[Utility of QTc interval for the diagnosis of cardiac autonomic neuropathy in type 2 diabetes mellitus].
Prolonged QTc interval is a rapid objective method for detecting diabetic cardiac autonomic neuropathy (CAN). Diabetic CAN is a well recognized complication of diabetes mellitus type 2, and its incidence has been reported to be 20-40%, but detection of CAN is not a practical screening method for a large number of diabetic patients.


METHODS
65 cases of type 2 diabetes mellitus with no clinical evidence of cardiac disease were subjected to a battery of 5 non-invasive autonomic function tests as recommended by Ewing; these included deep breath test, orthostatic stress (30:15 ratio), Valsalva ratio, diastolic blood pressure rise with sustained hand grip, and postural hypotension on standing. A score of 2 or larger denoted CAN. QT interval was calculated by Atria 3100 interpretive electrocardiograph. The QTc was determined with Bazett's formula, and a value exceeding 440 msec was considered prolonged.


RESULTS
24 cases of type 2 diabetes mellitus (36.92%) were found to have CAN. QTc prolongation was observed in diabetics (433.89 +/- 30.37 ms) by comparison with control group 421.2 +/- 24.6 ms (F = 4.9, p = 0.03). QTc was much higher in diabetics with CAN (442.4 +/- 32.69 ms) vs. diabetics without CAN (424.48 +/- 23.45 ms). QTc prolongation correlated positively with the degree of cardiac autonomic neuropathy.


CONCLUSIONS
The study has shown that QTc prolongation is an easy and specific testing method for diabetic cardiac autonomic failure.
Universitatea de Medicină şi Farmacie Gr. T. Popa Iaşi, Facultatea de Bioinginerie Medicală, Catedra Stiinţe Biomedicale Facultatea de Medicină.
Daniela
D
Matel
Al D
AD
Chiochină
Ana
A
Stratone
D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D003929:Diabetic Neuropathies / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000294:innervation / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D015994:Incidence; D008133:Long QT Syndrome / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012383:Romania / Q000453:epidemiology