Wide QRS Research Articles

Electrocardiogram Abnormality in Poisoned Patients with Tricyclic Antidepressant.

A wide variety of electrocardiogram (ECG) changes can manifest with antidepressant drugs, occurring at both therapeutic doses and toxic levels. Notably, ECG abnormalities like wide QRS and QT prolongation may be observed in poisoned patients with tricyclic antidepressants (TCAs), indicating severe conditions that necessitate the implementation of cardiac monitoring systems. This study aimed to investigate ECG Abnormality in poisoned patients with tricyclic antidepressants. This retrospective patient record study was conducted at Razi Hospital in Ahvaz, Iran, from 2006 to 2009. Patient information was extracted from hospital medical records after the established protocol. The chi-square test was employed for initial analysis; subsequently, logistic regression was applied to identify risk factors associated with abnormal ECG findings. We analyzed the data using SPSS (Version 19; IBM) statistical software. P < 0.05 was defined as statistically significant. Among the 210 poisoned patients, comprising 88 men (41.9%) and 122 women (58.1%), the majority fell within the age range of 15 to 25 years. In our study, the most commonly ingested drugs by poisoned patients were amitriptyline in 134 patients (63.8%) and nortriptyline in 42 patients (20%). A significant portion of 137 patients (65.2%) exhibited poisoning symptoms within ˂ 6 hours, while 73 patients (34.8%) showed symptoms between 6 and 24 hours. Our findings indicated that the initial symptoms in poisoned patients included a decreased level of consciousness in 168 patients (80%), nausea and vomiting in 20 patients (9.5%), and various other symptoms. Notably, our results revealed ECG changes in 70 patients, with 32 patients (15.2%) showing a QRS widening (> 0.1sec), 5 patients (2.4%) displaying a tall R wave in aVR, 5 patients (2.4%) exhibiting right axis deviation, and other observed changes. QRS widening in poisoned patients with tricyclic antidepressants is more frequently observed in symptomatic patients, highlighting the importance of ECG screening in these patients.

Wide QRS tachycardia: What is the mechanism?

Wide QRS tachycardia: What is the mechanism?

Frailty and long-term survival in patients undergoing cardiac resynchronization therapy

Aim: To access frailty and its impact on 10-year survival in patients with implanted devices for cardiac resynchronization therapy (CRT).Methods: 77 patients with congestive heart failure (74% men, 26% women; mean age of 58.7 ± 10.7 years) with NYHA class II–IV were enrolled. Frailty Index was calculated using 31 parameters (the ability to perform daily activities, clinical status, laboratory markers, comorbidities). Based on the frailty index patients were identified as not frail (&lt; 0.375; n = 41; 53%), and frail (≥ 0.375; n = 36; 47%).Results: The mean follow-up period was 49.0 ± 34.2 months. Survival at 10-year follow-up was 87.5% for non-frail patients, compared to 47.2% for frail patients (log-rank test p &lt; 0.001). In univariate analysis, frailty associated with 10-year mortality (OR 7.824; 95% CI 2.495 – 24.533; p &lt; 0.001). After adjustment for age, gender, rhythm, NYHA class, left ventricular ejection fraction, left bundle branch block, and QRS width, frailty remained a significant prognostic factor associated with 10-year mortality (OR 9.528; 95% CI 2.720 – 33.368; p &lt; 0.001). Also, according to logistic regression, the presence of frailty reduced the chance of superresponse (decrease of left-ventricular end -systolic volume ≥ 30%) to CRT (OR 0.278; 95% CI 0.100–0.770; p = 0.014).Conclusion: Frailty is widespread in patients with heart failure and implanted devices for CRT. In these patients frailty is associated with a more than seven-fold increased risk of death during 10-year follow-up and with a lower chance of superresponse to CRT.

