[The functional capacity of the coronary circulation in myocardial hypertrophy].
Experimental studies showed anatomic and functional abnormalities in coronary circulation of hypertensive hypertrophic hearts. Epidemiologic and clinical data suggest that hypertensive patients with myocardial hypertrophy are more prone or sensitive to myocardial ischemia. Although several factors have been invoked to explain these observations, pathophysiological abnormalities in coronary circulation of hypertrophied hearts due to pressure overload in man are unsettled. Recently we evaluated coronary flow, through thermodilution, during progressive reduction of perfusion pressure in hypertensive patients with and without left ventricular hypertrophy. While in hypertensives with normal left ventricular mass, no significant changes of coronary flow were observed during reduction of perfusion pressure until 70 mmHg were reached, in patients with myocardial hypertrophy coronary flow began to decrease at 90 mmHg. Meanwhile, a small but significant increase of oxygen myocardial extraction was recorded at 75 and 70 mmHg. These data suggest that even in man when hypertension and hypertrophy are concomitant, the lower range of coronary autoregulation is shifted to a higher perfusion pressure and that under these conditions, the myocardium may be vulnerable to treatment-induced relative hypotension.
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Istituto di Cardiologia, Università degli Studi, Milano.
D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000188:drug therapy / Q000503:physiopathology*; D017202:Myocardial Ischemia / Q000188:drug therapy / Q000503:physiopathology
Capacità funzionale del circolo coronarico nell'ipertrofia miocardica.