Abnormal Left Ventricular Mechanics of Ventricular Ectopic Beats: Insights Into Origin and Coupling Interval in Premature Ventricular Contraction-Induced Cardiomyopathy

Number of Premature Ventricular Complexes Predicts Long-Term Outcomes in Patients with Persistent Atrial Fibrillation

BACKGROUND

Premature ventricular complexes (PVCs) are common electrocardiographic abnormalities and may be a prognosticator in predicting mortality in patients with structurally normal hearts or chronic heart diseases. Whether PVC burden was associated with mortality in patients with chronic atrial fibrillation (AF) remained unknown. We investigated the prognostic value of PVC burden in patients with persistent AF.

METHODS

A retrospective analysis of 24 h Holter recordings of 1767 patients with persistent AF was conducted. Clinical characteristics, 24 h average heart rate (HR), and PVC measures, including 24 h PVC burden and the presence of consecutive PVCs (including any PVC couplet, triplet, or non-sustained ventricular tachycardia) were examined for the prediction of all-cause and cardiovascular mortality using the Cox proportional hazards model.

RESULTS

After a median follow-up time of 30 months, 286 (16%) patients died and 1481 (84%) patients survived. Multivariate analysis revealed that age, heart failure, stroke, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, beta-blocker, digoxin, oral anticoagulant use, and estimated glomerular filtration rate were significant baseline predictors of all-cause mortality and cardiovascular mortality. Twenty-four-hour PVC burden and the presence of consecutive PVCs were significantly associated with all-cause and cardiovascular mortality after adjusting for significant clinical factors. When compared to the first quartile of PVC burden (<0.003%/day), the highest quartile (>0.3%/day) was significantly associated with an increased risk of all-cause mortality (hazard ratio, 2.46; 95% CI, 1.77-3.42) and cardiovascular mortality (hazard ratio: 2.67; 95% CI, 1.76-4.06).

CONCLUSIONS

Twenty-four-hour PVC burden is independently associated with all-cause and cardiovascular mortality in patients with persistent AF.

Premature Ventricular Contraction-Induced Cardiomyopathy: Contemporary Evidence from Risk Stratification, Pathophysiology, and Management

Premature ventricular complexes (PVCs) are commonly encountered problems in clinical settings. The range of symptoms can be from asymptomatic to palpitations, fatigue, or heart failure symptoms. A higher burden of PVCs is a risk factor for development of PVC-induced cardiomyopathy (PIC). Rhythm evaluation by 12-lead ECG and an ambulatory monitoring device are essential. Currently, several imaging modalities, such as echocardiography and cardiac magnetic resonance imaging, are utilized to evaluate the underlying structure that may be related to PIC. Beta blockers and antiarrhythmic drugs are typically part of the initial management strategy. If these fail, catheter ablation of PVCs is typically the next step. The purpose of this article is to summarize the current evidence/knowledge about PIC.

Predictors and possible mechanisms of premature ventricular contraction induced cardiomyopathy

Premature ventricular complexes (PVCs) are encountered frequently in clinical practice. While PVCs may have various causes, a small number of individuals with PVCs develop cardiomyopathy in the absence of other potential etiologies. When correctly identified, patients with PVC-incuded cardiomyopathy can have dramatic improvement of their cardiomyopathy with treatment of their PVCs. In this focused review, we discuss potential predictors of PVC-induced cardiomyopathy, including PVC frequency, PVC characteristics, and modifiable patient risk factors. We also review some proposed mechanisms of PVC-induced cardiomyopathy and conclude with future directions for research and clinical practice.

Assessment of subtle cardiac dysfunction induced by premature ventricular contraction using two-dimensional strain echocardiography and the effects of successful ablation

INTRODUCTION AND OBJECTIVES

We aimed to assess the effects of successful ablation on impaired left ventricular global longitudinal strain (LV-GLS) in patients with frequent premature ventricular contractions (PVCs). We also evaluated the potential risk factors of impaired LV-GLS.

METHODS

Thirty-six consecutive patients without any structural heart disease, who were treated with radiofrequency (RF) ablation due to frequent PVCs, were included in the study. All patients were evaluated with standard transthoracic and two-dimensional speckle tracking echocardiography.

RESULTS

Mean LV-GLS before ablation was 17.3±3.7 and 20.5±2.6 after ablation; the difference was statistically significant (p<0.01). Patients were categorized into two groups: those with LV-GLS value >-16% and those ≤16%. Low PVC E flow/post-PVC E flow and PVC SV/post-PVC SV ratios were associated with impaired LV-GLS.

CONCLUSION

In symptomatic patients with frequent PVCs and normal left ventricular ejection fraction, we observed significant improvement in LV-GLS value following successful RF ablation. Patients with impaired LV-GLS more often display non-ejecting PVCs and post-extrasystolic potentiation (PEP) compared to patients with normal LV-GLS.

Mechanisms and Risk Factors for Premature Ventricular Contraction Induced Cardiomyopathy

Frequent premature ventricular contractions (PVCs) can cause a reversible form of cardiomyopathy in patients without structural heart disease. Because of the challenging nature of PVC-induced cardiomyopathy (PVICM), the mechanisms and risk factors for PVICM are still unclear. Based on the evidence from retrospective and observational studies, the risk factors for the development of PVICM, in addition to PVC exposure, include QRS duration, coupling interval and male sex. Based on animal models, abnormal calcium handling and cardiac remodeling may be the crucial mechanism underlying the development of cardiomyopathy. We have summarized the current knowledge on PVICM in this review. Understanding these mechanisms and risk factors is important for the diagnosis and management of this condition, which can lead to heart failure if left untreated.