Clinical characteristics and outcome of cardiac resynchronization therapy for heart failure in National Hospital of Sri Lanka from year 2005 to 2020 – a retrospective observational study

BackgroundCardiac resynchronization therapy (CRT) has been a well-established treatment modality for moderate to severe left ventricular systolic dysfunction with left ventricular desynchrony. This is the pioneering study that analyses the cohort who underwent CRT implantation at the National Hospital of Sri Lanka (NHSL) in Colombo from 2005 to 2020.ObjectivesThis study was carried out to describe socio-demographic factors, improvements in clinical outcome (symptoms, electrocardiographic, and echocardiographic features), and post-CRT complications in the study population, as well as to determine the efficacy of CRT in heart failure.MethodA retrospective observational study was conducted on all the living patients who had undergone CRT implantation from 2005 to 2020. The data was gathered from all the consented patients who visited the device programming clinic using a physician-administered questionnaire and clinical records. Data was analyzed using SPSS 25, and significant statistics were assessed with the McNemer test, the Student T test, and the Chi-Squared test.ResultsThe study included 50 patients with a mean age of 52.82+/− 11.66 years and female predominance (56%, n = 28). Idiopathic dilated cardiomyopathy (50%, n = 25) was the leading etiological factor, followed by ischemic cardiomyopathy (28%, n = 14). Clinical symptoms have improved significantly with CRT implantation (p < 0.001). A significant improvement was found in NYHA functional class (p < 0.001, 95% CI = 0.072 to 0.284), QRS width (p < 0.001, 95% CI = 0.229 to 0.534), ejection fraction (p < 0.001, 95% CI = − 16.437 to − 8.504), and LV EDD (p < 0.001, 95% CI = 2.89 to 9.24). Post-CRT complications included lead malfunction (6%, n = 3) and chronic (14%, n = 7), bleeding or hematoma (2%, n = 1), pocket erosion or infection (6%, n = 3), and infective endocarditis (2%, n = 1).ConclusionAccording to the study, CRT significantly improves both clinical and functional outcomes in patients with moderate to severe heart failure.

A machine learning approach to differentiate wide QRS tachycardia: distinguishing ventricular tachycardia from supraventricular tachycardia.

Differential diagnosis of wide QRS tachycardia (WQCT) has been a challenging issue. Published algorithms to distinguish ventricular tachycardia (VT) and supraventricular tachycardia (SVT) have limited diagnostic capabilities. A total of 278 patients with WQCT from January 2010 to March 2022 were enrolled. The electrophysiological study confirmed SVT in 154 patients and VT in 65 ones. Two hundred nineteen WQCT 12-lead ECGs were randomly divided into development cohort (n = 165) and testing cohort (n = 54) data sets. The development cohort was split into a training group (n = 115) and an internal validation group (n = 50). Forty ECG features extracted from the 219 WQCT ECGs are fed into 9 iteratively trained ML algorithms. This novel ML algorithm was also compared with four published algorithms. In the development cohort, the Gradient Boosting Machine (GBM) model displayed the maximum area under curve (AUC) (0.91, 95% confidence interval (CI) 0.81-1.00). In the testing cohort, the GBM model had a higher AUC of 0.97 compared to 4 validated ECG algorithms, namely, Brugada (0.68), avR (0.62), RWPTII (0.72), and LLA algorithms (0.70). Accuracy, sensitivity, specificity, negative predictive value, and positive predictive value of the GBM model were 0.94, 0.97, 0.90, 0.94, and 0.95, respectively. A GBM ML model contributes to distinguishing SVT from VT based on surface ECG features. In addition, we were able to identify important indicators for distinguishing WQCT.

Chemical ablation of the left ventricular endocardium reduces ventricular fibrillation inducibility in acute ischemic canine heart.

Ventricular fibrillation remains as the major cause of death in patients with acute myocardial infarction. Effects of trans-atrial chemical ablation of the left ventricular (LV) endocardium with Lugol's solution on ventricular fibrillation inducibility and ventricular conduction were examined in canines with acute myocardial ischemia. Chemical ablation of the LV endocardium with Lugol's solution or normal saline was preformed through a left atrial appendage in 14 canines 30 min after occlusion of the left anterior coronary artery. Ventricular fibrillation threshold decreased after the coronary artery occlusion and increased after endocardial chemical ablation. There was a significant difference in the ventricular fibrillation threshold after chemical ablation between with Lugol's solution and with normal saline (25.9 ± 9.2 mA vs. 11.3 ± 2.7 mA, p < .01). QRS width significantly increased from 88 ± to 116 ± (p < .01) after the chemical ablation with Lugol's solution, and the activation map of the ventricles demonstrated a left bundle branch block ventricular conduction pattern. Histological examination of the LV endocardium showed lymphocyte infiltration for a depth of 1 mm. Chemical ablation of the LV endocardium with Lugol's solution injures endocardial conduction system and increases ventricular fibrillation threshold in the early phase of myocardial ischemia in canines. The procedure may be useful in suppressing intractable ventricular tachyarrhythmias in patients with acute myocardial ischemia.

