Systolic time intervals and the QT-QS2 interval in young female diabetics

To detect subclinical cardiomyopathy in diabetic patients without evidence of coronary artery disease, systolic time intervals were measured in 51 insulin-treated young female diabetics (mean age 27 years and mean duration of diabetes 12 years) and in 15 healthy women of the same age. The ratio of the pre-ejection period to the left ventricular ejection time (PEP/LVET) was used as an index of left ventricular performance. The PEP/LVET ratio was normal in all diabetics and did not differ statistically from that in the control group. The electrical (QT) and electromechanical (QS2) systole were measured from the same high velocity recordings. The QT-QS2 interval (mean +/- SD) was shorter in the diabetic group (-16 +/- 22 ms vs. -33 +/- 9 ms, p less than 0.01). Ten diabetics but none of the healthy women, had the QT interval longer than the QS2. This was a result of both shortening of the QS2 and prolongation of the QT. In conclusion, our results suggest normal myocardial contractility in these young female diabetics. The significance and mechanism of the shortened QT-QS2 interval in the diabetics need further investigation.