Hemodialysis Efficiency Predictor in End-Stage Kidney Disease Using Real-Time Heart Rate Variability.

BACKGROUND: Autonomic dysfunction as a long-term complication may occur in end-stage kidney disease (ESKD) patients and can be diagnosed using heart rate variability (HRV) analyzed from electrocardiogram (ECG) recordings. There is limited data about HRV using real-time ECG to predict hemodialysis (HD) efficiency in patients with ESKD who are routinely doing HD in the real world. METHODS: A total of 50 patients (62.1 ± 10.7 years) with ESKD underwent continuous real-time ECG monitoring (237.4 ± 15.3 min) during HD for HRV using remote monitoring system. Their electrolyte levels were checked before and after HD. We compared HRV according to electrolyte levels. RESULTS: During the monitor, we checked the ECG and electrolyte levels simultaneously a total of 2374 times for all of the patients. Both time and frequency domain HRV were higher when the patients had lower K+ level (<0.5 mEq/L) and P+ level change (<2 mEq/L) before and after HD as compared to those with a higher K+ level (≥0.5 mEq/L) and P+ level change (≥2 mEq/L). Additionally, patients with lower K+ and P+ level change groups had higher incidences of arrhythmic events including atrial/ventricular premature complexes, despite no difference of mean heart rate (p < 0.001). CONCLUSIONS: Higher HRV was independently associated with a poorly controlled K+ and P+ level during HD in patients with ESKD. This is consistently evidenced by the independent association between higher HRV, K+ and P+ levels in real time, suggesting that low electrolyte changes before and after HD alone may cause cardiac autonomic dysfunction.

Frequent Premature Atrial Contractions Lead to Adverse Atrial Remodeling and Atrial Fibrillation in a Swine Model.

BACKGROUND: Frequent premature atrial complexes (PACs) are associated with future incident atrial fibrillation (AF), but whether PACs contribute to development of AF through adverse atrial remodeling has not been studied. This study aimed to explore the effect of frequent PACs from different sites on atrial remodeling in a swine model. METHODS: Forty swine underwent baseline electrophysiologic studies and echocardiography followed by pacemaker implantations and paced PACs (50% burden) at 250-ms coupling intervals for 16 weeks in 4 groups: (1) lateral left atrium (LA) PACs by the coronary sinus (Lat-PAC; n=10), (2) interatrial septal PACs (Sep-PAC; n=10), (3) regular LA pacing at 130 beats/min (Reg-130; n=10), and (4) controls without PACs (n=10). At the final study, repeat studies were performed, followed by tissue histology and molecular analyses focusing on fibrotic pathways. RESULTS: Lat-PACs were associated with a longer P-wave duration (93.0±9.0 versus 74.2±8.2 and 58.8±7.6 ms; P<0.001) and greater echocardiographic mechanical dyssynchrony (57.5±11.6 versus 35.7±13.0 and 24.4±11.1 ms; P<0.001) compared with Sep-PACs and controls, respectively. After 16 weeks, Lat-PACs led to slower LA conduction velocity (1.1±0.2 versus 1.3±0.2 [Sep-PAC] versus 1.3±0.1 [Reg-130] versus 1.5±0.2 [controls] m/s; P<0.001) without significant change in atrial ERP. The Lat-PAC group had a significantly increased percentage of LA fibrosis and upregulated levels of extracellular matrix proteins (lysyl oxidase and collagen 1 and 8), as well as TGF-ß1 (transforming growth factor-ß1) signaling proteins (latent and monomer TGF-ß1 and phosphorylation/total ratio of SMAD2/3; P<0.05). The Lat-PAC group had the longest inducible AF duration (terminal to baseline: 131 [interquartile range 30, 192] seconds versus 16 [6, 26] seconds [Sep-PAC] versus 22 [11, 64] seconds [Reg-130] versus -1 [-16, 7] seconds [controls]; P<0.001). CONCLUSIONS: In this swine model, frequent PACs resulted in adverse atrial structural remodeling with a heightened propensity to AF. PACs originating from the lateral LA produced greater atrial remodeling and longer induced AF duration than the septal-origin PACs. These data provide evidence that frequent PACs can cause adverse atrial remodeling as well as AF, and that the location of ectopic PACs may be clinically meaningful.

Real-time heart rate variability according to ambulatory glucose profile in patients with diabetes mellitus.