A porcine large animal model of radiofrequency ablation-induced left bundle branch block.

Electrocardiographic (ECG) features of left bundle branch (LBB) block (LBBB) can be observed in up to 20%-30% of patients suffering from heart failure with reduced ejection fraction. However, predicting which LBBB patients will benefit from cardiac resynchronization therapy (CRT) or conduction system pacing remains challenging. This study aimed to establish a translational model of LBBB to enhance our understanding of its pathophysiology and improve therapeutic approaches. Fourteen male pigs underwent radiofrequency catheter ablation of the proximal LBB under fluoroscopy and ECG guidance. Comprehensive clinical assessments (12-lead ECG, bloodsampling, echocardiography, electroanatomical mapping) were conducted before LBBB induction, after 7, and 21days. Three pigs received CRT pacemakers 7days after LBB ablation to assess resynchronization feasibility. Following proximal LBB ablation, ECGs displayed characteristic LBBB features, including QRS widening, slurring in left lateral leads, and QRS axis changes. QRS duration increased from 64.2 ± 4.2ms to 86.6 ± 12.1ms, and R wave peak time in V6 extended from 21.3 ± 3.6ms to 45.7 ± 12.6ms. Echocardiography confirmed cardiac electromechanical dyssynchrony, with septal flash appearance, prolonged septal-to-posterior-wall motion delay, and extended ventricular electromechanical delays. Electroanatomical mapping revealed a left ventricular breakthrough site shift and significantly prolonged left ventricular activation times. RF-induced LBBB persisted for 3weeks. CRT reduced QRS duration to 75.9 ± 8.6ms, demonstrating successful resynchronization. This porcine model accurately replicates the electrical and electromechanical characteristics of LBBB observed in patients. It provides a practical, cost-effective, and reproducible platform to investigate molecular and translational aspects of cardiac electromechanical dyssynchrony in a controlled and clinically relevant setting.

Wide QRS Tachycardias Management in Emergency Departments: What Really Matters

Wide QRS Tachycardias Management in Emergency Departments: What Really Matters

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.

Post-transcatheter aortic valve implantation isolated PR prolongation: incidence and clinical significance.

Conduction abnormalities post-transcatheter aortic valve implantation (TAVI) are common. Post-TAVI PR prolongation was mainly studied as an adjunct to new-onset bundle branch block. The net effect of isolated PR prolongation (IPRP) without post-TAVI QRS changes is not well known. The aim of this study was to define the incidence and clinical significance of post-TAVI IPRP. A total of 1108 consecutive TAVI patients were reviewed. Patients with IPRP were compared with patients without post-TAVI electrocardiogram (ECG) changes. Clinical outcomes included permanent pacemaker implantation (PPI) and overall mortality. A total of 146 patients with IPRP were compared with 290 patients without post-TAVI ECG changes. At 1 year follow-up, 4 (2.7%) and 7 (2.4%) patients underwent PPI (P = 0.838) and 10 (6.8%) and 25 (8.6%) died (P = 0.521), from the study and control groups, respectively. No patient with IPRP and narrow QRS underwent PPI during 1 year post-TAVI, and all death events were non-cardiac except one unknown cause. Permanent pacemaker implantation rates among patients with IPRP and wide QRS were higher (n = 4, 12.1%), compared with patients with wide QRS without post-TAVI ECG change (n = 3, 4%) however not reaching statistical significance (P = 0.126). Multivariate Cox proportional hazards model demonstrated that in patients with narrow QRS, neither PR prolongation nor baseline or maximal PR intervals was associated with the combined endpoint of PPI and mortality. However, in patients with wide QRS, baseline PR intervals and QRS width, but not PR prolongation were associated with the combined outcome. Post-TAVI IPRP in patients with narrow QRS is not associated with adverse outcome. This finding may translate clinically into a more permissive approach to these patients.

Electrocardiographic Changes with Age in Japanese Patients with Noonan Syndrome.

