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Left ventricular diastolic filling improvement obtained by intravenous verapamil in mild to moderate essential
F Franchi1, G Fabbri, A Monopoli
1Second Department of Special Medical Pathology, University of Florence, Italy.
Insights
Verapamil improves early left ventricular (LV) diastolic filling in hypertensive patients by enhancing peak filling rate, with sustained benefits observed 30 minutes post-administration. This study investigates the mechanism behind verapamil
Area of Science:
- Cardiology
- Pharmacology
Background:
- Essential hypertension can impair left ventricular (LV) diastolic function.
- Understanding the mechanisms by which antihypertensive drugs affect diastolic filling is crucial.
Purpose of the Study:
- To evaluate the mechanism by which verapamil improves LV diastolic early filling in patients with mild to moderate essential hypertension.
- To assess the impact of verapamil on various echocardiographic and hemodynamic parameters related to diastolic function.
Main Methods:
- 43 essential hypertensives and 20 normotensives underwent echocardiography and 99mTc radionuclide angiocardiography.
- Verapamil (i.v.) was administered to hypertensive patients, with measurements taken at baseline, 3 minutes, and 30 minutes.
- Phono-echo evaluation was performed to derive the LV isovolumetric relaxation index (IRTI).
Main Results:
- Verapamil increased peak filling rate (PFR) and tended to improve the PFR/peak ejection rate (PER) ratio within 3 minutes.
- Hemodynamic improvements included reduced mean arterial pressure and systemic arterial resistance index.
- A persistent improvement in the PFR/PER ratio was observed at 30 minutes, despite a return of other hemodynamic parameters to baseline.
Conclusions:
- Verapamil enhances early diastolic filling in essential hypertension, primarily through mechanisms affecting diastolic function rather than solely through vasodilation.
- The study suggests that verapamil's beneficial effects on diastolic filling persist beyond its immediate hemodynamic effects.
Abstract:
In order to try and evaluate through what prevailing mechanism verapamil (V) can induce an improvement in left ventricular (LV) diastolic early filling in mild to moderate essential hypertension, 43 properly classified essential hypertensives, aged 41-74 years (mean age 58.1 +/- 10.3), and 20 age-matched normotensives were studied. All subjects underwent both echocardiographic evaluation and 99mTc radionuclide angiocardiography in basal conditions between 8.00 a.m. and noon, after an overnight rest. In essential hypertensives gated equilibrium angiocardiography was repeated 3 and 30 min after i.v. V (0.1-mg/kg bolus, followed by 0.005 mg/kg/min for the period of radionuclide data acquisition). Simultaneously, supine arterial pressure was measured with a cuff manometer. In 36 essential hypertensives a phono-echo evaluation was obtained, both at 3 and 30 min after V, deriving a LV isovolumetric relaxation index (IRTI). Among diastolic early filling indices, we particularly considered the ratio of peak filling rate (PFR) to peak ejection rate (PER) in order to take into account the interaction of systolic performance with LV relaxation and diastolic early filling. Three minutes after V the increase in PFR (from 2.47 +/- 0.5 to 3.04 +/- 0.8 EDV/s, p less than 0.001) and the upwards tendency of PFR/PER were coupled with the enhancement in ejection fraction (from 61.1 +/- 13.3 to 63.9 +/- 13.8%, p less than 0.001) and heart rate (from 70.3 +/- 12.6 to 77.7 +/- 12.2 b/min, p less than 0.001) and with the reduction in mean arterial pressure (from 122 +/- 16 to 107 +/- 14 mm Hg, p less than 0.001), systemic arterial resistance index (from 3,234 +/- 968 to 2,432 +/- 678 dyn s cm-5 m2, p less than 0.001) and end-systolic volume index (from 32.9 +/- 17.1 to 31.5 +/- 18.3 ml/m2, p less than 0.02). On the contrary, 30 min after V, when systolic indices, heart rate, mean arterial pressure and systemic arterial resistance index had returned towards baseline values, PFR/PER showed a persistent improvement when compared with basal values (0.71 +/- 0.12 vs. 0.63 +/- 0.08, p less than 0.005). No changes were observed in LV volumes and IRTI, either at 3 or 30 min. Moreover, also the pulmonary blood volume ratio was unchanged. A weak negative correlation was found between delta % of IRTI and delta % of PFR/PER 30 min after drug administration (r = 0.58, p less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)