Reversal of dilated cardiomyopathy by the elimination of frequent left or right premature ventricular contractions

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.

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.

A Novel ECG-Based Deep Learning Algorithm to Predict Cardiomyopathy in Patients With Premature Ventricular Complexes

BACKGROUND

Premature ventricular complexes (PVCs) are prevalent and, although often benign, they may lead to PVC-induced cardiomyopathy. We created a deep-learning algorithm to predict left ventricular ejection fraction (LVEF) reduction in patients with PVCs from a 12-lead electrocardiogram (ECG).

OBJECTIVES

This study aims to assess a deep-learning model to predict cardiomyopathy among patients with PVCs.

METHODS

We used electronic medical records from 5 hospitals and identified ECGs from adults with documented PVCs. Internal training and testing were performed at one hospital. External validation was performed with the others. The primary outcome was first diagnosis of LVEF ≤40% within 6 months. The dataset included 383,514 ECGs, of which 14,241 remained for analysis. We analyzed area under the receiver operating curves and explainability plots for representative patients, algorithm prediction, PVC burden, and demographics in a multivariable Cox model to assess independent predictors for cardiomyopathy.

RESULTS

Among the 14,241-patient cohort (age 67.6 ± 14.8 years; female 43.8%; White 29.5%, Black 8.6%, Hispanic 6.5%, Asian 2.2%), 22.9% experienced reductions in LVEF to ≤40% within 6 months. The model predicted reductions in LVEF to ≤40% with area under the receiver operating curve of 0.79 (95% CI: 0.77-0.81). The gradient weighted class activation map explainability framework highlighted the sinus rhythm QRS complex-ST segment. In patients who underwent successful PVC ablation there was a post-ablation improvement in LVEF with resolution of cardiomyopathy in most (89%) patients.

CONCLUSIONS

Deep-learning on the 12-lead ECG alone can accurately predict new-onset cardiomyopathy in patients with PVCs independent of PVC burden. Model prediction performed well across sex and race, relying on the QRS complex/ST-segment in sinus rhythm, not PVC morphology.

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.

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.

The Ubiquitous Premature Ventricular Complex

Premature ventricular complexes (PVCs) are one of the most commonly encountered arrhythmias and are ubiquitous in clinical practice, both in the outpatient and inpatient settings. They are often discovered incidentally in asymptomatic patients, however, can cause myriad symptoms acutely and chronically. Long thought to be completely benign, PVCs have been historically disregarded without pursuing any further evaluation. Newer data have revealed that a high burden of PVCs with specific characteristics can significantly increase a patient's risk of developing PVC-induced cardiomyopathy. The aim of this literature review is to provide further clarification on the identification of high-risk PVCs, subsequent workup, and the currently available treatment options. PVCs arise from an ectopic focus within the ventricles. Patients with PVCs can be either asymptomatic or have severe disabling symptoms. The diagnostic workup for PVCs includes electrocardiogram (ECG) and 24-h Holter monitor to assess the QRS morphology and its frequency. A transthoracic echocardiogram (TTE) is done to look for structural heart disease and cardiomyopathy. Management of PVCs should be focused on identifying and treating the underlying causes, such as electrolyte abnormalities, substance use, and underlying structural heart disease. Beta-blockers are first-line therapy for symptomatic PVCs. Nondihydropyridine calcium channel blockers, classic antiarrhythmic agents, and amiodarone can be considered as second-line agents. Patients who are unable to tolerate medical therapy should undergo catheter ablation of the PVC focus to prevent PVC-induced cardiomyopathy. PVCs are common in clinical practice, and it is vital to identify patients at higher risk for PVC-induced cardiomyopathy to facilitate early intervention. Patients with no evidence of structural heart disease and infrequent PVCs should be monitored closely, while those who are symptomatic should be treated medically. For those who have failed medical therapy, catheter ablation of the PVCs focus is recommended. Catheter ablation has been shown to reduce PVCs burden and improve left ventricular ejection fraction (LVEF) in those with PVC-induced cardiomyopathy.

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.

Predictors of Left Ventricular Ejection Fraction Improvement after Radiofrequency Catheter Ablation in Patients with PVC-Induced Cardiomyopathy: A Systematic Review

Background

Frequent premature ventricular contractions (PVC) can result in PVC-induced cardiomyopathy (PVC-iCMP), leading to reduced Left Ventricular Ejection Fraction (LVEF) that can be improved by radiofrequency catheter ablation (RFCA). We performed a systematic review to determine the variables predicting LVEF improvement after RFCA in PVC-iCMP.

