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The effect of chlorthalidone on ventricular ectopic activity in patients with isolated systolic hypertension. The
J B Kostis1, C R Lacy, W D Hall
1University of Medicine and Dentistry of New Jersey (UMD-NJ)-Robert Wood Johnson Medical School, New Brunswick.
Insights
Chlorthalidone effectively treats isolated systolic hypertension without increasing ventricular premature complexes (VPCs). This diuretic, used in low doses, did not alter VPC frequency in elderly patients, even with mild potassium changes.
Area of Science:
- Cardiology
- Pharmacology
- Geriatrics
Background:
- Isolated systolic hypertension is common in the elderly.
- Diuretics are a first-line treatment for hypertension.
- The effect of diuretics on cardiac electrical activity, specifically ventricular ectopy, requires further investigation in this population.
Purpose of the Study:
- To investigate the effects of chlorthalidone on ventricular ectopic activity (VEA) in elderly patients with isolated systolic hypertension.
- To determine if chlorthalidone, at doses effective for cardiovascular event reduction, increases the occurrence of ventricular premature complexes (VPCs).
Main Methods:
- An ancillary study of the Systolic Hypertension in the Elderly Program (SHEP) involving 186 patients.
- Patients were randomized to receive either chlorthalidone (12.5 and 25 mg/day) or a placebo.
- Ventricular premature complexes (VPCs) were assessed using various metrics, including VPCs per 24 hours, presence of VPCs, and VPC pairs or ventricular tachycardia.
Main Results:
- No significant changes in VPCs were observed in either the chlorthalidone or placebo groups.
- Serum potassium decreased in the chlorthalidone group but remained stable in the placebo group.
- No correlation was found between serum potassium levels and VPCs or changes in VPCs within the chlorthalidone group.
Conclusions:
- Chlorthalidone, at effective doses for reducing stroke and cardiovascular events (12.5 or 25 mg/day), does not increase ventricular ectopic activity in elderly patients with isolated systolic hypertension.
- The findings suggest that chlorthalidone can be safely used in this population without exacerbating ventricular arrhythmias.
Abstract:
In an ancillary study of the Systolic Hypertension in the Elderly Program (SHEP), the effects of diuretics on ventricular ectopic activity were investigated in 186 patients with isolated systolic hypertension. Ventricular premature complexes (VPCs) were examined as the number of VPCs/24 hours, presence of > or = 1 VPC, presence of > or = 10 VPCs/24 hours, and presence of VPC pairs or ventricular tachycardia. Significant changes in VPCs were not observed either in the 92 patients randomized to chlorthalidone stepped-care (12.5 and 25 mg/day) or in the 94 placebo-treated patients (p > 0.1 for all VPC definitions and both groups). Serum potassium decreased from 4.4 +/- 0.5 to 4.1 +/- 0.5 mEq/liter (p = 0.002) in the chlorthalidone group and did not change (4.4 +/- 0.5 to 4.5 +/- 0.4 mEq/liter) in the placebo group. Potassium was prescribed routinely for confirmed hypokalemia < 3.5 mEq/liter. A relation between serum potassium and VPC or change in serum potassium and change in VPC was not observed in the chlorthalidone group. In summary, in patients with isolated systolic hypertension, chlorthalidone in doses that are effective in decreasing stroke and cardiovascular event rates (12.5 or 25 mg/day), did not increase VPCs.