Wave In Lead V1 Research Articles

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) < 80 ms. 2. V1–V6 interpeak interval > 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 > 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<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<0.746) nor in V6 (127.4±13ms vs 128.2±14.6ms, p<0.96). The measurement of the R wave peak time (RWPT) in V6 was 78.3±15ms vs 77±14 ms (p<0.72), and the V1-V6 inter-peak was 41.1±16ms in the MPSs vs 39±16 ms the PSAs (p<0.6), respectively, the Pearson correlation coefficients for these last two measurements being 0.91 (p <0.0001) and 0.91 (p <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.

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.

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.

Early impaired relaxation of the left ventricle in isolated, uncomplicated prehypertension without left ventricular hypertrophy can be detected by exercise electrocardiography

Nearly fifty percent of patients with isolated, uncomplicated prehypertension have impaired relaxation of the left ventricle even in the absences of left ventricular hypertrophy. Such early impairment of the left ventricular relaxation can be detected by exercise electrocardiography. Transient increase, in the area of the negative terminal deflection of the P wave in lead V1 (>0.04mVaec) during and/or early recovery suggested transient increase in the left atrial pressure due to unmasking of the early impairment of the left ventricular relaxation by exercise induced tachycardia.

Ventricular arrhythmias originating from different portions of the communicating vein of the left ventricular summit: electrocardiographic characteristics and catheter ablation

BackgroundIdiopathic ventricular arrhythmias (IVAs) arising from different portions of the communicating vein of the left ventricular summit (summit-CV) are not a rare phenomenon. Whereas its electrocardiographic (ECG) and electrophysiological characteristics are not fully investigated.ObjectiveThis study aimed to identify distinct ECG and electrophysiological features of IVAs originating from different portions of summit-CV.MethodsNineteen patients confirmed arising from summit-CV were included in this study.ResultsThe 19 patients were divided into proximal and distal portion groups based on their target sites in summit-CV. In the proximal portion group, 100% (11/11) VAs showed dominant negative (rs or QS) waves in lead I, while in the distal portion group, 87.5% (7/8) showed dominant positive waves (R, Rs or r) (p < 0.000). In lead V1, 100% (11/11) of the proximal portion group showed dominant positive waves (R or Rs), while 62.50% (5/8) of the distal portion group showed positive and negative bidirectional or negative waves (RS or rS) (p < 0.005). RI>4mV, SI<3.5mV, RV1<13mV, SV1>3.5mV, RI/SI>0.83, and RV1/SV1< 2.6 indicated a distal portion of summit-CV with the predictive value of 0.909, 1.000, 0.653, 0.972, 0.903, 0.966, respectively. A more positive wave in lead I and a more negative wave in lead V1 indicated more distal origin in summit-CV. Target sites in proximal and distal summit-CV groups showed similar electrophysiological characteristics during mapping.ConclusionsThere were significant differences in ECG characteristics of VAs at different portions of summit-CV, which could aid pre-procedure planning and facilitate radiofrequency catheter ablation (RFCA) procedures.

ЭЛЕКТРОКАРДИОГРАФИЧЕСКИЕ СИНДРОМЫ

Introduction. Sudden cardiac death (SCD) is a global health concern, often associated with specific clinical and electrocardiographic syndromes. While electrocardiography (ECG) is a crucial diagnostic tool in cardiology, it does not always provide a direct diagnosis or prediction of SCD. However, there are indirect criteria and syndromes that aid in diagnosing complex clinical cases in cardiology. Aim. This study aims to review various electrocardiographic syndromes known to predict sudden cardiac death, drawing from both domestic and foreign literature. Results. Wellens syndrome (WS) is an ECG pattern indicating a high risk of anterior wall myocardial infarction caused by anterior interventricular artery occlusion or critical stenosis. The de Winter pattern is an ECG sign associated with proximal LAD occlusion and the absence of ST segment elevation. Aslanger pattern is linked to coronary artery occlusion in patients with multivessel coronary artery disease, reflecting a combination of inferior MI and diffuse ischemia. Chaterrier's phenomenon (cardiac memory phenomenon) manifests as abnormal T wave inversion during normal sinus rhythm after myocardial electrical stimulation cessation.The Sgarbossa criteria aid in diagnosing acute myocardial infarction in patients with previous left bundle branch block. ECG signs of arrhythmogenic dysplasia of the right ventricle include negative T-waves in leads V1-V3 and an "epsilon" wave in lead V1, reflecting delayed depolarization of the right ventricle. Conclusion. Early recognition of these ECG patterns can aid in secondary prevention of AMI, fatal rhythm disturbances, and SCD, while also preventing overdiagnosis of myocardial ischemia in patients with implanted devices.

