The left atrial substrate plays a significant role in the development of complex atrial tachycardia in patients with precapillary pulmonary hypertension
Abstract
Background: Atrial fibrillation (AF) and related atrial tachyarrhythmias (AT), including type I atrial flutter (AFL) are frequently observed in patients with pulmonary hypertension (PH). Their relationship to hemodynamic changes, atrial size, and ventricular function are still not fully verified.
Methods: We retrospectively studied hemodynamic data, echocardiographic findings and arrhythmia incidence in 814 patients with invasively diagnosed precapillary PH (aged 59 +- 14 years; 46% males). Patients with combined or post-capillary PH were excluded.
Results: AF / AT were identified in 225 (28%) of all the study population. Compared to the subgroup without arrhythmia, patients with AF / AT had elevated right atrial pressure (11 +- 5 vs. 9 +- 5 mmHg), wedge pressure (11 +- 3 vs. 10 +- 3), a more enlarged right atrium (50 +- 12 vs. 47 +- 11 mm) and an increased left atrial diameter in the parasternal long axis projection, p < 0.05 for all comparisons.
In the multivariate model, the left atrial size, patient age, arterial hypertension, diabetes and type of PH were associated with AF / AT occurrence, p < 0.05. Patients with type I AFL were more frequently male (39 (80%) vs. 62 (42%)), were younger (61 +- 11 vs. 67 +- 10 years), had increased pulmonary artery mean pressure (50 +- 12 vs. 45 +- 12 mmHg), less advanced left atrial dilatation (38 +- 10 vs. 42 +- 7 mm), and a more enlarged right atrium (56 +- 12 vs. 48 +- 11) as compared to subjects with AF or other AT, p < 0.05.
Conclusions: The evidence of elevated wedge pressure and the enlargement of the left atrium especially in patients with AF suggest a parallel involvement of the left atrial substrate in arrhythmia formation despite invasively confirmed evidence of purely isolated precapillary PH. Substantial differences were noticed between patients with type I AFL and the remaining patients with other arrhythmia types.