Background: Autonomic neuropathy commonly occurs as a long-term complication of diabetes mellitus (DM) and can be diagnosed based on heart rate variability (HRV), calculated from electrocardiogram (ECG) recordings. There are limited data on HRV using real-time ECG and ambulatory glucose monitoring in patients with DM. The aim of this study was to investigate real-time HRV according to ambulatory glucose levels in patients with DM. Methods: A total of 43 patients (66.3 ± 7.5 years) with DM underwent continuous real-time ECG monitoring (225.7 ± 107.3 h) for HRV and ambulatory glucose monitoring using a remote monitoring system. We compared the HRV according to the ambulatory glucose profile. Data were analyzed according to the target in glucose range (TIR). Results: There were no significant differences in the baseline characteristics of the patients according to the TIR. During monitoring, we checked ECG and ambulatory glucose levels (a total of 15,090 times) simultaneously for all patients. Both time- and frequency-domain HRVs were lower when the patients had poorly controlled glucose levels (TIR < 70%) compared with well controlled glucose levels (TIR > 70%). In addition, heart and respiratory rates increased with real-time glucose levels (P < 0.001). Conclusions: Poorly controlled glucose levels were independently associated with lower HRV in patients with DM. This was further substantiated by the independent continuous association between real-time measurements of hyperglycemia and lower HRV. These data strongly suggest that cardiac autonomic dysfunction is caused by elevated blood sugar levels.

Effects of the beta-blocker carvedilol on arrhythmia and long-term clinical outcomes in benign prostate hypertrophy patients.

Benign prostatic hypertrophy (BPH) is associated with autonomic dysfunction and sympathetic nervous system mediated by the alpha receptor. However, limited data exist regarding the effects of the beta-blocker (BB) carvedilol on arrhythmia and urologic outcomes in BPH patients. Our database of patients diagnosed with BPH from 2015 to 2020 was used to obtain echocardiography and electrocardiogram data. Inclusion criteria were BPH patients taking BBs. International Prostate Symptom Score questionnaire were used to evaluate the urinary symptoms and quality of life. Among 448 patients with BPH (69.2 ± 10.9 years) taking BBs, 219 patients took carvedilol (48.9%) and 229 patients took a non-carvedilol BB (51.1%; bisoprolol, 184 patients, 80% or nebivolol, 45 patients, 20%). Difference in the baseline characteristics was not observed. During the median 36-month follow-up, a lower incidence of arrhythmic events (P = .029), total urologic events (P < .001), and less use of additive alpha-blocker was observed in the carvedilol group (P = .022). In multivariate analysis, less carvedilol use (P = .019), heart failure (P < .001), stroke (P < .001), and cardiomyopathy (P = .046) were independent risk factors for arrhythmic events. In addition, less carvedilol use (P = .009) and older age (P = .005) were independent risk factors for urologic events based on BB type at the median 36-month follow-up. The use of carvedilol was associated with less arrhythmic events in BPH patients with palpitation and decreased the incidence of urologic events in BPH compared with the use of non-carvedilol BBs in long-term follow-up.

Identification of supraventricular tachycardia mechanisms with surface electrocardiograms using a convolutional neural network.

Background: It remains difficult to definitively distinguish supraventricular tachycardia (SVT) mechanisms using a 12-lead electrocardiogram (ECG) alone. Machine learning may identify visually imperceptible changes on 12-lead ECGs and may improve ability to determine SVT mechanisms. Objective: We sought to develop a convolutional neural network (CNN) that identifies the SVT mechanism according to the gold standard of SVT ablation and to compare CNN performance against experienced electrophysiologists among patients with atrioventricular nodal re-entrant tachycardia (AVNRT), atrioventricular reciprocating tachycardia (AVRT), and atrial tachycardia (AT). Methods: All patients with 12-lead surface ECG during sinus rhythm and SVT and had successful SVT ablation from 2013 to 2020 were included. A CNN was trained using data from 1505 surface ECGs that were split into 1287 training and 218 test ECG datasets. We compared the CNN performance against independent adjudication by 2 experienced cardiac electrophysiologists on the test dataset. Results: Our dataset comprised 1505 ECGs (368 AVNRT, 304 AVRT, 95 AT, and 738 sinus rhythm) from 725 patients. The CNN areas under the receiver-operating characteristic curve for AVNRT, AVRT, and AT were 0.909, 0.867, and 0.817, respectively. When fixing the specificity of the CNN to the electrophysiologist adjudicators' specificity, the CNN identified all SVT classes with higher sensitivity: (1) AVNRT (91.7% vs 65.9%), (2) AVRT (78.4% vs 63.6%), and (3) AT (61.5% vs 50.0%). Conclusion: A CNN can be trained to differentiate SVT mechanisms from surface 12-lead ECGs with high overall performance, achieving similar performance to experienced electrophysiologists at fixed specificities.