Mechanisms of adaptive hypertrophic cardiac remodeling in a large animal model of premature ventricular contraction-induced cardiomyopathy

Frequent premature ventricular contractions (PVCs) promoted eccentric cardiac hypertrophy and reduced ejection fraction (EF) in a large animal model of PVC-induced cardiomyopathy (PVC-CM), but the molecular mechanisms and markers of this hypertrophic remodeling remain unexplored. Healthy mongrel canines were implanted with pacemakers to deliver bigeminal PVCs (50% burden with 200-220 ms coupling interval). After 12 weeks, left ventricular (LV) free wall samples were studied from PVC-CM and Sham groups. In addition to reduced LV ejection fraction (LVEF), the PVC-CM group showed larger cardiac myocytes without evident ultrastructural alterations compared to the Sham group. Biochemical markers of pathological hypertrophy, such as store-operated Ca2+ entry, calcineurin/NFAT pathway, β-myosin heavy chain, and skeletal type α-actin were unaltered in the PVC-CM group. In contrast, pro-hypertrophic and antiapoptotic pathways including ERK1/2 and AKT/mTOR were activated and/or overexpressed in the PVC-CM group, which appeared counterbalanced by an overexpression of protein phosphatase 1 and a borderline elevation of the anti-hypertrophic factor atrial natriuretic peptide. Moreover, the potent angiogenic and pro-hypertrophic factor VEGF-A and its receptor VEGFR2 were significantly elevated in the PVC-CM group. In conclusion, a molecular program is in place to keep this structural remodeling associated with frequent PVCs as an adaptive pathological hypertrophy.

Left ventricular remodeling in premature ventricular contraction-induced cardiomyopathy: Effect of coupling intervals and atrioventricular dissociation

Background

Left ventricular dyssynchrony (LVD) and postextrasystolic potentiation (PESP) associated with premature ventricular contractions (PVCs) may play a role in the development of premature ventricular contraction-induced cardiomyopathy (PVC-CM). Long-coupled (LC) PVCs have a greater LVD than short-coupled (SC) PVCs, whereas SC-PVCs have a stronger PESP than LC-PVCs.

Objective

The purpose of this study was to compare SC-PVCs and LC-PVCs to evaluate the roles of LVD, PESP, and atrioventricular dissociation (AVD) in the development of PVC-CM.

Methods

Thirty-six canines underwent pacemaker implantation to induce bigeminal right ventricular apical epicardial PVCs (50% burden) for 12 weeks. Telemetry assessed PVC burden and AVD. Animals were grouped as SC-PVC (coupling interval [CI] 200-220ms), LC-PVC (CI 330 ms), or sham (control). Echocardiographic changes, AVD, and hemodynamics were monitored for 12 weeks.

Results

PVC burden was similar between SC-PVC and LC-PVC groups but was statistically higher in the SC-PVC group (50% vs 47.5%; P = .028). After 12 weeks, left ventricular ejection fraction (LVEF) significantly decreased in both SC-PVC and LC-PVC groups (47.1% ± 1.4% and 45.5% ± 2%, respectively) compared to sham group (61% ± 1.6%; P <.001). Overall AVD was similar between SC-PVC and LC-PVC groups, and there was no significant correlation between AVD and reduction in LVEF at 12 weeks (r = 0.09, P = .5; and r = 0.06, P = .8, respectively). Additionally, both SC-PVC and LC-PVC groups experienced substantial declines in max and min dP/dt after 12 weeks compared to baseline.

Conclusion

Neither PVC CI nor AVD played an independent role in the development or severity of PVC-CM. LVD and PESP make equal relative contributions to the development of PVC-CM.

Abnormal Conduction-Induced Cardiomyopathy: JACC Review Topic of the Week

Nonischemic cardiomyopathies are a frequent occurrence. The understanding of the mechanism(s) and triggers of these cardiomyopathies have led to improvement and even recovery of left ventricular function. Although chronic right ventricular pacing-induced cardiomyopathy has been recognized for many years, left bundle branch block and pre-excitation have been recently identified as potential reversible causes of cardiomyopathy. These cardiomyopathies share a similar abnormal ventricular propagation that can be recognized by a wide QRS duration with left bundle branch block pattern; thus, we coined the term abnormal conduction-induced cardiomyopathies. Such abnormal propagation results in an abnormal contractility that can only be recognized by cardiac imaging as ventricular dyssynchrony. Appropriate diagnosis and treatment will not only lead to improved left ventricular ejection fraction and functional class, but may also reduce morbidity and mortality. This review presents an update of the mechanisms, prevalence, incidence, and risk factors, as well as their diagnosis and management, while highlighting current gaps of knowledge.

Relationship between premature ventricular complexes and stroke mortality in the general population

OBJECTIVES

Predictors for increased stroke mortality identify those who may need closer monitoring and better hospital care. While the link between premature ventricular complexes (PVCs) and incident ischemic stroke has been reported, studies on the association with fatal stroke are non-existent.

MATERIALS AND METHODS

We examined the association of PVCs with stroke mortality in 8047 participants (56.5 ± 0.39 years, 53% women, 80.9% Non-Hispanic Whites) without prior history of stroke from the Third National Health and Nutrition Examination Survey. National Death Index was used to identify the date and cause of death. PVCs were detected from 12‑lead standard electrocardiograms. Cox proportional hazard analysis was used to examine the association between any PVC with stroke mortality.

RESULTS

Approximately 2.1% (n = 134) participants had PVCs at baseline. Over a median follow-up of 22 years, 337 fatal strokes occurred. More strokes occurred in participants with baseline PVCs compared to those without (unadjusted cumulative incidence of stroke 9.5% vs. 2.5% respectively, p-value 0.001). In a multivariable-adjusted model, the presence of PVC was associated with an increased risk of stroke mortality (HR (95%CI): 2.50 (1.15-5.43). This association was stronger in participants with coronary heart disease (CHD) than those without it (HR (95%CI): 5.98 (2.2-16.2) vs. 1.97 (0.75-5.1) respectively; interaction-p = 0.008).

