Premature ventricular contraction diurnal profiles predict distinct clinical characteristics and beta‐blocker responses

ECTOPIC trial: The efficacy of flEcainide Compared To metOprolol in reducing Premature ventrIcular contractions. A randomized open label cross-over study in pediatric patients

BACKGROUND

Frequent premature ventricular contractions (PVCs) in children are usually considered benign. Symptoms and/or left ventricular dysfunction are indications for treatment with anti-arrhythmic drugs (AAD).

OBJECTIVE

To evaluate the efficacy of flecainide versus metoprolol in reducing PVCs in children.

METHODS

A randomized open label cross-over trial children with a PVC-burden of >15% on Holter; successively treated with metoprolol and flecainide or vice versa, with a drug free interval of at least two weeks. Holter measurements were repeated before and after the start of the AAD.

RESULTS

Sixty patients were screened, 19 patients could be included. Median age was 13.9 years (IQR 5.5 years). Mean baseline PVC-burden was 21.7% (N=18, SD±14.0) before the start of flecainide and 21.2% (N=17, SD±11.5) before the start of metoprolol. In a mixed model analysis the estimated mean reduction in PVC-burden was 10.6 percentage-points (95%-CI 5.8-15.3) for flecainide and 2.4 percentage-points (95%-CI -2.7-7.5) for metoprolol, with a significant difference of 8.2 percentage-points (95%-CI of 0.86-15.46, P=0.031). Exploratory analysis revealed that 9/18 patients treated with flecainide and 1/17 patients treated with metoprolol, had a reduction to a PVC-burden below 5%. No discriminating factors between flecainide-responders and non-responders were found; the mean plasma level was not significantly different (0.34 mg/L versus 0.52 mg/L, P=0.277).

CONCLUSIONS

In children with frequent PVCs flecainide led to a significant greater reduction of PVC-burden, compared to metoprolol. Flecainide was effective in only a subgroup of patients, which appears to be unrelated to the plasma level. (Dutch Trial Register number 26689).

The significance of heart rate variability in patients with frequent premature ventricular complex originating from the ventricular outflow tract

BACKGROUND

As an indicator of cardiac autonomic nervous activity, heart rate variability (HRV) is closely linked to premature ventricular complexes (PVCs). However, its role in patients with frequent PVCs originating from the ventricular outflow tract remains unclear.

HYPOTHESIS

Here, we hypothesize that there may be alterations in HRV among patients with frequent PVCs originating from the ventricular outflow tract, which could play significant roles in the management of such patients.

METHODS

A retrospective study was conducted, including 106 patients with frequent outflow tract PVCs and 106 healthy participants as controls. HRV was assessed based on the 24-hour Holter recording. The originating foci of PVCs were identified during radiofrequency catheter ablation.

RESULTS

Patients with frequent outflow tract PVCs exhibited decreased levels of high frequency (HF), standard deviation of all NN intervals, and standard deviation of the average NN intervals, but increased ratios of low frequency to HF (LF/HF ratio), even after propensity score-matched analysis. Further investigation revealed that patients with PVCs originating from right ventricular outflow tract (RVOT) had much higher LF/HF ratios. Multivariate logistic regression analysis demonstrated that the LF/HF ratio was independently associated with PVCs originating from RVOT. Receiver operating characteristics curve indicated that the LF/HF ratio effectively determined the origin of PVCs (the area under the curve = 0.75, p < .001).

CONCLUSIONS

Patients with frequent outflow tract PVCs exhibited impaired HRV. Additionally, the LF/HF ratio played a significant role in determining the origin of outflow tract PVCs.

Premature Ventricular Complexes: Benign versus Malignant - How to approach?

Premature Ventricular Complexes (PVCs) refer to electrical activity arising from ventricles resulting in ventricular contraction independent of the native rhythm. PVCs by themselves are common in the general population but based on the origin of the PVCs, either related to anatomical or electrical substrate, the disease process has a widely varied presentation and prognosis. The clinical presentation of symptoms may vary from being extremely benign, or very severe (malignant). Benign PVCs include those that are asymptomatic or induce very mild symptoms including palpitations, lightheadedness, chest discomfort, or the sensation of skipped beats. The middle range of PVCs present as heart failure or heart failure complicated by PVCs. The malignant variety may present as syncope, or sudden cardiac death. In this review we describe the multiple facets of PVC presentation and strategies of clinical management.

