Effect of sublingual nitroglycerin on left ventricular wall movement in patients with coronary artery disease. Comparison with propranolol and saphenous bypass grafting.

The effects of trinitrin and propranolol on left ventricular function were compared with those of saphenous bypass grafting in patients with ischaemic heart disease. Simultaneous echocardiograms, apexcardiograms and phonocardiograms were recorded and digitized before and after drug administration or operation. As expected, trinitrin caused a reduction in left ventricular cavity size, an increase in peak VCF and an increase in heart rate, while propranolol consistently reduced heart rate and peak VCF. Asynchronous onset of wall movement was unaffected by propranolol or trinitrin, but when present preoperatively, consistently improved after saphenous bypass grafting. Abnormalities of relaxation, usually due to asynchronous termination of contraction, were aggravated by trinitrin or propranolol in those patients in whom contraction was initially incoordinate, but after operation, they tended to improve along with systolic abnormalities. The time interval, Q to minimum LV cavity dimension is frequently reduced in patients with ischaemic heart disease, and treatment with propranolol increases the frequency of this abnormality. Saphenous bypass grafting, however, was associated with a consistent return towards normal, regardless of changes in heart rate. Thus although trinitrin, propranolol and saphenous bypass grafting all relieve angina, their effects on left ventricular function are significantly different.