Visualization of Left Ventricular Endocardium Activation Time during Cardiac Conduction System Pacing

Introduction. Right ventricular myocardial pacing leads to asynchronous contraction of the left ventricle (LV) and can impair its contractility over time. Stimulation of the conduction system of the heart ensures physiological activation of the ventricles.&#x0D; The aim. To visualize the pattern of propagation of the electrical front on the activation map of the LV endocardium during conduction system pacing and during right ventricular myocardial pacing.&#x0D; Materials and methods. In two patients with the conduction system pacing, who were operated at the National Amosov Institute of Cardiovascular Surgery, invasive LV activation mapping was performed on various options of cardiac pacing using the EnSite Precision TM navigation system. One patient with complete atrioventricular block had nonselective His bundle pacing. The second patient had dilated cardiomyopathy and indications for cardiac resynchronization therapy and ablation of the atrioventricular junction due to chronic tachyform of atrial fibrillation. After an unsuccessful attempt to place LV lead in coronary sinus, a lead for left bundle branch pacing was implanted. Different activation maps of the LV endocardium were built in two patients with two types of cardiac pacing: right ventricular myocardial pacing and cardiac conduction system pacing.&#x0D; Results. The total LV endocardial activation time was significantly different in the two studied patients with different pacing options. In a patient with non-selective stimulation of His bundle, the total LV endocardial activation time was 43 ms (QRS width 126 ms, the interval from the stimulus to the peak of the R wave in lead V6 78 ms). After switching to right ventricular myocardial pacing with a decrease in the pacing amplitude, the total LV endocardial activation time prolonged to 90 ms (QRS width 165 ms, the interval from the stimulus to the peak of the R wave in lead V6 117 ms). In a patient with left bundle branch pacing, total LV endocardial activation time was 51 ms (QRS width 160 ms, the interval from the stimulus to the peak of the R wave in lead V6 66 ms). With switching exclusively to right ventricular pacing the total LV endocardial activation time prolonged to 93 ms (stimulated QRS width 180 ms). At the same time, the activation pattern of the LV endocardium was significantly different, since the right ventricular lead was located closer to the apex.&#x0D; Conclusions. Conduction system pacing provides rapid physiological LV activation and potentially avoids the negative consequences of asynchronous slow ventricular activation during right ventricular pacing.

Case of a misleading ECG

An elderly man with severe chronic obstructive pulmonary disease and a history of complete heart block with pacemaker placement was found to have pacemaker lead infection and required device extraction. He had a standard dual chamber pacemaker in place, however the ECG obtained showed paced QRS complexes with presence of R wave in lead V1 and QS in lead I suggestive of left ventricular pacing. Additional imaging with CT scan obtained for confirmation revealed that the heart was displaced to the left posterior hemithorax secondary to pulmonary disease. Due to significant posterolateral rotation of the heart, a right ventricular paced rhythm can demonstrate Q/S waves in the lateral leads (I, aVL, V5–6) and R waves in the right precordial leads (V1–3). This can be misdiagnosed as a left ventricular paced rhythm.

Guidance on left bundle branch pacing using continuous pacing technique and changes in lead V1 characteristics under real-time monitoring.

