disease was investigated. A combination of high-dose methylprednisolone, immunoglobulin and intra-aortic balloon pump was given immediately. Hemodynamics gradually stabilized, and ventricular tachycardia did not recur. The rS change in the V2 lead may be helpful to distinguish VT from supraventricular tachycardia.

Machine Learning Identifies Arrhythmogenic Features of QRS Fragmentation in Human Cardiomyopathy: Implications for Improving Risk Stratification

Heterogeneous ventricular activation can provide the substrate for ventricular arrhythmias (VA), but its manifestation on the ECG as a risk stratifier is not well-defined. To characterize the spatiotemporal features of QRS peaks that best predict VA in patients with cardiomyopathy (CM) using machine learning (ML). Prospectively enrolled CM patients with prophylactic defibrillators (n=95) underwent digital, high-resolution ECG recordings during intrinsic rhythm and ventricular pacing at 100-120bpm. Intra QRS peaks in the signal-averaged precordial leads were identified and their characteristics (amplitude, width and timing within the QRS) were transformed into 4-bin histograms. Random forest models of these characteristics in each lead alongside clinical data were trained on 76 patients and tested on 19 patients with cross-validation to determine the features that predicted VA. Patients were followed for 45 (22-48) months and 21% had VA. The individual ML models determined (AUROC) intrinsic QRS peak amplitude (0.88), width (0.78) and location (0.84) to all predict VA. In a combined model including all QRS peak characteristics, peaks with amplitude <31uV in V1, a width 4-8ms in V1, and location in the final quarter of the QRS of V1 were most predictive. Neither clinical data nor QRS peak characteristics assessed during ventricular pacing improved VA prediction when combined with intrinsic QRS peak characteristics. Arrhythmogenic QRS fragmentation is characterized by narrow, low-amplitude peaks in the terminal QRS of lead V1. These features alone without clinical variables or ventricular pacing are sufficient to accurately risk stratify CM patients.

Electrocardiogram sampling frequency for optimal performance of complexity analysis and machine learning models: Discrimination between subjects with and without paroxysmal atrial fibrillation using sinus rhythm electrocardiograms

BackgroundCurrent clinical practice to diagnose atrial fibrillation (AF) requires repeated, episodic monitoring and significantly underperform in their ability to detect AF episodes. ObjectiveThere is therefore potential for artificial intelligence based methods to assist in the detection of AF. Better understanding the optimal parameters for this detection can potentially improve the sensitivity in detecting AF. MethodTen second, 12-lead electrocardiogram signals were analysed using complexity algorithms combined with machine learning techniques to predict patients who had a previously detected AF episode but had since returned to normal sinus rhythm. An investigation was performed into the impact of sampling frequency of the electrocardiogram signal on the accuracy of the machine learning models used. ResultsUsing a single complexity algorithm showed a peak accuracy of 0.69 when using signals sampled at 125Hz. In particular it was noted that improved accuracy occurred when using lead V6 compared to other available leads. ConclusionBased on these results there is potential for 12-lead electrocardiogram signals to be recorded at 125Hz as standard and used in conjunction with complexity analysis to aid in the detection of subjects with AF.

Electrocardiographic markers of depolarization and repolarization in lead V1 predict right ventricular dysfunction in patients with heart failure

Abstract Background Right ventricular (RV) dysfunction is an important predictor of survival in patients with heart failure (HF) with both preserved (HFpEF) and reduced ejection fraction (HFrEF). To date there is limited data on the value of the electrocardiogram in predicting RV function. Purpose Given these considerations the aim of our study was to assess the possible relationship between several electrocardiographic (ECG) parameters and right ventricular function evaluated by echocardiography. Methods We included 109 patients (age 61±14 years, 68men) of whom 89 had HF (HFpEF N=62 and HFrEF N=27) and 20 patients without HF. Twelve-lead ECG and echocardiograms were performed in all patients. We assessed echocardiographic parameters of global and regional RV function. Results Time to Intrinsicoid deflection in lead V1 (TID-V1) and the QTc interval measured in lead V1 (QTc-V1) were significantly more prolonged in patients with HF vs. patients with no HF (36±24ms vs. 23±15ms; p=0.03, and 450±40ms vs. 427±20ms; p=0.047 respectively). TID-V1 correlated significantly with the tricuspid annulus systolic excursion (TAPSE) and RV fractional area change (FAC; r=-0.31; p=0.02, and r=-0.35; p=0.029 respectively). QTc-V1 correlated with parameters of global and regional RV function including FAC, RV apex longitudinal strain, RV free wall strain, and global RV strain (r=-0.42; p=0.0004, r=0.35; p=0.0032, r=0.21; p=0.045, and r=0.41; p=0.0005). RV dysfunction as defined by RV-FAC&amp;lt;35% was predicted by TID-V1 &amp;gt; 30ms with a sensitivity of 61% and specificity of 75%; AUC=0.752 and by QTc-V1&amp;gt;440ms with a sensitivity of 80% and specificity of 57%; AUC=0.888, and by a multivariate logistic regression model that also included TID-V1 and QTcV1, age, TAPSE, and LV ejection fraction with an AUC=0.967 (Figure). Conclusions Lead V1 time to intrinsic deflection and QTc-V1 predict RV dysfunction independent of echocardiographic parameters of ventricular function in patients with HF.

