Signal-averaged electrocardiogram in Ebstein's anomaly

Electocardiographic features in Ebstein's disease

INTRODUCTION

Ebstein's disease (ED) is a rare and heterogeneous congenital heart disease affecting the tricuspid valve and the right ventricle. Few studies have analyzed the electrocardiographic features of this disease.

AIM

To describe the electrocardiographic features observed in Ebstein's disease.

METHODS

We conducted a retrospective descriptive study that enrolled 26 patients followed for ED.

RESULTS

The mean age of discovery of the ME was 103.5±99 months [0-31 years]. The diagnosis of ME is most often made between 5 and 10 years. We noted right atrial hypertrophy in 11 patients (42%), right ventricular hypertrophy in half of the patients. Right axial deviation was noted in 11 patients (42%). Eight patients (30%) had wide QRS≥ 120 ms. Seven of these 8 patients (27%) had a fragmented QRS appearance. A right bandle block was noted in 22 patients (84%), it was a complete block in 7 cases (27%). A preexcitation was found in 6 patients (23%). The localization of accessory pathway was right postero-septal in all cases. Rhythmic disorders were noted in 9 patients (34%). It was a junctional tachycardia in 3 patients (11%), atrial flutter in 4 patients (15%) and atrial fibrillation in 2 patients (7%). A second degree atriventricular block was observed in one patient, it was Mobitz I type. Two cases of postoperative rhythm disturbances were recorded: paroxysmal atrial fibrillation and junctional tachycardia related to Wolf Parkinson White (WPW) syndrome.

CONCLUSION

Surface ECG in the ED is often pathological with prevalence of rhythm disturbances related to WPW syndrome.

Tricuspid and Pulmonic Valve Pathology

PURPOSE OF REVIEW

This review describes the normal structure and pathologic changes that affect the right-sided cardiac valves and chambers.

RECENT FINDINGS

The anatomy and pathology described have been known for many years. Knowledge of these findings has gained relevance. The pattern of endocarditis is changing. New diagnostic techniques have allowed better characterization of lesions responsible for cardiac dysfunction. Novel, less invasive interventions have made recognition of abnormalities more clinically relevant. There are many different pathologic entities that can affect the right-sided cardiac valves. These are discussed in this review.

Ebstein Anomaly With QRS Fragmentation on Electrocardiogram

Ebstein anomaly is a rare congenital disorder that involves the tricuspid valve and the right ventricle. It is associated with interatrial communication, which allows for paradoxical embolization causing unilateral blindness. Abnormal conduction through the atrialized right ventricle leads to QRS fragmentation on electrocardiogram. Its presence suggests a more severe abnormality and a higher risk of arrhythmia. The QRS fragmentation disappears after corrective surgery with resection of the atrialized right ventricle.

Fragmented QRS complex in adult patients with Ebstein anomaly and its association with arrhythmic risk and the severity of the anomaly

BACKGROUND

Fragmented QRS complex (fQRS) on 12-lead ECG, a marker of myocardial scar, is a predictor of arrhythmic events in patients with ischemic and nonischemic cardiomyopathy. We investigated whether the presence of fQRS is associated with the severity of the anomaly and with increased arrhythmic events in adult patients with Ebstein anomaly (EA).

METHODS AND RESULTS

In 51 consecutive adult patients with EA (median age, 37 years; 18 males), the severity index of EA calculated from echocardiographic data and clinical arrhythmic events were analyzed. The extent of fQRS in each patient was measured by counting the number of ECG leads showing fQRS. There were 35 (68.6%) patients with fQRS (fQRS group) and 16 (31.4%) patients without fQRS (non-fQRS group). fQRS was observed more frequently in the inferior (n=26) and precordial (n=25) leads versus the lateral leads (n=5). The patients in the fQRS group had a worse functional class, greater cardiothoracic ratios, more severe tricuspid regurgitation, larger atrialized right ventricular areas, higher EA severity scores, and more frequent arrhythmic events compared with those in the non-fQRS group. The atrialized right ventricular area showed a positive correlation with the fQRS extent (r=0.51; P<0.001). In multivariable Cox regression models, the presence of fQRS was independently associated with arrhythmic events (P=0.036).

CONCLUSIONS

Fragmented QRS on 12-lead ECG was associated with larger atrialized right ventricular area and an increased risk of arrhythmic events in adult patients with EA.

QRS duration and QRS fractionation on surface electrocardiogram are markers of right ventricular dysfunction and atrialization in patients with Ebstein anomaly

BACKGROUND

Ebstein anomaly is a rare and heterogeneous congenital heart defect affecting the tricuspid valve and right ventricular (RV) myocardium. Few studies have analysed the electrocardiographic features of Ebstein anomaly and none has addressed correlations with disease severity.

METHODS

Patients with Ebstein anomaly who had undergone electrocardiography and cardiac magnetic resonance (CMR) within 6 weeks between 2001 and 2009 were included. Exclusion criteria were: associated congenital cardiac defect, previous RV myoplasty and/or reduction surgery, class I anti-arrhythmic drug therapy, and paced/pre-excited QRS. Standard electrocardiogram (ECG) findings were correlated with CMR-based RV measures and clinical profile.

