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Influence of therapy on silent ischemia and ventricular arrhythmias in hypertensive patients
J Szlachcic1, J F Tubau, B O'Kelly
1Department of Cardiology, Veterans Administration Medical Center, San Francisco, California.
Insights
Nitrendipine therapy reduced silent ischemia in asymptomatic hypertensive patients, while hydrochlorothiazide (HCTZ) did not. HCTZ therapy increased premature ventricular contractions (PVCs), whereas nitrendipine did not affect them.
Area of Science:
- Cardiology
- Pharmacology
- Hypertension Management
Background:
- Silent myocardial ischemia and arrhythmias are significant concerns in asymptomatic hypertensive patients.
- Thallium-201 (Tl-201) scintigraphy is used to detect ischemia in these patients.
- Assessing the impact of antihypertensive therapies on these subclinical cardiac events is crucial.
Purpose of the Study:
- To evaluate the effects of hydrochlorothiazide (HCTZ) and nitrendipine on silent ischemia and arrhythmias.
- To compare the efficacy of HCTZ and nitrendipine in managing cardiac events in hypertensive individuals.
Main Methods:
- A double-blind, crossover study involving 10 asymptomatic hypertensive males with positive Tl-201 scintigraphy.
- Patients received placebo, HCTZ, and nitrendipine for 8 weeks each, with blood pressure and 48-h Holter monitoring.
- Ischemia quantified by ST-segment depression episodes, duration, and AUC; arrhythmias assessed by premature ventricular contractions (PVCs) and ventricular tachycardia.
Main Results:
- Both HCTZ and nitrendipine significantly reduced diastolic blood pressure but not systolic blood pressure.
- Nitrendipine significantly decreased the number, duration, and AUC of ischemic episodes.
- HCTZ therapy increased PVCs, while nitrendipine did not alter PVC frequency.
Conclusions:
- Nitrendipine effectively reduces silent myocardial ischemia in asymptomatic hypertensive patients.
- Hydrochlorothiazide therapy may increase the risk of arrhythmias, specifically PVCs.
- Nitrendipine appears to be a favorable option for managing both blood pressure and silent ischemia in this population.
Abstract:
To assess whether therapy with hydrochlorothiazide (HCTZ) or the calcium antagonist nitrendipine influences silent ischemia or arrhythmias, we studied 10 asymptomatic hypertensive male patients with positive Tl-201 scintigraphy in a double-blind, crossover protocol. Blood pressure (BP) and 48-h Holter monitoring were obtained after 2 weeks of placebo and 8 weeks each of HCTZ and nitrendipine therapy. Ischemia was defined as greater than 1 mm ST-segment depression lasting greater than 1 min and was quantified by the number of episodes, duration, and area under the curve (AUC). The mean number of PVCs per hour and the number of episodes of ventricular tachycardia (greater than 3 beats) were also assessed. Diastolic BP was significantly reduced by both HCTZ and nitrendipine (98 +/- 6 vs. 90 +/- 6 vs. 88 +/- 7 mm Hg, respectively, p less than 0.05), but systolic BP was unchanged for either drug. The number of ischemic episodes was reduced by nitrendipine, from 2.4 +/- 3 to 0.8 +/- 2, (p less than 0.05) but not by HCTZ (2.4 +/- 3 to 1.5 +/- 3, p = NS). The duration of ischemia (37 +/- 43 vs. 5 +/- 9 min, p less than 0.05) as well as the AUC (41 +/- 45 vs. 7 +/- 14 mm/min, p less than 0.05) were reduced only by nitrendipine. The number of PVCs rose with HCTZ therapy, from 19 +/- 34 to 69 +/- 88 (p less than 0.05) and was unchanged by nitrendipine (19 +/- 34 vs. 19 +/- 40, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)