Methods

We developed a “population, intervention, outcome and predictive factors” framework and searched MEDLINE, Embase, Cochrane Library, Cochrane Collaboration and Cochrane Database of Systematic Reviews (CDSR) for full-text, peer-reviewed publications. These publications addressing predictive factors of LVEF improvement showed ≥5% improvement only if deemed significant by the respective study, ≥10% or ≥ 50% after RFCA ablation in patients with PVC-iCMP with no type/date/language limitation until the end of 2017.

Results

Our initial search yielded 2226 titles, 1519 of which remained after removing the duplicates. Finally, 11 articles - 2 cohorts, 7 quasi-experimental studies, 1 case-control and 1 meta-analysis- were included. Sustained successful ablation, higher baseline PVC burden, LVEF, QRS duration, post-PVC systolic blood pressure rise and post-PVC pulse pressure change, the absence of an underlying cardiomyopathy, younger age, and variability of the frequency of PVCs during the day and lower left ventricular end-diastolic diameter (LVEDD) have been suggested as predictive factors for LVEF improvement in patients with PVC-iCMP.

Conclusion

The mentioned factors may all be useful to identify PVC-iCMP patients who would benefit from RFCA, although the evidence is not yet strong enough.

Management of asymptomatic arrhythmias: a European Heart Rhythm Association (EHRA) consensus document, endorsed by the Heart Failure Association (HFA), Heart Rhythm Society (HRS), Asia Pacific Heart Rhythm Society (APHRS), Cardiac Arrhythmia Society of Southern Africa (CASSA), and Latin America Heart Rhythm Society (LAHRS)

Asymptomatic arrhythmias are frequently encountered in clinical practice. Although studies specifically dedicated to these asymptomatic arrhythmias are lacking, many arrhythmias still require proper diagnostic and prognostic evaluation and treatment to avoid severe consequences, such as stroke or systemic emboli, heart failure, or sudden cardiac death. The present document reviews the evidence, where available, and attempts to reach a consensus, where evidence is insufficient or conflicting.

Assessment of premature ventricular beats in athletes

INTRODUCTION

Premature ventricular complexes (PVC) are generally considered as a benign electrocardiographic abnormality in the athletic population. However it may be indicative of underlying heart disease which may increase the risk of sudden death. This implies the need for cardiological evaluation before indicating the ability to practice competitive sports.

AIM

The aim of this study was to evaluate an athlete population with PVC and establish underlying etiologies in order to take a decision regarding practicing sports.

METHODS

This is a prospective study which included athletes examined in the Tunisian National Centre of Sports Medicine and Sports Science (TNCSM) from January 2013 to June 2015 who presented PVC on an electrocardiogram.

RESULTS

Five thousand seven hundred and ninety eight athletes were referred to the TNCSM. We identified 42 athletes having PVC with a prevalence of 1.8%. The average age of the study population was 21.6±5.99 years. 83% were men. 88% were asymptomatic. The electrocardiogram was considered normal in 62% of the athletes according to the Seattle criteria. At the Holter monitoring, the average number of PVC was 920 PVC/24hours. Thirteen athletes had doublets and 11 had triplets. One patient had polymorphic PVC and an R/T phenomenon. The transthoracic echocardiography (TTE) was normal in 71% of cases. Three athletes had hypertrophic cardiomyopathy (HCM). All patients underwent a stress test. The PVC disappeared in 12% of athletes MRI was performed in 10 athletes confirming the three cases of HCM and revealing a case of arrhythmogenic right ventricular dysplasia and a case of compression of the right ventricle by pectus exacavatum.

CONCLUSION

After this assessment, five athletes were not allowed to practice sport. This study shows the necessity of a thorough cardiological assessment of athletes with ventricular arrhythmia in order to detect underlying heart disease and prevent sudden death in this young apparently healthy population.

Assessment of the effects of frequent ventricular extrasystoles on the left ventricle using speckle tracking echocardiography in apparently normal hearts

Objective:

Impairment in left ventricular (LV) function due to excessive ventricular extrasystoles (VESs) occurs during long-time follow-up. Speckle tracking echocardiography (STE) has been shown to be superior to conventional methods for evaluating cardiac functions. We aimed to use STE for early detection of LV dysfunction in patients with apparently normal hearts who have frequent VESs.

