Isometric exercise (IME) produces significant hemodynamic changes in the cardiovascular system. We have used IME to study the effect of age on diastolic left ventricular (LV) function in 100 normal volunteers. The E/A ratio (peak velocity of early/atrial filling phases), deceleration time (DT), and isovolumic relaxation time (IVRT) of the transmitral flow were assessed during echocardiography with pulsed-Doppler ultrasound at rest and at peak IME using handgrip. LV mass index (LVMI) and LV ejection fraction (LVEF) were also calculated. Both E/A and IVRT reduced significantly with increasing age. The LVEF decreased (P <.0001), whereas LVMI increased (P <.05) with advancing age. The LVEF was inversely related to LVMI (P <.05). An inverse relationship was noted between E/A and LVMI (P <.01) during IME. The contribution of the atrial contraction to the total diastolic flow increased significantly with advancing age (P <.02) and increased from 0.29 +/- 0.04 at rest to 0.34 +/- 0.08 during IME (P <.0001). It is concluded that with progressing age, the left ventricle becomes stiffer resulting in a reduction in early filling and a compensatory increase in flow due to atrial contraction. A progressive increase in LVMI, which accompanies aging may contribute to stiffening of the left ventricle and deterioration in diastolic function of the left ventricle. This is exaggerated by IME.

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SUMMARY Twenty-seven patients with complete right bundle-branch block as the only abnormal finding were studied using high speed M-mode echocardiography to determine the effect of the electrical delay on the mechanical events of right ventricular systole. Pulmonary valve opening (PVOm) was delayed in all cases. In some the delay was mainly between mitral valve closure (MVC) and tricuspid valve closure (TVC), and this was designated proximal block. In the others the main delay was between tricuspid valve closure and pulmonary valve opening and this was designated distal block. The patients were divided into those with proximal and those with distal block by calculating the ratio TVC-PVOm/MVC-TVC. Twelve out of 13 of those with distal delay but only one out of 14 of those with proximal delay had episodes of syncope or near syncope. These results are consistent with previous theories about the pathophysiology of right bundle-branch block.

The purpose of this randomized controlled study was to assess the haemodynamic effects, safety and tolerability in acute myocardial infarction (AMI) of one month of oral captopril, one month of oral isosorbide mononitrate and 24 h of intravenous magnesium. It was carried out in four United Kingdom and six Polish hospitals in consecutive phases: oral captopril vs oral mononitrate vs placebo were compared among 400 patients in a 'three-way' study; and then oral captopril vs placebo and oral mononitrate vs placebo were compared among 474 patients in '2 x 2' and '2 x 2 x 2' factorial studies (with 208 patients in the latter study also randomized between intravenous magnesium and open control). The factorial studies differed from the three-way study in that one group of patients was allocated both oral captopril and oral mononitrate, a higher maintenance dose of captopril was used (following the same initial dose), and once daily controlled-release mononitrate was used. In the three-way study, the mean of the lowest systolic blood pressures recorded during the first 4 h after randomization were (mmHg +/- standard error): 104 +/- 2 captopril vs 105 +/- 1 mononitrate vs 112 +/- 2 placebo (P < 0.001 for captopril or for mononitrate vs placebo), and in the factorial studies were 105 +/- 1 captopril vs 110 +/- 1 placebo (P < 0.01) and 106 +/- 1 mononitrate vs 108 +/- 1 placebo (NS). There was an excess of hypotension recorded among patients allocated active treatment (captopril > mononitrate > placebo) and there was a small, but significant, excess of cardiogenic shock with captopril compared with control in the factorial study. However, in these studies, neither captopril nor mononitrate were associated with any overall increase in the incidence of hypotension considered severe enough to lead to treatment being stopped. No other serious complications were observed, and compliance with study tablets at hospital discharge was not significantly different between the active and placebo groups. Patients allocated magnesium in the 2 x 2 x 2 factorial study had a slightly lower mean systolic blood pressure just after the initial 15 min bolus injection (126 +/- 2 magnesium vs 134 +/- 3 control; P < 0.05) but there were no significant differences during the subsequent 24 h maintenance infusion period. Apart from some facial flushing, magnesium did not appear to be associated with any complications.(ABSTRACT TRUNCATED AT 400 WORDS)