Dual-chamber CRT-D using ICD lead implantation in the LBBAP position

Abstract Background Interest in conduction system pacing (CSP) has increased in recent years. For left bundle branch area pacing (LBBAP), 4F and 6F pacing leads have been shown to be effective and safe. No information is available on the potential use of ICD leads for LBBAP. Aim The objective of the study was to demonstrate the feasibility of implanting an ICD lead in the LBBAP position to reduce the number of leads for CRT-D therapy. Patients and Methods We implanted the 7F ICD lead in the LBBAP position through a new 10F CSP delivery sheath in ten consecutive patients. Periprocedural data, QRS morphology and degree of QRS reduction were analyzed. Results Ten consecutive patients (one female) aged 69.5±9.2 years were treated with the above-mentioned method. Eight patients had ischemic cardiomyopathy and two patients had nonischemic cardiomyopathy. All patients had a CRT-D indication. Eight patients had a wide QRS complex with complete LBB and a QRS complex of 184.8±25.8 ms. Two patients had a narrow QRS complex but first-degree AV block with a PR interval greater than 240 ms. Left ventricular ejection fraction was 31.8±8.6%. Operative and fluoroscopy times were 103.6±30.3 minutes and 10.5±6.1 minutes, respectively. On average, 1.7 ± 0.6 screwing attempts were required per patient. The intraprocedural LBBAP threshold was 0.78±0.6V/1.0ms, the impedance was 530.8±86.5 ohm, and the R-wave amplitude was 9±3.3mV. The unipolar paced QRS complex was 123.6±15.9ms, the bipolar paced QRS complex was 129.5±12.8ms, and the bipolar paced QRS complex on the next day was 133.3±11.7. The mean duration from stimulus to R-wave peak in lead V6 was 82.9 ± 19.7 ms. The R-wave interpeak interval between leads V6 and V1 was 43.4 ± 9.7 ms. All but one patient received an effective defibrillation threshold test at 30J (n=8) and 36J (n=1). One patient was not tested during the procedure due to high risk. Conclusion This first-in-human study of ICD lead implantation in the LBBAP position demonstrated its feasibility and efficacy in achieving conduction system stimulation. This approach may lead to a reduction in the number of leads implanted for cardiac resynchronization therapy. Figure 1. A- RAO view, angiography of the RV for verification of the TVA-summit. B- LAO view, angiography from the CSP- sheath after reaching final position of the LBBAP lead (right sided interventricular septum - yellow dotted line). C – 12 lead ECG (speed 50mm/sec) demonstrating paced and native QRS complexes. D – Fluoroscopy in RAO view, final result. E – Fluoroscopy in LAO view, final result. F – Transthoracic echocardiography the next day (4Ch view) demonstrates optimal LBBAP lead position.. RAO – right anterior oblique; LAO – left anterior oblique; TVA – tricuspid valve anulus; CSP – conduction system pacing; LBBAP – left bundle branch area pacing.Figure 1.

Automatic measurement of stimulation to maximum negative dv/dt in V5 and V6 leads to confirm left bundle capture for conduction system pacing

Abstract Introduction Left bundle area conduction system pacing is obtained when the ventricular pacing lead is implanted into the right ventricular septum and captures the left bundle branch, demonstrated by right bundle branch morphology in the lead V1 and short stimulation to R-wave peak time (SRWPT) in leads V5 or V6. Manual measurements are challenging and result in significant variability. Maximum negative dv/dt in leads V5 and V6, occurring immediate after maximal lateral wall depolarization, represents the ideal measurement of synchronicity of left ventricular depolarization, as suggested by the guidelines. Objective To test feasibility of automatic algorithm to measure the maximum negative dV/dt in comparison to manual SRWPT measurement in V5 and V6. Method Data was collected from 7 patients with confirmed left bundle branch capture. Three trained operators manually measured SRWPT in leads V5 and V6 (Figure A). An algorithm capable of automatically measuring stimulation to maximum dv/dt was retrospectively applied to the same measured beats. Variability and correlation of measurements was compared between manual and automatic using the Bartlett Test for equal variance. Results In total, 137 individual beats were measured in the 2 leads by three operators resulting in 822 manual measurements. The mean variability of SRWPT in V5 and V6 was 2.9 ± 0.7 msec and 3.1 ± 1.1 msec, respectively (inter-operator correlation of 0.83). In contrast the stimulation to max negative dv/ dt mean variability in V5 and V6 was 1.3 ± 0.4 msec and 1.2 ± 0.5 msec, respectively (P &amp;lt; 0.001). The comparison of variation in measurement between manual and automatic measures are shown in a box and whisker plot in figure 2. Conclusion Manual measurement of SRWPT can be challenging resulting in higher variability compared to an automatic algorithm measuring max negative dv/dt. This study demonstrates the feasibility of automatic interval measurement in conduction system pacing; however, further studies are required to validate the reliability of such tool.Fig 1.Example ECG interval measurement

A novel electrocardiogram-based model for prediction of dementia: the Atherosclerosis Risk in Communities (ARIC) study