Methods:

Fifty-five patients with frequent VESs were identified according to the Lown classification (Grade 2; unifocal more than 30 times in 1 h). Subjects aged 22-60 years with frequent VESs that had been detected for at least 1 year were included in the study according to the inclusion criteria. Forty-five subjects with similar demographic characteristics, but without VESs, were included as the control group. All participants were evaluated by STE.

Results:

Fifty-five patients with frequent VESs (mean age 47 years, range 22-60 years; 42.2% male) and 45 control subjects (mean age 46 years, range 22–60 years; 37.8% male) were enrolled in the study. Global LV longitudinal strain (GLS) was decreased in patients with frequent VESs (-18.41±3.37 and -21.82±2.43; p<0.001). In addition, global LV circumferential strain was decreased in patients with frequent VESs (-16.83±6.06, -20.51±6.02; p<0.001). The frequency and exposure time of VESs were negatively correlated with GLS (r=-0.398, p<0.001; r=-0.191, p=0.001, respectively).

Conclusion:

STE revealed that LV functions were decreased in patients with VESs. This deterioration increased with the frequency and exposure time of VESs. Impairment of LV function due to excessive VESs occurs during long-time follow-up. STE may be used for early detection of LV dysfunction.

Premature ventricular contraction-induced cardiomyopathy: an emerging entity

INTRODUCTION

Over the past 10-15 years, there has been an increasing amount of evidence that frequent premature ventricular contractions (PVCs) are associated with the development of a reversible cardiomyopathy. Areas covered: This review considers current evidence of the association between PVCs and the development of cardiomyopathy, risk factors, and available treatment modalities based on available published literature. Expert commentary: The field is rapidly evolving, although evidence is based primarily on observational studies. Pharmacological therapy may suppress PVCs and lead to resolution of cardiomyopathy in many patients. In addition, catheter ablation has emerged as an effective treatment modality that has compared favorably to pharmacological antiarrhythmic therapy. The excellent outcome in successfully treated patients should prompt physicians to consider whether frequent PVCs may be a contributing factor in patients with heart failure.

Long-Term Follow-Up of Catheter Ablation of Ventricular Arrhythmias: Experiences from a Tertiary Referral Center in Taiwan

BACKGROUND

Radiofrequency catheter ablation (RFCA) is an alternative therapeutic management for drug-refractory ventricular arrhythmias (VA). However, long-term follow-up of clinical outcome after RFCA for VAs in Taiwan remains unknown.

METHODS

From 1999 to 2013, patients undergoing RFCA for VAs from a single referral center were consecutively enrolled. The annual distribution of cases, clinical characteristics, etiology, disease entity and electrophysiological studies were investigated. The clinical outcomes and recurrences between distinct entities were compared.

RESULTS

A total of 502 patients receiving RFCA of VAs were eligible, including 388 patients for idiopathic VAs and 114 for substrate VAs. The annual distribution displayed a tendency towards a gradual increase in ablation cases within 2009-2013 compared with the prior decade (p < 0.001). Acute success was achieved in 453 patients (90.2%), partial success in 3 (0.6%), and failed ablation in 46 (9.2%). During a mean follow-up of 39.77 ± 48.75 months, 126 (25.1%) patients developed recurrences. Kaplan-Meier analysis demonstrated better prognosis after RFCA in patients with idiopathic fascicular VT and RVOT VAs (p < 0.001) and attenuation of the occurrences of sustained VT/VF, ICD therapies, and mortality in patients with BrS and ARVD/C (p = 0.036), as well as overall ICD interventions in substrate VAs (p < 0.001).

CONCLUSIONS

RFCA could be an effective and alternative strategy in the elimination of idiopathic VAs and prevention of malignant events in substrate VAs at an experienced referral center in Taiwan. Distinct location of arrhythmogenic trigger and disease entities may result in non-uniform recurrences and prognosis.

KEY WORDS

Idiopathic; Radiofrequency catheter ablation; Recurrence; Substrate; Ventricular arrhythmias.

Arrhythmia-Induced Cardiomyopathies: Mechanisms, Recognition, and Management

Arrhythmia-induced cardiomyopathy (AIC) is a potentially reversible condition in which left ventricular dysfunction is induced or mediated by atrial or ventricular arrhythmias. Cellular and extracellular changes in response to the culprit arrhythmia have been identified, but specific pathophysiological mechanisms remain unclear. Early recognition of AIC and prompt treatment of the culprit arrhythmia using pharmacological or ablative techniques result in symptom resolution and recovery of ventricular function. Although cardiomyopathy in response to an arrhythmia may take months to years to develop, recurrent arrhythmia can result in rapid decline in ventricular function with development of heart failure, suggesting residual ultrastructural abnormalities. Reports of sudden death in patients with normalized left ventricular ejection fraction cast doubt on the complete reversibility of this condition. Several aspects of AIC, including specific pathophysiological mechanisms, predisposing factors, optimal therapeutic strategies to prevent ultrastructural changes, and long-term risk of sudden death remain unresolved and need further research.

