The basis for differences in ethanol-induced myocardial depression in normal subjects.

The acute effects of ethanol (ETOH) on cardiac function in 32 normal subjects has been studied utilizing systolic time intervals. Seven (group I) 13 (group II), and 12 subjects (group III), reported an average daily consumption of less than 1 oz, 1-2 oz, and more than 2 oz of ETOH, respectively. Progressively higher control values from group I to group III in PEP, PEPI, ICT and PET/LVET were observed (PEP-I vs PEPI-III: P smaller than 0.05; PEP/LVET-I vs PEP/LVET-II and PEP/LVET-III: P smaller than 0.05). There was progressively less change in these variables following acute ETOH (P smaller than 0.02-0.05 in group I; P equals NS in group III, group II intermediate). This indicates some degree of chronic myocardial impairment in group II and especially in group III, which tends to be proportionate to the degree of chronic ETOH exposure. These data are not necessarily disparate with previous reports of little or even a salutary hemodynamic effect of ETOH in normal subjects. Thus, the relative stability of LVET post ETOH, coupled with the observed increase in heart rate, is consistent with previous reports of ETOH-induced rate-dependent increments in cardiac output with unchanging stroke volumes, in spite of the presence of acute myocardial depression. The observations reported herein demonstrate the probable incremental influence of ETOH consumption in a chain of events which may culminate in alcoholic cardiomyopathy.