CONCLUSIONS

PVCs are associated with an increased risk of stroke mortality, especially among individuals with CHD. Whether improved hospital care or modifying PVCs could change outcomes should be examined in prospective studies.

Cardiomyopathy induced by premature ventricular contractions with ventricular escape beats in the compensatory pause: A case report and brief review of the literature

RATIONALE

We reported a case with cardiomyopathy induced by frequent premature ventricular contractions (PVCs) and followed ventricular escape beats (VEBs). PVCs with VEBs in the compensatory pause which induced cardiomyopathy is rarely reported. Also, the case exhibited many characteristics of PVCs which were more likely to induce cardiomyopathy, like the location of origin, the longer coupling interval, and the QRS wave companied with the P wave.

PATIENT CONCERNS

A 53-year-old man with left ventricular (LV) dysfunction presented with palpation, chest distress, and dyspnea for 3 years. Holter revealed a high burden of ventricular rhythm of PVCs and another wide QRS patterns (96,562 total beats with 87,330 wide QRS beats in 24 hours). The LV ejection fraction decreased to 34% and the left ventricle, right and left atria all dilated.

DIAGNOSIS

He was diagnosed with PVC-induced cardiomyopathy.

INTERVENTIONS

The patient experienced intracardiac electrophysiological examination which revealed frequent PVCs followed by VEBs in the compensatory pause. Activation mapping of the PVCS and ablation were performed.

OUTCOMES

PVCs and VEBs disappeared after ablation. The LV ejection fraction increased to 46% at 2 days after the procedure. The diameters of the right and left atria were also significantly reduced.

LESSONS

VEBs may occur during the compensatory pause of PVCs. PVCs with VEBs can lead to a high burden of ventricular rhythm and LV dysfunction. Ablation of the PVCs can also eliminate VEBs and improve the LV function.

Premature Ventricular Contractions Are Presaged by a Mechanically Abnormal Sinus Beat

BACKGROUND

Frequent premature ventricular contractions (PVCs) can lead to cardiomyopathy; it is unclear if there are abnormal myocardial mechanics operative in the PVC and non-PVC beats.

OBJECTIVES

The aim of this study was to investigate regional and global myocardial mechanics, including dyssynchrony, in patients with frequent PVCs.

METHODS

Fifty-six consecutive patients referred for PVC ablation were prospectively studied. During sinus rhythm (SR) and PVC beats, left ventricular (LV) global longitudinal strain (GLS), LV dyssynchrony (measured as the SD of time to peak GLS), and dyssynergy (measured as maximum regional strain minus minimum regional strain at aortic valve closure) were quantified using 2-dimensional strain echocardiography. GLS, dyssynchrony, and dyssynergy were compared in remote SR, pre-PVC SR, PVC, and post-PVC SR beats.

RESULTS

In SR beats remote from the PVC, GLS was -17.3% ± 4%, dyssynchrony was 49 ± 14 ms, and dyssynergy was 22% ± 9%. Myocardial mechanics were significantly abnormal during PVCs compared with remote SR beats (GLS -7.7% ± 3% [P < 0.001], dyssynchrony 115 ± 37 milliseconds [P < 0.001], and dyssynergy 26% ± 10% [P < 0.001]). There were significant mechanical abnormalities in the SR beat preceding the PVC, which demonstrated significantly lower LV strain (pre-PVC SR, -13% ± 4%; P < 0.001) and more dyssynchrony (pre-PVC SR, 63 ± 19 milliseconds; P < 0.001) compared with remote SR beats. Dyssynergy was significantly higher for pre-PVC SR and PVC beats compared with remote SR (pre-PVC SR, 25% ± 8% [P < 0.001]; PVC, 26% ± 10% [P < 0.001]).

CONCLUSIONS

In patients with frequent PVCs, the SR beat preceding the PVC demonstrates significant mechanical abnormalities. This finding suggests that perturbations in cellular physiological processes such as excitation-contraction coupling may underlie the generation of frequent PVCs.

The Burden of Ventricular Premature Complex Is Associated With Cardiovascular Mortality

Background

Ventricular premature complex (VPC) is one of the most common ventricular arrhythmias. The presence of VPC is associated with an increased risk of heart failure (HF).

Method

We designed a single-center, retrospective, and large population-based cohort to clarify the role of VPC burden in long-term prognosis in Taiwan. We analyzed the database from the National Cheng Kung University Hospital-Electronic Medical Record (NCKUH-EMR) and NCKUH-Holter (NCKUH-Holter). A total of 19,527 patients who underwent 24-h Holter ECG monitoring due to palpitation, syncope, and clinical suspicion of arrhythmias were enrolled in this study.

Results

The clinical outcome of interests involved 5.65% noncardiovascular death and 1.53% cardiovascular-specific deaths between 2011 and 2018. Multivariate Cox regression analysis, Fine and Gray's competing risk model, and propensity score matching demonstrated that both moderate (1,000–10,000/day) and high (>10,000/day) VPC burdens contributed to cardiovascular death in comparison with a low VPC burden (<1,000/day).

Conclusion

A higher VPC burden via Holter ECG is an independent risk factor of cardiovascular mortality.

Post-extrasystolic potentiation as a predictor of premature ventricular contraction-cardiomyopathy in an animal model

AIMS

High premature ventricular contractions (PVCs) burden does not always predict the development of PVC-cardiomyopathy (CM). We sought to evaluate post-extrasystolic potentiation (PESP) of left ventricular ejection fraction (LVEF) to predict the severity of PVC-CM in an animal model.