Effects of Empagliflozin on Diuretics Reduction in Outpatient Heart Failure Patients.

Background and Objectives: Inhibitors of sodium-glucose cotransporter 2 (SGLT2i) reduce the risk of hospitalization for heart failure (HF). We aimed to examine the effect of empagliflozin on change of diuretics dose in outpatient HF patients. Methods: We retrospectively reviewed the medical records of 612 patients who were treated using both empagliflozin and diuretics. We excluded patients who did not meet the criteria for HF. Dose and duration of empagliflozin and diuretics were measured. Results: Of 612 patients, a total of 251 was analyzed and followed for a mean 430.0±175.4 days. The mean age was 69.3, 51.8% were female, and 93.2% had type 2 diabetes. The distribution of initial diuretics type when starting empagliflozin showed that furosemide comprised 24.7%, spironolactone 20.7%, thiazide 36.9%, and others. Total 23.1% of patients reduced diuretic dose, 13.1% increased diuretic dose, 41.4% continued at the same diuretic dose, and 22.3% switched to different diuretics. Among patients who were using furosemide, 36.0% reduced diuretics dose. There was a diuretic reduction in 22.6% of HF preserved ejection fraction (HFpEF, left ventricular ejection fraction [LVEF] ≥50%) and in 26.5% of HF reduced EF (HFrEF, LVEF <50%). The average doses furosemide at the start of empagliflozin decreased from 16.3mg/day to 8.5mg/day at the time of follow-up. Conclusions: Among outpatient clinic HF patients treated with both diuretics and empagliflozin, 23.1% of patients had their diuretics reduced, and the mean dose of furosemide was reduced by about half. This suggests that empagliflozin has clinical advantages in managing outpatient HF patients.

Increased Right Ventricular Pressure as a Predictor of Acute Decompensated Heart Failure in End-Stage Renal Disease Patients on Maintenance Hemodialysis.

Background and Objectives: Many patients with end-stage renal disease (ESRD) on hemodialysis (HD) have reduced vascular compliance and are likely to develop heart failure (HF). This study aimed to determine the factors associated with acute decompensation events among ESRD patients undergoing HD. Methods: We retrospectively investigated ESRD patients on HD using a medical record review. We divided the patients into those admitted to hospital due to acute decompensated heart failure (ADHF) and those who were not. We compared the medical histories, electrocardiograms, and echocardiographic and laboratory data between the two groups. Results: Of the 188 ESRD patients on HD, 87 were excluded, and 101 were enrolled (mean age: 63.7 years; 52.1% male). Thirty patients (29.7%) were admitted due to ADHF. These patients exhibited similar left ventricular ejection fraction (LVEF), left ventricular (LV) mass index, and E/E' values compared to the non-ADHF group. However, the ADHF group exhibited significantly higher tricuspid regurgitation (TR) jet velocity (2.9±0.6 vs. 2.5±0.4 m/s; p=0.004) and right ventricular systolic pressure (RVSP) (43.5±17.2 vs. 34.2±9.9 mmHg; p=0.009) than the non-ADHF group, respectively. A multivariate logistic regression analysis demonstrated that the TR jet velocity (odds ratio, 8.356; 95% confidence interval, 1.806-38.658; p=0.007) was an independent predictor of ADHF after adjusting for age and sex, while the LVEF and E/E' were not. Conclusions: Our data showed that an increased TR jet velocity was an independent predictor of ADHF events in ESRD patients on HD, but the LVEF and E/E' were not.

Pulsed Field Ablation of Left Ventricular Myocardium in a Swine Infarct Model.