The changes in the morphology and characteristics of the V1 leads during left bundle branch capturing still need to be fully understood. This study aims to provide some suggestions about the LBB capture process through the morphology and characteristics of the V1 lead. LBBP using the continuous pacing and morphology monitoring technique during screw-in using a revolving connector (John Jiang's connecting cable). The morphology and features of V1 leads are recorded by continuous monitoring technology. The most common morphology in the LVSP stage is QR, while in the NS-LBBP (low output) stage and the NS-LBBP (lower output) stage, it is rSR. In the S-LBBP stage, it is rsR. The predominant morphology is with r/R waves in S-LBBP, which includes variations like rSR, rsR, rSr, rsr, rR, rs, rS, and R type, making up 96.7% of the total. The r waves in lead V1 are associated with agitated myocardium conducted from the left bundle branch. The initial r-wave in lead V1 may be a marker during the follow-up of patients with selective LBB capture.

Sinus rhythm QRS morphology reflects right ventricular activation and anatomical ventricular tachycardia isthmus conduction in repaired tetralogy of Fallot

Patients with repaired tetralogy of Fallot (TOF) are at risk for ventricular tachycardia (VT) related to well-described anatomical isthmuses. The purpose of this study was to explore QRS morphology as an indicator of anatomical isthmus conduction. Patients with repaired TOF and complete right bundle branch block referred for transcatheter pulmonary valve replacement (PVR) or presenting with sustained VT underwent comprehensive 3-dimensional mapping in sinus rhythm. Electrocardiographic characteristics were compared to right ventricular (RV) activation and anatomical isthmus conduction properties. Twenty-two patients (19 pre-pulmonary valve replacement and 3 clinical VT) underwent comprehensive 3-dimensional mapping (median 39 years; interquartile range [IQR] 27-48 years; 12 [55%] male). Septal RV activation (median 40 ms; IQR 34-46 ms) corresponded to the nadir in lead V1 and free wall activation (median 71 ms; IQR 64-81 ms) to the transition point in the upstroke of the R' wave. Patients with isthmus block between the pulmonary annulus and the ventricular septal defect patch and between the ventricular septal defect patch and the tricuspid annulus (when present), were more likely to demonstrate lower amplitude R' waves in lead V1 (5.8 mV vs 9.4 mV; P = .005), QRS fragmentation in lead V1 (15 [94%] vs 2 [13%]; P < .001), and terminal S waves in lead aVF (15 [94%] vs 6 [40%]; P < .001) than those with intact conduction. During catheter ablation, these QRS changes developed during isthmus block. For patients with repaired TOF, the status of septal isthmus conduction was evident from sinus rhythm QRS morphology. Low-amplitude, fragmented R' waves in lead V1 and terminal S waves in the inferior leads were related to septal isthmus conduction abnormalities, providing a mechanistic link between RV activation and common electrocardiographic findings.

New ECG Algorithm for the Prediction of Culprit Vessel in Acute Myocardial Infarction Involving Lateral Part of the Ventricle: Ilkay Classification.

Isolated lateral myocardial infarction sometimes does not meet ST-segment elevation myocardial infarction (STEMI) criteria according to contiguous leads. This condition could cause late diagnosis and the need for revascularization therapy. To accurately predict the occlusion of lateral surface of the left ventricle, we defined a new electrocardiogram (ECG) algorithm by using angiographic and electrocardiographic correlations. This was a retrospective, multicenter observational study. The study population consisted of 200 patients with STEMI affecting lateral surface of myocardium, between 2021 and 2022. According to the coronary angiography results, we identified 74 eligible patients for study protocol. The study patients were divided into two groups: isolated DB (14 patients) or circumflex obtuse marginal group (60 patients). ST depression in lead V2 had high positive predictive values for the prediction of obtuse marginal occlusion (positive predictive values (PPV), 100%; negative predictive value (NPV), 90%). ST elevation in V2 in ECG, in conjunction with ST depression in lead III had high positive predictive values for prediction of diagonal branch of LAD. Moreover, the presence of hyperacute T wave (≥10 mm) in lead V2 and ≥2 mm ST depression in lead III had large diagonal branch of LAD (PPV, 98%; NPV, 100%). However, <10 mm T wave in lead V2 and <2 mm ST depression in lead III had small diagonal branch of LAD. We comprehensively classified the lateral STEMI definition through new electrocardiographic scheme as Ilkay classification, whereby we could accurately predict infarct-related artery and its occlusion level in lateral myocardial infarction.

