Copyright © 1988 by the European Society of Cardiology.
© 1988 The European Society of Cardiology
Electrocardiographic alterations suggestive of myocardial injury elicited by rapid pressure lowering in hypertension
Istituto di Cardiologia, Centro di Studio per le Ricerche Cardiovascolari del Consiglio Nationale delle Ricerche, Istituto G. Sisini, Foundazione I. Monzino University of Milan Milan, Italy
Received 25 September 1987; revised 14 January 1988; .
Correspondence should be addressed to: Maurizio D. Guazzi, Istituto di Cardiologia, Via Bonfadini, 214, 20138 Milano, Italy
Abstract
In hypertensive cardiac hypertrophy, the elevated coronary perfusion pressure compensates importantly for the raised coronary resistance. An imbalance between perfusion and left ventricular (LV) mass, such as that occurring with rapid or excessive blood pressure lowering, may result in an inadequate oxygen supply.
In 28 primary hypertensives (Group A) with LV mass index within the mean +l SD (96+19 gm2) of 145 controls, and in 26 patients whose LV mass exceeded these values (Group B), we lowered the diastolic blood pressure rapidly to 8590 mm Hg, using both s.l. nifedipine and i.v. nitroprusside. During each test, eight patients in Group B had inversion of T waves in lead I, a VL V3-V6, which waxed and waned in parallel with the pressure fall and recovery, and was independent of conduction disturbances, variations or group differences in the QRS axis QT interval, heart rate, LV fractional shortening and wall stress.
A coronary steal phenomenon or passive collapse in compliant lesions consequent to vasodilatation may trigger acute myocardial ischaemia in the presence of severe coronary disease. Patients developing the ECG alterations, however, were free from angina and four, who were subjected to coronary angiography, had normal arteriograms. Patients with the myocardial injury pattern showed greater LV mass indices and larger falls in diastolic pressure for it to reach normal levels.
The supply of energy to the hypertrophied hypertensive heart seems to depend importantly on the coronary perfusion pressure, suggesting the cautious use of rapid acting drugs.
Key Words: Coronary perfusion LV mass nifedipine subendocardium.