Etiology of QT prolongation and T wave changes in chronic alcoholism.

Etiology of QT prolongation and T wave high voltage was studied in 90 chronic alcoholics in relation to history of alcoholism, blood chemical values, heart rate and QRS voltage with a technic of multiple regression analysis. Incidences of QT prolongation (22%), T wave high voltage in lead V2 (9%), hypopotassemia (23%), hypocalcemia (26%) and hypomagnesemia (28%) were high, despite these examinations were done after relatively long abstention period (35 days on average). Sinus tachycardia (19%) and QRS high voltage (SV1 + RV5 exceeding 4 mV, 41%) were also frequent. Unexpectedly, QT interval did not correlate to serum electrolytes, including calcium. Major factors associated with QT prolongation were sinus tachycardia, longer abstention period and larger amount of daily alcohol consumption. Although the reason of each association was not quite clear, alcoholic myocardial damage may be a cause of QT prolongation. Voltage of T wave in lead V2 was sensitive to serum potassium level, but the observed tendency of hypopotassemia acted to the direction against high voltage of T wave. The sole factor positively associated with high voltage of TV2 was high QRS voltage, which may be a manifestation of left ventricular hypertrophy.