Left-to-right atrioventricular activation delay, a novel measure of AV-conduction, predicts clinical outcomes in non-LBBB patients

Abstract Funding Acknowledgements Type of funding sources: None. Background The PR-interval reflects atrial and atrioventricular activation. A prolonged PR has been linked to heart failure (HF), atrial fibrillation and mortality. This might at least in part be the consequence of compromised cardiac performance (e.g. left ventricular filling). On the other hand, very long PR may just be a marker of advanced heart disease. Alternative measures that account for atrial and ventricular activation might better predict adverse hemodynamic consequences of delayed atrioventricular conduction. The DEEPER-PR mechanistic pilot study suggested that various novel measures of AV conduction are associated with Doppler-derived cardiac performance. However, the clinical significance of these novel parameters is unknown. Study objective: To examine the association of novel measures of AV conduction with clinical outcomes in a HFrEF population with non-LBBB and a wide QRS (non-LBBB ICD-only MADIT-CRT subset). Methods Time intervals from anonymized scanned baseline 12-lead ECGs from the Multicenter Automatic Defibrillator Implantation Trial – Cardiac Resynchronization Therapy (MADIT-CRT), non-LBBB patients (n=537) were assessed in detail using ImageJ (public domain software provided by NIH). The primary endpoint of the study was the combined endpoint of heart failure (HF) or death events. The earliest onset of atrial activation (P wave onset), zero crossing of the P wave in lead V1, earliest onset of the QRS complex, time interval to the first peak of the R wave in V1 and V6, and QRS width were determined. The PR interval and 8 novel parameters (see figure 1) were measured and calculated accordingly. Bivariate non-parametric correlations were calculated to ascertain the associations between these covariates. In addition, Kaplan-Meier analyses by quintiles of all AV delay measures, and multivariable Cox regression analyses were performed among ICD-only patients (n=209) to determine the associated risk regarding of the combined MADIT-CRT clinical outcome of HF events or death. Results Weak correlations were found between the AV delay variables (figure 2). Four of the variables (P0PV1, P0R, PePV6, PR) were significantly associated to the risk of HF or death with the upper quintile defining a high-risk HF population, as compared to quintiles 1 to 4 (see figure 3). This indicated a threshold behavior of the associations. P0PV1 was the most powerful risk predictor (Chi-square=16.31, HR for Q5 vs. Q1-4=3.12, CI=1.80-5.41, p&amp;lt;0.001), followed by PRmax (Chi-square=13.19, HR for Q5 vs. Q1-4=2.81, CI=1.61-4.92, p&amp;lt;0.001), P0R (Chi-square=10.42, HR=2.54, CI=1.44-4.48, p=0.001), and PePV6 (Chi-square=7.96, HR for Q5 vs. Q1-4=2.2, CI=1.29-4.07, p=0.005). Conclusion This post-hoc ECG-based study identified in MADIT-CRT non-LBBB patients the left-to-right atrioventricular activation delay (P0PV1) as the most powerful risk predictor of HF or death. Prospective evaluation of this measure is warranted.

