Mechanisms of Intra-Atrial Re-Entrant Tachycardias in Congenital Heart Disease: Types and Predictors.

Intra-atrial re-entrant tachycardia (IART) is a severe complication in patients with congenital heart disease (CHD). Cavotricuspid isthmus (CTI)-related IART is the most frequent mechanism. However, due to fibrosis and surgical scars, non-CTI-related IART is frequent. The main objective of this study was to describe the types of IART, circuit locations, and to analyze predictors of CTI versus non-CTI-related IART. This is an observational study that includes all consecutive patients with CHD who underwent a first IART ablation in a single referral tertiary hospital from January 2009 to December 2015 (94 patients; 39.4% women; age: 36.55 ± 14.9 years, 40.4% with highly complex cardiac disease). During the study, 114 IARTs were ablated (1.21 ± 0.41 IARTs per patient). CTI-related IART was the only arrhythmia in 51% (n = 48) of patients; non-CTI-related IART was the only mechanism in 27.7% (n = 26), and 21.3% of patients (n = 20) presented the two types of IART. Severe dilation of the systemic ventricle, absence of severe dilation of the venous atrium, highly complex cardiac defects, and nontypical electrocardiography (ECG) were related to non-CTI-related IART in univariate analysis. In multivariate analysis, nontypical ECG (odds ratio 3.64; 1.01 to 4.9; p = 0.049) and grade III CHD complexity (odds ratio 9.43; 1.44 to 11.7; p = 0.001) were predictors of non-CTI-related IART. In conclusion, in our population with a high proportion of complex CHD, CTI-related IART was the most frequent mechanism, although non-CTI-related IART was present in 49% (alone or with concomitant CTI-related IART). High-grade CHD complexity and nontypical ECG were strongly related to non-CTI IART.

Pulmonary hypertension and congenital heart disease: An insight from the REHAP National Registry.

BACKGROUND: Pulmonary arterial hypertension (PAH) is common in patients with congenital heart disease (CHD). Although Eisenmenger syndrome may be on decline, other types of PAH-CHD are increasing and little is known on long-term outcome of this population. We report the PAH-CHD population of Spain via a national registry with focus on long-term survival. METHODS AND RESULTS: A total of 240 consecutive patients (age 37.7 ± 14.1 years, 67.9% females) with PAH-CHD included in the REHAP registry were analysed. Patients were classified into 3 groups: 1) Eisenmenger syndrome, 2) postoperative-PAH and 3) PAH associated with small defects. Over a median follow-up time of 4.5[1.6-7.1]years, 50 patients (20.8%) died or underwent lung/heart-lung transplantation. Patients with Eisenmenger syndrome had better survival than postoperative-PAH (HR 0.1 95% CI: 0.2-0.9, p=0.048) but no advantage compared to small defects (HR 4.4, 95% CI 0.6-31.4, p=0.15). In the overall PAH-CHD population, patients in NYHA functional class III-IV had a 3-fold increased risk of death (HR 3.0, 95% CI: 1.5-5.9, p=0.001). Amongst patients with Eisenmenger syndrome, a pre-tricuspid shunt had a 2.6-fold increase risk of death (HR 2.6, 95% CI: 1.2-5.6, p=0.03). There was no significant difference in survival between patients with postoperative-PAH and patients with iPAH (HR 0.99 95% CI: 0.6-1.7, p=0.97). CONCLUSION: PAH-CHD is associated with mid to long-term mortality. Outcome relates closely to functional class, type of PAH-CHD and within the Eisenmenger cohort, with location of the shunt. Adults with postoperative-PAH have the worse prognosis in the PAH-CHD cohort, reinforcing the need for lifelong close follow-up of such patients.

Adverse left ventricular mechanics in adults with repaired tetralogy of Fallot.

Left ventricular (LV) dysfunction is a predictor of adverse outcomes in patients with repaired tetralogy of Fallot (TOF). However, the mechanisms for LV dysfunction are not well understood. The aim of the study was to determine whether the prolonged QRS duration of right branch bundle block was associated with adverse LV mechanics. Seventy-five patients (mean age 31 +/- 2 years) with repaired TOF were studied. LV and right ventricular (RV) volumes and ejection fractions (EFs) were assessed using cardiac magnetic resonance imaging. Vector velocity imaging was used to assess longitudinal strain and intraventricular dyssynchrony. Prolonged QRS duration was associated with increased RV and LV dimensions (p = 0.01) and decreased function (RVEF r = -0.60, p <0.001 and LVEF r = -0.77, p <0.001). In addition, prolonged QRS duration was associated with heterogeneous ventricular mechanical activation and reduced strain in the lateral and septal left ventricle walls. Degree of intraventricular dyssynchrony correlated with LVEF (r = -0.59, p <0.001), QRS duration (r = 0.74, p <0.001), and septal strain (r = 0.70, p <0.001). In conclusion, LV dysfunction and dyssynchrony were observed in patients with TOF and were associated with QRS duration. It was possible that abnormal LV mechanics in combination with RV dysfunction may explain the relation between QRS duration and adverse cardiac outcomes.