Effects of propranolol and timolol on left ventricular volumes during exercise in patients with coronary artery disease

Abstract

The hemodynamic effects of beta-receptor blocking agents on the ejection fraction of patients with coronary artery disease during exercise have been studied previously using radionuclide techniques. Left ventricular volume measurements and the peak systolic pressure/end-systolic volume (PSP/ESV) index have been shown to be variables of left ventricular function that are less influenced by preload and afterload than is ejection fraction. Left ventricular volumes and PSP/ESV were therefore measured in 18 patients with proven coronary artery disease in the control state and after 2 weeks of daily maintenance therapy with either 240 mg propranolol or 60 mg timolol. Values at rest and during symptom-limited upright exercise were compared using the first pass technique and a multicrystal scintillation camera. Left ventricular volumes were measured by the area-length method. Because there was no difference between the propranolol and timolol groups, the results for both groups were combined. The ejection fraction at rest after beta-receptor blocker treatment was not significantly different from pretreatment measurements because of an increase in both end-diastolic and end-systolic volumes (p less than 0.01). However, the value for peak systolic pressure/end-systolic volume (PSP/ESV) index at rest was lower after treatment. The exercise ejection fraction was greater after treatment (p less than 0.01), owing to an increase in end-diastolic volume and unchanged end-systolic volume. In addition, there was a significant improvement in the directional change in the PSP/ESV ratio between rest and exercise from pretreatment to treatment (-1.1 +/- 2.5 to +0.2 +/- 1.2, p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise release of cardiac natriuretic peptides is markedly enhanced when patients with coronary artery disease are treated medically by beta-blockers

“…Up to now, however, no study has analyzed the effect of these drugs on the exercise secretion of NPs. Exercising under beta-blockers leads to an increase cardiac preload, as evidenced by larger LV cavities at end diastole (31,32); thus, it may be wondered whether this also leads to an increase in wall tension or pressure high enough to trigger enhanced peptide release.…”

Effects of Atropine on Left Ventricular Volumes and Ejection and Filling Rates at Rest and During Exercise

“…In canine heart preparations DeGeest et al (1965) reported a lower systolic and an increased diastolic left ventricular (LV) pressure induced by vagal stimulation. Vagal blockade results in diminished LV diameters in dogs (Bishop & Horwitz, 1971), whereas ,-adrenoceptor blockade has the opposite effect, at least in humans (Chamberlain, 1966;Kalischer et al, 1984). Total autonomic nervous blockade causes a reduction in both stroke volume (SV) and LV ejection fraction (EF) at rest in healthy subjects, while cardiac output (CO) is maintained through relative tachycardia (Jose & Taylor, 1969;Kelbek et al, 1987).…”

Effects of atropine on left ventricular volumes and ejection and filling rates at rest and during exercise.

“…In canine heart preparations DeGeest et al (1965) (Bishop & Horwitz, 1971), whereas ,-adrenoceptor blockade has the opposite effect, at least in humans (Chamberlain, 1966;Kalischer et al, 1984). Total autonomic nervous blockade causes a reduction in both stroke volume (SV) and LV ejection fraction (EF) at rest in healthy subjects, while cardiac output (CO) is maintained through relative tachycardia (Jose & Taylor, 1969;Kelbek et al, 1987).…”