BACKGROUND: Pulsed field ablation (PFA) leads to cell death by irreversible electroporation. There are limited data about PFA lesion characteristics in the ventricle, particularly in the presence of myocardial scar. OBJECTIVES: This study sought to evaluate the lesion characteristics of PFA and radiofrequency energy (RFA) in healthy and infarcted left ventricular (LV) myocardium in swine. METHODS: Swine (n = 10) underwent either: 1) 120-minute left anterior descending coronary artery balloon occlusion myocardial infarction and survived for 6 to 8 weeks (n = 8); or 2) served as healthy control subjects (n = 2). PFA or RFA was delivered to the LV endocardium in regions of healthy myocardium or scar identified with electroanatomical mapping. Bipolar, biphasic PFA was delivered for 2.5 seconds × 4 applications/site using 2 different catheters: linear quadripolar (FOCAL) or multispline 8-pole catheter (BASKET). Gross and histologic measurements of lesion size were performed. RESULTS: In the PFA group, 21 lesions were delivered to healthy LV and 20 to areas of scar. Overall, there was no significant difference in lesion depth between catheter groups (FOCAL linear vs BASKET; P = 0.740), whereas lesion width was greater for BASKET (10.6 ± 2.4 mm vs 13.3 ± 3.3 mm; P = 0.007). In myocardial scar, lesion depth was not significantly different between PFA catheters (P = 0.235). However, lesion depth for PFA was greater than for RFA (PFA vs RFA; 6.1 ± 1.7 mm vs 3.8 ± 1.7 mm; P = 0.005). CONCLUSIONS: PFA allows rapid, safe, and effective ablation of surviving islands of myocardium within and around infarcted LV substrate. This technology holds promise for treating infarct-related ventricular tachycardia in humans.

Left Ventricular Dysfunction in Outpatients with Frequent Ventricular Premature Complexes.

Frequent ventricular premature complexes (VPCs) and VPC QRS duration are risk factors for left ventricular (LV) dysfunction. To determine which clinical characteristics and electrocardiographic features are associated with LV dysfunction (ejection fraction, <50%) and frequent VPCs, we retrospectively reviewed data from a single-center registry of all patients diagnosed with frequent VPCs at a Korean outpatient clinic. We identified 412 consecutive outpatients (mean age, 54.7 ± 16.8 yr; 227 women [55.1%]) who were diagnosed with frequent VPCs and had no structural heart disease from January 2010 through December 2017. Available transthoracic echocardiograms and 24-hour Holter monitoring data were evaluated to correlate the occurrence of VPCs and symptoms. Typical VPC-related symptoms (palpitations or dropped beats) were observed in 251 patients (61.1%). Electrocardiograms revealed VPCs with a left bundle branch block-like morphology in 327 patients (79.5%) and VPCs with an inferior axis in 353 (85.8%). Twenty-six patients (6.3%) were diagnosed with VPC-related LV dysfunction. The mean VPC burden did not differ significantly by LV functional status (11.06% ± 10.13% [normal] vs 14.41% ± 13.30% [impaired]; P=0.211). Patients with impaired LV function were more often men (P=0.027), had no typical VPC-related symptoms (P=0.006), and had significantly longer VPC QRS durations (mean, 157 ms vs 139 ms; P <0.01). Our findings suggest that male sex, absence of typical VPC-related symptoms, and a VPC QRS duration >157 ms are associated with LV dysfunction in patients with frequent VPCs, findings that may be useful in predicting such dysfunction.

Effect of Epicardial Pulsed Field Ablation Directly on Coronary Arteries.

BACKGROUND: The unique tissue selectivity of pulsed field ablation (PFA) allows for minimizing collateral damage to the nerves/esophagus. However, the safety profile of epicardial PFA on coronary arteries (CAs) has not been well defined. OBJECTIVES: This study sought to evaluate the effect of epicardial PFA directly on CAs in a swine model. METHODS: In 4 swine, an 8-F linear quadripolar PFA catheter (FARAPULSE Inc) was introduced into the pericardial space via a subxiphoid puncture. After coronary angiography (Angio), QRS synchronized, biphasic, bipolar PFA was delivered directly on the left anterior descending artery, left circumflex artery, or normal myocardium (control) (2.0 kV × 4 applications per site). Angio was repeated immediately after ablation and repeated every 5 minutes to quantify the degree of CA narrowing. After 4- or 8-week survival, repeat Angio was performed followed by gross and histologic lesion analyses. RESULTS: A total of 15 lesions were delivered (8 left anterior descending arteries, 3 left circumflexes, and 4 controls). Target site Angio revealed median of 47% (IQR: 38%-69%) acute luminal narrowing immediately after PFA, which gradually resolved over 30 minutes. Epicardial PFA lesions extended into the myocardium with a median depth of 4.1 mm (IQR: 3.6-5.6 mm) passing across the CAs and adipose tissue. However, 87.5% of the CAs demonstrated minimal to mild CA stenosis associated with neointimal hyperplasia and tunica media fibrosis. CONCLUSIONS: In a swine model, epicardial PFA directly on CAs allowed the creation of myocardial lesions but led to a CA response characterized by acute moderate spasm and chronic mild stenosis via neointimal hyperplasia.

