[Evaluation of left ventricular function in diabetics by studying systolic time intervals]

Systolic time intervals were measured before and four minutes after maximal exercise stress testing in 54 patients without obvious cardiac disease. Twenty seven patients (average age 46 years) had diabetes of over 5 years standing (group II); group I comprised 27 normal controls (average age 46 years). All patients underwent maximal treadmill stress testing using the Bruce protocol and the maximal heart rate was achieved without any signs of coronary insufficiency. No significant difference was observed in the basal systolic time intervals of the two groups. The difference was not significant 4 minutes after the stress test. However, when the changes before and after exercise were compared, the patients in group I had a significant increase in heart rate (p less than 0,001), a reduction in the duration of electromechanical systole (QB2; p less than 0,02) in the preejectional period (PEP; p less than 0,001) and in the PEP/LVET ratio: p less than 0,01, whilst left ventricular ejection time (LVET) remained unchanged. The patients in group II only showed an increase in heart rate (p less than 0,01) and LVET (p less than 0,001). The differences in the systolic time intervals after exercise between these two groups probably reflect a degree of cardiac dysfunction which is not apparent at rest.