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Abstract

Cardiovascular complications are the most common causes of mortality and morbidity in diabetic patients. Autonomic neuropathy is one of the complications in diabetic patients, which may also involve cardiovascular system. Autonomic system abnormality may increase QTc interval. On the other hand patients with prolonged QTc interval are prone to ventricular arrhythmias, especially unique torsade-de-point and also sudden cardiac death. This study intends to detect the prevalence of QTc prolongation in diabetic and nondiabetic patients as well as its correlation with diabetic autonomic neuropathy. This study includes 200 diabetic (case group) and 200 non-diabetic patients (control group) with comparable age and gender. Evaluation of autonomic nervous system was carried out in all cases with prolonged QTc interval. Autonomic nervous system evaluation in control group was performed too. The results of the study in the case and the control group were compared. The prevalence of prolonged QTc interval was significantly higher in the case group in comparison with the control group, 8 vs. 2% respectively (p value = 0.012, OR = 4.3). Sympathetic nervous system evaluation test in cases with QTc interval prolongation and negative exercise test demonstrates abnormal results in more than 50% of case group (OR = 3). Parasympathetic nervous system evaluation tests in case group showed abnormal results in comparison with control group (OR = 9). Abnormality of parasympathetic nervous system is more common than (3 fold) abnormality in sympathetic nervous system. With regard to the prolonged QTc interval in the case group in comparison with the control group and abnormal autonomic nervous system function in more than half of the case group, the probability of ventricular arrhythmia, torsade de points, has increased. The mentioned ones are in increased risk of sudden cardiac death. Rendering approaches for decreasing the risk of sudden cardiac death in diabetic patients are seriously recommended.

Differences and Similarities in Neuropathy in Type 1 and 2 Diabetes: A Systematic Review

“…In our findings, we observed that there is a greater sympathetic than parasympathetic impairment, as indicated by the screening tests for autonomic cardiac neuropathy [15,17,19,28,29,[31][32][33]35]. These results are consistent with the research of Pourmoghaddas and Hekmatnia [76] who confirmed that parasympathetic abnormality was three times greater than the sympathetic affectation in diabetic CAN. Furthermore, tests that examine parasympathetic activity, such as HR response 15 and 30 s after changing position, HR response during deep respiration and HR response during Valsalva maneuver, were found to be more impaired in type 2 diabetics [15,17,19,33], with the exception of the HR variation test during rest, which was more affected in type 1 diabetics [17,19].…”

Cardiac autonomic dysfunction in sickle cell anaemia and its correlation with QT parameters

“…To the best of our knowledge, there are no studies that evaluated the relationship between cardiac autonomic dysfunction and QT parameters in SCA in our environment. However, some workers have shown direct linear relationship between the extent of CAN and QTc interval in patients with epilepsy and type 2 diabetes mellitus 252627. In a study involving type 2 diabetic patients by Kumhar et al ., and Kahn et al ., strong correlations were found between QT parameters and cardiac autonomic dysfunction 122627.…”

“…However, some workers have shown direct linear relationship between the extent of CAN and QTc interval in patients with epilepsy and type 2 diabetes mellitus 252627. In a study involving type 2 diabetic patients by Kumhar et al ., and Kahn et al ., strong correlations were found between QT parameters and cardiac autonomic dysfunction 122627. Incidentally, one of the patients studied by Kahn et al ., who had both cardiac autonomic dysfunction and prolonged QTc died unexpectedly.…”

Sudden Cardiac Death in Low- and Middle-Income Countries

“…DM-specific accelerated forms of atherosclerosis may exist with enhanced thrombogenicity [40]. Additionally, there is a high prevalence of abnormal QT interval prolongation among diabetic individuals [41,42]. QT interval prolongation, regardless of the primary cause, has been associated with increased overall cardiac mortality [43].…”