Abstract Background Current dementia prediction models, such as the UK Biobank Dementia Risk Score (UKBDRS, 12 variables), are limited by having variables that are difficult to obtain, subjectively measured, and self-reported. Although individual ECG parameters are linked to higher dementia risk, no study has combined multiple ECG parameters to create an ECG model for dementia prediction. Purpose Using data from the ARIC study, a prospective community-based cohort of Black and White participants in the USA that started in 1987-89, we created an ECG model (based on 7 pre-defined ECG parameters linked to dementia) and compared its model discrimination with the UKBDRS. Methods Participants without prevalent dementia from 2 baselines were included: Visit 4 (V4, 1996-98) and V5 (2011-13). Seven ECG parameters were examined: heart rate, abnormal P-wave terminal force in lead V1 (PTFV1), prolonged P wave duration, abnormal P wave axis, advanced interatrial block, left ventricular hypertrophy (LVH, Cornell voltage criteria), and corrected QT interval (QTc). Dementia cases were identified through 2019 using in-person and phone cognitive assessments, hospitalisation codes, and death certificates. Using a backward selection method (keeping variables with P&amp;lt;0.10 and age, since it is an important dementia risk factor), parsimonious Cox regression models were constructed for prediction of dementia over the longest available follow-up (V4: 23 years, V5: 8 years). Model discrimination of the ECG models and UKBDRS variables was evaluated by the Harrell’s C-statistic (95% CI). Results At V4, 11,520 participants (mean age, 62.8 ± 5.7 years; 56% women; 22% Black) were included; 2,427 developed dementia. At V5, 5,667 participants (mean age, 75.4 ± 5.1 years; 59% women; 22% Black) were included; 830 developed dementia. Figures 1 and 2 show the C-statistic (95%) and area under the ROC curve for the ECG model and UKBDRS variables at V4 and V5, respectively. The C-statistic (95% CI) for both ECG models were &amp;gt;0.70 and comparable with the corresponding UKBDRS models. Conclusion For middle-aged and older adults, a dementia prediction model comprising age and 4 ECG variables has good discrimination for dementia that is comparable with the 12-variable UKBDRS model. Since ECG variables are easily obtainable and objectively measured, these ECG models will be easier to adopt than the UKBDRS model. Further work to validate this model in an external cohort and develop a risk score will facilitate clinical translation.

Comparative study of the surface and endocavitary signals of cardiac pacing system analyzers with respect to the conventional polygraphy systems signals during implantation of conduction system pacing

Abstract Introduction and objectives Left bundle branch area pacing (LBBAP), is a novel modality of physiologic pacing that requires an adequate assessment of the endocardium as well as the body-surface electrocardiographic signals for a successful pacing-lead implantation. We aimed to assess if LBBAP criteria(1), specifically left ventricular septal pacing (LVSP) and left bundle branch pacing (LBBP) criteria, can be satisfactory measured using the signals resulting from different cardiac pacing analyzers (PSAs) by comparing them to the ‘conventional’ signals obtained from multichannel polygraph systems (MPSs) during the implantation procedure. Methods Comparative observational, prospective, multicenter study of consecutive patients who underwent a LBBAP strategy as first intention. LBBP was defined in the presence of a paced QRS with right bundle branch morphology in V1 (initial r wave in lead V1) and at least one of the following criteria: 1. V6-R-Wave Peak Time (RWPT) &amp;lt; 80 ms. 2. V1–V6 interpeak interval &amp;gt; 33 ms. 3. QRS transition from non-selective left bundle branch pacing to selective left bundle branch pacing or NS-LBBP to left ventricular septal pacing during pacing threshold. 4. Sudden increase of V6-RWPT &amp;gt; 15 ms because of reducing pacing output. 5. Left bundle potential-V6RWPT = stim-V6RWPT (±10 ms). For patients without initial r wave in V1, LBBP was considered in the presence of QRS transition during pacing. LVSP was defined by a paced QRS showing a typical terminal R-wave in V1, anatomical position of the lead in the left ventricular septum documented by fluoroscopy and not fulfilling the additional criteria previously described for LBBP. Results 63 patients were included. The basal characteristics of the patients are shown in Figure I. No significant differences (p&amp;lt;0.96) were observed in the basal QRS between the MPSs (129±29ms) and the PSAs (129±28ms). Initial "W" morphology in V1 during initial pacing was obtained in 90% of patients, without differences between both measurement systems. There were no significant differences between the MPSs and the PSAs in the paced QRS in V1 (140±10ms vs 141±12ms, p&amp;lt;0.746) nor in V6 (127.4±13ms vs 128.2±14.6ms, p&amp;lt;0.96). The measurement of the R wave peak time (RWPT) in V6 was 78.3±15ms vs 77±14 ms (p&amp;lt;0.72), and the V1-V6 inter-peak was 41.1±16ms in the MPSs vs 39±16 ms the PSAs (p&amp;lt;0.6), respectively, the Pearson correlation coefficients for these last two measurements being 0.91 (p &amp;lt;0.0001) and 0.91 (p &amp;lt;0.0001) (Figure II). Finally, according to electrocardiographic criteria measured by the MPSs, LBBP was achieved in 69% of patients, accomplishing 31% of the patients LVSP criteria, being the same proportions observed when PSAs measures where applied. Conclusions The signals resulting from the different PSAs can be useful to assess septal as well as LBBP criteria as an alternative to the ‘conventional’ signals obtained from MPSs.

