Determinants of Ventricular Arrhythmias in Mitral Valve Prolapse.

BACKGROUND: Mitral valve prolapse (MVP) may be associated with ventricular arrhythmias (VA) even in the absence of significant valvular regurgitation. Curling, mitral annulus disjunction (MAD) and myocardial fibrosis (late gadolinium enhancement [LGE]) may account for arrhythmogenesis. OBJECTIVES: This study investigated the determinants of VA in patients with MVP without significant regurgitation. METHODS: This study included 108 patients with MVP (66 female; median age: 48 years) without valve regurgitation. All patients underwent 12-lead electrocardiography, 12-lead 24-hour electrocardiographic Holter monitoring, exercise stress test, and cardiac magnetic resonance. Patients were divided into 2 groups (arrhythmic and no-arrhythmic MVP), according to the presence of VA with a right bundle branch block pattern. RESULTS: The 62 patients (57%) with arrhythmic MVP showed: 1) higher MAD (median length: 6.0 vs 3.2 mm; P = 0.017); 2) higher prevalence of curling (79% vs 52%; P = 0.012); and 3) higher prevalence of left ventricular LGE (79% vs 52%; P = 0.012). Mediation analysis showed that curling had both a direct (P = 0.03) and indirect effect mediated by LGE (P = 0.04) on VA, whereas the association between MAD and VA was completely mediated by LGE. Patients with severe VA showed more pronounced morphofunctional alterations, in terms of MAD (7.0 vs 4.6 mm; P = 0.004) and presence and severity of curling (respectively, 91% vs 64%; P = 0.010; and 4 vs 3 mm; P = 0.004), compared to those without severe VA. CONCLUSIONS: In patients with MVP the occurrence of VA with right bundle branch block morphology is the expression of more severe morphologic, mechanical, and tissue alterations. Curling has both a direct and an indirect effect on VA.

Ventricular arrhythmias recorded on 12-lead ambulatory electrocardiogram monitoring in healthy volunteer athletes and controls: what is common and what is not.

AIMS: Premature ventricular beats (PVBs) in athletes are often benign, but sometimes they may be a sign of an underlying disease. We evaluated the prevalence, burden, and morphology of PVBs in healthy voluntary athletes and controls with the main purpose of defining if certain PVB patterns are 'common' and 'training related' and, as such, are more likely benign. METHODS AND RESULTS: We studied 433 healthy competitive athletes [median age 27 (18-43) years, 74% males] and 261 age- and sex-matched sedentary subjects who volunteered to undergo 12-lead 24 h ambulatory electrocardiogram (ECG) monitoring (24H ECG), with a training session in athletes. Ventricular arrhythmias (VAs) were evaluated in terms of their number, complexity [i.e. couplet, triplet, or non-sustained ventricular tachycardia (NSVT)], exercise inducibility, and morphology. Eighty-six percent of athletes and controls exhibited a total of ≤10 PVBs/24 h, and >90% did not show any couplets, triplets, or runs of NSVT > 3 beats. An higher number of PVBs correlated with increasing age (P < 0.01) but not with sex and level of training. The most frequent morphologies among the 36 athletes with >50 PVBs were the infundibular (44%) and fascicular (22%) ones. In a comparison between athletes and sedentary individuals, and male and female athletes, no statistically significant differences were found in PVBs morphologies. CONCLUSION: The prevalence and complexity of VAs at 24H ECG did not differ between athletes and sedentary controls and were not related to the type and amount of sport or sex. Age was the only variable associated with an increased PVB burden. Thus, no PVB pattern in the athlete can be considered 'common' or 'training related'.

Long-Term Outcomes of Tachycardia-Induced Cardiomyopathy Compared with Idiopathic Dilated Cardiomyopathy.

