Diabetes Metab J.  2013 Jun;37(3):190-195. 10.4093/dmj.2013.37.3.190.

Corrected QT Interval Prolongation during Severe Hypoglycemia without Hypokalemia in Patients with Type 2 Diabetes

• Beom JW
• Kim JM
• Chung EJ
• Kim JY
• Ko SY
• Na SD
• Kim CH
• Park G
• Kang MY

• KMID: 2174293
• DOI: http://doi.org/10.4093/dmj.2013.37.3.190

Abstract

BACKGROUND
To evaluate the effects of severe hypoglycemia without hypokalemia on the electrocardiogram in patients with type 2 diabetes in real-life conditions.
METHODS
Electrocardiograms of adult type 2 diabetic patients during the episodes of severe hypoglycemia and the recovered stage were obtained and analysed between October 1, 2011 and May 31, 2012. Patients who maintained the normal serum sodium and potassium levels during the episodes of severe hypoglycemia were only selected as the subjects of this study. Severe hypoglycemia was defined, in this study, as the condition requiring active medical assistance such as administering carbohydrate when serum glucose level was less than 60 mg/dL.
RESULTS
Nine type 2 diabetes patients (seven men, two women) were included in the study. The mean subject age was 73.2+/-7.7 years. The mean hemoglobin A1c level was 6.07%+/-1.19%. The median duration of diabetes was 10 years (range, 3.5 to 30 years). Corrected QT (QTc) intervals were significantly increased during the episodes of severe hypoglycemia compared to the recovered stage (447.6+/-18.2 ms vs. 417.2+/-30.6 ms; P<0.05). However, the morphology and the amplitude of the T waves were not changed and ST-segment elevation and/or depression were not found during the episodes of severe hypoglycemia.
CONCLUSION
In this study, QTc interval prolongation during the episodes of severe hypoglycemia was observed without hypokalemia. Therefore, the distinct alterations in cardiac repolarization during the episodes of severe hypoglycemia may not be associated with hypokalemia.

Keyword

Diabetes mellitus, type 2; Electrocardiography; QT interval; Severe hypoglycemia

MeSH Terms

Adult
Depression
Diabetes Mellitus, Type 2
Electrocardiography
Glucose
Hemoglobins
Humans
Hypoglycemia
Hypokalemia
Male
Medical Assistance
Potassium
Sodium
Glucose
Hemoglobins
Potassium
Sodium

Figure

• 

  Fig. 1 Two representative electrocardiographic recordings of our subjects. On electrocardiograms, there did not show ischemic changes such as ST-segment abnormality and T wave inversion and did not show tachycardia during severe hypoglycemia. The comparison of corrected QT (QTc) interval between severe hypoglycemia and the recovered stage showed each (A) 432 ms versus 396 ms and (B) 442 ms versus 402 ms.

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  Fig. 2 Corrected QT (QTc) interval, individual values during severe hypoglycemia and the recovered stage in all subjects. Only oral glucose-lowering agents users are indicated by continuous lines, insulin users by dashed lines.

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