Local ventricular activation at the distal great cardiac vein determines right- and left-sided approach for catheter ablation of outflow tract arrhythmias: a simple and rapid discriminator

Abstract Background When the precordial transition zone (TZ) of idiopathic outflow tract arrhythmias (OTAs) is present around lead V3, it may be difficult to precisely determine which outflow tract is responsible for the origin of the OTAs from the ECG characteristics. Purpose We hypothesized that mapping around the distal portion of the great cardiac vein (dGCV) would be useful for identifying which outflow tract is the origin of OTAs during radiofrequency catheter ablation (RFA). Methods Among 28 OTA patients who underwent dGCV mapping and successful RFA at our institution from June 2021 to February 2024, 16 whose TZ during the OTAs was ＞lead V2 and ＜lead V4 were included in this study. In all patients, activation mapping around the dGCV with the novel 2.7 Fr over-the-wire (OTW)-type decapolar catheter was performed during the OTAs. Results In all patients, the mapping catheter could be easily placed in the dGCV. In patients whose OTAs were successfully ablated from the left-sided OT (n=7), the local ventricular activation time in the dGCV during OTAs preceded the QRS onset (LAT-dGCV) by -26.1±7.0 msec, which was significantly earlier than that of OTAs successfully ablated from the right-sided OT (n=9; -4.0±5.7 msec; p&amp;lt;0.001). An LAT-dGCV &amp;gt;-18 msec indicated a left-sided OTA, and right-sided and left-sided OTAs were completely distinct. Patients with an LAT-dGCV &amp;gt;-18 msec and mapping initiated first in the left-sided OT had shorter procedure times than those with mapping initiated first in the right-sided OT (p&amp;lt;0.001). Conclusions Mapping the dGCV with this OTW-type catheter is easy and safe. The earliness of the local ventricular activation in the dGCV during OTAs could easily and precisely differentiate between right-sided and left-sided OTAs, resulting in a successful ablation with a shorter procedure time.

Type 2 diabetes individuals have a shorter QRS duration, prolonged QTc interval, flatter T wave, and reduced left ventricular cycle volumes compared to matched controls in the UK Biobank

Abstract Background Type 2 diabetes is associated with an increased risk of heart failure even in the absence of overt coronary artery disease, though underlying mechanisms are unclear. ECG and cardiac magnetic resonance (CMR) imaging provide windows into subclinical changes in myocardial structure and function and could be exploited to understand this. Purpose We investigate differences in ECG and CMR biomarkers in a large cohort of participants with type 2 diabetes, compared to a matched control cohort. We hypothesise that individuals with diabetes may exhibit concurrent differences in biomarkers, reflecting underlying cardiac remodelling. Methods We carried out a pair-matched cross-sectional study to examine the association between type 2 diabetes and multi-modal cardiac biomarkers. The exposure cohort consists of 1,781 UK Biobank participants with an imaging and ECG visit, prevalent type 2 diabetes and no known cardiovascular events at the time of visit. The control cohort is matched on age, sex and body mass index (BMI), and consists of 1,781 participants without diabetes. ECG and CMR biomarkers derived from UK Biobank data were used as outcome variables. We built four multiple multivariate linear regression models, incrementally adjusted for socio-demographic, lifestyle, and clinical covariates. Results Both cohorts were mostly male (63.6%), had a median age of 67 years [IQR: 72-85] and a median BMI of 27.8 kg/m2 [24.6-31.0]. Individuals with type 2 diabetes were more likely to be non-white (7.9% vs 2.7%, p&amp;lt;0.001), current or previous smokers (43.6% vs 40.6%, p=0.04), have lower diastolic blood pressure (79 [72-85] vs 81 [74-88] mmHg, p&amp;lt;0.001), and take cholesterol medication (72.3% vs 27.2%, p&amp;lt;0.001); anti-hypertensives (56.3% vs 27.3%, p&amp;lt;0.001); insulin (13.7% vs 0.1%, p&amp;lt;0.001); and metformin (53.1% vs 0.1%, p&amp;lt;0.001). They had a higher ventricular rate, shorter QRS duration, longer QTc interval, and flatter T wave amplitude, as well as lower left ventricular end-diastolic and end-systolic volumes, among other differences (Table 1). Covariates including cholesterol medication, metformin, and HbA1c were excluded as they were strongly correlated with diabetes, age and/or sex (Pearson correlation coefficient &amp;gt;0.3 or &amp;lt;-0.3). After full adjustment, we found that the exposure variable, diabetes, had a statistically significant association with ventricular rate, QRS duration, T wave offset, T wave amplitude in lead V3, left ventricular stroke volume and global average thickness (p&amp;lt;0.05) (Table 2). Conclusion Our results reveal that individuals with type 2 diabetes exhibit a shorter QRS, longer QTc, and lower end-diastolic and end-systolic volumes, compared to matched controls. This may be indicative of subclinical cardiac abnormalities, both electrophysiological and mechanical. Our association analysis suggests that other factors correlated with diabetes may be also responsible for certain biomarker differences and their underlying causes.

Prolonged ventricular activation time as a novel biomarker identifying burn-out phase of hypertrophic cardiomyopathy

