Left ventricular diastolic filling improvement obtained by intravenous verapamil in mild to moderate essential hypertension: a complex effect.

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)