Arrhythmias worth treating in PAH patients

By Eleanor McDermid, Senior medwireNews Reporter

Supraventricular arrhythmias (SVAs) are common in patients with pulmonary arterial hypertension (PAH) but can be successfully managed with standard treatments, a study shows.

However, patients with SVAs tended to have a poorer prognosis than those without, the researchers report in Heart, Lung and Circulation.

Katarzyna Małaczyńska-Rajpold (Poznan University of Medical Sciences, Poland) and colleagues identified SVAs in 35% of 48 patients with PAH, which they note is a much higher frequency than in the general population.

Despite treatment, patients with SVAs had a 6-year survival rate of just 41.9%, compared with 66.3% for those without, but the difference was not statistically significant, which the team attributes to the small number of patients in in the study. Four of the six patient deaths in the SVA group occurred during the first year of follow-up, with two of these being attributed to arrhythmia.

Patients with SVAs most commonly had atrial fibrillation, atrial tachycardia or atrial flutter, and four patients had more than one type of arrhythmia. In 59% of patients, onset of SVA was associated with clinical deterioration, right ventricular failure or both.

The team used standard treatments for SVA, including pharmacological rate or rhythm control, direct current cardioversion and radiofrequency ablation. Treatment alleviated the clinical effects of SVA; however, among all 17 patients, nine had recurrence of the arrhythmia an average of 5.3 months after treatment.

The SVA group had significantly higher mean right atrial pressure than the comparison group, at 11.6 versus 7.1 mmHg, and a larger right atrial area, at 33.4 versus 25.8 mm2. These factors could indicate “more severe PAH resulting in significant atrial remodelling and formation of an arrhythmia substrate and, consequently, may explain the high recurrence rate of SVA”, the team suggests.

The researchers highlight four patients who had an atrial tachycardia that had an atrial rate between 150 and 230 per minute, an isoelectric line between the P’ waves and no F wave. It seemed to arise from a macro-reentry loop involving right atrial isthmus and “could not be easily classified as one of the commonly known types of SVA.”

Małaczyńska-Rajpold and team suggest this arrhythmia may occur in any disease associated with right atrium enlargement, rather than being specific to PAH.

But they add that, although radiofrequency ablation of cavo-tricuspid isthmus (CTI) successfully terminated this arrhythmia, the broad CTI often found in PAH patients “may cause some technical problems for the electrophysiologist”.

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