BACKGROUND: data on the natural course and prognosis of tachycardia-induced cardiomyopathy (TICMP) and comparison with idiopathic dilated cardiomyopathies (IDCM) are scarce. OBJECTIVE: To compare the clinical presentation, comorbidities, and long-term outcomes of TICMP patients with IDCM patients. METHODS: a retrospective cohort study of patients hospitalized with new-onset TICMP or IDCM. The primary endpoint was a composite of death, myocardial infarction, thromboembolic events, assist device, heart transplantation, and ventricular tachycardia or fibrillation (VT/VF). The secondary endpoint was recurrent hospitalization due to heart failure (HF) exacerbation. RESULTS: the cohort was comprised of 64 TICMP and 66 IDCM patients. The primary composite endpoint and all-cause mortality were similar between the groups during a median follow-up of ~6 years (36% versus 29%, p = 0.33 and 22% versus 15%, p = 0.15, respectively). Survival analysis showed no significant difference between TICMP and IDCM groups for the composite endpoint (p = 0.75), all-cause mortality (p = 0.65), and hospitalizations due to heart failure exacerbation. Nonetheless, the incidence of recurrent hospitalization was significantly higher in TICMP patients (incidence rate ratio 1.59; p = 0.009). CONCLUSIONS: patients with TICMP have similar long-term outcomes as those with IDCM. However, it portends a higher rate of HF readmissions, mostly due to arrhythmia recurrences.

The characteristics of a 12-lead electrocardiogram measuring premature ventricular contractions originating from the tricuspid annulus using the clock position method.

OBJECTIVE: This study aimed to analyze the conventional surface electrocardiogram (ECG) characteristics of premature ventricular contractions (PVCs) originating from the tricuspid annulus and to investigate the efficacy of locating their origins according to ECG results. METHODS: Eight patients who underwent radiofrequency ablation in the First Hospital of Shanxi Medical University (China) were included in the study. Pace mapping (PM) was used to analyze the characteristics of the PVCs originating from the tricuspid annulus recorded via 12-lead body surface ECGs. RESULTS: An R-wave was found in leads I, V5 , and V6 . The QRS wave was narrower when the PVCs originated from the septum and shifted in lead V3 (R-wave amplitude/S-wave amplitude in the precordial lead-1). The QRS wave was broadest when the PVCs originated from the 7 to 9 o'clock position. The augmented vector left lead showed RS, QS, or RSR-type waves with a low amplitude when the PVCs originated from the upper part of the annulus. When the PVCs originated from the lower part of the annulus, the augmented vector right lead reflected multidirectional and QS-type waves. CONCLUSION: The ECG-lead characteristics related to the origin of PVCs in the tricuspid annulus indicate some level of significance and can be used to formulate a specific diagnosis.

Reproducibility of ventricular arrhythmias at exercise testing for prediction of non-ischaemic left ventricular scar in athletes.

AIMS: The non-ischaemic left ventricular scar (NILVS) is an emerging substrate of ventricular arrhythmias (VA) in the athlete. We tested the diagnostic value of VA reproducibility at repeated exercise testing (ET). METHODS AND RESULTS: We included consecutive athletes who underwent cardiac magnetic resonance (CMR) for evaluation of VA and two consecutive ET off-therapy within 12 months. Those with a positive family history of premature sudden death/cardiomyopathy, syncope/pre-syncope, ECG or echocardiography abnormalities, or low-risk VA (exercise-suppressed infundibular or fascicular VA) were excluded. The NILVS was defined as subepicardial/midmyocardial stria of late gadolinium enhancement involving >5% of the LV mass. Reproducibility was defined as the occurrence of VA with the same pattern and behaviour during repeated ET. Of 325 athletes who underwent CMR for evaluation of VA, 75 were included, and 30 showed NILVS involving three [2-4] LV segments. At first ET, athletes with NILVS showed a higher prevalence of exercise-induced VA (93% vs. 53%, P < 0.001), while other VA characteristics did not differ between groups. At repeated ET, reproducibility was observed in 97% of athletes with vs. 13% without NILVS (P < 0.001). The remaining 87% of athletes with normal CMR either did not show any VA at repeated ET (59%) or showed arrhythmias with different patterns, mostly infundibular. Reproducibility yielded a positive predictive value for NILVS of 83% and a negative predictive value of 98%. CONCLUSION: VA reproducibility at repeated ET predicted an underlying NILVS in athletes with VA and otherwise normal clinical work-up. This finding may improve risk stratification and appropriate CMR referral of athletes with apparently idiopathic VA.

