Bradycardias in Patients with Pulmonary Hypertension-Prevalence, Pathophysiology and Clinical Relevance.

Introduction: Arrhythmias are a frequent complication of pulmonary hypertension (PH). Supraventricular tachycardias (SVT) are predominantly reported and are associated with clinical deterioration and an increased mortality. In contrast, the prevalence and clinical relevance of bradycardias is largely unclear. Therefore, the aim of the present study was to determine a prevalence of bradycardias in PH patients and to outline their clinical relevance.

Material and methods: Between January 2000 and June 2013, consecutive PH patients were pro- and retrospectively enrolled in two cohorts. Patients received either a 24 h or 72 h Holter ECG.

Results: A total of 314 patients (58% female, mean age: 63 years) from PH groups 1-5 (39%, 11%, 19%, 28%, 3%) were included. Basic heart rhythm was sinus rhythm in 87% of patients (9% atrial fibrillation, 2% atrial flutter and 2% paced rhythm). Further arrhythmias were detected in 34% of patients (SVT: 12%, non-sustained ventricular tachycardia: 16%) with a 6% prevalence of relevant bradycardias. Atrioventricular block was revealed in 5% of patients (seven first-degree, one and three second-degree Wenckebach and Mobitz type, respectively, four third-degree), and 1% revealed sinoatrial block (one second-degree, third-degree and unspecified each).

Conclusions: The prevalence of bradycardias appears to be about 5-10% in PH patients. Most of them are short and self-limiting. However, some patients experience syncope or clinical deterioration and, therefore, need specific treatment. To find these patients, long-term ECG monitoring combined with ECG-symptom correlation may be useful. Bradycardic medication should be excluded as a cause.