P4534Incidence of arrhythmia and relation to mortality in a contemporary cohort of adults with pulmonary arterial hypertension associated with congenital heart disease

Abstract

Background: Adults with congenital heart disease (CHD) represent an expanding patient population with approximately 5-10% developing pulmonary arterial hypertension (PAH), which affects life expectancy and quality of life. Arrhythmias are common amongst these patients, but their incidence and impact on outcome remains uncertain. Purpose: To assess the incidence of arrhythmia and its impact on mortality in a contemporary adult PAH-CHD cohort. Methods: All adult patients with PAH-CHD followed in our tertiary centre between January 2007 and December 2015 were included. Clinical information, including prior arrhythmias, was extracted at the time of their oldest full assessment within this period. Patients were, thereafter, followed for new-onset atrial or ventricular arrhythmia. The relation of arrhythmia to mortality and predictors of arrhythmia during follow-up were assessed using Cox analysis. Results: Overall, 311 patients (mean age 35±12.3 years, 36.7% male) were included in the study; 45.0% had a post-tricuspid shunt, 44.4% complex anatomy and only 10.6% a pre-tricuspid shunt. The majority of patients, (n=181, 58.2%) had Eisenmenger syndrome and 48 (15.4%) had had a prior defect repair. Down syndrome was present in 94 (30.2%) patients. Other comorbidity was present in a minority of patients, including systemic hypertension in 15 (4.8%) patients, diabetes mellitus in 5 (1.6%) patients and treated dyslipidaemia in 5 (1.6%) patients. At baseline, 50 (16.1%) patients had prior history of arrhythmia: 5 (10.0%) bradyarrhythmia, 45 (90%) tachyarrhythmia. Sixteen (32%) patients had had atrial fibrillation and 22 (44%) atrial flutter or other macro-reentrant tachycardia. Ventricular arrhythmias included 4 (8%) patients with non-sustained and 3 (6%) with sustained ventricular tachycardia (VT). During a median follow-up of 7.2 years, 66 (21.2%) patients died, whereas 67 (21.5%) had a new arrhythmia (incidence 3.8% per year, 18.4% at 5 years, see Figure depicting arrhythmia free survival with 95% CI). Fourteen (20.9%) patients developed atrial fibrillation, 36 (53.7%) atrial tachycardia, 12 (17.9%) nonsustained VT, 3 (4.5%) sustained VT and 2 (3.0%) a bradyarrhythmia. Prior history of arrhythmia was a strong predictor of mortality (HR 2.44, 95% CI: 1.46- 4.11, p=0.0007), particularly when treating arrhythmia as a time-varying covariate (HR 4.41, 95% CI: 2.12-9.17, p<0.0001). Predictors of new-onset arrhythmia during follow-up included age (HR 1.03, p=0.002), prior arrhythmia (HR 2.55, p=0.007) and PAH-CHD after defect repair (HR compared to Eisenmenger syndrome 2.60, p=0.004). Conclusions: Arrhythmias are common in PAH-CHD, particularly in patients with a previously repaired defect. Arrhythmia occurs in older patients with more advanced disease and those with prior repair, who may be more prone to right ventricular dysfunction, and can cause a sudden decline in cardiac output explaining its strong relation to mortality. (Figure presented).