Little information is available on age-related electrocardiographic changes in patients with Noonan syndrome. This single-center study evaluated the electrocardiograms of patients with Noonan syndrome. We divided the patients (n = 112; electrocardiograms, 256) into four groups according to age: G1 (1 month-1 year), G2 (1-6 years), G3 (6-12 years), and G4 (>12 years). Typical Noonan syndrome-related electrocardiographic features such as left-axis deviation, abnormal Q wave, wide QRS complex, and small R wave in precordial leads were detected. A high percentage of QRS axis abnormalities was found in all groups. Significant differences in right-axis deviation (RAD) were noted among the groups: 56.5% of G1 patients showed RAD compared with 33.3% of G2, 21.1% of G3, and 19.2% of G4 patients. The small R was also significantly different among the groups: 32.6% of G1 patients showed a small R wave compared with 14.9% of G2, 8.5% of G3, and 15.4% of G4 patients. Of the 53 patients with Noonan syndrome aged 1 month to 2 years, 18 had T-positive V1 with a higher prevalence of pulmonary stenosis and cardiac interventions. QRS axis abnormalities, small R in V6, and T-positive V1 could help diagnose Noonan syndrome in infants or young children.

Virtual pacing of a patient's digital twin to predict left ventricular reverse remodelling after cardiac resynchronization therapy.

Identifying heart failure (HF) patients who will benefit from cardiac resynchronization therapy (CRT) remains challenging. We evaluated whether virtual pacing in a digital twin (DT) of the patient's heart could be used to predict the degree of left ventricular (LV) reverse remodelling post-CRT. Forty-five HF patients with wide QRS complex (≥130 ms) and reduced LV ejection fraction (≤35%) receiving CRT were retrospectively enrolled. Echocardiography was performed before (baseline) and 6 months after CRT implantation to obtain LV volumes and 18-segment longitudinal strain. A previously developed algorithm was used to generate 45 DTs by personalizing the CircAdapt model to each patient's baseline measurements. From each DT, baseline septal-to-lateral myocardial work difference (MWLW-S,DT) and maximum rate of LV systolic pressure rise (dP/dtmax,DT) were derived. Biventricular pacing was then simulated using patient-specific atrioventricular delay and lead location. Virtual pacing-induced changes ΔMWLW-S,DT and ΔdP/dtmax,DT were correlated with real-world LV end-systolic volume change at 6-month follow-up (ΔLVESV). The DT's baseline MWLW-S,DT and virtual pacing-induced ΔMWLW-S,DT were both significantly associated with the real patient's reverse remodelling ΔLVESV (r = -0.60, P < 0.001 and r = 0.62, P < 0.001, respectively), while correlation between ΔdP/dtmax,DT and ΔLVESV was considerably weaker (r = -0.34, P = 0.02). Our results suggest that the reduction of septal-to-lateral work imbalance by virtual pacing in the DT can predict real-world post-CRT LV reverse remodelling. This DT approach could prove to be an additional tool in selecting HF patients for CRT and has the potential to provide valuable insights in optimization of CRT delivery.

Is left bundle branch pacing (LBBP) associated with better depolarization and repolarization kinetics than right ventricular mid septal pacing (RVSP)? - Comparison of frontal QRS -T angle in patients with LBBP, RVSP and normal ventricular conduction