PO-02-013 EFFICACY OF LEFT BUNDLE BRANCH PACING IN PATIENTS WITH DIFFERENT LEFT BUNDLE BRANCH BLOCK MORPHOLOGIES

Left bundle branch pacing (LBBP) is a novel technique to deliver cardiac resynchronization therapy (CRT) by correcting intrinsic LBBB to achieve electrical and mechanical resynchrony. Whether the efficacy of LBBP is different across different LBBB morphologies has not been reported. To explore the efficacy of LBBP in patients with different LBBB morphologies. Consecutive patients who received LBBP due to either heart failure (HF) with LBBB or atrioventricular block accompanied with a LBBB pattern escape rhythm were recruited. The changes of QRS duration (ΔQRSd) and left ventricular activation time (ΔLVAT) were compared before and after LBBP. Relationships of ΔQRSd and ΔLVAT with cardiac function in HF patients were also explored. HF patients were followed up for at least 6 months. Electrical resynchrony and cardiac function were compared based on 4 major LBBB morphological criteria. Comparison 1: LBBB meeting Strauss criteria vs not; Comparison 2: presence of q wave in lead I and aVL vs not; Comparison 3: presence of QS vs rS morphology of QRS in lead V1; and Comparison 4: presence of S wave in lead V6 vs not. A total of 82 patients were enrolled from January 2018 to August 2022. In Comparison 1, 59 patients had LBBB meeting Strauss criteria vs 23 not meeting criteria. Patients with LBBB meeting Strauss criteria had greater reduction in QRSd (56.95±24.10ms vs 36.83±32.16ms, P<0.05) and LVAT (56.47±14.90ms vs 41.52±17.13ms, P<0.001). Forty-two HF patients met the Strauss criteria had greater LVEF improvement (19.92±6.89% vs 12.41±13.10%, P<0.05) compared to those not meeting the criteria. Comparison 4 included 61 patients without S wave in lead V6 and these patients exhibited better electrical synchrony after LBBP (ΔQRSd: -55.18±24.79ms vs -40.05±33.67ms, P<0.05; ΔLVAT: -55.74±14.70ms vs -41.67±18.55ms, P<0.05) than patients with S wave in V6. Among them, 51 patients without S wave in V6 had HF and showed greater LVEF improvements than those with S wave in V6 (ΔLVEF: 18.65±10.13% vs 6.61±7.78%, P<0.05). Correlation analyses showed significant associations between both ΔQRSd (R=0.55, P <0.001) and ΔLVAT (R=0.39, P <0.01) with LVEF improvement. In multivariate analysis, ΔQRSd>53 ms is an independent predictor of cardiac super response (LVEF improvement>15%). LBBB pattern meeting the Strauss criteria and absence of S wave in lead V6 can predict better electrical resynchrony and LVEF improvement by LBBP.

Transient Increase in the Terminal Negative Deflection of the P Wave in Lead V1 during Treadmill Testing Identifies Exercise Induced Aggravated Left Ventricular Dysfunction

Terminal negative deflection of the P wave in lead V1 is produced by posteriorly directed depolarization of the left atrium. A value of more than 0.04 mm sec suggests increase in left atrial pressure. Transient new appearance of this finding during treadmill testing suggests transient exercise induced increase in left atrial pressure. Indirectly it suggests transient exercise induced/aggravated increase in left ventricular end diastolic pressure. In presence of clinical and/or electrocardiographic findings of myocardial ischemia, this finding suggest ischemia induced left ventricular dysfunction. Earlier this finding appears during exercise and longer it lasts during recovery, more severe is the left ventricular dysfunction.