Predictors of long-term success after catheter ablation of premature ventricular complexes.

INTRODUCTION: Some patients have late recurrence after acutely successful radiofrequency catheter ablation (RFCA) of premature ventricular complexes (PVCs). The aim of this study was to evaluate predictors of long-term success following acutely successful PVC RFCA. METHODS: We identified consecutive patients at our institution with frequent PVCs undergoing RFCA and reviewed procedural data and medical records. Acute success was defined as elimination of targeted PVCs for at least 30-min after RFCA. Long-term success was defined as absence of targeted PVCs during all follow-up visits and PVC-burden <5% on follow-up monitoring. RESULTS: Among 241 patients (mean age 57 ± 15 years, 58% male), 161 (66.8%) had long-term success with median follow-up of 17.7 (IQR, 12.2-29.8) months. Unadjusted predictors of late PVC recurrence were increasing age, diabetes mellitus and alcohol use, while female-sex, shorter ablation-time, right ventricular PVC-origin, single PVC morphology, and earliest bipolar activation ≥24 ms pre-QRS were predictors of long-term success. In multivariate-analysis, female-sex, single-PVC morphology and earliest-onset of PVC ≥ 24 ms pre-QRS were independent predictors for long-term success. The positive-predictive value of earliest-bipolar onset of PVC ≥ 24 ms pre-QRS for long-term success was 0.77 (p < .001). Negative-predictive value of PVC < 15 ms pre-QRS for long-term success was 0.86 (p = .003), suggesting that RFCA when the bipolar electrogram preceded QRS by <15 ms was unlikely to result in long-term success. CONCLUSIONS: Female-sex, single-PVC morphology, and earliest-onset of bipolar electrogram ≥24 ms pre-QRS were multivariable predictors of long-term success in patients with PVCs undergoing RFCA. RFCA at sites with local onset <15 ms pre-QRS are unlikely to be successful.

Association of dipping status of blood pressure, visual field defects, and retinal nerve fiber layer thickness in patients with normotensive glaucoma.

The aim of this study was to evaluate the association between dipping status of blood pressure (BP), visual field defects (VFDs), and retinal nerve fiber layer (RNFL) thickness in patients with normotensive glaucoma (NTG). Our University echocardiography, electrocardiogram, 24-hour BP monitor and glaucoma database were reviewed from 2016 to 2018 to identify patients with NTG and hypertension (HTN). These NTG patients were followed for a mean 26.4 ±â€Š13.6 months and were divided into 2 groups according to the absence or presence of VFDs. Among the 110 patients with NTG, 55 (50%) patients had VFDs. There were no differences of baseline characteristics between 2 groups. In univariate analysis, extreme dipper status at night in the 24-hour BP monitoring, HTN, age, diabetes mellitus, and hyperlipidemia were significantly associated with VFDs. In multivariate analysis, extreme dipper status at night in the 24-hour BP monitoring (odds ratio [OR] 4.094; P = .045) and HTN (OR 2.368; P = .048) were independent risk factors for VFDs at 2-year follow-up. Moreover, the RNFL thickness was thinner in NTG patients with VFDs (P < .001). VFDs group had more increased fluctuation of systolic and diastolic BP in 24-hour BP monitoring and that the extreme dipper status at night in the 24-hour BP monitoring and HTN itself were also associated with higher incidence of VFDs and thinning changes of the RNFL in patients with NTG, suggesting that more intensive medical therapy with close clinical follow-up will be required for these patients.

Changes in QRS Duration Are Associated with a Therapeutic Response to Sacubitril-valsartan in Heart Failure with Reduced Ejection Fraction.

