Mechanism and prognostic role of qR in V1 in patients with pulmonary arterial hypertension.

ABSTRACT

BACKGROUND: The presence of qR pattern in lead V1 of the 12-lead surface ECG has been proposed as a risk marker of death in patients with pulmonary arterial hypertension (PAH). We aimed to validate these findings in the modern era of PAH treatment and additionally to assess the relation of qR in V1 to PAH severity. We also investigated the possible mechanisms underlying this ECG sign. METHODS: Consecutive patients with PAH excluding patients with congenital heart defect were recruited between February 2008 and January 2016. A 12-lead standard ECG was acquired and analyzed for the presence of qR in V1 and other potential prognostic patterns. Cardiac magnetic resonance and echocardiography were used for structural (masses and volumes) and functional (ejection fraction, eccentricity index) characterization of left (LV) and right (RV) ventricles. Standard markers of PAH severity were also assessed. RESULTS: We enrolled 66 patients (19 males), aged 50.0±15.7years with idiopathic PAH (n=52) and PAH associated with connective tissue disease (n=14). qR in V1 was present in 26(39.4%) patients and was associated with worse functional capacity, hemodynamics and RV function. The main structural determinants of qR in V1 were RV to LV volume ratio (OR 3.99; 95% CI 1.47-10.8, p=0.007) and diastolic eccentricity index (OR 15.0; 95% CI 1.29-175.5, p=0.03). During observation time of 30.5±19.4months, 20 (30.3%) patient died, 13 (50%) patients with qR and 7 (17.5%) patients without qR pattern. Electrocardiographic determinants of survival were qR (HR 3.06, 95% CI 1.21-7.4; p=0.02) and QRS duration (HR 1.02, 95% CI 1.01-1.04; p=0.01). CONCLUSIONS: Presence of qR in V1 reflects RV dilation and diastolic interventricular septum flattening. It is a sign of advanced PAH and predicts the risk of death in this population.