Abstract Background Patients with hypertrophic cardiomyopathy (HCM) classically have preserved systolic function and decreased left ventricular end-diastolic volume. However, in a small sub-population, patients paradoxically develop systolic dysfunction, left ventricular dilatation, and ventricular wall thinning, which is known as end-stage hypertrophic cardiomyopathy or "burned-out cardiomyopathy’. Although an electrocardiogram (ECG) is a pivotal tool in HCM, its role in the detection of burned-out HCM has not been investigated. Purpose We assessed the ventricular activation time (VAT), an ECG marker of the duration of ventricular depolarization, as a predictive tool in the detection of the HCM burn-out phase. Methods We prospectively studied consecutive patients diagnosed with HCM via echocardiography at our medical center between 2017 and 2022. The ECG, along with echocardiography, was performed on the same day as the diagnosis. VAT was measured in milliseconds between the onset of the QRS complex to the peak or R wave on the V5 and V6 precordial ECG lead. HCM burn-out phase was supported when the left ventricular ejection fraction (LVEF) was below 50%, measured with echocardiography. Statistical analysis was performed using the SPSS software. Results Forty-five patients with HCM were studied, and their mean age was 51, while 78% (35/45) were male. Echocardiography data upon diagnosis revealed a mean maximum wall thickness of 19 (±3mm) and a mean left ventricular ejection fraction of 65% (±5%). Left ventricular outflow obstruction was present in 31% (14/45). During the study, 24% (11/45) presented atrial fibrillation, 44% (20/45) had an ICD implantation, and 22% (10/45) progressed to the burn-out phase of HCM. HCM patients who presented atrial fibrillation (63±31 vs. 46±14msec, p=0.018) or burn-out phase (65±32 vs. 46±13msec, p=0,009) had a significantly higher VAT than those subsets without. Notably, there was a significant positive relationship between VAT a burn-out phenotype (r=0,385, p=0.009). HCM patients with greater VAT also had a significantly higher risk of presenting a larger left atrial diameter (r=0,295, p=0.048), an increased left ventricular end-diastolic diameter (r=0.306, p=0.041), and a trend of presenting a lower LVEF (r=-0,262, p=0.082). Finally, we revealed a positive relationship between VAT and atrial fibrillation incidence (r=0,352, p=0.018). Conclusion Prolongation of VAT predicts the incidence of burn-out stage in patients with HCM and atrial fibrillation. Therefore, it seems to be a promising, inexpensive ECG marker for HCM progression and severity. Our findings emphasize the pivotal role of the ECG as a useful and inexpensive tool in the diagnostic follow-up of HCM.

Oral anticoagulants or antiplatelets for cryptogenic stroke: a systematic review and meta-analysis

Abstract Background Cryptogenic strokes comprise 20 to 30% of ischemic strokes and include a substantial proportion classified as embolic stroke of undetermined source (ESUS). However, the optimal antithrombotic strategy for cryptogenic stroke remains contentious. Purpose We conducted a systematic review and meta-analysis to compare the efficacy and safety of oral anticoagulants (OAC) versus antiplatelets in patients with cryptogenic stroke. Methods Six electronic databases of PubMed, Embase, Web of Science, the Cochrane Library, Google Scholar and ClinicalTrials.gov were searched from inception to Feb 15, 2024 to identify relevant randomized controlled trials (RCTs) comparing stroke recurrence and major bleeding rates between OAC and antiplatelets in cryptogenic stroke patients. We included trials adhering to a stringent diagnostic work-up for cryptogenic stroke, defined as cerebral infarction not attributed to definite sources of cardioembolism, large artery atherosclerosis, or small artery disease despite undergoing comprehensive investigations. The primary outcome was recurrent ischemic stroke, and the secondary outcome was major bleeding based on International Society of Thrombosis and Hemostasis criteria. Subgroup analysis was conducted for ESUS patients with an increased risk of cardiac emboli, such as patent foramen ovale (PFO) and atrial cardiopathy, defined as lead V1 terminal P-wave &amp;gt; 5000 μV × ms in electrocardiogram, serum N-terminal pro-B-type natriuretic peptide level &amp;gt; 250 pg/mL, and left atrial diameter (LAE) &amp;gt; 4 cm, or LAE index ≥ 3 cm/m2 on echocardiogram. Hazard ratio (HR) with 95% confidence (CI) was used as a measure of the effect estimates for aforementioned outcomes. Random-effects meta-analysis was performed using a restricted maximum likelihood model given between-study variance is inevitable. Results Our meta-analysis included 9 RCTs with a total of 15,139 patients (OAC = 7,343; antiplatelets = 7,796). ARCADIA, RE-SPECT ESUS, and NAVIGATE ESUS Trial investigated apixaban, dabigatran, and rivaroxaban, respectively, while warfarin was primarily used as OAC in the remaining six trials. Aspirin was predominantly utilized for antiplatelet therapy. There was no significant difference in recurrent ischemic stroke between OAC and antiplatelets (HR, 0.90; 95% CI, 0.78 to 1.04; I2 = 0%). However, OAC use was associated with a significantly higher risk of major bleeding (HR, 1.66; 95% CI, 1.07 to 2.56; I2 = 36%). Subgroup analysis in ESUS patients revealed comparable rates of recurrent ischemic stroke in those with atrial cardiopathy (HR, 0.91; 95% CI, 0.65 to 1.29; I2 = 0%) and PFO (HR, 0.72; 95% CI, 0.49 to 1.07; I2 = 0%). Conclusions Our meta-analysis suggests that OAC use does not decrease the risk of recurrent ischemic stroke compared with antiplatelet use but is associated with a significantly higher risk of major bleeding in patients with cryptogenic stroke.Primary (A) and secondary (B) outcomesSubgroup analysis for recurrent stroke