Bicuspid Aortic Valve and Premature Ventricular Beats in Athletes.

BACKGROUND: The aim of this study was to identify a possible link between bicuspid aortic valve (BAV) and premature ventricular beats (PVBs), particularly from left and right ventricular outflow tracts, and to investigate possible associations between these arrhythmias and echocardiographic abnormalities. METHODS: A comparison of sportspeople with and without BAV was performed to identify PVBs' occurrence in these two series. Then, subdividing the BAV group on the presence of cardiovascular complications due to BAV, we compared arrhythmic features between these two subgroups and echocardiographic findings between athletes with and without left and right outflow tract PVBs. RESULTS: PVBs in 343 athletes with BAV were compared with 309 athletes without BAV, showing an increased frequency (29% vs. 11.8%, p < 0.001; OR 3.1; CI 2.1-4.7) and origin from the left (18.4% vs. 3.2%, p < 0.001, OR 6.7; CI 3.4-13.4) and right (15.2% vs. 3.6%, p < 0.001, OR 4.8; CI 2.5-9.5) outflow tracts compared to other ventricular areas (fascicular PVBs p = 0.81, other morphologies p = 0.58). No difference in PVBs' occurrence was found between near normal valve BAV and pathological BAV, nor was a difference in echocardiographic characteristics found between patients with and without outflow tract arrhythmias. CONCLUSIONS: A possible causal link between BAV and PVBs was highlighted, but no association between PVBs and complicated BAV was emphasized.

Electrophysiological Substrate in Patients with Barlow's Disease.

Mitral valve prolapse (MVP) is the most common valvular heart disease, affecting 2-3% of the general population. Barlow's disease is a clinical syndrome characterised by MVP. Initially thought a benign condition, MVP is now recognised as a cause of sudden cardiac death and ventricular arrhythmias. The development of new imaging techniques has contributed recently to the identification of novel risk factors. Catheter ablation of ventricular arrhythmias in patients affected by MVP is traditionally considered challenging. In this review, the authors summarise the evidence on arrhythmogenesis in the context of MVP, along with risk stratification of sudden cardiac death and the available treatment options, including new catheter ablation techniques.

Case Report: Premature Ventricular Beats-Induced Chronic Cough and Cough Syncope.

Background: Chronic cough is a common complaint that in rare cases can be caused by premature ventricular beats (PVCs). Materials and Methods: In this report, we present the case of a healthy 44-year-old female who presented persistent cough and cough syncope that was attributed to PVCs. Results: The cough disappeared after radiofrequency ablation, and no recurrence of arrhythmia or cough was observed. Conclusion: PVCs should be considered a probable cause of chronic cough and cough syncope in differential diagnosis.

Etiology is a predictor of recurrence after catheter ablation of ventricular arrhythmias in pediatric patients.

