Effects of Beta Adrenergic Blockade on the Circulation, with Particular Reference to Observations in Patients with Hypertrophic Subaortic Stenosis

Abstract

The circulatory effects of blocking the beta adrenergic receptors with Nethalide were studied in 10 patients with hypertrophic subaortic stenosis and in five postoperative subjects undergoing right heart catheterization. In the resting state, the heart rate and the rate of pressure development in the right ventricle diminished slightly, but cardiac index was not altered by the administration of Nethalide. These observations suggest that tonic sympathetic activity is not of major importance in basal subjects in the supine position. Nethalide attenuated the increase in heart rate and right ventricular dp/dt associated with exercise, and abolished the response of these two variables to the administration of isoproterenol. In the patients with hypertrophic subaortic stenosis Nethalide had little effect on the severity of the obstruction at rest, but reduced the intensification of the obstruction produced by exercise or isoproterenol. The possible clinical benefits of blocking the beta adrenergic receptors in these patients were discussed.

Recent Advances in Hypertrophic Cardiomyopathy: A System Review

“…Small and mostly retrospective studies suggest that oral propranolol can abolish or reduce resting and provocable LVOTO and provide symptomatic beneit [49,50]. Donald et al's study showed that β-blocker abolished the increase in gradient caused by isoproterenol and, more importantly, halved the increase in gradient caused by exercise [51]. In a 5-year follow-up, a study demonstrated that propranolol signiicantly improved the HCM patient's syndrome (dyspnea, angina, palpitations, dizziness, and syncope) by 58-100% [52].…”

Hypertrophic cardiomyopathy: diagnosis, risk stratification and treatment

“…33,41,65 Reduced inotropy and longer ventricular filling times associated with β-blockade can reduce obstructive symptoms. Some centres have taken the approach of using verapamil as a first-line agent, but this strategy can be associated with acute exacerbation of obstruction due to preferential lowering of systemic vascular resistance.…”

Preoperative and Operative Management of Patients With Phaeochromocytoma

“…Pronethalol is effective against ventricular arrhythmias (Harrison, Braunwald, Glick, Mason, Chidsey, and Ross, 1964;Cohen, Effat, Goodwin, Oakley, and Steiner, 1964) and has been used to protect against arrhythmias during operative removal of a phaeochromocytoma (Riddell et al, 1963). Pronethalol antagonizes arrhythmias produced by cardiac glycosides (Stock and Dale, 1963;Vaughan Williams and Sekiya, 1963).…”