Effect of burden and origin sites of premature ventricular contractions on left ventricular function by 7-day Holter monitor

Recent studies have shown that premature ventricular contractions (PVCs) could enlarge the heart, but its risk factors are incompletely understood as a single 24-hour recording cannot reflect the true PVC burden due to day-to-day variability. Our purpose was to investigate the effect of burden and origin sites on left ventricular (LV) function in patients with PVCs by 7-day Holter electrocardiography (ECG). From May 2012 to August 2013, 112 consecutive patients with PVCs were recruited from the authors' affiliated hospital. All patients received 2-dimensional transthoracic echocardiography, 12-lead routing ECG and 7-days Holter ECG. Serum N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were measured. A total of 102 participants with PVCs were included in the final analysis. Origin of PVCs from the tricuspid annulus had the highest burden and NT-proBNP level. LV papillary muscle had a higher LV ejection fraction (EF) level and a lower LV end-systolic dimension (ESD) than other PVC foci (P<0.05). The high burden group had a higher LV end-diastolic dimension (EDD) and LVESD but lower LVEF than the other two groups (P<0.05). Female, older age, physical work, and history of PVCs had a significantly positive correlation with symptoms. Male, older age, physical work, and high burden were positive predictors of enlarged LVEDD, LVESD and higher serum NT-proBNP level, but lower LVEF. Seven-day dynamic ECG Holter monitor showed the true PVC burden on patients with PVCs. PVCs with a lower burden or origin from the LV papillary muscle and the fascicle were relatively benign, while PVCs with a higher burden or origin from the tricuspid annulus may lead to cardiac dysfunction.

Impact of ventricular ectopic burden in a premature ventricular contraction-induced cardiomyopathy animal model

BACKGROUND

Frequent premature ventricular contractions (PVCs) have been associated with PVC-induced cardiomyopathy (CM) in some patients.

OBJECTIVE

The purpose of this study was to understand the cardiac consequences of different PVC burdens and the minimum burden required to induce left ventricular (LV) dysfunction.

METHODS

Right ventricular apical PVCs at a coupling interval of 240 ms were introduced at different PVC burdens in 9 mongrel canines. A stepwise increase in PVC burden was implemented every 8 weeks from 0% (baseline), 7%, 14%, 25%, 33% to 50% using our premature pacing algorithm. Echocardiogram and 24-hour Holter were obtained at 4- and 8-week period for each PVC burden with a single blinded reader assessing all echocardiographic parameters including those assessed by speckle tracking imaging (EchoPAC workstation, General Electric). CM was defined as left ventricular ejection fraction (LVEF) <50% or LVEF drop >10% points. Interleukin-6 and pro-brain natriuretic peptide levels were obtained at the end of each PVC burden.

RESULTS

The mean LVEF (mean heart rate) at 8 weeks for each PVC burden (0%, 7%, 14%, 33%, and 50%) were 57% ± 2.9% (85 ± 13 beats/min), 54.4% ± 3% (81 ± 10 beats/min), 53.3% ± 5% (77 ± 12 beats/min), 51.1% ± 4.2% (79 ± 14 beats/min), 47.7% ± 3.8% (80 ± 14 beats/min), and 44.7% ± 1.9% (157 ± 43 beats/min). PVC-induced CM was present in 11.1%, 44.4%, and 100% of animals with 25%, 33%, and 50% PVC burden, respectively. E/A ratio and radial strain decreased while left atrial size increased beyond 33% PVC burden. No changes in pro-brain natriuretic peptide and interleukin-6 levels were noted at any PVC burden.

CONCLUSION

LV systolic function (LVEF and radial strain) declined linearly as PVC burden increased. PVC-induced CM developed in some canines with 25% and 33% PVC burden, but developed in all animals with 50% PVC burden.

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

BACKGROUND

Left ventricular (LV) dyssynchrony caused by premature ventricular contractions (PVCs) has been proposed as a mechanism of PVC-induced cardiomyopathy. We sought to understand the impact of different PVC locations and coupling intervals (prematurity) on LV regional mechanics and global function of the PVC beat itself.