AimsTo assess the frontal QRS- T angle (f QRS- T angle) in patients with left bundle branch pacing (LBBP) as compared to right ventricular mid septal pacing (RVSP) implanted for symptomatic high degree atrioventricular (AV) block and to compare with control subjects with normal ventricular conduction (CSNVC) MethodsA total of one-fifty subjects were chosen (50 patients with LBBP, 50 patients with RVSP and 50 CSNVC). The indication for pacemaker implantation was symptomatic high degree AV block. Baseline clinical and electrocardiogram (ECG) parameters like QRS duration (QRSD), QRS axis and f QRS-T angle and Ejection Fraction (EF) were assessed. f QRS-T angle was measured as the difference between the computerised mean frontal QRS and T wave axes in the limb leads. If the difference between the QRS axis and T-wave axis exceeds 180°, then the resultant QRS-T angle would be calculated as 360° minus the absolute angle to obtain a value between 0° and 180°. Baseline, immediate post procedural and 6 month follow up (f/u) ECGs and EF were chosen for the analysis. ResultsPatients who underwent LBBP had significantly shorter paced QRSD than patients who had undergone RVSP (112 ± 12 ms vs 146 ± 13 ms; 95 % confidence interval (CI): 43, −31; p<0.001). There was no significant difference in the QRSD before and after LBBP. The QRSD before and after pacing in RVSP was 111 ± 27 ms and 146 ± 13 ms; 95 % CI: 43, −28; p < 0.001. The QRSD in control patients with NVC was 82.94 ± 9.59 ms.RVSP was associated with wider f QRS-T angle when compared with LBBP (103 ± 53° vs 82 ± 43°; 95 % CI: 39, −1.0; p = 0.037). The baseline and immediate post procedure f QRS-T angle in LBBP was 70 ± 48° and 82 ± 43°; 95 % CI: 31, 5.3; p = 0.2. At 6 months f/u, the f QRS-T angle was 61 ± 43°; 95 % CI: 8.5, 35; p=0.002. The baseline and immediate post procedure f QRS-T angle in RVSP was 67 ± 51° and 103 ± 53°; 95 % CI: 54, −17; p < 0.001. At 6 months f/u, the f QRS-T angle in RVSP group was 87 ± 58°; 95 % CI: 2.6, 29; p = 0.020. The f QRS T angle in control patients with NVC was 24 ± 16°. When subgroup analysis was done the difference in the f QRS-T angle was significant between RVSP and LBBP groups only in patients who had wide QRS escape.The mean LVEF at 6-month follow-up in LBBP vs RVSP was 61 ± 3.7 % vs 57.1 ± 7.8 %; 95 % CI:1.48, 6.32, p = 0.002. In the RVSP group, three patients developed pacing induced cardiomyopathy (PIC) whereas no patients in the LBBP group developed PIC at 6-month follow-up; p=0.021. One patient with PIC had deterioration of functional status with new onset HF symptoms. The patient symptoms improved with medical therapy and needed no hospitalisation. The patient declined further interventions including upgradation to CRT or LBB pacing. No deaths or ventricular arrhythmias were observed during the study period. ConclusionLBBP is associated with narrower f QRS-T angle as compared to RVSP both at post implant period and at 6 month f/u period. These findings might be due to the more physiological depolarization and repolarization kinetics associated with LBBP. RVSP was associated with 6 % incidence of PIC. Hence wide f QRS-T angle might be a predictor of PIC.

Incidence and predictors of heart failure with improved ejection fraction category in a HFrEF patient population.

The aim of the study was to assess the incidence and predictive factors of the development of heart failure with improved ejection fraction (HFimpEF) category during a 1year follow-up period in a heart failure with reduced ejection fraction (HFrEF) patient population managed in a heart failure outpatient clinic. The study evaluated data from patients enrolled in the Hungarian Heart Failure Registry (HHFR). The incidence and predictive factors of the development of the HFimpEF category after 1year follow-up were assessed in the group of patients who had HFrEF at baseline. We evaluated the incidence and predictors of the development of HFimpEF after a 1year follow-up in relation to time since diagnosis of HFrEF in patients diagnosed within 3months, between 3months and 1year, and beyond 1year. The predictive factors of the development of HFimpEF were analysed using univariate and multivariate logistic regression analysis. Of the 833 HFrEF patients enrolled in the HHFR, the development of HFimpEF was observed in 162 patients (19.5%) during 1year follow-up. In the whole patient population, independent predictors of the development of HFimpEF were female gender [odds ratio (OR): 1.73; 95% confidence interval (CI): 1.01-2.96; P<0.05], non-ischaemic aetiology (OR: 1.95; 95% CI: 1.15-3.30; P<0.05), and left ventricular end-diastolic diameter (LVEDD) <60mm (OR: 2.04; 95% CI: 1.18-3.51; P<0.05). The 1year incidence of HFimpEF decreased in relation to time since diagnosis of HFrEF. The incidence of HFimpEF was 27.1% in patients diagnosed within 3months, 18.4% in patients diagnosed between 3months and 1year, and 12.2% in patients diagnosed beyond 1year. Non-ischaemic aetiology (OR: 4.76; 95% CI: 1.83-12.4; P<0.01) and QRS width (OR: 0.81; 95% CI: 0.71-0.94; P<0.01) for patients diagnosed within 3months, LVEDD (OR: 0.54; 95% CI: 0.32-0.90; P<0.05) and left atrial diameter ≤45mm (OR: 5.44; 95% CI: 1.45-20.4; P<0.05) for patients diagnosed between 3months and 1year, and LVEDD<67mm (OR: 2.71; 95% CI: 1.07-6.88; P<0.05) for patients diagnosed beyond 1year were found to be independent predictive factors. In our study, in this HFrEF patient population managed in a heart failure outpatient clinic, the 1year incidence of HFimpEF was found to be ~20%. The 1year incidence of HFimpEF decreased in relation to time since diagnosis of HFrEF. The most important predictors of the development of HFimpEF were female sex, non-ischaemic aetiology, narrower QRS width, and smaller diameter of the left ventricle and left atrium.