METHODS AND RESULTS

Right ventricular apical bigeminal PVCs were introduced for 12 weeks in 11 canines to induce PVC-CM. Echocardiograms were performed to obtain LVEF without ectopy (Echo-1) and during PVCs (200 and 350 ms coupling intervals, Echo-2, and Echo-3, respectively), and premature atrial contractions (PACs) (Echo-4) at baseline and after 12 weeks of bigeminal PVCs. PESP was calculated as delta-LVEF between the sinus beat post-ectopy LVEF (Echo-2, -3, and -4, respectively) and LVEF without PVC (Echo-1) at baseline and 12 weeks of high PVC burden. A hyperdynamic LV function (LVEF > 70%) was noted in all animals only with early-coupled PVCs (LVEF at 200 ms: 74.4 ± 6%) at baseline. While PVC PESP at 200 ms had a strong significant correlation with the final 12-week LVEF (R = 0.8, P = 0.003), PVC PESP at 350 ms and PAC PESP had a positive but non-significant correlation (R = 0.53, P = 0.09, and R = 0.29, P = 0.34, respectively). Premature ventricular contraction PESP at 350 ms was significantly higher after PVC-CM had developed (delta-LVEF baseline 2.7 ± 2.9% vs. 12 weeks 18.6 ± 12.3% P < 0.001).

CONCLUSION

Bigeminal early-coupled PVCs cause hyperdynamic left ventricular function in the structurally normal canine heart due to PESP. The degree of PESP at baseline is inversely proportional to the PVC-CM severity at 12 weeks and maybe a predictor of PVC-CM as it may assess the myocardial adaptation reserve to PVCs.

Premature ventricular contraction increases the risk of heart failure and ventricular tachyarrhythmia

Premature ventricular contraction (PVC), a common arrhythmia affecting 1–2% of the general population, has been considered to have a benign clinical course. However, people with PVC often develop heart failure and ventricular arrhythmias such as ventricular tachycardia. We aimed to clarify the risk of heart failure and lethal ventricular arrhythmias in people with PVC. The Korean National Health Insurance Service database was used for this study. People who underwent nationwide health check-ups in 2009 were enrolled in this study and clinical follow-up data until December 2018 were analyzed. Newly diagnosed PVC in 2009 (≥ 1 inpatient or outpatient claim) were identified and cumulative incidence of heart failure (≥ 1 inpatient claim) and ventricular arrhythmias (≥ 1 inpatient or outpatient claim) were compared. A total of 4515 people were first diagnosed with PVC in 2009 among 9,743,582 people without prior history of PVC, heart failure, or ventricular arrhythmias. People with newly diagnosed PVC in 2009 had a significantly higher incidence of heart failure compared to those without PVC [adjusted hazard ratio (HR)  1.371; 95% confidence interval (CI)  1.177–1.598; p  < 0.001]. Significant interaction was observed between age and PVC with young age people at greater risk of developing heart failure for having PVC. The incidence of ventricular arrhythmia was also significantly increased in people with PVC (HR  5.588; 95% CI  4.553–6.859; p  < 0.001). Age and chronic kidney disease had significant interactions with PVC. In conclusion, the incidence of heart failure and ventricular arrhythmia was significantly increased in people with PVC. Outpatient follow-up of people with PVC can be helpful to detect early signs of heart failure or advanced forms of ventricular arrhythmia.

Clinical and translational insights on premature ventricular contractions and PVC-induced cardiomyopathy

The medical community's understanding of the consequences of premature ventricular contractions (PVCs) and PVC-induced cardiomyopathy has been derived mostly from observational and large population-based studies. Due to the difficulty of predicting the development of PVC-cardiomyopathy, the acute and chronic cardiac effects of PVCs and the mechanism of PVC-cardiomyopathy have been derived from pre-clinical studies with large animal models. Recently, these studies have described myocardial substrates that could potentially increase morbidity and mortality in patients with frequent PVCs and PVC-cardiomyopathy. In this paper, we provide an up-to-date comprehensive review of these pre-clinical and clinical studies.

Cardiac afferent signaling partially underlies premature ventricular contraction-induced cardiomyopathy

BACKGROUND

The mechanisms underlying premature ventricular contraction (PVC)-induced cardiomyopathy (PIC) remain unknown. Transient receptor potential vanilloid-1 (TRPV1) afferent fibers are implicated in the reflex processing of cardiac stress.

OBJECTIVE

The purpose of this study was to determine whether cardiac TRPV1 afferent signaling promote PIC.

METHODS

A PIC swine model (50% PVC burden) was created via an implanted pacemaker. We selectively depleted cardiac TRPV1 afferent fibers using percutaneous epicardial application of resiniferatoxin (RTX). Animals were randomized to PVC only (n = 11), PVC+RTX (n = 11), or control (n = 6). We examined early-stage (4 weeks after implantation; n = 5) and late-stage PIC (8 weeks after implantation; n = 6). At terminal experimentation, animals underwent echocardiography, serum sampling, and physiological and autonomic reflex testing.

RESULTS

Depletion of cardiac TRPV1 afferents by RTX treatment was confirmed by absent sensory fibers and absent functional responses to TRPV1 activators. Left ventricular ejection fraction was worse in late-stage than early-stage PIC (P <.01). At 4 weeks (early stage), left ventricular ejection fraction was higher in PVC+RTX vs PVC animals (51.7% ± 1.6% vs 45.0% ± 2.1%; P = .030), whereas no significant difference between PVC and PVC+RTX was observed at 8 weeks (late stage). Histologic studies demonstrated reduced fibrosis in PVC+RTX vs PVC alone at 4 weeks (2.27% ± 0.14% vs 3.01% ± 0.21%; P = .020), suggesting that RTX mitigated profibrotic pathways induced by persistent PVCs.

