Markers of ventricular tachyarrythmias in patients with acromegaly

Sudden cardiac death is a known complication of acromegaly. Little is known of the exact mechanism leading to sudden cardiac death in these patients. Ventricular tachyarrhythmias may be an important cause. If this is so, clinical markers of ventricular tachyarrhythmias may be more common in this group of patients. The presence of these markers allow better risk stratification among acromegalic patients.

We performed signal averaged electrocardiography and analysed 12 lead electrocardiography for QT dispersion on 17 acromegaly patients who attended the UKM endocrine clinic within a period of 5 months and compared them with similar age matched controls. Signal averaged electrocardiogram was performed using Marquette Mac 12/15 ECG analyser and QT intervals were measured manually from 12 lead ECG tracings. Late potential positivity was defined by the standard Breithardt criteria. QT dispersion was defined as the longest minus the shortest QT interval from all 12 lead tracings. Echocariography was done to assess left ventricular hypertrophy in patients and controls.

Late potential positivity was found to be more common in acromegaly patients compared with controls (chi-square, p < 0.05, n = 34) and QT dispersion was also found to be significantly higher in the acromegaly group compared with control s (mean +/- SE QT dispersion respectively 121.0 +/- 8.6 ms vs 86.2 +/- 7.0 ms, t-test, p < 0.05, n = 34). Left ventricular hypertrophy was present in five acromegaly patients and two in the control group.

Acromegaly patients have a higher incidence of late potential positivity and higher QT dispersion compared with age matched controls. These findings might explain the increase susceptibility of these patients to sudden cardiac deaths from ventricular tachyarrhythmias.