BACKGROUND: Ventricular arrhythmias (VAs) are rare in pediatric patients, especially in absence of structural heart disease (SHD). Few data are available regarding the invasive VAs treatment with catheter ablation (CA) in pediatric patients and predictors of outcomes have not been fully investigated. OBJECTIVE: To describe the clinical presentation, procedural characteristics, and outcomes in pediatric patients undergoing CA for VAs. METHODS: Eighty-one consecutive pediatric patients (58 male [72%], 15.5 ± 2.2 years) treated by CA for ventricular tachycardia (VT) or premature ventricular beats (PVBs) were retrospectively evaluated. Study endpoints were VAs recurrence and mortality for any cause. RESULTS: Ninety-five procedures were performed in 81 patients, 52 (55%) PVBs and 43 (45%) VT ablations. During a follow-up of 35.0 months (interquartile range = 13.0-71.0), 14 patients (14.7%) had a VA recurrence: 11 (33.3%) patients treated with CA for VT and 3 (6.2%) patients treated for PVBs (p < .001). One patient (1%) died 26 months after the procedure during an electrical storm. Patients with SHD had higher VAs recurrence rate, as compared with idiopathic VAs (pairwise log-rank p < .001). Patients treated with CA for VT had higher VA recurrence rate, as compared with PVB patients (pairwise log-rank p = .002). At Cox multivariate analysis only SHD was an independent predictor of VAs recurrence (hazard ratio = 5.56, 95% confidence interval = 2.68-11.54, p < .001). CONCLUSION: CA of VAs is effective and safe in a pediatric population. CA of idiopathic and fascicular VAs are associated with lower recurrence rate, than VAs in the setting of SHD.

Long-term outcomes of ablation for ventricular arrhythmias in mitral valve prolapse.

PURPOSE: Prior studies reporting efficacy of radiofrequency catheter ablation for complex ventricular ectopy in mitral valve prolapse (MVP) are limited by selective inclusion of bileaflet MVP, papillary muscle only ablation, or short-term follow-up. We sought to evaluate the long-term incidence of hemodynamically significant ventricular tachycardia (VT) or fibrillation (VF) in patients with MVP after initial ablation. METHODS: We studied consecutive patients with MVP undergoing ablation for complex ventricular ectopy between 2013 and 2017 at our institution. Of 580 patients with MVP, we included 15 (2.6%, 10 women; mean age 50 ± 14 years, 53% bileaflet) with complex ventricular ectopy treated with initial ablation. RESULTS: Over a median follow-up of 3406 (1875-6551) days or 9 years, 5 of 15 (33%) patients developed hemodynamically significant VT/VF after their initial ablation and underwent placement of an implantable cardioverter defibrillator (ICD). Three of 5 also underwent repeat ablations. Sustained VT was inducible prior to index ablation in all 5 who developed VT/VF, compared to none of the 10 patients who did not develop VT/VF after index ablation (p = 0.002). Complex ventricular ectopy at index ablation was multifocal in all 5 patients who underwent repeat intervention versus 4 of 10 patients (40%) who did not (p = 0.04). All 3 patients with subsequent VT/VF who underwent repeat ablation had a new clinically dominant focus of ventricular arrhythmia and 3 of the patients with ICD had appropriate VT/VF therapies. CONCLUSIONS: In the long term, a subset of MVP patients treated with ablation for ventricular arrhythmias, all with multifocal ectopy on initial EP study, develop hemodynamically significant VT/VF. Our findings suggest the progressive nature of ventricular arrhythmias in patients with MVP and multifocal ectopy.

Clinical correlates and outcome of the patterns of premature ventricular beats in Olympic athletes: a long-term follow-up study.