Electrocardiographic Characteristics, Identification, and Management of Frequent Premature Ventricular Contractions

Premature ventricular complexes (PVCs) are frequently encountered in clinical practice. The association of PVCs with adverse cardiovascular outcomes is well established in the context of structural heart disease, yet not so much in the absence of structural heart disease. However, cardiac magnetic resonance (CMR) seems to contribute prognostically in the latter subgroup. PVC-induced myocardial dysfunction refers to the impairment of ventricular function due to PVCs and is mostly associated with a PVC burden > 10%. Surface 12-lead ECG has long been used to localize the anatomic site of origin and multiple algorithms have been developed to differentiate between right ventricular and left ventricular outflow tract (RVOT and LVOT, respectively) origin. Novel algorithms include alternative ECG lead configurations and, lately, sophisticated artificial intelligence methods have been utilized to determine the origins of outflow tract arrhythmias. The decision to therapeutically address PVCs should be made upon the presence of symptoms or the development of PVC-induced myocardial dysfunction. Therapeutic modalities include pharmacological therapy (I-C antiarrhythmic drugs and beta blockers), as well as catheter ablation, which has demonstrated superior efficacy and safety.

Mechanisms, time course and predictability of premature ventricular contractions cardiomyopathy-an update on its development and resolution

Frequent premature ventricular contractions (PVCs) associated left ventricular systolic dysfunction (LVSD) is a well-known clinical scenario and numerous predictors for cardiomyopathy (CMP) development have been already thoroughly described. It may present as a "pure" form of dissynchrony-induced cardiomyopathy or it may be an aggravating component of a multifactorial structural heart disease. However, the precise risk to develop PVC-induced CMP (which would allow for tailored-patient monitoring and/or early treatment) and the degree of CMP reversibility after PVC suppression/elimination (which may permit appropriate candidate selection for therapy) are unclear. Moreover, there is limited data regarding the time course of CMP development and resolution after arrhythmia suppression. Even less known are the other components of PVC-induced CMP, such as right ventricular (RV) and atrial myopathies. This review targets to synthetize the most recent information in this regard and bring a deeper understanding of this heart failure scenario. The mechanisms, time course (both in experimental models and clinical experiences) and predictors of reverse-remodelling after arrhythmia suppression are described. The novel experience hereby presented may aid everyday clinical practice, promoting a new paradigm involving more complex, multi-level and multi-modality evaluation and possible earlier intervention at least in some patient subsets.

Prevalence and heart rate variability characteristics of premature ventricular contractions detected by 24-hour Holter among outpatients with palpitations in China: a cross-sectional study

OBJECTIVE

To analyse the prevalence and heart rate variability (HRV) characteristics of premature ventricular contraction (PVC) detected by 24-hour Holter among Chinese outpatients with palpitations.

DESIGN

A cross-sectional study.

SETTING

This study was conducted in a tertiary hospital.

PARTICIPANTS

A total of 4754 outpatients who received 24-hour Holter for palpitations.

MAIN OUTCOME MEASURES

Prevalence, HRV time-domain and frequency-domain analyses of 24-hour Holter, and echocardiographic parameters were assessed. Propensity score matching (PSM) was applied to balance baseline variables (age, gender) to decrease the bias between comparison groups.

RESULTS

The prevalence of PVC was 67.7% (3220/4754), and was higher in men than women (69.9% vs 66.0%, p=0.004); the prevalence of frequent PVCs (PVC burden≥5%) was 7.7% (368/4754). Older patients had the highest frequency of PVC among all patients. However, among 3220 patients with PVC, younger patients' PVC burden was much higher. Matched 1:1 by age and gender, the HRV time-domain parameters in patients with PVC were all lower than those in patients without PVC (all p<0.05); for the HRV frequency-domain parameters, the patients with frequent PVCs had a higher low frequency/high frequency (LF/HF) ratio (5.4 vs 2.8, p<0.001) than those with PVC burden less than 5%.

CONCLUSIONS

The prevalence of PVC and frequent PVCs were 67.7% and 7.7%, respectively, detected by 24-hour Holter among Chinese outpatients with palpitations. Decreased HRV time-domain parameters suggested the occurrence of PVC, and increased LF/HF ratio represented the imbalance of autonomic nervous system in patients with frequent PVCs. Further studies are needed to understand the HRV indexes in PVC patients.

Predictors of positive response to beta-blockers for treatment of premature ventricular complexes

BACKGROUND

The aim of the present study is to investigate the possible factors that might be predictive of effective antiarrhythmic effect of beta-blockers on premature ventricular complexes (PVC).

