Endocrine Abstracts

JOINT3527

Introduction: Acromegaly is a rare hormonal disorder due to hypersecretion of growth hormone (GH) by a benign pituitary tumor. Cardiac damage is a constant feature of this rare disease and is the leading cause of death in acromegaly. The specific cardiac involvement of acromegaly is characterized by myocardial hypertrophy associated with diastolic dysfunction. A significant increase of Intraventricular conduction defects and arrhythmias has been described in acromegaly. However, high-grade atrioventricular blocks are less common.

Case Report: 75 years old acromegalic male with a history of hypertension and dyslipidemia, ongoing obstructive sleep apnea and exertional chest tightness. He was admitted to the Otorhinolaryngology department to undergo tracheotomy for an upper airway obstruction. The pre-anesthesia evaluation found a Mobitz II Atrioventricular block. In view of the impact of the obstructive syndrome, a tracheotomy was performed, but a shift to severe bradycardia then a transient ventricular pause occurred. Cardiac auscultation revealed normal S1 and S2 without additional heart sounds. Electrocardiogram at admission showed a bradycardia at 47 bpm related to a 2/1 Mobitz II Atrioventricular block, a right bundle branch block with QRS duration at 138ms, a left anterior fascicular bloc and an isolated premature ventricular beat. Electrophysiological study revealed prolonged HV interval indicating the need for pacemaker implantation. The patient has been implanted with a dual-chamber pacemaker then discharged from hospital.

Discussion and Conclusion: Cardiac arrhythmias and sudden cardiac death are major contributors to increased mortality in acromegaly. Elevated beat-to-beat QT variability and late potentials correlate with ventricular tachyarrhythmias. Intraventricular conduction defects and arrhythmias are common, and while high-grade atrioventricular blocks are less frequent, prevalence varies (7–40%) due to study size, control group differences, monitoring techniques, and significant arrhythmia definitions. There is evidence of the impact of treatment of acromegaly on cardiac conduction tissue. Treatment with somatostatin analogs can reduce clinically significant arrhythmias in some cases by reducing heart rate, PVBs, and QT interval. Regarded for a long time as the primary contributors to mortality in individuals with acromegaly, recent evidence suggests that acromegalic patients experiencing cardiovascular complications now exhibit a mortality rate comparable to the general population. Interstitial fibrosis and cardiac hypertrophy associated with acromegaly could promote arrhythmias and conduction abnormalities of which high-grade heart block is an exceptional manifestation. Treatments of acromegaly reduce the incidence of cardiovascular complications and have a positive impact on rhythm disturbances.

Keywords: Acromegaly, Cardiomyopathy, Arhythmia, High-grade atrioventricular blocks, Somatostatin