BACKGROUND: Recent studies have demonstrated that angiotensin receptor neprilysin inhibitors (ARNIs) can reverse the cardiac remodeling effects that occur in heart failure with reduced ejection fraction (HFrEF). These studies have also suggested that ARNIs have favorable effects on ventricular dyssynchrony. We assessed the changes in QRS duration associated with ARNIs in patients with HFrEF. METHODS: We retrospectively investigated patients with HFrEF (defined by a left ventricular ejection fraction [LVEF] ≤ 35%) who were treated with ARNIs for at least six months. We divided the patients into QRS shortening and non-QRS shortening groups according to their electrocardiogram (ECG) findings. We also compared changes in echocardiographic parameters between the groups. RESULTS: A total of 68 patients with HFrEF were included (mean age: 62.5 years, 74.6% male). Twenty-one patients had significant ischemic heart disease (IHD). Thirty-five patients exhibited QRS-duration shortening on follow-up ECGs (mean change: -7.8 msec), and 33 patients showed no changes or increased QRS duration (mean change: 5.1 msec). The QRS shortening group exhibited significant improvement in LVEF (12.5 ± 15.3% vs. 1.7 ± 9.5%; p < 0.001) when compared with the non-QRS shortening group. The QRS shortening group also had significantly lower LV end-diastolic dimension (LVEDD), LV end-systolic dimension (LVESD) and LV mass index (LVMI) than did the non-QRS shortening group. The change in QRS duration was significantly correlated with the change in LVEF (r = -0.329, p = 0.011) and LVESD (r = 0.298, p = 0.022). CONCLUSIONS: Among patients with HFrEF treated with ARNIs, the QRS shortening group showed favorable LV systolic function recovery, and reversal of cardiac remodeling compared to those of the non-QRS shortening group. Change in the QRS duration, which reflects LV synchrony, may be associated with response to ARNIs in patients with HFrEF.

Eosinophilic Esophagitis with Angina Pectoris.

Eosinophilic esophagitis (EoE) is an immune or antigen-mediated chronic inflammatory esophageal disorder that is relatively rare in Asian countries. The main symptoms of EoE are dysphagia and food impaction. Although chest pain is a symptom of EoE, it is also a symptom of coronary heart disease. This paper reports a case of EoE with angina pectoris in a 45-year-old male who was referred to the authors' hospital for chest pain. He was diagnosed with angina pectoris because of mild stenosis in the left coronary artery on coronary angiography. On the other hand, the symptoms did not improve with angina medication therapy. Therefore, he underwent a chest CT scan, which revealed esophageal thickening. Esophagogastroduodenoscopy was performed. His endoscopic findings showed linear furrows with edema, and >90 eosinophils existed per high-power field on the histology findings. He was diagnosed with EoE. Through additional examinations, he was also diagnosed with asthma. The patient was treated with a proton pump inhibitor and a fluticasone inhaler. His symptoms and abnormal endoscopic findings disappeared after eight weeks of treatment. This case shows that physicians should consider the possibility of the symptoms for EoE when unexplained chest pain persists.

Electrocardiographic features of the presence of occult myocardial disease in patients with VPD-induced cardiomyopathy.

BACKGROUND: Frequent ventricular premature depolarizations (VPDs) can cause reversible cardiomyopathy (CMP). However, many patients maintain a normal left ventricular (LV) function with a high VPD burden. The electrocardiographic characteristics of VPD-induced CMP have not been elucidated. METHODS: One hundred and eighty (91 men, age; 51 ± 15 years) patients with frequent idiopathic VPDs (>10% VPDs/day or >10 000 VPDs/day) were studied. All patients underwent successful ablation and were then divided into two groups according to the echocardiographic findings before and after the ablation procedure. RESULTS: Group A (n = 139) had a normal LV function with VPD frequencies, and Group B (n = 41) had reversible LV dysfunction after ablation. The VPD QRS duration (QRSd) was wider in patients with CMP (Group A vs Group B; 137.2 ± 12.0 milliseconds vs 159.7 ± 5.3 milliseconds, P < .001). VPDs with a terminal QRS delay marked by a notch followed by a discrete lower amplitude signal after the peak R wave in any precordial lead were identified. The incidence of terminal signals was higher in the CMP group (Group A vs Group B; 2.1% vs 53.6%, P < .001). CONCLUSIONS: The wider VPD QRSd and terminal QRS delay in patients with VPD-induced CMP suggest subclinical cell-to-cell conduction abnormalities as a potential factor predisposing VPD-induced CMP.