Artificial intelligence-based identification of left ventricular systolic dysfunction from 12-lead electrocardiograms: external validation and advanced application of an existing model.

The diagnostic application of artificial intelligence (AI)-based models to detect cardiovascular diseases from electrocardiograms (ECGs) evolves, and promising results were reported. However, external validation is not available for all published algorithms. The aim of this study was to validate an existing algorithm for the detection of left ventricular systolic dysfunction (LVSD) from 12-lead ECGs. Patients with digitalized data pairs of 12-lead ECGs and echocardiography (at intervals of ≤7 days) were retrospectively selected from the Heart Center Leipzig ECG and electronic medical records databases. A previously developed AI-based model was applied to ECGs and calculated probabilities for LVSD. The area under the receiver operating characteristic curve (AUROC) was computed overall and in cohorts stratified for baseline and ECG characteristics. Repeated echocardiography studies recorded ≥3 months after index diagnostics were used for follow-up (FU) analysis. At baseline, 42 291 ECG-echocardiography pairs were analysed, and AUROC for LVSD detection was 0.88. Sensitivity and specificity were 82% and 77% for the optimal LVSD probability cut-off based on Youden's J. AUROCs were lower in ECG subgroups with tachycardia, atrial fibrillation, and wide QRS complexes. In patients without LVSD at baseline and available FU, model-generated high probability for LVSD was associated with a four-fold increased risk of developing LVSD during FU. We provide the external validation of an existing AI-based ECG-analysing model for the detection of LVSD with robust performance metrics. The association of false positive LVSD screenings at baseline with a deterioration of ventricular function during FU deserves a further evaluation in prospective trials.

Feasibility study on cardiac resynchronization in the treatment of heart failure by single left bundle branch pacing

To examine the feasibility of single left bundle branch pacing for cardiac resynchronization therapy (CRT) by carrying out a frequency adaptive atrioventricular delay (RAAVD) algorithm and automatic optimization of the single left bundle branch pacing atrioventricular interval (AVI) based on the right atrioventricular interval (RAS–RVS). Thirty-six patients with CRT class Ia indications according to the European Society of Cardiology 2016 guidelines and implanted with RAAVD functional three-chamber pacemakers were prospectively enrolled in this study. Patients were divided into a single left bundle branch pacing group (n = 21) and a standard biventricular pacing group (n = 15). The optimization of the two groups was performed under standard cardiac colour Doppler ultrasound, followed by the comparison of the QRS width, cardiac function improvement, and echocardiography indicators. The ratio of AVI to the right atrial-right ventricular interval (RAS–RVS) after single LV pacing optimization was defined as the single left bundle branch pacing coefficient (LUBBPε). In comparison to the BVP, the QRS was significantly narrowed (P = 0.017), accompanied by a significantly increased proportion of patients with NYHA class I and II, as well as the 6MWT. Compared with standard biventricular pacing, LVEDD was significantly shortened (P = 0.045), accompanied by significantly improved LAD, AVVTI, EA distance/RR, IVMD, and TS-SD after the operation. RAS–RVS was 156 ± 33 ms, the optimized AVI was 102 ± 10 ms, and LUBBPε was calculated to be 0.66 ± 0.06. Depending on the LUBBPε, a three-chamber pacemaker with a single left bundle branch pacing system was developed based on RAS–RVS-optimized AVI automatically. A three-chamber pacemaker with single left bundle branch pacing can achieve CRT based on RAS–RVS, reaching the optimal AVI of 66% of RAS–RVS.