CONCLUSION

TRPV1 afferent depletion alleviates left ventricular dysfunction in early- but not late-stage PIC. This temporal effect suggests that multiple pathways promote PIC, of which TRPV1 afferents are a part.

Outcomes of Premature Ventricular Contraction-Cardiomyopathy in the Veteran Population: A Secondary Analysis of the CHF-STAT Study

OBJECTIVES

This study sought to assess the rate and outcomes of premature ventricular contractions (PVC)-cardiomyopathy from the CHF-STAT (Survival Trial of Antiarrhythmic Therapy in Congestive Heart Failure) trial, a population with cardiomyopathy (left ventricular [LV] ejection fraction of <40%) and frequent PVCs (>10 PVCs per hour).

BACKGROUND

PVCs are associated with heart failure and PVC-cardiomyopathy. The prevalence of PVC-cardiomyopathy and outcome benefits of PVC suppression are not clear.

METHODS

A secondary analysis of the CHF-STAT study was performed to compare the rate of successful PVC suppression (≥80% PVC reduction), LV recovery (defined as improvement in LV ejection fraction of ≥10% points), and PVC-cardiomyopathy between amiodarone and placebo groups at 6 months. PVC-cardiomyopathy was defined if both PVC reduction of ≥80% and LV ejection fraction improvement of ≥10% were present at 6 months. Cardiac events (death or resuscitated cardiac arrest) were compared between PVC-cardiomyopathy versus non-PVC-cardiomyopathy during a 5-year follow-up.

RESULTS

The rates of successful PVC suppression and LV recovery were significantly higher in the amiodarone (72% and 39%, respectively) when compared to the placebo group (12% and 16%, respectively; p < 0.001), regardless of cardiomyopathy etiology. PVC-cardiomyopathy was present in 29% and 1.8% of patients in the amiodarone and placebo groups, respectively (p < 0.001). Similar PVC-cardiomyopathy rates were found in ischemic (24% amiodarone vs. 2% placebo; p < 0.001) and nonischemic populations (41% amiodarone vs. 1.5% placebo; p < 0.001). Death and resuscitated cardiac arrest were significantly lower in patients with PVC-cardiomyopathy and those treated with amiodarone.

CONCLUSIONS

The overall prevalence of PVC-cardiomyopathy in the CHF-STAT study was significant regardless of ischemic substrate (29%, overall population; 41%, nonischemic cardiomyopathy). Treatment of PVC-cardiomyopathy with amiodarone is likely to improve survival in this high-risk population.

Eccentric hypertrophy in an animal model of mid- and long-term premature ventricular contraction-induced cardiomyopathy

BACKGROUND

Tachycardia and heart rate irregularity are proposed triggers of premature ventricular contraction-induced cardiomyopathy (PVC-cardiomyopathy). Bigeminal premature atrial and ventricular contractions (PACs and PVCs) increase heart rate and result in rhythm irregularities but differ in their effects on ventricular synchrony. Comparing chronic bigeminal PACs with PVCs would provide insights into mechanisms of PVC-cardiomyopathy.

OBJECTIVE

To compare the impact of chronic PACs and PVCs on ventricular hemodynamics, structure, and function.

METHODS

Pacemakers were implanted in 27 canines to reproduce atrial (PACs, n = 7) or ventricular bigeminy (PVCs, n = 11) for 12 weeks, and compared to sham-operated animals (n = 9). Four additional animals were exposed to long-term bigeminal PVCs (48 weeks). Hemodynamic changes were assessed using a pressure-transducing catheter at baseline and 12 weeks. Cardiac remodeling was monitored by transthoracic echocardiography throughout the 12- and 48-week protocols in the respective groups.

RESULTS

PVC group demonstrated a significant decrease in left ventricular (LV) ejection fraction and contractility (max dP/dt), impaired LV lusitropy (min dP/dt), and increase in LV dimensions and LV mass at 12 weeks without further deterioration beyond 16 weeks. Despite increased LV mass, relative wall thickness decreased, consistent with eccentric hypertrophy. No significant cardiac remodeling was noted in either sham or PAC groups at 12 weeks.

CONCLUSION

In contrast to bigeminal PACs, PVCs result in a cardiomyopathy characterized by reduced LV ejection fraction, LV dilation, and eccentric hypertrophy that plateaus between 12 and 16 weeks. The lack of remodeling in chronic PACs suggests that tachycardia and heart rate irregularity do not play a significant role on the development of PVC-cardiomyopathy.

Association of premature ventricular complexes and risk of ischemic stroke: A systematic review and meta-analysis

Recent studies have suggested that patients with premature ventricular complexes (PVCs) may have a higher risk of ischemic stroke. However, the data are limited and inconclusive. We conducted a systematic review and meta‐analysis to investigate the association between PVCs and the risk of ischemic stroke. A comprehensive literature review was conducted by searching for published articles indexed in MEDLINE and EMBASE databases from inception through September 25, 2020, to identify studies that compared the risk of ischemic stroke between patients with PVCs and individuals without PVCs. Pooled risk ratio (RR) and 95% confidence interval (CI) were calculated using a random‐effect, generic inverse variance method of Dersimonian and Laird. A total of four observational studies (2 prospective and 2 retrospective cohort studies) with 42 677 participants met the eligibility criteria and were included in the meta‐analysis. We found that patients with PVCs have a significantly higher risk of ischemic stroke than individuals without PVCs with the pooled RR of 1.31 (95% CI, 1.07–1.60, I² = 43%). From our systematic review and meta‐analysis, we found that PVCs are associated with a higher risk of ischemic stroke. Whether this association is causal and how it should be addressed in clinical practice require further investigations.