Smart watch for the detection of exercise-induced transient ST segment changes

Abstract Background Smartwatches are largely used and allowed to perform electrocardiogram one lead, usually a modified DI, used to diagnose atrial fibrillation. It is unknown whether or not smartwatches could be used to identify electrocardiographic transient ST changes during exercise-induced myocardial ischemia. The present study assessed the feasibility and reliability of using an Apple watch to record V5 in subjects scheduled for standard ECG stress tests. Methods One hundred eighty-nine subjects were included in this study. The mean age was 61+9 years, and 21.6 % were women (41 subjects). A single thoracic lead V5 was obtained with an Apple watch, positioned at the fifth intercostal space anterior axillary line, by creating a circuit between the back of the watch and the right index resting on the crown for 30 seconds. Four subjects were excluded because of the poor quality of the Apple watch signal. Forty-nine patients (25,92%) had a positive stress test with standard 12 lead ECG, 136 (71,96 %) negative stress test, and 4 (2,12%) the ECGs were non-diagnostic. The mean difference or bias between the Apple Watch and standard exercise-induced ST changes was quantified as 0.054, suggesting a generally minimal discrepancy in their readings. This consistency is critically affirmed by Cohen's Kappa (k) coefficient of 0.665. 9-1.0) Results A total of 189 subjects were included in the study; the mean age was 61 years (SD 9), and 21.6 % were women (41 subjects). Insightful outcomes were gleaned from the Bland-Altman analysis, which probed the concordance between the smartwatch ECG and the conventional standard ECG in measuring ST-segment deviations (Bias 0,054; SD 0.31, from -0.56 to 0.67, 95% limits of agreement), as vividly depicted in Figure. The dashed blue lines in Figure demarcate the 95% limits of agreement, which span from -0.56 to 0.67, offering a tangible visualization of the range within which most individual differences resided. A notable harmony was unveiled in the intricate exploration of the concordance between the two diagnostic methodologies, substantiated by an agreement of 87.6%. This demonstrates that, in most instances, the methodologies provided analogous results, exhibiting a commendable consistency between them in a substantial proportion of cases. Assuming the results of standard ECGs as the reference values, Apple Watch ST deviation showed a sensitivity of 69% and specificity of 94 %. The positive predictive value was 0.80952381, and the negative predictive value was 0,8951049. Conclusions In conclusion, this study demonstrated that the Apple Watch could detect transient ST changes with a sensitivity of 69% and a specificity of 94 %. Further prospective studies should be performed to assess the potential role of detecting transient myocardial ischemia with a smartwatch in a general population at risk.

Lateral QRS amplitude is independently associated with outcome after cardiac resynchronization therapy: Advancing patient selection?

BackgroundCardiac resynchronization therapy (CRT) is a cornerstone in the treatment of selected heart failure patients. However, a relevant proportion of patients do not show beneficial response. Identification of simple, additive, and outcome-relevant selection criteria may improve selection of patients. ObjectiveWe sought to determine whether baseline QRS amplitude is associated with outcome in CRT. MethodsQuantification of intrinsic, pre–CRT implantation QRS amplitude was performed in an observational multinational 2-center retrospective cohort analysis (derivation cohort Zurich, n = 178, 2000–2015; validation cohort Leuven, n = 183, 1999–2016) with a composite end point of all-cause mortality, ventricular assist device implantation, or heart transplantation at 5 years. ResultsHigher baseline to peak amplitude in lateral leads (lead I and V6) was associated with a lower risk of reaching the composite end point (lead I: hazard ratio, 0.86 [95% confidence interval, 0.78–0.95] per millivolt, P = .002; lead V6: hazard ratio, 0.94 [95% confidence interval, 0.88–1.00] per millivolt, P = .043). Concordance index–based comparison of quartile, spline, and receiver operating characteristic curve analysis suggested cutoff values of 6 mV for lead I and 3 mV for V6 for optimal discrimination of outcome. External validation confirmed the cutoff of 3 mV in lead V6 as a highly significant discriminator of outcome (P < .001) associated with a risk reduction of 65%. ConclusionLow QRS amplitude in lateral electrocardiogram leads is associated with higher risk of poor outcome in CRT patients. A cutoff of 3 mV in lead V6 proved highly discriminative. Further studies need to confirm the additive value of QRS amplitude in selection of patients for CRT and to assess whether CRT may be made available to more patients.

Efficacy and safety of leadless ventricular pacemaker: a single-center retrospective observational study.

The Micra leadless pacemaker (MLP) has been demonstrated to be safe and effective as a substitute for conventional transvenous ventricular pacemakers (TVP). However, its application in the general population is still restricted. The aim of this retrospective study was to assess the safety and efficacy of MLP. Clinical data and device parameters were gathered on every patient receiving MLP implantation between 1 January 2019 and 31 December 2023, in the First Affiliated Hospital of Soochow University. The efficacy of MLP on the primary composite endpoint, atrioventricular (AV) synchrony, hospitalization, and post-implantation quality of life was assessed. Safety outcomes included implantation procedural characteristics, acute and chronic complications, and stability of pacing parameters. Meanwhile, we compared pacing parameters, AV synchrony, and improvement of life quality between patients who had been implanted with the MicraTM VR (Medtronic Micra™ MC1VR01) and Micra™ AV (Medtronic Micra™ MC1AVR1). Multivariate linear regression models were used to unearth potential predictors of echocardiography or electrocardiogram (ECG) parameters on pacing parameters. A total of 94 patients were included, and implantation was successful in all of the cases. A single patient experienced effusion hours after the implantation, indicating a low rate of both acute and chronic complications. In patients with complete AV block (AVB), Micra AV increased AV synchrony from 23.2%±6.3% to 80.8%±5.7%. After 28 days of implantation, the patients' Minnesota Living with Heart Failure Questionnaire (MLHFQ) score decreased from 27.1±18.6 to 20.0±17.6, and none of them required hospital readmission. Left ventricular end-diastolic diameter (LVEDD, 50.0±6.7 cm), left ventricular end-systolic diameter (LVESD, 32.6±3.9 cm), and ECG R wave in lead V5 (RV5, 1.3±0.6 mV) can be employed for the prediction of pacemaker threshold [0.50 (0.38-0.67) mV], sensing voltage (10.1±4.7 mV), and impedance (785.9±226.4 Ohm) correspondingly. Despite being a small, single-center, retrospective study, our study provided data for assessing the safety and efficacy of MLP. Clinicians and patients can make well-informed therapy decisions by being aware of its benefits and forecasting pacing parameters.