APPLE WATCH FAILURE TO RECORD ELECTROCARDIOGRAM FOLLOWING UNIPOLAR LEFT BUNDLE BRANCH AREA PACING

BackgroundWearable devices to monitor heart rhythm allow for rapid correlation of symptoms with ECG. Left Bundle Branch Area Pacing (LBBAP) can be utilized to maintain electrical and mechanical LV synchrony. The limitations of wearable device ECG capture in the setting of LBBAP is not known. We report three cases of patients who reported failure of Apple Watch (AW) ECG recording following implantation of LBBAP systems.NarrativePatient 1 presented with symptomatic AV block and LVEF of 45%. A LBBAP system (Medtronic 3830 lead) was implanted set to unipolar ventricular pacing. LB capture was confirmed on 12 lead ECG demonstrating a terminal R wave in lead V1 and short LV activation time in leads V5/V6 at high and low output pacing. At follow up, the patient reported that his AW ECG stopped functioning following pacemaker implant. While in the office, the watch repeatedly reset itself every second and failed to record (Figure 1). When pacing polarity was programmed to bipolar, the AW ECG recording was successful.Patient 2 underwent a successful implantation of LBBAP (Biotronik Solia S lead) programmed to unipolar ventricular pacing. At a follow up visit, the patient reported failure of his AW ECG system to record. Following reprogramming to bipolar pacing, the watch could record ECG tracings.Patient 3 underwent LBBAP implantation with a 3830 lead set to unipolar pacing and reported failure of his AW to record an ECG. Reprogramming to bipolar pacing resulted in anodal capture with prolongation of left ventricular activation time. While unipolar pacing, a KardiaMobile 6L system successfully recorded an ECG. (Figure 2)ConclusionSuccessful KardiaMobile 6L system ECG recording.View Large Image Figure ViewerDownload Hi-res image Download (PPT) BackgroundWearable devices to monitor heart rhythm allow for rapid correlation of symptoms with ECG. Left Bundle Branch Area Pacing (LBBAP) can be utilized to maintain electrical and mechanical LV synchrony. The limitations of wearable device ECG capture in the setting of LBBAP is not known. We report three cases of patients who reported failure of Apple Watch (AW) ECG recording following implantation of LBBAP systems. Wearable devices to monitor heart rhythm allow for rapid correlation of symptoms with ECG. Left Bundle Branch Area Pacing (LBBAP) can be utilized to maintain electrical and mechanical LV synchrony. The limitations of wearable device ECG capture in the setting of LBBAP is not known. We report three cases of patients who reported failure of Apple Watch (AW) ECG recording following implantation of LBBAP systems. NarrativePatient 1 presented with symptomatic AV block and LVEF of 45%. A LBBAP system (Medtronic 3830 lead) was implanted set to unipolar ventricular pacing. LB capture was confirmed on 12 lead ECG demonstrating a terminal R wave in lead V1 and short LV activation time in leads V5/V6 at high and low output pacing. At follow up, the patient reported that his AW ECG stopped functioning following pacemaker implant. While in the office, the watch repeatedly reset itself every second and failed to record (Figure 1). When pacing polarity was programmed to bipolar, the AW ECG recording was successful.Patient 2 underwent a successful implantation of LBBAP (Biotronik Solia S lead) programmed to unipolar ventricular pacing. At a follow up visit, the patient reported failure of his AW ECG system to record. Following reprogramming to bipolar pacing, the watch could record ECG tracings.Patient 3 underwent LBBAP implantation with a 3830 lead set to unipolar pacing and reported failure of his AW to record an ECG. Reprogramming to bipolar pacing resulted in anodal capture with prolongation of left ventricular activation time. While unipolar pacing, a KardiaMobile 6L system successfully recorded an ECG. (Figure 2) Patient 1 presented with symptomatic AV block and LVEF of 45%. A LBBAP system (Medtronic 3830 lead) was implanted set to unipolar ventricular pacing. LB capture was confirmed on 12 lead ECG demonstrating a terminal R wave in lead V1 and short LV activation time in leads V5/V6 at high and low output pacing. At follow up, the patient reported that his AW ECG stopped functioning following pacemaker implant. While in the office, the watch repeatedly reset itself every second and failed to record (Figure 1). When pacing polarity was programmed to bipolar, the AW ECG recording was successful. Patient 2 underwent a successful implantation of LBBAP (Biotronik Solia S lead) programmed to unipolar ventricular pacing. At a follow up visit, the patient reported failure of his AW ECG system to record. Following reprogramming to bipolar pacing, the watch could record ECG tracings. Patient 3 underwent LBBAP implantation with a 3830 lead set to unipolar pacing and reported failure of his AW to record an ECG. Reprogramming to bipolar pacing resulted in anodal capture with prolongation of left ventricular activation time. While unipolar pacing, a KardiaMobile 6L system successfully recorded an ECG. (Figure 2) Conclusion

Relationship of V1 Derivation Biphasic P Waves with Morbidity and Mortality in Myocardial Infarction Cases.