BACKGROUND: The pattern of premature ventricular beats, as a clue to site of origin, may help identify underlying cardiac diseases. AIM: To assess the value of premature ventricular beat patterns in managing athletes with ventricular arrhythmias. METHODS: Athletes with 50 or more isolated premature ventricular beats/24 hours, and/or multifocal and/or repetitive premature ventricular beats at baseline, and/or exercise, and/or 24-hour electrocardiograms were selected for this analysis. Premature ventricular beats were defined as 'common' (outflow tract or fascicular origin), or 'uncommon' (other morphologies and/or multifocal or repetitive). RESULTS: From 4595 athletes consecutively examined, 205 (4%, 24.6 ± 6.9 years, 67% men) were included, 118 (58%) with uncommon and 87 (42%) with common premature ventricular beats. In particular, 81 (39%) showed complex patterns; 63 (31%) right/left ventricular outflow tract origin; 24 (12%) fascicular origin; 20 (10%) right bundle branch block pattern, intermediate/superior axis, wide QRS; and 17 (8%) left bundle branch block pattern, intermediate/superior axis. Uncommon premature ventricular beat patterns were predominant among men (62% vs. 38%; P < 0.001) but not among women. Uncommon premature ventricular beats were equally prevalent in endurance, mixed and skill disciplines, but lower in power sports. Cardiac diseases were detected in 11 (5%), 10 with uncommon patterns. Over a 6-year follow-up, cardiac diseases occurred in four (0.6%/year), all with uncommon patterns. Overall, cardiac diseases at baseline and during follow-up were detected in 14/118 athletes with uncommon versus one/87 with common premature ventricular beats (P = 0.003). CONCLUSIONS: Evaluation of premature ventricular beat patterns in Olympic athletes identified cardiac diseases, requiring disqualification and/or follow-up, in 12% with uncommon versus 1% with common patterns. This result suggests that athletes with uncommon premature ventricular beat patterns should undergo comprehensive cardiac evaluation and/or serial follow-up, irrespective of gender or sporting discipline.

Evaluation and treatment of premature ventricular contractions in heart failure with reduced ejection fraction.

Premature ventricular complexes (PVCs) are often observed in patients presenting with heart failure with a reduced ejection fraction (HFrEF). PVCs may in some patients be considered to be the cause of heart failure, while in others it may be the consequence of heart failure. PVCs are important prognostic markers in HFrEF. The uncertainty whether PVCs are the cause or effect in HFrEF impacts clinical decision making. In this review, we discuss the complexity of the cause-effect relationship between PVCs and HFrEF. We demonstrate a workflow with the use of a trial period of amiodarone that may discover whether the reduced LVEF is reversible, the symptoms are due to PVCs and whether biventricular pacing can be increased by the reduction of PVCs. The use of non-invasive and invasive (high-density) mapping techniques may help to improve accuracy and efficacy in the treatment of PVC, which will be demonstrated. With these results in mind, we conclude this review highlighting the future directions for PVC research and treatment.

Clinical Classification of Arrhythmogenic Right Ventricular Cardiomyopathy.

INTRODUCTION: Commonly accepted clinical classification of arrhythmogenic right ventricular cardiomyopathy (ARVC) is still not developed. OBJECTIVE: To study the clinical forms of ARVC. METHODS: Fifty-four patients (38.7 ± 14.1 years, 42.6% men) with ARVC. Follow-up period: 21 (6-60) months. All patients underwent electrocardiography, 24 h-Holter monitoring, echocardiography, and DNA diagnostic. Magnetic resonance imaging was performed in 49 patients. RESULTS: According to the features of clinical course of ARVC, 4 clinical forms were identified. (I) Latent arrhythmic form (n = 27) - frequent premature ventricular contractions and/or nonsustained ventricular tachycardia (VT) in the absence of sustained VT and syncope; characterized by absence of fatal arrhythmic events. (II) Manifested arrhythmic form (n = 11) - sustained VT/ventricular fibrillation; the high incidence of appropriate implantation of cardioverter-defibrillator (ICD) interventions (75%) registered. (III) ARVC with progressive chronic heart failure (CHF, n = 8) as the main manifestation of the disease; incidence of appropriate ICD interventions was 50%, mortality rate due to CHF was 25%. (IV) Combination of ARVC with left ventricular noncompaction (n = 8); characterized by mutations in desmosomal or sarcomere genes, aggressive ventricular arrhythmias, appropriate ICD interventions in 100% patients. Described 4 clinical forms are stable in time, do not transform into each other, and they are genetically determined. CONCLUSIONS: The described clinical forms of ARVC are determined by a combination of genetic and environmental factors and do not transform into each other. The proposed classification could be used in clinical practice to determine the range of diagnostic and therapeutic measures and to assess the prognosis of the disease in a particular patient.

