Tocainide and metoprolol: an efficacious therapeutic combination in the treatment of premature ventricular beats

Therapeutic Inefficacy and Proarrhythmic Nature of Metoprolol Succinate and Carvedilol Therapy in Patients With Idiopathic, Frequent, Monomorphic Premature Ventricular Contractions

BACKGROUND

Antiarrhythmic drugs remain the first-line therapy for treatment of idiopathic ventricular arrhythmias.

STUDY QUESTION

The aim of this study was to assess the therapeutic efficacy of extended-release metoprolol succinate (MetS) and carvedilol for idiopathic, frequent, monomorphic premature ventricular contractions (PVCs).

STUDY DESIGN

Study population consisted of 114 consecutive patients: 71 received MetS and 43 received carvedilol.

MEASURES AND OUTCOMES

All patients underwent 24-hour Holter monitoring at baseline and during drug therapy. PVC-burden response to drug therapy was categorized as "good" (≥80% reduction), "poor" (either <80% reduction or ≤50% increase), and "proarrhythmic" responses (>50% increase) based on change in PVC burden compared with baseline.

RESULTS

Most common presenting symptom was palpitations (65.8%), followed by coincidental discovery (29%). The mean MetS and carvedilol dosages were 65.57 ± 30.67 mg/d and 23.66 ± 4.26 mg/d, respectively. "Good," "poor," and "proarrhythmic" responses were observed in 11.3% and 16.3%, 63.4% and 67.4%, and 25.3% and 16.3% of patients treated with MetS and carvedilol, respectively. In patients with relatively high (≥16%) PVC burden, the sum of "poor"/"proarrhythmic" response was observed in 95.5% and 86.4% of patients treated with MetS and carvedilol, respectively. "Proarrhythmic" response was observed in 21.9% of the patients, particularly in the presence of relatively lower (≤10%) baseline PVC burden. Patients with "good" response during beta-blocker therapy had higher baseline daily average intrinsic total heart beats compared with patients with "poor"/"proarrhythmic" response combined (96,437 ± 26,488 vs. 86,635 ± 15,028, P = 0.047, respectively). Side effects and intolerance were observed in 5.6% and 18.6% of patients treated with MetS and carvedilol, respectively.

CONCLUSIONS

MetS and carvedilol for idiopathic, frequent, monomorphic PVCs are frequently inefficient. Therapeutic efficacy decreases further in patients with relatively high (≥16%) PVC burden. Relatively higher baseline daily intrinsic total heart beats may be used to predict "good" response before beta-blocker therapy.

Chinese Herbal Medicine Dingji Fumai Decoction for Ventricular Premature Contraction: A Real-World Trial

Background

Chinese herbal medicine Dingji Fumai Decoction (DFD) is widely clinically used for ventricular premature contraction (VPC). This real-word trial was designed to assess the safety and effectiveness of DFD for VPC.

Methods

This was a double-blinded, randomized placebo-controlled trial. Patients with VPC were randomized (1 : 1) to treatment with DFD combined with metoprolol (DFD arm) or metoprolol combined with placebo (MET arm). A primary end point was a composite of clinical symptoms and signs determined by the traditionalChinese medicine syndrome score and the number of VPC determined by the Holter examination. Second outcomes were adverse events, medication compliance, and laboratory examination.

Results

144 patients were randomized to DFD arm (76 patients) or MET arm (68 patients), and 136 cases (71 in DFD arm and 65 in MET arm) finally completed this trial. After a 12-week follow-up, DFD arm significantly decreased traditional Chinese medicine syndrome score and the number of VPC compared with MET arm (P = 0.003 and 0.034, respectively). There was no adverse drug effect and patient medication compliance was good.

Conclusions

Superiority with DFD arm for VPC was demonstrated over MET arm for both the safety and effectiveness end points.

Which Is The Appropriate Arrhythmia Burden To Offer RF Ablation For RVOT Tachycardias?

Premature ventricular complexes (PVCs) and ventricular tachycardia (VT) in patients with structurally normal hearts originate from the right ventricular outflow tract (RVOT) in the majority of cases. In the last few decades catheter ablation of these arrhythmias has been proven to be effective. RVOT VT/PVCs may cause disabling symptoms or arrhythmia induced cardiomyopathy. However, the PVC burden at which catheter ablation should be recommended is still controversial. What adds to the controversy is why some patients with only a low number of PVCs can be highly symptomatic and may even develop arrhythmia induced cardiomyopathy, whilst others may have a higher PVC/VT burden and remain asymptomatic and do not develop cardiomyopathy for a long period of time. Therefore, although catheter ablation of RVOT PVCs has high success and low complication rates, the time point of when ablation should be recommended is currently still under debate. This review discusses the treatment strategies and prognosis for RVOT tachycardias and focuses on the question of which arrhythmia burden is appropriate to offer RF ablation.

Combination antiarrhythmic treatment among class Ia, Ib, and II agents for ventricular arrhythmias

Ventricular arrhythmia suppression trials were performed to compare the efficacies and side effects of disopyramide and mexiletine used alone and in combination, and to compare the efficacies and side effects of mexiletine and propranolol used alone and in combination, in patients with chronic ventricular premature contractions (VPCs, greater than or equal to 3000 beats/day). The study on the combination of disopyramide and mexiletine included 26 patients (19 men and 7 women). Disopyramide 100 mg tid or mexiletine 150 mg tid was administered as single-drug therapy, and disopyramide 50 mg plus mexiletine 100 mg tid was administered as combination therapy. Each patient underwent Holter monitoring during four different periods: baseline, disopyramide alone, mexiletine alone, and combination therapy. The mean number of VPCs/hr at baseline was 796 +/- 522 (mean +/- SD), which was significantly decreased with all three therapies (p less than 0.01 in each) to a) 415 +/- 480 with disopyramide alone, b) 341 +/- 368 with mexiletine alone, and c) 345 +/- 408 with the combination therapy. The number of patients demonstrating a significant reduction in VPCs (greater than or equal to 75%) and the elimination of ventricular tachycardia (VT; three or more consecutive VPCs) did not differ significantly among the three therapies. The prematurity index (PI), vulnerability index (VI), and QTc tended to be aggravated by disopyramide therapy alone, but these values were corrected by combination therapy. No patients withdrew from the study due to side effects during combination therapy, although three patients withdrew from the study due to severe side effects during single-drug therapy.(ABSTRACT TRUNCATED AT 250 WORDS)