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Effects of intravenous verapamil administration on left ventricular diastolic function in systemic hypertension
Insights
Intravenous verapamil in hypertensive patients lowered blood pressure and ejection fraction, but improved diastolic filling rates in select individuals. This calcium channel blocker impacts cardiac function and hemodynamics in hypertension.
Area of Science:
- Cardiology
- Pharmacology
- Cardiovascular Physiology
Background:
- Hypertension is a prevalent condition affecting cardiovascular health.
- Verapamil, a calcium channel blocker, is used to manage hypertension.
- Understanding verapamil's effects on cardiac function is crucial for patient management.
Purpose of the Study:
- To investigate the hemodynamic and cardiac functional effects of intravenous verapamil in hypertensive patients.
- To assess changes in heart rate, blood pressure, ejection fraction, and diastolic filling parameters.
Main Methods:
- Utilized high-temporal-resolution radionuclide angiography in 27 hypertensive patients.
- Administered intravenous verapamil (0.1 mg/kg bolus followed by 0.007 mg/kg/min infusion).
- Monitored heart rate, blood pressures (systolic, diastolic, mean), ejection fraction, and diastolic filling parameters.
Main Results:
- Verapamil increased heart rate (69 to 75 bpm) and decreased blood pressure (155/102 to 142/95 mm Hg).
- Ejection fraction significantly decreased (65% to 60%).
- Peak filling rate improved in patients with initially subnormal rates, correlating with higher LV mass index.
Conclusions:
- Intravenous verapamil effectively reduces blood pressure in hypertensive patients.
- Verapamil can negatively impact ejection fraction.
- Diastolic function improvements are observed in specific patient subgroups, suggesting tailored therapeutic responses.
Abstract:
The effects of intravenous verapamil administration (0.1 mg/kg as a bolus followed by an infusion of 0.007 mg/kg/min) were studied using high-temporal-resolution radionuclide angiography in 27 patients with hypertension. Verapamil administration increased heart rate from 69 +/- 11 to 75 +/- 12 beats/min (p less than 0.001) and decreased systolic, diastolic and mean blood pressures (BPs) from 155 +/- 21/102 +/- 12 mm Hg (mean 119 +/- 14) to 142 +/- 19/95 +/- 12 mm Hg (mean 109 +/- 13) (p less than 0.001 for all). Ejection fraction decreased significantly (from 65 +/- 10% to 60 +/- 11%, p less than 0.005); peak filling rate, however, increased significantly only in patients in whom it was subnormal in the basal study (from 2.2 +/- 0.4 to 3.0 +/- 0.6 end-diastolic counts/s, p less than 0.001). These latter patients had significantly higher values of left ventricular (LV) mass index than patients with normal or increased peak filling rate (129 +/- 22 vs 112 +/- 22 g/m2, respectively, p less than 0.05). The isovolumic relaxation period changes were inversely related to the baseline values (r = 0.83, p less than 0.001). In the subgroup of patients in whom isovolumic relaxation period lengthened, time to end systole decreased (from 360 +/- 31 to 329 +/- 30 ms, p less than 0.025) and time to onset of rapid filling increased (from 420 +/- 31 to 451 +/- 34 ms, p less than 0.025), whereas these 2 intervals had opposite patterns in patients in whom isovolumic relaxation period decreased or did not change.(ABSTRACT TRUNCATED AT 250 WORDS)