Atrial Cardiomyopathy Predicts the Functional Outcome and Mortality in Stroke Patients.

Atrial cardiomyopathy (ACM) is characterized by atrial dysfunction. This study aims to assess the prognostic significance of ACM in patients with noncardioembolic stroke (NCS). Patients with NCS within seven days of onset were prospectively enrolled between January 2019 and December 2020. ACM was defined as either an N-terminal pro-brain natriuretic peptide (NT-pro BNP) ＞250 pg/ml or a P-terminal force in precordial lead V1 (PTFV1) ≥ 5000µV·ms. A poor functional outcome was determined as a score of 3-6 on the modified Rankin Scale (mRS) within a 2-year follow-up period. Logistic regression and Cox regression analyses were employed to examine the relationship between ACM and the long-term prognosis of patients with NCS. A total of 1,346 patients were enrolled, of whom 299 (22.2%) patients were diagnosed with ACM. A total of 207(15.4%) patients experienced a poor functional outcome, and 58 (4.3%) patients died. A multivariate logistic regression analysis indicated that ACM was significantly associated with a poor functional outcome in NCS patients [adjusted odds ratio (aOR): 2.01; 95% confidence interval (CI): 1.42-2.87; p＜0.001]. Additionally, a multivariate Cox regression analysis showed that an NT-pro BNP ＞250 pg/ml was significantly associated with an increased risk of all-cause mortality [adjusted hazard ratio (aHR), 2.51; 95% CI: 1.42-4.43; p=0.001]. ACM may serve as a novel predictor of a poor long-term functional outcome in patients with NCS. Elevated NT-pro BNP levels (＞250 pg/ml) were found to be associated with a higher risk of all-cause mortality. These findings warrant further validation in multicenter studies.

Study on the feasibility of distinguishing ventricular and pre-excited arrhythmia rhythms by a new algorithm

BackgroundThe differentiation and diagnosis of ventricular tachycardia (VT) and pre-excited tachycardia (PXT) remains a challenging task, especially when typical AV dissociation is not present. The purpose of this article is to study the feasibility of a new theoretical algorithm for identifying ventricular arrhythmias (VA) and pre-excited arrhythmias (PA) rhythms (which can be used to distinguish VT from PXT, etc.). MethodThis study involved the deduction of a new algorithm by combining knowledge of cardiac anatomy, vectorcardiography, and cardiac electrophysiology. The new algorithm evaluated the diagnostic value through intracardiac electrophysiology in 205 cases of VA and PA. The new algorithm diagnoses VA based on the following 4-step process:1.The QRS complex in leads II, III, and aVF shows a unidirectional R wave, and lead aVR shows a QS pattern.2.S waves are predominant in two or more of leads I, aVF, and V6.3.Lead V2 shows ≥3 phase waves or returning branch notching (note: returning branch refers to the band of QRS complexes returning to the baseline).4.Lead V5 shows a negative wave in the initial portion or returning branch notching.If none of these criteria are met, the diagnosis is PA. The diagnostic value of the new algorithm is compared with the Steurer algorithm and the Vereckei algorithm (diagnosed based on the QRS waveform characteristics of the two algorithms during electrophysiological verification, excluding the diagnosis of atrioventricular dissociation). ResultsThe new algorithm showed significant advantages in terms of AUC value (0.83 vs. 0.61 vs. 0.57), sensitivity (83.6 % vs. 23.3 % vs. 24.8 %), and accuracy (82.9 % vs. 48.3 % vs. 46.3 %) compared to the Steurer algorithm and Vereckei algorithm based on QRS waveform characteristics for diagnosing VA (137 cases) and PA (68 cases). This indicates that the new algorithm is more accurate in identifying idiopathic VA. While there was a significant difference in specificity between the New algorithm and Steurer algorithm (82.3 % vs. 98.5 %, p < 0.05), the difference with Vereckei algorithm (82.3 % vs. 89.7 %) was not significant.In the New algorithm, the sensitivity and specificity for each step are as follows:-Step 1: Sensitivity 34.3 %, Specificity 94.1 %.-Step 2: Sensitivity 24.1 %, Specificity 98.5 %.-Step 3: Sensitivity 18.3 %, Specificity 100 %.-Step 4: Sensitivity 6.6 %, Specificity 89.7 %.Step 1 had the highest AUC value, indicating the best overall diagnostic performance among all steps. Step 2 and Step 3 also performed well, while Step 4 had relatively poorer diagnostic performance. ConclusionThe new algorithm is suitable for identifying the origin of VA and PA rhythms.

P-wave terminal force is related to left pulmonary vein reconnection in patients with atrial fibrillation recurrence after pulmonary vein isolation.