Feasibility and safety of left bundle branch area pacing in cardiac amyloidosis. A single center experience.

Conventional right ventricle (RV) pacemaker stimulation has been associated with worse clinical outcomes in patients with cardiac amyloidosis (CA). Left bundle branch area pacing (LABPP) has been suggested as a promising alternative. We sought to assess the safety, feasibility, and outcomes of LABPP in patients with CA. We retrospectively analyzed echocardiography and pacing parameters and clinical outcomes in 23 consecutive patients with CA and LBBAP implanted from June 2020 to October 2022. LBBAP was successfully performed in 22 over 23 patients (19 male, 78.6±11.7 years, 20 ATTR, mean LVEF 45.5±16.2%). After the procedure, 9 patients showed Qr pattern and 11 a qR pattern in V1 on ECG. Average procedure time was 67±28min. After 7.7±5.2 months follow-up, no procedure-related complications had occurred. Although, a significant reduction in QRS width (p=.001) was achieved, we did not observe significant changes in LVEF and Nt ProBNP at 6 months of follow-up. Pacing parameters were stable during follow-up: LBB capture threshold and R wave amplitude were 1.0± 0.5V and 10.6±6.0 mV versus 0.8± 0.1V, p=.21 and 10.6±5.1mV (p=.985) at follow up. LBBAP is safe and feasible pacing technique for patients with CA. LBBAP is associated with significant narrowing of QRSd without worsening in LVEF and Nt-proBNP.

Wide QRS complex tachycardia: Elucidating the mechanism by atrial pacing maneuvers

Wide QRS complex tachycardia: Elucidating the mechanism by atrial pacing maneuvers

Comparison of de novo implantation vs. upgrade cardiac resynchronisation therapy: a multicentre experience

Background The clinical safety and consequences of upgrade procedures compared with de novo cardiac resynchronisation therapy (CRT) implantation in heart failure remain unclear. The present study aimed to assess clinical and procedural consequences of patients undergoing CRT upgrade as compared to de novo CRT implantations. Methods In this prospective cohort study, two subgroups were considered as the study population as (1) de novo group that CRT was considered on optimised medical treatment with heart failure of NYHA functional class from II to IV, left ventricular ejection fraction (LVEF) of ≤35%, and QRS width of >130 ms and (2) upgrade group including the patients with previously implantable cardioverter defibrillator (ICD) with the indications for upgrading to CRT. The two groups were compared regarding the changes in clinical outcome and echocardiography parameters. Results The procedure was successful in 95.9% of patients who underwent CRT upgrade and 100% of those who underwent de novo CRT implantation. It showed a significant improvement in LVEF, severity of mitral regurgitation and NYHA functional classification, without any difference between the two study groups. Overall procedural related complications were reported in 10.8% and 3.8% (p = .093) and cardiac death in 5.4% and 2.5% (p = .360), respectively, with no overall difference in postoperative outcome between the two groups. Conclusions Upgrading to CRT is a safe and effective procedure regarding improvement of functional class, left ventricular function status and post-procedural outcome.

Wide QRS complex tachycardia: differential diagnosis and acute treatment

The methodical guidelines are devoted to the pressing problem of clinical cardiology – the diagnosis and treatment of wide QRS complex tachycardia, requiring an individualized approach to patients’ management. The basic principles of determination of wide QRS complex tachycardias and their electrophysiological mechanisms are reviewed. The etiology of wide QRS complex tachycardias, their clinical picture and ECG criteria for differential diagnosis, particularly between ventricular tachycardia and supraventricular tachycardia with aberrant ventricular conduction, are outlined. The basic principles of wide QRS complex tachycardias diagnosis are discussed, and the ECG signs of the certain «wide» are presented. The results of the studies, aimed at the development of the diagnostic criteria and algorithms for differential diagnosis of wide QRS complex tachycardias, are analyzed. The acute treatment of narrow and wide QRS complex tachycardias are presented. The antiarrhythmic drugs and their use are given, and the principles of catheter treatment of tachycardia are stated. The guidelines are addressed to cardiologists, internists, the functional diagnostics physicians, general practitioners (family physicians), interns.