Sudden cardiac death in adults with congenitally corrected transposition of the great arteries.

BACKGROUND: Congenitally corrected transposition of the great arteries (ccTGA) is a rare congenital heart disease. There have been only few reports of sudden cardiac death (SCD) in patients with ccTGA and reasonable ventricular function. METHODS: A retrospective review of the medical records of all patients attending our adult congenital heart centre, with known ccTGA. RESULTS: From a database of over 3500 adult patients with congenital heart disease, we identified 39 (∼1%) with ccTGA and 'two-ventricle' circulations. 65% were male. The mean age at diagnosis was 12.4±11.4 years and the mean age at last time of review was 34.3±11.3 years. 24 patients (56%) had a history of surgical intervention. 8 (19%) had had pacemaker implantation and 2 had had a defibrillator implanted for non-sustained ventricular tachycardia (NSVT). In 544 years of patient follow-up, there had been five cases of SCD in our population; 1 death per 109 patient-years. Two of these patients had had previously documented supraventricular or NSVT. However, they were all classified as New York Heart Association (NYHA) class I or II, and systemic (right) ventricular function had been recorded as normal, mildly or mildly-moderately impaired, at most recent follow-up. CONCLUSIONS: Our experience suggests the need for improved risk stratification and/or surveillance for malignant arrhythmia in adults with ccTGA, even in those with reasonable functional class on ventricular function.

Chronic high dose captopril decreases total heart rate variability and increases heart rate in C57BL/6J mice.

The effects of high dose captopril, within the therapeutic range, on autonomic activity are unknown in those with normal cardiovascular function. Thus the study aims were to assess the effects of high dose captopril on autonomic function in mice. Autonomic activity was measured using heart rate variability (HRV). ECG recordings were obtained from 18 Male C57BL/6J mice (20-25 g) subdivided into control (N=8) or mice receiving oral captopril (0.688 mg/ml captopril in the drinking water for 6 weeks, N=10). HRV results for linear and non-linear parameters were attenuated following chronic captopril for 6 weeks compared to control. Captopril was associated with a trend for an increase in average heart rate and approximate entropy (ApEn), a non-linear measure of HRV decreased significantly compared to control (p<0.05). In conclusion high dose captopril reduces total HRV and increases heart rate in normotensive mice with normal cardiac function.