Arrhythmia-Induced Cardiomyopathy: JACC State-of-the-Art Review

Arrhythmias coexist in patients with heart failure (HF) and left ventricular (LV) dysfunction. Tachycardias, atrial fibrillation, and premature ventricular contractions are known to trigger a reversible dilated cardiomyopathy referred as arrhythmia-induced cardiomyopathy (AiCM). It remains unclear why some patients are more prone to develop AiCM despite similar arrhythmia burdens. The challenge is to determine whether arrhythmias are fully, partially, or at all responsible for an observed LV dysfunction. AiCM should be suspected in patients with mean heart rate >100 beats/min, atrial fibrillation, and/or premature ventricular contractions burden ≥10%. Reversal of cardiomyopathy by elimination of the arrhythmia confirms AiCM. Therapeutic choice depends on the culprit arrhythmia, patient comorbidities, and preferences. Following recovery of LV function, patients require continued follow-up if an abnormal myocardial substrate is present. Appropriate diagnosis and treatment of AiCM is likely to improve quality of life and clinical outcomes and to reduce hospital admission and health care spending.

Premature Ventricular Contractions and Cardiomyopathy

Premature ventricular contractions (PVCs) are a common arrhythmia that may cause symptoms of variable severity. PVCs have recently garnered interest in their ability to induce adverse structural heart remodeling in an entity known as PVC-induced cardiomyopathy. This entity is a retrospective diagnosis that likely remains under-recognized and may occur concurrently with other forms of cardiomyopathy. The appropriate identification and management of PVCs in the setting of associated cardiomyopathy may have a significant impact on cardiac function and the clinical course, including recovery of left ventricular ejection fraction and improvement in patient functional status. Treatment consists of catheter ablation and/or antiarrhythmic drug therapy, but continued monitoring and follow-up are required, as the recurrence of high PVC burden may lead to redevelopment of cardiomyopathy.

Association between cytokines and two circulating micro-RNAs and development of premature ventricular contractions-induced cardiomyopathy

Objective(s):

Recent progress in understanding the pathogenesis of premature ventricular contraction (PVC)-induced cardiomyopathy (PIC) has suggested a key role for inflammation. The aim of this study was to evaluate the expression of messenger RNAs (mRNAs) and the protein production of interleukin-6 (IL-6), IL-10, tumor necrosis factor alpha (TNF-α) and interferon-γ (IFN-γ) and two circulating micro-RNAs related to inflammation and cardiovascular disease; miR-155 and miR-146.

Materials and Methods:

The study population was comprised 25 patients with PIC and 25 patients with normal left ventricular ejection fraction despite frequent PVCs. TNF-α, IL-6, IL10, and IFN-γ levels were evaluated in peripheral blood mononuclear cells (PBMCs) by flow cytometry and their mRNAs were assessed by real time PCR. We analyzed circulating levels of these cytokines by enzyme linked immunosorbent assay (ELISA). Two circulating micro-RNAs, miR-155 and miR-146a, were also investigated.

Results:

The flow cytometry findings showed that the median fluorescence intensity (MFI) of antibodies reacted with the IL-6 and TNF-α were higher in PIC group than the control group (P-value<0.001). In ELISA, the levels of IL-6 (P-value<0.001) and TNF-α (P-value <0.001) and in RT-PCR the relative expression levels of IL-6 (P-value<0.001) and TNF-α (P-value<0.001) were significantly higher in the PIC group. The relative expression levels of miR-155 and miR-146a were not significantly different between 2 groups (P-value>0.05).

Conclusion:

In our patients with PIC, there was an elevation in the expression levels of IL-6 and TNF-α in PBMCs. This finding may provide further insights into the inflammatory pathways involved in PIC.

Role of Imaging in the Management of Ventricular Arrhythmias

The management of ventricular arrhythmias (VA) has evolved over time to an advanced discipline, incorporating many technologies in the diagnosis and treatment of the myriad types of VA. The first application of imaging is in the assessment for structural heart disease, as this has the greatest impact on prognosis. Advanced imaging has its greatest utility in the planning and execution of ablation for VA. The following review outlines the application of different imaging modalities, such as ultrasonography, magnetic resonance imaging, computed tomography, and positron emission tomography, for the treatment of VA.

Characteristics and Prevalence of Premature Ventricular Complex: A Telemedicine Study

Background

Premature ventricular complex (PVC) is the etiology of cardiomyopathy known as PVC-induced cardiomyopathy. Various studies have shown certain characteristics that predispose to cardiomyopathy. Present study was the first community-based study conducted to determine the characteristics and prevalence of PVC in certain population, especially Makassar City.

Methods

This study used a cross-sectional study method conducted from June 2017 to May 2018 using data from Telemedicine Electrocardiogram (ECG) at Hasanuddin University Hospital. The characteristics of PVC were QRS PVC duration, coupling interval (CI), PVC morphology in lead V1.

Results

We calculated 8,847 ECGs, and found 98 ECGs with PVC (1.1%). Incidence of PVC was higher in women than men (52%). Characteristics of PVC with QRS duration include < 140 ms (45.9%); 140 - 159 ms (31.6%); and > 160 ms (22.4%), respectively; and PVC with CI < 300 ms (2%), CI 300 - 599 ms (88%), and CI > 600 ms (10%). Left bundle branch block (LBBB) and right bundle branch block (RBBB) morphology were found in (76.5%) and (19.4%) subjects in turn. Statistically, QRS PVC duration and PVC morphology showed significant differences based on age group (sequentially, P = 0.012 and P = 0.014). While gender only showed a significant difference in QRS PVC duration (P = 0.030).