METHODS AND RESULTS

Using our premature pacing algorithm, pentageminal PVCs at coupling intervals of 200 to 375 ms were delivered from the epicardial right ventricular apex, RV outflow tract, and LV free wall, as well as premature atrial contractions, from the left atrial appendage at a coupling interval of 200 ms in 7 healthy canines. LV short-axis echocardiographic images, LV stroke volume, and dP/dtmax were obtained during all ectopic beats and ventricular pacing. LV dyssynchrony was assessed by dispersion of QRS-to-peak strain (earliest-last QRS-to-peak strain) between 6 different LV segments during each of the aforementioned beats (GE, EchoPac). LV dyssynchrony was greater during long-coupled rather than short-coupled PVCs and PVCs at 375 ms compared with rapid ventricular pacing at 400 ms (P<0.0001), whereas no difference was found between PVC locations. Longer PVC coupling intervals were associated with greater stroke volume and dP/dtmax despite more pronounced dyssynchrony (P<0.001).

CONCLUSIONS

PVCs with longer coupling intervals demonstrate more pronounced LV dyssynchrony, whereas PVC location has minimal impact. LV dyssynchrony cannot be attributed to prematurity or abnormal ventricular activation alone, but rather to a combination of both. This study suggests that late-coupled PVCs may cause a more severe cardiomyopathy if dyssynchrony is the leading mechanism responsible for PVC-induced cardiomyopathy.

Treatment Or Cure Of Right Ventricular Outflow Tract Tachycardia

Right ventricular outflow tract (RVOT) ventricular tachycardias (VT) occur in the absence of structural heart disease and are called idiopathic ventricular arrhythmias. These arrhythmias are thought to be produced by adenosine-sensitive, cyclic AMP mediated, triggered activity and are commonly observed in adolescents and young adults. In the ECG, they appear with a wide QRS complex, a left bundle branch block morphology and, usually, an inferior QRS axis. In the last few years, there has been an increasing number of reports suggesting the possibility of a curative treatment of RVOT VT by means of catheter ablation. This paper reviews the rate of cure of such arrhythmias by discussing the effects of catheter ablation on symptoms, arrhythmia detection, possibility of induction, and short- and long-term follow-up studies.

Coupling interval dispersion and body mass index are independent predictors of idiopathic premature ventricular complex-induced cardiomyopathy

INTRODUCTION

Patients with frequent premature ventricular complexes (PVCs) might be at risk for the developing or exacerbation of left ventricular (LV) dysfunction. However, some patients with a high-PVC burden do not develop cardiomyopathy, while other patients with low-PVC burden can develop cardiomyopathy. The purpose of this study was to evaluate the positive predictors of idiopathic PVCs-induced cardiomyopathy.

METHODS AND RESULTS

We investigated 214 patients undergoing successful ablation of PVCs who had no other causes of cardiomyopathy. We divided the study cohort into 2 groups: ejection fraction (EF) ≥ 50% (normal LV) and EF < 50% (LV dysfunction). We analyzed the clinical characteristics, including the electrocardiogram and findings at electrophysiology study. Among these patients, 51 (24%) had reduced LVEF and 163 (76%) had normal LV function. Patients with LV dysfunction had significantly longer coupling interval (CI) dispersion (maximum-CI-minimum-CI) and had significantly higher PVC burden compared to those with normal LV function (CI-dispersion: 115 ± 25 milliseconds vs. 94 ± 19 milliseconds; P < 0.001; PVC burden: 19% vs. 15%; P = 0.04). Furthermore, patients with LV dysfunction had significantly higher body mass index (BMI) compared to those with normal LV function (BMI > 30 kg/m(2) ; 37% vs. 13%; P = 0.001). Logistic regression analysis showed that CI-dispersion, PVC burden, and BMI (>30 kg/m(2) ) are independent predictors of PVC-induced cardiomyopathy.

CONCLUSIONS

In addition to the PVC burden, the CI-dispersion and BMI are associated with PVC-induced cardiomyopathy.

The Association Between the Neutrophil-to-Lymphocyte Ratio and the Presence of Ventricular Premature Contractions in Young Adults

Inflammation has recently emerged in the pathogenesis of several cardiovascular disorders, including arrhythmias. The neutrophil-lymphocyte ratio (NLR) is a simple marker for the assessment of inflammatory status. Therefore, we aimed to investigate the relationship between the NLR and the ventricular premature contraction (VPC) existence. Patients aged between 18 and 40 years who were referred to the cardiology clinic were enrolled in the study. All patients' complete blood counts and 24-hour Holter recordings were analyzed. The NLR was higher within the VPC group compared to the control group (P < .001). According to the NLR tertiles, VPCs were more common in the higher NLR tertile (P < .001). A cutoff point of 1.80 for the NLR had 71% sensitivity and 60% specificity in predicting VPC in apparently healthy individuals. After multivariate analysis, only the NLR remained significant predictor of presence of VPC. In conclusion, the NLR is independently and significantly associated with VPC existence.