Establishing reference ranges for ambulatory electrocardiography parameters: meta-analysis.

OBJECTIVE: Despite the widespread and increasing use of ambulatory electrocardiography (ECG), there is no consensus on reference ranges for ambulatory electrocardiogram parameters to guide interpretation. We sought to determine population distribution-based reference ranges for parameters measured during ambulatory electrocardiogram in healthy adults, based on existing literature. METHODS: We searched multiple databases from 1950 to 2020. Articles reporting original data from ≥24-hour ambulatory electrocardiogram monitoring in healthy adults were included. Data extraction and synthesis were performed according to Meta-analysis of Observational Studies in Epidemiology guidelines. The prevalence/mean and SD for common parameters (sinus pauses, conduction abnormalities and ectopy) were extracted by age group (18-39, 40-59, 60-79 and 80+ years). RESULTS: We identified 33 studies involving 6466 patients. Sinus pauses of >3 s were rare (pooled prevalence <1%) across all ages. Supraventricular ectopy of >1000/24 hours increased with age, from 0% (95% CI 0% to 0%) in those aged 18-39 years to 6% (95% CI 0% to 17%) in those aged 60-79 years. Episodes of supraventricular tachycardia increased from 3% (95% CI 1% to 6%) in those aged 18-39 years to 28% (95% CI 9% to 52%) in those aged 60-79 years. Ventricular ectopy of >1000/24 hours also increased with age, from 1% (95% CI 0% to 2%) in those aged 18-39 years to 5% (95% CI 1% to 10%) in those aged 60-79 years. Episodes of non-sustained ventricular tachycardia ranged from 0% (95% CI 0% to 1%) in those aged 18-39 years to 2% (95% CI 0% to 5%) in those aged 60-79 years. CONCLUSION: Despite the limitations of existing published data, this meta-analysis provides evidence-based reference ranges for ambulatory electrocardiogram parameters and highlights significant age-dependent differences that should be taken into account during interpretation.

Screening young athletes for diseases at risk of sudden cardiac death: role of stress testing for ventricular arrhythmias.

AIMS: The athletic preparticipation evaluation (PPE) protocol proposed by the European Society of Cardiology includes history, physical examination and resting electrocardiogram (ECG). The aim of this study was to assess the results of adding constant-load ECG stress testing (EST) to the protocol for the evaluation of ventricular arrhythmias (VA) inducibility. METHODS: We evaluated a consecutive cohort of young athletes with history, physical examination, resting ECG and EST. Athletes with VA induced by EST underwent 24-hour 12-lead Holter monitoring and echocardiography. Cardiac magnetic resonance (CMR) was reserved for those with frequent, repetitive or exercise-worsened VA, and for athletes with echocardiographic abnormalities. RESULTS: Of 10,985 athletes (median age 15 years, 66% males), 451 (4.1%) had an abnormal history, physical examination or resting ECG and 31 (0.28%) were diagnosed with a cardiac disease and were at risk of sudden cardiac death. Among the remaining 10,534 athletes, VA at EST occurred in 524 (5.0%) and a previously missed at-risk condition was identified in 23 (0.22%); the most common (N = 10) was an echocardiographically silent non-ischaemic left-ventricular fibrosis evidenced by CMR. The addition of EST increased the diagnostic yield of PPE by 75% (from 0.28% to 0.49%) and decreased the positive predictive value by 20% (from 6.9% to 5.5%). During a 32 ± 21 months follow-up, no cardiac arrests occurred among either eligible athletes or non-eligible athletes with cardiovascular disease. CONCLUSIONS: The addition of exercise testing for the evaluation of VA inducibility to history, physical examination and ECG resulted in an increase of the diagnostic yield of PPE at the expense of an increase in false-positive findings.