To evaluate the biphasic P (V1bP) wave in lead V1 in terms of three-vessel disease (TVD), bypass, and mortality in patients with acute coronary syndrome. A descriptive study. Department of Emergency Medicine, University of Health Sciences, Bagcilar Training and Research Hospital, Turkey, between January 2018 and December 2019. A total of 497 patients were admitted to the emergency department due to acute coronary syndrome. Patients were grouped as the right atrium and the left atrium according to the direction of the V1bP wave. Gensini score (GS), left ventricular ejection fraction (LVEF), TVD, bypass, and mortality rates were compared according to these groups. According to the atrial involvement of the patients, the median age was 66 (58-74) years, 220 (44.3%) females and 277 (55.7%) males. In the left atrial group in the V1bP wave, anterior myocardial infarction was the most common in 128 (41.8%) patients, mortality in 17 (5.6%), TVD in 69 (22.5%), and bypass in 13 (4.2%) patients. In the right atrial group, it was found that 127 (66.5%) patients had inferior myocardial infarction, 34 (17.8%) mortality, 66 (34.6%) TVD, and 19 (9.9%) bypass TVD; GS was 89 (80-117) points and LVEF was 45 (36-55)%. In addition, a significant relationship was found with mortality (p=0.019), bypass (p<0.001) and complications (p=0.043). Although the variables showed differences in acute coronary syndrome, mortality, LVEF, GS, mild and/or moderate correlations were found. V1bP wave can be a determining parameter for acute coronary syndromes in terms of TVD, bypass, and mortality. Emergency department, Biphasic p in lead V1, Three-vessel disease, Bypass, Mortality.

Clinical and electrocardiographic characteristics in patients with fulminant myocarditis.

BackgroundThe purpose of this study was to evaluate clinical and electrocardiographic characteristics in patients with fulminant myocarditis.MethodsA total of 72 patients were divided into three groups: pericarditis (control: n = 25), acute myocarditis (n = 27), and fulminant myocarditis (n = 20). Patients' characteristics and electrocardiograms on admission were retrospectively analyzed in the three groups.ResultsBNP levels in the fulminant group were significantly higher than those in the other two groups. ST elevation was observed at lead aVR in the fulminant myocarditis group, whereas ST depression was observed at lead aVR in the other groups (p = .001). The maximum degree of ST elevation among the three groups was similar. However, the number of ST‐elevation leads in the fulminant myocarditis group was significantly lower than that in the other groups (p = .004). The voltage of R wave in lead V5 in the fulminant myocarditis group was significantly lower than that in the other groups (p = .005). Moreover, in the Cabrera sequence, the prevalence of ST elevation in the inferior leads, aVR, and V3–V6 in the fulminant myocarditis group was significantly or nearly significantly lower than that in the other groups.ConclusionsIn fulminant myocarditis, ST‐segment elevation was observed in lead aVR, and contrarily, the number and extent of ST‐segment elevation and R wave voltage were smaller than those in the other groups. These results suggest that the number of myocytes with maintained action potential may be reduced following progressive myocardial damage and interstitial edema due to severe inflammation.

Derivation and Validation of a Screening Model for Hypertrophic Cardiomyopathy Based on Electrocardiogram Features.

BackgroundHypertrophic cardiomyopathy (HCM) is a widely distributed, but clinically heterogeneous genetic heart disease, affects approximately 20 million people worldwide. Nowadays, HCM is treatable with the advancement of medical interventions. However, due to occult clinical presentations and a lack of easy, inexpensive, and widely popularized screening approaches in the general population, 80–90% HCM patients are not clinically identifiable, which brings certain safety hazards could have been prevented. The majority HCM patients showed abnormal and diverse electrocardiogram (ECG) presentations, it is unclear which ECG parameters are the most efficient for HCM screening.ObjectiveWe aimed to develop a pragmatic prediction model based on the most common ECG features to screen for HCM.MethodsBetween April 1st and September 30th, 2020, 423 consecutive subjects from the International Cooperation Center for Hypertrophic Cardiomyopathy of Xijing Hospital [172 HCM patients, 251 participants without left ventricular hypertrophy (non-HCM)] were prospectively included in the training cohort. Between January 4th and February 30th, 2021, 163 participants from the same center were included in the temporal internal validation cohort (62 HCM patients, 101 non-HCM participants). External validation was performed using retrospectively collected ECG data from Xijing Hospital (3,232 HCM ECG samples from January 1st, 2000, to March 31st, 2020; 95,184 non-HCM ECG samples from January 1st to December 31st, 2020). The C-statistic was used to measure the discriminative ability of the model.ResultsAmong 30 ECG features examined, all except abnormal Q wave significantly differed between the HCM patients and non-HCM comparators. After several independent feature selection approaches and model evaluation, we included only two ECG features, T wave inversion (TWI) and the amplitude of S wave in lead V1 (SV1), in the HCM prediction model. The model showed a clearly useful discriminative performance (C-statistic > 0.75) in the training [C-statistic 0.857 (0.818–0.896)], and temporal validation cohorts [C-statistic 0.871 (0.812–0.930)]. In the external validation cohort, the C-statistic of the model was 0.833 [0.825–0.841]. A browser-based calculator was generated accordingly.ConclusionThe pragmatic model established using only TWI and SV1 may be helpful for predicting the probability of HCM and shows promise for use in population-based HCM screening.

