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.

Keywords: Atrial fibrillation; Atrial flutter; Atrial tachycardia; Pulmonary hypertension.

Fig. 1

Distribution of right atrial pressure and pulmonary artery wedge pressure in relation to arrhythmia manifestation. PAWP – pulmonary artery wedge pressure; RAP – right atrial pressure

Fig. 2

Clinical, demographical, haemodynamic and echocardiographic data in patients with atrial fibrillation and flutter. Values are expressed as mean ± standard deviation or as n (%). AF – atrial fibrillation; AFL – atrial flutter; 6MWT – six-minute walking test; PAMP – pulmonary arterial mean pressure; PAWP – pulmonary arterial wedge pressure; LA – left atrium; RA – right atrium; RV – right ventricle; TAPSE – tricuspid annular plane systolic excursion

Fig. 3

An example of RA and LA arrhythmogenic substrate. Example of 3D electro-anatomical bipolar voltage maps of both right and left atrium (see Table 4 for more individual details). Red colour represents areas with reduced bipolar voltage (< 0.1 mV). LA – left atrium; RA – right atrium