RESULTS

The mean age of the 63 study patients was 22 ± 13 years. An RV conduction delay (rsR' pattern in right precordial leads) was present in 45 patients (71%). The QRS duration correlated with anatomic RV diastolic volume (r = +0.56, P < 0.0001) and inversely with RV ejection fraction (EF; r = -0.62, P < 0.0001). The presence of QRS fractionation predicted greater atrialized RV volume (80 ± 31 vs. 45 ± 37 mL/m(2), P < 0.001). Normal QRS duration was associated with smaller anatomic RV diastolic volume (150 ± 57 vs. 256 ± 100 mL/m(2); P < 0.0001), higher RV EF (48 ± 6 vs. 34 ± 14%; P < 0.0001), higher oxygen consumption (VO(2)) at cardiopulmonary exercise (25.8 vs. 21.8 mL/kg/min, P = 0.05) and lower incidence of oxygen desaturation with exercise (25 vs. 65%, P = 0.02).

CONCLUSION

Delayed and prolonged depolarization of the RV is common in patients with Ebstein anomaly. The QRS duration is a marker of RV enlargement and dysfunction. QRS fractionation is associated with a greater atrialized RV volume. A preserved surface ECG identifies a subset of patients with Ebstein anomaly with mild morphological and functional abnormalities and better clinical profile.

Cardioplegia and ventricular late potentials in cardiac surgical patients

BACKGROUND AND OBJECTIVE

Ventricular late potentials (LP) recording with signal-averaged electrocar- diogram allow identifying patients at risk of sudden death and ventricular tachycardia. Cardiac surgery with cardiopulmonary bypass (CPB) could predispose to the development of myocardial ischemia related to imperfect cardioplegia. To the best of our knowledge, no study investigated the protection of cardioplegia and CPB regarding the occurrence of LP in patients without previous myocardial infarction and undergoing cardiac surgery.

METHODS

In 61 elective patients scheduled for cardiac surgery involving CPB, signal-averaged electrocar- diogram was performed the day before and 24-48 h after the surgery. The electrodes were positioned according to Frank's orthogonal derivations. Twenty five patients were excluded because of poor quality signals, leaving 36 patients (age, 64 ± 14) available for the analyses. An abnormal signal-averaged electrocardiogram was considered when ≥2 of the recorded indexes were present. McNemar's tests were performed on the dichotomized values to investigate differences in pre-post scores.

RESULTS

The mean CPB duration was of 110 ± 57 min. Patients scheduled for cardiac surgery do not exhibited LP after CPB (no significant difference in pre-post CPB scores, P = NS). The probability of a patient with a negative score transitioning to a positive score was 0.23 (P = NS).

CONCLUSIONS

The present study in cardiac surgical patients suggests that cardioplegia associated to CPB has no significant impact on the occurrence of LP, irrespective of surgery performed.

Ebstein’s anomaly of the tricuspid valve

Ebstein's anomaly of the tricuspid valve is a rare lesion comprising less than 1% of patients with congenital heart disease. Among congenital heart lesions, Ebstein's anomaly is one of the most diverse in presentation, severity, and management. In its most severe form, it is also one of the most lethal. In this article we present a case of a patient who developed cardiac symptoms in adulthood. We follow this with a review of the pathology, clinical presentation, evaluation, and management of Ebstein's anomaly.

Usefulness of post-ventriculotomy signal averaged electrocardiograms in congenital heart disease

Signal-averaged electrocardiography is a sensitive and specific technique for detecting the slow conduction electrophysiologic substrates of reentrant monomorphic ventricular tachycardia. Although well established, the method has not been used for electrophysiologic assessment after right ventriculotomy for the intracardiac repair of congenital heart disease. This 8-year prospective study provided this assessment. Recordings were obtained from 242 post-ventriculotomy patients with congenital heart disease aged 16 to 72 years (139 males, 103 females). Because ventricular volume or pressure overload can prolong the QRS duration, 40 unoperated patients with hemodynamic overload served as controls. Orthogonal X, Y, and Z body surface electrodes were used to detect ventricular late potentials by permitting the examination of portions of the electrocardiogram otherwise obscured by noise and artifacts. Positive signal-averaged electrocardiographic (SAECG) results were based on established criteria derived from 3 time-domain variables calculated by an automated algorithm. Late potentials were detected in 151 of 242 patients (62%) and were significantly higher than controls (p = 0.0001). Radiofrequency ablation of an inducible slow conduction substrate rendered 20 of 23 positive post-ventriculotomy SAECG results negative, and surgical revision of the ventriculotomy scar rendered 19 of 19 positive SAECG results negative. In conclusion, negative SAECG results connote the absence of a reentrant substrate, and therefore, the absence of risk for reentrant monomorphic ventricular tachycardia, whereas positive SAECG results connote the presence of a slow conduction substrate and the potential risk for monomorphic ventricular tachycardia.