Association between complete right bundle branch block and atrial fibrillation development.

BackgroundComplete right bundle branch block (CRBBB) is an important predictor of atrial fibrillation (AF) recurrence after pulmonary vein isolation. However, the association between CRBBB and AF development remains unclear.MethodsWe performed a retrospective study of 2639 patients (male, n = 1549; female, n = 1090; mean age, 58 ± 13 years). CRBBB was defined as a late R (R′) wave in lead V1 or V2 with a slurred S wave in lead I and/or lead V6 with a prolonged QRS duration (≥120 ms).ResultsAmong the 2639 patients, CRBBB was detected in 40 patients (1.5%), and the prevalence of AF was 7.4% (196/2639). The proportion of patients with AF and CRBBB was higher than the proportion of patients with AF without CRBBB (22.5% vs. 7.2%; p = 0.001). In the forward multivariate logistic analysis, CRBBB (odds ratio [OR], 3.329; 95% confidence interval [CI], 1.350–8.211; p = 0.009), complete left bundle branch block (OR, 2.209; 95% CI, 1.238–3.940; p = 0.007), age (OR, 1.020; 95% CI, 1.005–1.035; p = 0.009), valvular heart disease (OR, 2.332; 95% CI, 1.531–3.552; p < 0.001), left atrial diameter (OR, 1.133; 95% CI, 1.104–1.163; p < 0.001), left ventricular ejection fraction (OR, 1.023; 95% CI, 1.006–1.041; p = 0.007), and class I or III anti‐arrhythmic drug use (OR, 10.534; 95% CI, 7.090–15.651; p < 0.001) were associated with AF.ConclusionComplete right bundle branch block was significantly associated with AF development in hospitalized patients with cardiovascular diseases.

Evaluation of the shortening of the stimulus-to-peak left ventricular activation time at continuous low output to confirm left bundle branch capture.

BackgroundLeft bundle branch area pacing (LBBAP) is a physiological pacing method for treatment of atrioventricular block. However, there is a need for a new convenient and safe method for performing left bundle branch pacing (LBBP) and to confirm left conduction system capture.ObjectiveThis study aimed to explore a new convenient and safe method for performing selective LBBP.MethodsA total of 28 patients who had indications for pacing therapy and received LBBAP were recruited retrospectively. Demographic and baseline patient characteristics, electrocardiograms, pacing parameters, and intracardiac electrogram pattern were evaluated. Continuous unipolar pacing at low output (2 V / 0.5 ms) was performed during the whole period of LBBP lead implantation. Successful left bundle branch (LBB) capture was defined as the abrupt change of the pacing stimulus to the peak of R wave in lead V5 during continuous pacing at low output (2 V / 0.5 ms).ResultsThe parameters of the 2 shortenings (stimulus-to-peak left ventricular activation time [S-peak LVAT] before shortening, S-peak LVAT after shortening, and the duration of shortening) all showed a significant positive correlation (Pearson product-moment correlation coefficient [PCC] = 0.915, P < .001; PCC = 0.897, P < 0.001; PCCs = 0.765, P < 0.001). Shortening of the S-peak LVAT with continuous low output had a 100% sensitivity and 33.3% specificity for predicting stimulus-ventricular potential interval (S-V interval).ConclusionAbrupt shortening of the S-peak LVAT at continuous low output was associated with abrupt shortening of the S-peak LVAT at low and high output. High rate of selective LBB capture can be achieved with the method of continuous low output, shortening the S-peak LVAT.