Long-term effect of continuing sports activity in competitive athletes with frequent ventricular premature complexes and apparently normal heart

The long-term outcome of athletes with frequent ventricular premature complexes (VPCs) and apparently normal heart has not been fully clarified. To evaluate the clinical and prognostic significance of VPCs and the influence of continuing sports activity during follow-up, we studied 120 healthy athletes (96 men; median age 16 years) in whom frequent VPCs (>100 VPCs/24 hours) were discovered by chance during preparticipation screening. All athletes were followed up for a median of 84 months. During follow-up, 96 underwent serial 24-hour Holter recording and 62 underwent serial echocardiography. The median number of VPCs/24 hours on basal Holter was 3,760. During follow-up, 81 athletes continued sports activity, whereas 39 did not. No athlete died or developed overt heart disease. The median number of VPCs/24 hours decreased in both athletes who continued sports activity and those who did not (from 3,805 to 1,124, p <0.0001 and from 5,787 to 1,298, p <0.0001, respectively). During follow-up, left ventricular ejection fraction slightly decreased to <55% in 9 of 62 athletes who, in respect to the remaining 53, had more VPCs/24 hours both in the basal state (12,000 vs 3,880) and during follow-up (10,702 vs 1,368), and a longer follow-up (95 vs 36 months). In conclusion, (1) frequent VPCs in athletes without heart disease have a long-term benign prognostic significance, (2) sporting activity does not modify this benign outcome, (3) during follow-up, the burden of VPCs decreases whether or not subjects continue sports activity, and (4) in 14.5% of athletes, ejection fraction slightly decreases over time.

Relative efficacy of catheter ablation vs antiarrhythmic drugs in treating premature ventricular contractions: a single-center retrospective study

BACKGROUND

It is unknown whether radiofrequency ablation (RFA) or antiarrhythmic therapy is superior when treating patients with symptomatic premature ventricular contractions (PVCs).

OBJECTIVE

To determine the relative efficacy of RFA and antiarrhythmic drugs (AADs) on PVC burden reduction and increasing left ventricular systolic function.

METHODS

Patients with frequent PVCs (>1000/24 h) were treated either by RFA or with AADs from January 2005 through December 2010. Data from 24-hour Holter monitoring and echocardiography before and 6-12 months after treatment were compared between the 2 groups.

RESULTS

Of 510 patients identified, 215 (40%) underwent RFA and 295 (60%) received AADs. The reduction in PVC frequency was greater by RFA than with AADs (-21,799/24 h vs -8,376/24 h; P < .001). The left ventricular ejection fraction (LVEF) was increased significantly after RFA (53%-56%; P < .001) but not after AAD (52%- 52%; P = .6) therapy. Of 121 (24%) patients with reduced LVEF, 39 (32%) had LVEF normalization to 50% or greater. LVEF was restored in 25 of 53 (47%) patients in the RFA group compared with 14 of 68 (21%) patients in the AAD group (P = .003). PVC coupling interval less than 450 ms, less impaired left ventricular function, and RFA were independent predictors of LVEF normalization performed by using multivariate analysis.

CONCLUSION

RFA appears to be more effective than AADs in PVC reduction and LVEF normalization.

Radiofrequency ablation can reverse the structural remodeling caused by frequent premature ventricular contractions originating from the right ventricular outflow tract even in a "normal heart"

OBJECTIVE

The aim of this study was to evaluate whether frequent premature ventricular contractions originating from the right ventricular outflow tract remodel the cardiac structure and function in patients with a "seemingly normal heart" and whether radiofrequency ablation can reverse this remodeling.