Conclusions

The prevalence of PVC in the population of Makassar City is similar to the prevalence in other general populations. There are differences in the distribution and prevalence of PVC based on their characteristics according to age group and gender.

Premature ventricular contractions activate vagal afferents and alter autonomic tone: implications for premature ventricular contraction-induced cardiomyopathy

Mechanisms behind development of premature ventricular contraction (PVC)-induced cardiomyopathy remain unclear. PVCs may adversely modulate the autonomic nervous system to promote development of heart failure. Afferent neurons in the inferior vagal (nodose) ganglia transduce cardiac activity and modulate parasympathetic output. Effects of PVCs on cardiac parasympathetic efferent and vagal afferent neurotransmission are unknown. The purpose of this study was to evaluate effects of PVCs on vagal afferent neurotransmission and compare these effects with a known powerful autonomic modulator, myocardial ischemia. In 16 pigs, effects of variably coupled PVCs on heart rate variability (HRV) and vagal afferent neurotransmission were evaluated. Direct nodose neuronal recordings were obtained in vivo, and cardiac-related afferent neurons were identified based on their response to cardiovascular interventions, including ventricular chemical and mechanical stimuli, left anterior descending (LAD) coronary artery occlusion, and variably coupled PVCs. On HRV analysis before versus after PVCs, parasympathetic tone decreased (normalized high frequency: 83.6 ± 2.8 to 72.5 ± 5.3; P < 0.05). PVCs had a powerful impact on activity of cardiac-related afferent neurons, altering activity of 51% of neurons versus 31% for LAD occlusion (P < 0.05 vs. LAD occlusion and all other cardiac interventions). Both chemosensitive and mechanosensitive neurons were activated by PVCs, and their activity remained elevated even after cessation of PVCs. Cardiac afferent neural responses to PVCs were greater than any other intervention, including ischemia of similar duration. These data suggest that even brief periods of PVCs powerfully modulate vagal afferent neurotransmission, reflexly decreasing parasympathetic efferent tone.NEW & NOTEWORTHY Premature ventricular contractions (PVCs) are common in many patients and, at an increased burden, are known to cause heart failure. This study determined that PVCs powerfully modulate cardiac vagal afferent neurotransmission (exerting even greater effects than ventricular ischemia) and reduce parasympathetic efferent outflow to the heart. PVCs activated both mechano- and chemosensory neurons in the nodose ganglia. These peripheral neurons demonstrated adaptation in response to PVCs. This study provides additional data on the potential role of the autonomic nervous system in PVC-induced cardiomyopathy.

Distal-to-proximal delay for ablation of premature ventricular contractions

INTRODUCTION

Ablation of premature ventricular contractions (PVCs) has emerged as a safe and effective treatment in patients experiencing a high PVCs burden. Mapping of PVCs origin may sometimes be challenging. We sought to evaluate the accuracy of a new electrophysiological criterion, the distal-to-proximal (DP) delay, at localizing the optimal site for ablation of ventricular ectopic foci.

METHODS AND RESULTS

Consecutive patients with ablation attempts of symptomatic PVCs were included. Prematurity and DP delay-that is, the time duration between the onset of ablation catheter distal bipolar electrogram and the onset of proximal bipolar electrogram-were measured at successful and unsuccessful ablation sites by three blinded experienced electrophysiologists. Mean DP delay at effective ablation sites (N = 30) was significantly higher than at ineffective sites ( N = 55) (23 ± 9 vs 11 ± 8 milliseconds; P < 0.0001). DP delay had good-to-excellent interrater reliability. A DP delay greater than or equal to 15 milliseconds had the highest accuracy at predicting a successful ablation site (sensitivity 0.97, the area under receiver operating characteristic curve 0.87; P < 0.0001).

CONCLUSION

DP delay is an additional, simple, and effective electrophysiological parameter to accurately localize PVCs foci.

Neonatal cardiomyocyte hypertrophy induced by endothelin-1 is blocked by estradiol acting on GPER

Estradiol (E₂) prevents cardiac hypertrophy, and these protective actions are mediated by estrogen receptor (ER)α and ERβ. The G protein-coupled estrogen receptor (GPER) mediates many estrogenic effects, and its activation in the heart has been observed in ischemia and reperfusion injury or hypertension models; however, the underlying mechanisms need to be fully elucidated. Herein, we investigated whether the protective effect of E₂ against cardiomyocyte hypertrophy induced by endothelin-1 (ET-1) is mediated by GPER and the signaling pathways involved. Isolated neonatal female rat cardiomyocytes were treated with ET-1 (100 nmol/l) for 48 h in the presence or absence of E₂ (10 nmol/l) or GPER agonist G-1 (10 nmol/l) and GPER antagonist G-15 (10 nmol/l). ET-1 increased the surface area of cardiomyocytes, and this was associated with increased expression of atrial and brain natriuretic peptides. Additionally, ET-1 increased the phosphorylation of extracellular signal-related protein kinases-1/2 (ERK1/2). Notably, E₂ or G-1 abolished the hypertrophic actions of ET-1, and that was reversed by G-15. Likewise, E₂ reversed the ET-1-mediated increase of ERK1/2 phosphorylation as well as the decrease of phosphorylated Akt and its upstream activator 3-phosphoinositide-dependent protein kinase-1 (PDK1). These effects were inhibited by G-15, indicating that they are GPER dependent. Confirming the participation of GPER, siRNA silencing of GPER inhibited the antihypertrophic effect of E₂. In conclusion, E₂ plays a key role in antagonizing ET-1-induced hypertrophy in cultured neonatal cardiomyocytes through GPER signaling by a mechanism involving activation of the PDK1 pathway, which would prevent the increase of ERK1/2 activity and consequently the development of hypertrophy.

