BACKGROUND QRS narrowing following cardiac resynchronization therapy with biventricular (BiV) or left ventricular (LV) pacing is likely affected by patient-specific conduction characteristics (PR, qLV, LV-paced propagation interval), making a universal programming strategy likely ineffective. We tested these factors using a novel, device-based algorithm (SyncAV) that automatically adjusts paced...

Despite the recent advent of and the successful results from catheter ablation, pharmacological therapy is still used by most clinicians as the first line therapy in patients with regular supraventricular tachycardias. Before prescribing an antiarrhythmic agent, documentation of the arrhythmia using a 12-lead electrocardiogram (ECG) is necessary to identify the type of tachycardia. The ECG diag...

Criss-cross heart, defined as crossing of the long axis of the atrioventricular (AV) valves, is an extremely rare congenital heart defect. The unusual arrangement of the cardiac inlets observed in criss-cross heart was first described by Lev and Rowlatt in 1961. The term “criss-cross heart” was initially coined by Anderson et al in 1972. The reported incidence of criss-cross heart is no greater...

The gap-junctional proteins connexin43 and connexin42 have been shown to be expressed in the developing and mature avian heart, but their respective spatiotemporal distributions are unknown. In the present study, we have immunolocalized connexin42 in the conduction tissues of the adult avian heart (nonbranching bundle, bundle branches, and Purkinje fibers) and vascular endothelial cells. Connex...

We present the case of a 21 year-old woman with unremarkable medical history except for tachycardia episodes. The ECG showed a delta wave pre-excitation by a left lateral pathway. One radiofrequency pulse temporarily terminated the accessory pathway conduction, revealing a nodal conduction with complete left bundle branch block.

His bundle recordings were obtained in 121 patients with chronic bundle branch block and the patients were followed for a mean period of 18 months. Seventy-nine patients had an infranodal conduction time (H-Q) less than 70 msec while 42 had H-Q greater than or equal to 70 msec. There was no significant difference in mean age, smoking history, diabetes, syncope, dizziness, blood pressure, and se...

A posteromedian muscle ridge is found in the left ventricle between the two atrioventricular valves in congenital malformations of the heart, where malalignment exists between the ventricular septum and the junction ofboth atrioventricular valve rings; this is seen in transposition with straddling tricuspid valve and double inlet ventricle with outflow chamber. In hearts with normal alignment o...

BACKGROUND The purpose of this study was to evaluate electrode temperatures obtained using a radiofrequency ablation system that incorporates closed loop feedback control to achieve preset target electrode temperatures and to determine if closed loop temperature control results in a lower incidence of developing a coagulum. METHODS AND RESULTS Two hundred seventy patients underwent catheter a...

BACKGROUND Patients with left bundle branch block have a preserved right bundle branch conduction and the efficacy of left ventricular pacing could be explained with the fusion between artificial pulse delivered in the left lateral wall and the spontaneous right ventricular activation. Moreover, the efficacy of left ventricular pacing could be enhanced with an optimal timing between the spontan...

We have studied the disposition of the cardiac conducting tissues in four hearts from situs solitus individuals possessing primitive ventricles without outlet chambers. These hearts correspond to the type of univentricular heart defined as common ventricle by Lev. All the hearts studied possessed normally positioned great arteries. Two groups, each consisting of two hearts, could be distinguish...