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Suppression of complex ventricular arrhythmias by oral flecainide
Abstract:
The effectiveness and safety of oral flecainide for suppression of complex ventricular arrhythmias was tested in nine patients in a short-term (4 wk), single-blind, placebo-controlled experiment. The prevalence of multiform premature ventricular complexes (PVCs), couplets and nonsustained ventricular tachycardia (VT) (less than 3 PVCs at rate less than 100/min) was determined by 48-hr Holter monitoring on placebo and flecainide (200 to 300 mg b.i.d.) therapy. Multiform PVCs/hr were reduced by 96% in eight of nine patients (P less than 0.001). Couplets per 24-hr period were suppressed entirely in six patients (P less than 0.001). Couplets per 24-hr period were suppressed entirely in six patients (P less than 0.001) and reduced by 92% in the remaining two patients. VT runs per 24 hr were abolished in six patients (P less than 0.02) and reduced by 91% in one. As a group the frequency of PVCs per hour, couplets per 24 hr and VT per 24 hr was reduced by 96% (P less than 0.01) over than in the preceding placebo period. Flecainide (P less than 0.02) slowed heart rate by 10% and prolonged PR, QRS, and QTc intervals by 31%, 47% and 6%. No hematologic, hepatic, or renal abnormalities were found. Side effects were mild, transient, and central nervous system related; blurring of vision was the most frequent effect and was reported in four patients.
Insights
Oral flecainide effectively suppressed complex ventricular arrhythmias, including premature ventricular complexes and ventricular tachycardia, in a short-term study. No significant safety concerns were identified, with only mild, transient side effects reported.
Area of Science:
- Cardiology
- Clinical Pharmacology
Background:
- Complex ventricular arrhythmias pose a significant clinical challenge.
- Antiarrhythmic drug therapy is a cornerstone in managing these conditions.
Purpose of the Study:
- To evaluate the efficacy and safety of oral flecainide in suppressing complex ventricular arrhythmias.
- To assess the impact of flecainide on heart rate and electrocardiographic intervals.
Main Methods:
- A 4-week, single-blind, placebo-controlled study involving nine patients.
- 48-hour Holter monitoring was used to quantify premature ventricular complexes (PVCs), couplets, and nonsustained ventricular tachycardia (VT).
- Flecainide was administered at 200 to 300 mg twice daily.
Main Results:
- Flecainide significantly reduced multiform PVCs/hr by 96% (P < 0.001) in eight of nine patients.
- Complete suppression of couplets was observed in six patients, with a 92% reduction in two others (P < 0.001).
- Ventricular tachycardia runs were abolished in six patients and reduced by 91% in one (P < 0.02).
- Overall frequency of PVCs, couplets, and VT decreased by 96% (P < 0.01).
- Flecainide slowed heart rate by 10% (P < 0.02) and prolonged PR, QRS, and QTc intervals.
Conclusions:
- Oral flecainide demonstrates significant efficacy in suppressing complex ventricular arrhythmias.
- The drug was well-tolerated, with no hematologic, hepatic, or renal abnormalities.
- Mild, transient central nervous system side effects, primarily blurred vision, were the most common adverse events.