METHODS

Data of 190 eligible consecutive patients to whom beta-blocker therapy had been initiated for treatment of PVC's were retrospectively evaluated. The Holter recording acquired before beta-blocker initiation and the first Holter acquired after beta blocker initiation during follow up was comprehensively evaluated for each patient. Parameters obtained from pre- and post-beta-blocker 24 h Holter recordings were compared with each other and possible predictors were evaluated for positive response to beta-blocker therapy.

RESULTS

Sixty-one patients (32.1%) were observed to respond beta-blocker therapy with at least 50% reduction of daily PVC burden. Patients who responded to beta-blockers had significantly higher ratio of patients who had positive correlation between hourly heart rate and corresponding hourly PVC number (fast HR-PVC status) compared with non-responders (73.8% vs 48.1%, p < 0.001). Binary logistic regression analysis revealed PVC QRS width (Odds ratio: 0.971; p: 0.037) and fast HR-PVC status (Odds ratio: 2.935; p: 0.007) as the independent predictors of positive response to beta-blockers for treatment of PVC.

CONCLUSION

Positive correlation between hourly heart rate and PVC incidence was found to be independent positive predictor and PVC QRS width was found to be independent negative predictor of beta-blocker success in our study. This observation might have important clinical implications to guide medical treatment of PVCs in clinical practice.

Effectiveness of medical therapy for treatment of idiopathic frequent premature ventricular complexes

INTRODUCTION

The relative effectiveness of medical therapy compared with a conservative approach of monitoring in patients with idiopathic frequent premature ventricular complexes (PVCs) is uncertain. We evaluated the effectiveness of medical versus conservative therapy for frequent PVCs.

METHODS

Patients with frequent PVCs (≥5%) were prospectively enrolled in this cohort study between 2016 and 2020. In patients with normal cardiac function and no structural heart disease, those receiving medical therapy were compared with controls without therapy. Patients were followed longitudinally for change in PVC burden and with serial echocardiography.

RESULTS

Overall, 120 patients met inclusion criteria (mean: 56.5 ± 14.6 years, 54.2% female) with 53 on beta-blockers or calcium channel blockers (BBs/CCBs), 27 on Class I or III antiarrhythmic drugs (AADs), and 40 patients treated conservatively. Median initial PVC burden ranged from 15.5% to 20.6%. The median relative reduction of PVCs was 32.7%, 30.5%, and 81.3%, in the conservative therapy, BBs/CCBs, and AADs cohorts, respectively. AADs had greater PVC reduction compared with BBs/CCBs (p = 0.017) and conservative therapy (p = 0.045). PVC reduction to <1% was comparable across groups at 35.0%, 17.0%, 33.3%, respectively. Four patients (4/120, 3.3%) developed left ventricular dysfunction. Rates of adverse drug reactions and medication discontinuation were similar between groups, with no serious adverse events noted.

CONCLUSION

In patients with idiopathic frequent PVCs, BB, and CCB have limited effectiveness in PVC reduction. Class I and III AADs have superior effectiveness for medical therapy in symptomatic patients, but only achieved complete PVC resolution suppression in one-third of patients.

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.

Predictors of adequate intraprocedural premature ventricular complex (PVC) frequency during idiopathic PVC ablation

BACKGROUND

The aim of the present study was to determine the predictors of adequate intraprocedural premature ventricular complex (PVC) frequency for successful mapping and ablation of idiopathic PVCs.

METHODS

A total of 101 consecutive patients (45 men; age: 47.9 ± 14.2 years) who had undergone idiopathic PVC ablation between 01 November 2018 and 24 June 2020 constituted our study population. Clinical and demographic data, procedural details and 24 h rhythm recordings that had been recorded before the procedure were retrospectively evaluated. Total PVC burden and diurnal variability assessed by the ratio of night time (22:00-06:00) over day time (06:00-22:00) PVC burden was calculated. The relationship between hourly PVC number and heart rate was also evaluated for each patient. Clinical characteristics and Holter parameters were compared between groups with and without adequate intraprocedural frequency of PVCs that permitted activation mapping.

RESULTS

In all, 27 patients (26.7%) had infrequent intraprocedural PVCs which necessitated isoproterenol infusion or cancellation of ablation procedure due to inability of activation mapping. PVC burden was significantly higher in the group with frequent intraprocedural PVCs (26.1 ± 9.4% vs 21.2 ± 10.3%; p: 0.026). There were no significant differences between groups regarding the relationship between hourly PVC number and heart rate or the ratio of night/day PVC burden. Binary logistic regression analysis revealed the 24 h Holter PVC burden as the sole parameter that is significant predictor of frequent intraprocedural PVCs permitting activation mapping.

