Identification of clinically relevant phenotypes in patients with Ebstein anomaly.

BACKGROUND: Ebstein anomaly (EA) is a heterogeneous congenital heart defect (CHD), frequently accompanied by diverse cardiac and extracardiac comorbidities, resulting in a wide range of clinical outcomes. HYPOTHESIS: Phenotypic characterization of EA patients has the potential to identify variables that influence prognosis and subgroups with distinct contributing factors. METHODS: A comprehensive cross-sectional phenotypic characterization of 147 EA patients from one of the main referral institutions for CHD in Colombia was carried out. The most prevalent comorbidities and distinct subgroups within the patient cohort were identified through cluster analysis. RESULTS: The most prevalent cardiac comorbidities identified were atrial septal defect (61%), Wolff-Parkinson-White syndrome (WPW; 27%), and right ventricular outflow tract obstruction (25%). Cluster analysis showed that patients can be classified into 2 distinct subgroups with defined phenotypes that determine disease severity and survival. Patients in cluster 1 represented a particularly homogeneous subgroup with a milder spectrum of disease, including only patients with WPW and/or supraventricular tachycardia (SVT). Cluster 2 included patients with more diverse cardiovascular comorbidities. CONCLUSIONS: This study represents one of the largest phenotypic characterizations of EA patients reported. The data show that EA is a heterogeneous disease, very frequently associated with cardiovascular and noncardiovascular comorbidities. Patients with WPW and SVT represent a homogeneous subgroup that presents with a less severe spectrum of disease and better survival when adequately managed. This should be considered when searching for genetic causes of EA and in the clinical setting.

Cardiac conduction disturbance detected in a pediatric population.

OBJECTIVE: To delineate the prevalence and clinical implications of cardiac conduction disturbance (CCD) in school-age children. STUDY DESIGN: Between 1999 and 2001, a citywide survey of 432,166 elementary and high school students had been performed in Taipei by questionnaire, electrocardiography, phonocardiography, and physical examination. Patients with any abnormalities on this survey were referred for final diagnosis. RESULTS: After excluding those with congenital heart disease (CHD), the prevalence of CCD was 0.75%, higher in males than in females (0.78% vs 0.71%). Incomplete right bundle branch block (IRBBB; 0.32%), complete right bundle branch block (CRBBB; 0.11%), ventricular premature contraction (0.11%), and Wolff-Parkinson-White syndrome (0.067 %) were the most common diagnoses. Second-degree atrioventricular block, IRBBB, CRBBB, and intraventricular conduction delay were more common in males; and atrial premature contraction was more common in females. The prevalence of CCD increased with age, from 0.48% in elementary school students to 0.97% in high school students. After detection of CCD, 39 patients with previously undiagnosed atrial septal defect (ASD) and 15 high-risk patients were found. The sensitivity of IRBBB in screening for ASD was 34.67%. CONCLUSIONS: The prevalence of CCD in children without CHD was 0.75%. Detection of CCD helped identify patients with unrecognized ASD and high-risk cardiac patients.

[Wolff-Parkinson-White syndrome in Ebstein's anomaly]. / La anomalía de Ebstein asociada al síndrome de Wolff- Parkinson-White.

The abnormal development of the tricuspid valve in patients with Ebstein's anomaly results in several activation abnormalities including delayed intraatrial conduction, right bundle branch block, and ventricular preexcitation. In the present review, the aim was to define the ECG characteristics before and after ablation of an accessory A-V pathway in patients with Ebstein's anomaly. In a series of 224 patients studied at the Instituto Nacional de Cardiologia "Ignacio Chávez", Sixty-four patients (28%) had documented tachycardia. Thirty-three patients with recurrent tachycardia were found to have a single right-sided AP that was successfully ablated. Only 21 of 33 patients (62%), had typical of ECG pattern of preexcitation. In addition, none of the patients had an ECG pattern of RBBB during sinus rhythm. Radiofrequency catheter ablation resulted in appearance of RBBB in 94% patients. The absence of RBBB in patients with Ebstein's anomaly and recurrent tachycardia had a 98% sensitivity and 92% specificity for the diagnosis of an AP. One third of patients with Ebstein's anomaly and symptomatic tachyarrhythmias have minimal or absent ECG features of ventricular preexcitation. In these patients, the absence of RBBB pattern is a strong predictor of an AP.