Rare cause of infranodal block

The patient exhibits multiple features suggestive of Timothy syndrome, which is a multisystem autosomal-dominant condition with findings that include prolonged QT interval, hand and foot abnormalities, dysmorphic facial features, and mental retardation. A 2:1 infranodal atrioventricular block may occasionally be seen in the setting of severely prolonged QT interval. Functional nature of atrioventricular block is demonstrated by resumption of 1:1 conduction with changes in heart rate

Bundle Branch Reentry: Mechanisms, diagnosis and management

ISBN: 978938605679

The Crux of the Heart –– the Closest Approach of the Right Atrium to the Left Ventricle

Background: Accessory pathways, the source of atrioventricular reentry tachycardia, occasionally connect the left ventricle to the right atrium. This is possible because, in some patients, a portion of the right atrium abuts the left ventricle on the posterior wall of the heart, near the mid-coronary sinus. This anatomic region is known as the “crux” of the heart. These accessory pathways can be difficult to ablate because of the unusual and unexpected substrate. While the presence of these accessory pathways is described in the literature, the prevalence of the underlying anatomic substrate is not currently known. Purpose: To measure the closest approach of the left ventricle to the right atrium by reviewing a consecutive series of standard-of-care computed tomography (CT) scans of the heart taken in patients undergoing interventional cardiac procedures such as catheter ablation of the left atrium. Methods: Contrast-enhanced cardiac CT exams acquired with electrocardiography-gated retrospective image reconstruction and that had good image quality (i.e. appropriate contrast enhancement of the cardiac structures of interest and low motion artifacts of the acquired images) were reviewed. After scanning the axial images of the relevant anatomy, single or double oblique cuts were made of the three-dimensional data set, and the closest approach of the left ventricle to the right atrium was measured and tabulated. Results: A total of 47 consecutive CT scans acquired between March 2014 and April 2015 from patients (36 male, 11 female) undergoing catheter ablation for atrial fibrillation were reviewed for this study. The mean distance between the right atrium and left ventricle was 3.6 ± 1.0 mm. The maximum value was 6.8 mm. For the remaining 46 patients, the right atrium was less than 5.3 mm from the left ventricle at the point of closest approach. The images showed a single muscular wall between the two chambers at this point, indicating that the right atrium was in contact with the left ventricle. Conclusion: The right atrium came into direct contact with the left ventricle in all studied patients except one. This has important implications for catheter ablation of certain accessory pathways

Perioperative amiodarone in cardiovascular surgery: pharmacist dosing service

Conclusion: The patients receiving the pharmacist amiodarone dosing protocol for CV surgery had a numerically lower incidence of post-operative atrial fibrillation though number of patients included was low preventing statistical significance from being reached. Using a pharmacist protocol for dosing amiodarone in CV surgery may be effective to increase amiodarone use and decrease post-operative atrial fibrillation

Bundle branch reentry: A mechanism of ventricular tachycardia in the absence of myocardial or valvular dysfunction

AbstractObjective, The aim of this study was to present bundle branch recentry as the mechanism of sustained ventricular tachycardia in the absence of myocardial or valvular dysfunction.Background. Previous reports have documented the relation between structural heart disease and bundle branch reentrant ventricular tachycardia. Myocardial or valvular dysfunction has thus far been recognised as the only anatomic substrate for the development of this tachycardia.Methods. Three patients with a wide QRS complex tachycardia underwent noninvasive and invasive cardiac evaluation and electrophysiologic studies to identify the substrate and mechanism of tachycardia. Catheter ablation of the right bundle branch using radiofrequency current was performed in each patient.Results. The patients were ail men (aged 54, 34 and 72 years) who presented with presyncope, palpitation and cardiac arrest, respectively. Electrocardiography during sinus rhythm revealed nonspecific intraventricular conduction delay in all three patients. Cardiac evaluation revealed no evidence of myocardial or valvular dysfunction in any patient. The baseline HV interval was prolonged in each patient (90, 100 and 75 ms, respectively). Programmed right ventricular stimulation initiated bundle branch reentrant tachycardia with typical left (three patients) and right (one patient) bundle branch block pattern. Catheter ablation of the right bundle branch using radiofrequency current abolished bundle branch reentry in all three patients. After 26-, 13- and 8-month follow-up periods, complete right bundle branch block persisted, and all three patients remained asymptomatic without antiarrhythmic drugs.Conclusions. Sustained bundle branch reentry can be a clinical arrhythmia in patients with no identifiable myocardial or valvular dysfunction except for isolated conduction abnormalities in the His-Purkinje system. This mechanism of tachycardia should be recognized during electrophysiologic evaluation, given the seriousness of this arrhythmia and the availability of effective treatment

Cardiac resynchronization therapy in patients with challenging anatomy due to venous anomalies or adult congenital heart disease

BACKGROUND: Cardiac resynchronization therapy (CRT) has proven salutary effects in patients with congestive heart failure, systolic dysfunction, and electromechanical dyssynchrony in the setting of ischemic, nonischemic, and congenital cardiomyopathy. While CRT device implants have become routine in the adult ischemic or nonischemic cardiomyopathy populations, patients with congenital heart disease offer special challenges due to unusual anatomic variations. METHODS: A comprehensive assessment of anatomic abnormalities is essential prior to implant. In addition, implant techniques and equipment must be tailored to the expected anatomy. A flexible approach is necessary-implant may require equipment and techniques adapted from vascular intervention. CONCLUSION: This article describes our approach to CRT implant in patients with congenital heart disease, and is illustrated by reports of several cases