QT Dispersion and Electrocardiographic Changes in Women With Gestational Diabetes Mellitus

Effect of spinal anesthesia on the QT interval in term and post-term pregnancies scheduled for elective cesarean section: a prospective study

Objectives: In this study, we aimed to investigate the effects of spinal anesthesia on the QT interval in patients with term and post-term pregnancy that were scheduled for elective cesarean section.Materials and methods: Forty pregnant women scheduled for elective cesarean section under spinal anesthesia were assigned into two groups: Post-term group (Group P) (n = 20) and Term group (Group T) (n = 20). After entering the operation room, standard monitoring [electrocardiography (ECG), noninvasive blood pressure, heart rate, respiratory rate, and peripheral oxygen saturation] was performed. The patient was placed in the sitting position and spinal anesthesia was performed with a median approach at the L3-L4a level using a 25G Quincke-type spinal needle. After cerebrospinal fluid was viewed, 12.5 mg (2.5 mL) hyperbaric bupivacaine was administered intrathecally over 1 min. Other ECG records were made at min 1 (T1), 5 (T2), and 10 (T3) after the induction of spinal anesthesia and after skin closure (T4). QT and QT dispersion were measured from ECG. Heart rate-corrected QT (QTc) and QT dispersion (QTcd) values were calculated using the Bazett formula.Results: Demographic characteristics of the patients were similar in both groups. Postoperative QTc, QTd, and QTcd values were significantly increased in Group P compared to those in Group T (p < .05).Conclusion: Spinal anesthesia led to increased postoperative QTc, QTd, and QTcd values in the patients with a gestational age of ≥42 weeks who underwent cesarean section. Accordingly, it is advisable to perform postoperative strict cardiac monitoring particularly in post-term pregnant women undergoing spinal anesthesia.

Electrocardiographic Changes in Diabetes Mellitus

Diabetes mellitus (DM) has been known for many years to be associated with poor cardiovascular prognosis. Due to the sensitive neuropathy, the coronary artery disease in diabetic patients is frequently asymptomatic. Also twelve leads resting ECG can be within normal limits even in an advanced stage of coronary artery disease. Therefore in addition to the standard ECG other electrocardiographic procedures started to be studied in order to find some typical signs of myocardial damages caused by DM. Repeatedly reported results showed in DM patients without cardiovascular complications the tachycardia, shortening of the QRS and QT intervals, increase of the dispersion of QT interval, decreased amplitudes of depolarization waves, shortened activation time of ventricular myocardium and a flattening of T waves confirmed by the lower value of maximum and minimum in repolarization body surface isopotential maps. Most of these changes are even more pronounced in patients with cardiac autonomic neuropathy. Comparison with similar ECG changes in other diseases suggests that the electrocardiographic changes in DM patients are not specific and that they are particularly caused by an increased tone of the sympathetic nervous system what was indirectly confirmed by the heart rate variability findings in these patients.

ECG Body Surface Mapping in Patients With Gestational Diabetes Mellitus and Optimal Metabolic Compensation

Women with gestational diabetes mellitus (GDM) are at increased risk for cardiovascular diseases (CVD) events compared with women without GDM. The aim of the present study was to evaluate 200 parameters of the heart electric field in 35 women with GDM under optimal glycemic compensation compared to 32 healthy pregnant women. All examinations were performed in the 36th week of gestation. The parameters in ECG body surface mapping (BSM) were registered by the diagnostic system Cardiag 112.2. The absolute values of maximum and minimum in depolarization and repolarization isopotential, isointegral and isoarea maps were not significantly different between the groups. These findings correspond to the result of heart rate variability examination. However BSM revealed the significant prolongation of QRS complex (p=0.05), shortening of ventricular myocardial activation time (ICHVAT) (p=0.01), prolongation of mean QT duration (p=0.01) and increase of QT interval dispersion (p=0.01) in women with GDM. Duration of QRS and ICHVAT significantly correlated with interventricular septum and posterior wall thickness in GDM group, QTd interval correlated significantly with HbA1C level. We conclude that despite of optimal metabolic control several significant abnormalities detected by ECG BSM are still present in patients with GDM.