METHODS

Sixty-eight patients with idiopathic frequent premature ventricular contractions originating from the right ventricular outflow tract and normal heart structure and function were enrolled in this study. The patients were divided into three groups according to the therapeutic method: radiofrequency ablation group (24 cases), anti-arrhythmia drug group (26 cases), and control group (18 cases without any treatment). Clinical Registration number: ChiCTR-ONRC-12002834 RESULTS: The basic patient characteristics were comparable between the three groups, except for the premature ventricular contraction rate, which was significantly lower in the control group. After six months of follow up, the premature ventricular contraction rate was significantly reduced in the radiofrequency ablation group, which was accompanied by a significant decrease in the following cardiac cavity inner diameters, as determined by echocardiography: right atrium (33.33±3.78 vs. 30.05±2.60 mm, p = 0.001), right ventricle (23.24±2.40 vs. 21.05±2.16 mm, p = 0.020), and left ventricle (44.76±4.33 vs. 41.71±3.44 mm, p = 0.025). These results were similar in the anti-arrhythmia drug group, although this group exhibited a smaller extent of change (right atrium: 33.94±3.25 vs. 31.27±3.11 mm, p = 0.024; right ventricle: 22.97±3.09 vs. 21.64±2.33 mm, p = 0.049; left ventricle: 45.92±6.38 vs. 43.84±5.67 mm, p = 0.039), but not in the control group (p>0.05). There was a tendency toward improvement in the cardiac functions in both the radiofrequency ablation and anti-arrhythmia drug groups. However, these differences were not statistically significant (p>0.05).

CONCLUSIONS

These results indicate that radiofrequency ablation can potentially reverse the cardiac remodeling caused by frequent premature ventricular contractions even in structurally normal hearts and that frequent premature ventricular contractions should be abated even in structurally normal hearts.

Neurohormonal, structural, and functional recovery pattern after premature ventricular complex ablation is independent of structural heart disease status in patients with depressed left ventricular ejection fraction: a prospective multicenter study

OBJECTIVES

This study aimed to assess the benefit after ablation of premature ventricular complexes (PVC) in patients with frequent PVC and left ventricular (LV) dysfunction, regardless of previous structural heart disease (SHD) diagnosis, PVC morphology, or estimated site of origin.

BACKGROUND

Ablation of PVC in patients with LV dysfunction is usually restricted to patients with suspected PVC-induced cardiomyopathy.

METHODS

Consecutive patients with frequent PVC and LV dysfunction accepted for ablation at 4 centers were prospectively included. Of the 80 patients included, 27 (34%) had a diagnosis of SHD.

RESULTS

Successful sustained ablation (SSA) was achieved in 53 (66%) patients, and LVEF improved in these patients from 33.7 ± 8% to 43.8 ± 9.4% and 45.8 ± 10.9% at 6 and 12 months, respectively (p < 0.05), without differences related to previous diagnosis of SHD (p = 0.69). BNP decreased from 109 [64 to 242] pg/ml to 60 [25 to 170] pg/ml, 50 [14 to 130] pg/ml, and 60 [19 to 81] pg/ml at 1, 6, and 12 months (p < 0.05). Patients in NYHA class I increased from 12 (23%) to 42 (79%) at 12 months (p < 0.05). A 13% baseline PVC burden had 100% sensitivity and 85% specificity to predict an absolute increase ≥ 5% in LVEF after SSA. Although 20 patients with >13% PVC and SSA had class I indication for cardioverter defibrillator implantation, these indications were absent at 6 months post-ablation.

CONCLUSIONS

Independently of the presence of SHD, the SSA of frequent PVC in patients with depressed LVEF induced a progressive clinical and functional improvement. Improvement in heart failure parameters was related to baseline PVC burden and persistence of ablation success.

Reversal of Dilated Cardiomyopathy After Successful Radio-Frequency Ablation of Frequent Atrial Premature Beats, a New Cause for Arrhythmia-Induced Cardiomyopathy

Incessant atrial premature beats as a potential cause for tachycardia-induced cardiomyopathy was suspected in a patient presenting with dilated non-ischemic cardiomyopathy and severely altered left ventricular ejection fraction. The elimination of a left atrial focus by percutaneous RF ablation led to normalization of the clinical status, of atrial and ventricular dimensions and left ventricular systolic function.