CONCLUSION

The 24 h PVC burden was the only predictor of adequate intraprocedural PVC frequency permitting activation mapping during idiopathic PVC ablation.

The Efficacy of Anti-Arrhythmic Drugs in Children With Idiopathic Frequent Symptomatic or Asymptomatic Premature Ventricular Complexes With or Without Asymptomatic Ventricular Tachycardia: a Retrospective Multi-Center Study

The aim of the study is to compare the efficacy of flecainide, beta-blockers, sotalol, and verapamil in children with frequent PVCs, with or without asymptomatic VT. Frequent premature ventricular complexes (PVCs) and asymptomatic ventricular tachycardia (VT) in children with structurally normal hearts require anti-arrhythmic drug (AAD) therapy depending on the severity of symptoms or ventricular dysfunction; however, data on efficacy in children are scarce. Both symptomatic and asymptomatic children (≥ 1 year and < 18 years of age) with a PVC burden of 5% or more, with or without asymptomatic runs of VT, who had consecutive Holter recordings, were included in this retrospective multi-center study. The groups of patients receiving AAD therapy were compared to an untreated control group. A medication episode was defined as a timeframe in which the highest dosage at a fixed level of a single drug was used in a patient. A total of 35 children and 46 medication episodes were included, with an overall change in PVC burden on Holter of -4.4 percentage points, compared to -4.2 in the control group of 14 patients. The mean reduction in PVC burden was only significant in patients receiving flecainide (- 13.8 percentage points; N = 10; p = 0.032), compared to the control group and other groups receiving beta-blockers (- 1.7 percentage points; N = 18), sotalol (+ 1.0 percentage points; N = 7), or verapamil (- 3.9 percentage points; N = 11). The efficacy of anti-arrhythmic drug therapy on frequent PVCs or asymptomatic VTs in children is very limited. Only flecainide appears to be effective in lowering the PVC burden.

Long ECGs reveal rich and robust dynamical regimes in patients with frequent ectopy

We have analyzed the electrocardiographic data collected during continuous 7-day ambulatory recordings in patients with frequent premature ventricular complexes (PVCs). We analyze the dependence of the frequency and patterns of PVCs on the heart rate and the time of the day. Patients display rhythms of a complex yet consistent structure. In a given patient, the pattern remains robust over different days and particular repetitive patterns appear at specific heart rates, suggesting the appearance of bifurcations in the dynamics. Over the course of 24 h, we find that in some patients, patterns appear to depend only on the heart rate, whereas in others, both the time of the day and the heart rate play a role in controlling the dynamics. Identifying parameter values at which bifurcations occur facilitates the development of dynamical models for arrhythmia. The use of powerful recording and analysis techniques will enable improved analysis of data and better understanding of mechanisms of arrhythmia in individual patients.

Efficacy of radiofrequency catheter ablation for premature ventricular contractions in children

PURPOSE

This study evaluated the efficacy and safety of transcatheter radiofrequency ablation (RFCA) in treating ventricular premature contractions (PVCs) in children, summarized the countermeasures during intraoperative ventricular fibrillation (VF), and improved the safety of ventricular premature treatment.

METHODS

A retrospective analysis was conducted on 75 children with PVCs who received RFCA in the Second Affiliated Hospital of Wenzhou Medical University from January 2010 to April 2019. Data including age, sex, body weight, ejection fraction, left ventricular end diastolic diameter, burden and number of PVCs/24 h, origin of PVCs, and its complications were collected. Paired t test was used to compare changes in cardiac function before and after surgery.

RESULTS

Among the 75 cases treated with RFCA, 68 were successfully ablated, giving a success rate of 90.67%. After ablation, the left ventricular ejection fraction (LVEF) of the children was 69.13 ± 3.81%, which was significantly higher than that before surgery (69.13 ± 3.81% vs. 66.21 ± 3.22%, P = 0.012). One of the patients experienced VF during the operation, with no other complications. The initial locus of origin was the anterior septum of the right ventricular outflow tract, but VF occurred during the ablation process. Mean follow-up time was 39 ± 33 months, with two recurrent cases (2.94%).

CONCLUSIONS

Performing RFCA in children is safe and effective, with a low recurrence rate and few complications. VF is not an indication to cease surgery; the key to eliminating complications is repositioning the catheter and finding a more accurate origin point.