In patients with atrial fibrillation (AF) recurrence after pulmonary vein (PV) isolation, noninvasive markers predicting PV reconnection or PV reconnection sites have not been fully elucidated. This study investigated the relationship between the P-wave terminal force in lead V1 (PTFV1) and the PV reconnection or reconnection site in patients with AF recurrence. We retrospectively studied consecutive patients who underwent second AF ablation between April 1, 2018, and June 1, 2023. PTFV1 was investigated before the first AF ablation (pre-ablation PTFV1) and before the second AF ablation (post-ablation PTFV1). In addition, we examined the ratio of the post-ablation to pre-ablation PTFV1 (PTFV1 ratio). These values were compared between patients with and without PV reconnection, with and without left PV (LPV) reconnection, and with and without right PV (RPV) reconnection. The analysis included 56 patients. PTFV1 was reduced because of the first AF ablation. In addition, the values were more decreased in patients without PV reconnection than with PV reconnection. The PTFV1 ratio was significantly smaller in the patients without LPV reconnection than with LPV reconnection; no significant difference was observed between the patients with and without RPV reconnection. Receiver operating characteristic curve analysis showed that a PTFV1 ratio > 0.69 predicted LPV reconnection with 70.0% sensitivity and 66.7% specificity. In conclusion, the PTFV1 ratio may be a noninvasive marker predicting LPV reconnection in patients with AF recurrence.

The positive F wave in lead V1 of typical atrial flutter is caused by activation of the right atrial appendage: Insight from mapping during entrainment from the right atrial appendage.

Typical atrial flutter (AFL) is a macroreentrant tachycardia in which intracardiac conduction rotates counterclockwise around the tricuspid annulus. Typical AFL has specific electrocardiographic characteristics, including a negative sawtooth-like wave in the inferior lead and a positive F wave in lead V1. This study aimed to analyze the origin of the positive F wave in lead V1, which has not been completely understood. This study enrolled 10 patients who underwent radiofrequency catheter ablation for a typical AFL. Electroanatomical mapping was performed both during typical AFL and entrainment from the right atrial appendage (RAA). The 12-lead electrocardiogram (ECG) and three-dimensional (3D) electroanatomical maps were analyzed. The positive F wave in lead V1 changed during entrainment from the RAA in all the cases. The 3D map during entrainment from the RAA revealed an area of antidromic capture around the RAA, which collided with the orthodromic wave in the anterior right atrium. This area of antidromic capture around the RAA was the only difference from the 3D electroanatomical map of AFL and is considered the cause of the change in the F wave in lead V1 during entrainment. The analysis of the differences in the 12-lead ECG and 3D maps between tachycardia and entrainment from the RAA clearly demonstrated that activation around the RAA is responsible for the generation of the positive F wave in lead V1 of typical AFL.

Permanent left bundle branch area pacing improves mitral regurgitation and cardiac function in patients with right bundle branch block

BackgroundPermanent left bundle branch area pacing (LBBAP) has been established as an effective means to correct left bundle branch block. Right bundle branch block (RBBB), emerge as a distinct form of cardiac conduction abnormality, can be seen in the context of LBBAP procedure. However, the correction potential of LBBAP in patients with RBBB remains largely unexplored.ObjectiveThe objective of this study was to evaluate the efficacy and safety of permanent LBBAP in patients with RBBB.MethodsNinety-two consecutive patients who underwent successful permanent LBBAP were recruited from May. 2019 to Dec. 2022 in Fuwai Central China Cardiovascular Hospital. Among them, 20 patients with RBBB were included in our analysis. These patients were followed up at 1, 3, 6 and 12 months post-LBBAP. The QRS duration (QRSd) on the V1 lead of the 12-lead elctrocardiogram was measured and compared before and after the LBBAP procedure. Additionally, mitral regurgitation, tricuspid regurgitation and cardiac function were assessed using transthoracic echocardiography, specifically focusing on left ventricular ejection fraction (LVEF) and mitral regurgitation severity. The acute pitfills and delayed complications associated with the LBBAP procedure were recorded to evaluate its safety. SPSS 23.0 was used to perform statistical analysis with Student’s t test or one way ANOVA or nonparametric tests (paired Wilcoxon test). A p value less than 0.05 was defined as significant.ResultsThe demographic breakdown of the RBBB cohort revealed a mean age of 66.35 ± 11.55 years, 60% being male. Comorbidities were prevalent, including severe atrioventricular block (AVB) in 75%, sick sinus syndrome (SSS) in 20%, heart failure in 25%, atrial fibrillation in 30%, coronary heart diseases in 45%, hypertension in 35%, and diabetes mellitus in 15%. Regarding the LBBAP procedure, the average operation time was 106.53 ± 2.72 min, with 45% of patients (9 individuals) requiring temporary cardiac pacing during the surgery. Notably, the LBBAP procedure significantly narrow the QRS duration in RBBB patients, from 132.60 ± 31.49ms to 119.55 ± 18.58 ms (P = 0.046). Additionally, at the 12-month follow-up, we observed a marked improvement in LVEF, which increased significantly from 55.15 ± 10.84% to 58.5 ± 10.55% (P = 0.018). Furthermore, mitral regurgitation severity improved, with a median reduction from 4.46 (0.9, 7.3) to 2.29 (0, 3.49) cm2 (P = 0.033). Importantly, no cases of ventricular septum perforation or pericardial effusion were reported during the LBBAP procedure or during the follow-up period.ConclusionLBBAP provides an immediate reduction in QRS duration for patients suffering from RBBB, accompanied by improvements in mitral regurgitation and cardiac function as evident in the 12-month follow-up period.