Advantage of recording single-unit muscle sympathetic nerve activity in heart failure

Elevated sympathetic activation is a characteristic feature of heart failure (HF). Excessive sympathetic activation under resting conditions has been shown to increase from the early stages of the disease, and is related to prognosis. Direct recording of multiunit efferent muscle sympathetic nerve activity (MSNA) by microneurography is the best method for quantifying sympathetic nerve activity in humans. To date, this technique has been used to evaluate the actual central sympathetic outflow to the periphery in HF patients at rest and during exercise; however, because the firing occurrence of sympathetic activation is mainly synchronized by pulse pressure, multiunit MSNA, expressed as burst frequency (bursts/min) and burst incidence (bursts/100 heartbeats), may have limitations for the quantification of sympathetic nerve activity. In HF, multiunit MSNA is near the maximum level, and cannot increase further than the heartbeat. Single-unit MSNA analysis in humans is technically demanding, but provides more detailed information regarding central sympathetic firing. Although a great deal is known about the response of multiunit MSNA to stress, little information is available regarding the responses of single-unit MSNA to physiological stress and disease. The purposes of this review are to describe the differences between multiunit and single-unit MSNA during stress and to discuss the advantages of single-unit MSNA recording in improving our understanding the pathology of increased sympathetic activity in HF.

Ventricular ectopy and long-term cardiac function

Premature ventricular complexes (PVCs) that are frequently noted, although they may be benign, are commonly associated with structural heart disease and serve as a trigger for sustained ventricular arrhythmias. Although it has not been documented that chronic PVCs can impair cardiac systolic function, there have been reports of improved function with the abatement of PVCs. Our objective in this study was to determine the association between frequent PVCs and left ventricular systolic function over long-term follow-up. We reviewed all ambulatory electrocardiographic monitor data at our medical center during a 1-year interval. Patients with at least 1000 PVCs per 24 hours and 2 consecutive echocardiograms (>3 months apart) were selected for analysis of left ventricular systolic function. The primary end-point was a change in left ventricular ejection fraction (LVEF) in relation to PVC frequency. Results were analyzed adjusting for covariates. Thirty-seven patients, 27% of whom had structural heart disease, had ≥1000 PVC/24 hours, LVEF ≥ 40% (mean age, 61 years; male, 62%; mean LVEF, 52.7%), and follow-up echocardiograms. PVC frequency (8559/24 hours) was not significantly associated with change in LVEF over a mean follow-up of 40 months. Additionally, confounders such as diabetes, hypertension, coronary artery disease, and medications had no correlation with the primary end-point. Our data suggest that PVC burden observed in our study over approximately 3 years is not associated with a reduction in LVEF during follow-up in patients with baseline normal or mildly reduced systolic function.

Left ventricular systolic dysfunction induced by ventricular ectopy: a novel model for premature ventricular contraction-induced cardiomyopathy

BACKGROUND

Premature ventricular contractions (PVCs) commonly coexist with cardiomyopathy. Recently, PVCs have been identified as a possible cause of cardiomyopathy. We developed a PVC-induced cardiomyopathy animal model using a novel premature pacing algorithm to assess timeframe and reversibility of this cardiomyopathy and examine the associated histopathologic abnormalities.

METHODS AND RESULTS

Thirteen mongrel dogs were implanted with a specially programmed pacemaker capable of simulating ventricular extrasystoles. Animals were randomly assigned to either 12 weeks of bigeminal PVCs (n = 7) or no PVCs (control, n = 6). Continuous 24-hour Holter monitoring corroborated ventricular bigeminy in the PVC group (PVC, 49.8% versus control, < 0.01%; P<0.0001). After 12 weeks, only the PVC group had cardiomyopathy, with a significant reduction in left ventricular ejection fraction (PVC, 39.7 ± 5.4% versus control, 60.7 ± 3.8%; P < 0.0001) and an increase in left ventricular end-systolic dimension (PVC, 33.3 ± 3.5 mm versus control, 23.7 ± 3.6 mm; P < 0.001). Ventricular effective refractory period showed a trend to prolong in the PVC group. PVC-induced cardiomyopathy was resolved within 2 to 4 weeks after discontinuation of PVCs. No inflammation, fibrosis, or changes in apoptosis and mitochondrial oxidative phosphorylation were observed with PVC-induced cardiomyopathy.

CONCLUSIONS

This novel PVC animal model demonstrates that frequent PVCs alone can induce a reversible form of cardiomyopathy in otherwise structurally normal hearts. PVC-induced cardiomyopathy lacks gross histopathologic and mitochondrial abnormalities seen in other canine models of cardiomyopathy.

Reversal of ventricular premature beat induced cardiomyopathy by radiofrequency catheter ablation

Frequent monomorphic ventricular premature beats (VPBs) may lead to left ventricular dysfunction. We describe two patients with frequent monomorphic VPBs and dilated cardiomyopathy in whom left ventricular function normalised after elimination of the VPBs by radiofrequency catheter ablation. The recent literature on this topic is summarised and potential candidates for catheter ablation are discussed. (Neth Heart J 2010;18:493-8.).