Assessment of subtle cardiac dysfunction in patients with frequent premature ventricular complexes by real-time three-dimensional speckle tracking echocardiography

BACKGROUND

To evaluate subtle and early premature ventricular complex (PVC)-induced ventricular impairment in patients with frequent PVCs and without structural heart disease by real-time 3-dimensional (3D) speckle tracking echocardiography (RT3D-STE).

HYPOTHESIS

Patients with frequent premature ventricular complexes with normal left ventricular ejection fraction have subtle left ventricular dysfunction.

METHODS

Forty patients (22 male) with a single source of frequent PVCs and 40 healthy controls (24 male) underwent assessment by conventional 2-dimensional (2D) echocardiography and RT3D-STE. Left ventricular ejection fraction (LVEF), and global longitudinal, circumferential, radial, and area strain (GLS, GCS, GRS, and GAS, respectively) and individual segment strain were calculated using off-line analysis software and compared between the 2 groups.

RESULTS

There were no significant differences in baseline clinical or 2D echocardiographic variables including LVEF between groups. However, all RT3D-STE assessed variables, including GLS, GCS, GRS, GAS, and individual segment strain, were significantly lower (P < 0.05) in the PVC group than the control group, and showed strong correlations, most prominently GCS (r = -0.84, P = 0.020), with LV function as assessed by LVEF. 3D-STE measurements showed good intraobserver, interobserver, and test-retest agreement.

CONCLUSIONS

In patients with frequent PVCs and normal LVEF, 3D -STE revealed lower global and regional strain values than in healthy controls. RT3D-STE is a novel, feasible and reproducible method to assess cardiac function and appears suitable to detect subtle left ventricular dysfunction.

Premature Ventricular Contraction Coupling Interval Variability Destabilizes Cardiac Neuronal and Electrophysiological Control: Insights From Simultaneous Cardioneural Mapping

BACKGROUND

Variability in premature ventricular contraction (PVC) coupling interval (CI) increases the risk of cardiomyopathy and sudden death. The autonomic nervous system regulates cardiac electrical and mechanical indices, and its dysregulation plays an important role in cardiac disease pathogenesis. The impact of PVCs on the intrinsic cardiac nervous system, a neural network on the heart, remains unknown. The objective was to determine the effect of PVCs and CI on intrinsic cardiac nervous system function in generating cardiac neuronal and electric instability using a novel cardioneural mapping approach.

METHODS AND RESULTS

In a porcine model (n=8), neuronal activity was recorded from a ventricular ganglion using a microelectrode array, and cardiac electrophysiological mapping was performed. Neurons were functionally classified based on their response to afferent and efferent cardiovascular stimuli, with neurons that responded to both defined as convergent (local reflex processors). Dynamic changes in neuronal activity were then evaluated in response to right ventricular outflow tract PVCs with fixed short, fixed long, and variable CI. PVC delivery elicited a greater neuronal response than all other stimuli (P<0.001). Compared with fixed short and long CI, PVCs with variable CI had a greater impact on neuronal response (P<0.05 versus short CI), particularly on convergent neurons (P<0.05), as well as neurons receiving sympathetic (P<0.05) and parasympathetic input (P<0.05). The greatest cardiac electric instability was also observed after variable (short) CI PVCs.

CONCLUSIONS

Variable CI PVCs affect critical populations of intrinsic cardiac nervous system neurons and alter cardiac repolarization. These changes may be critical for arrhythmogenesis and remodeling, leading to cardiomyopathy.

Medical therapy to prevent recurrence of ventricular arrhythmia in normal and structural heart disease patients

INTRODUCTION

Recurrent ventricular arrhythmias (VA) are a source of significant morbidity in patients without structural heart disease (SHD) and also mortality in patients with SHD. The treatment goals for these two patient populations differ greatly. Areas covered: The secondary prevention of recurrent VA in patients without and with SHD will be reviewed, focusing on clinical data (especially randomized, controlled trials) in the literature as determined through searches in PubMed and ClinicalTrials.gov. This will include β blockers, non-dihydropyridine calcium channel blockers and antiarrhythmic drugs in both subgroups and non-antiarrhythmic medications in SHD. Expert commentary: The available options for medical therapy for VA in both normal hearts and SHD are insufficient, due to substandard efficacy and toxicities. While non-pharmacologic therapies may provide an excellent option, further drug development and randomized trials are needed, as is a reappraisal of the current mode of utilization.

Quantification of Left Ventricular Function With Premature Ventricular Complexes Reveals Variable Hemodynamics

BACKGROUND

Premature ventricular complexes (PVCs) are prevalent in the general population and are sometimes associated with reduced ventricular function. Current echocardiographic and cardiovascular magnetic resonance imaging techniques do not adequately address the effect of PVCs on left ventricular function.

METHODS AND RESULTS

Fifteen subjects with a history of frequent PVCs undergoing cardiovascular magnetic resonance imaging had real-time slice volume quantification performed using a 2-dimensional (2D) real-time cardiovascular magnetic resonance imaging technique. Synchronization of 2D real-time imaging with patient ECG allowed for different beats to be categorized by the loading beat RR duration and beat RR duration. For each beat type, global volumes were quantified via summation over all slices covering the entire ventricle. Different patterns of ectopy, including isolated PVCs, bigeminy, trigeminy, and interpolated PVCs, were observed. Global functional measurement of the different beat types based on timing demonstrated differences in preload, stroke volume, and ejection fraction. An average of hemodynamic function was quantified for each subject depending on the frequency of each observed beat type.

CONCLUSIONS

Application of real-time cardiovascular magnetic resonance imaging in patients with PVCs revealed differential contribution of PVCs to hemodynamics.