Andrew D. McGavigan

The right ventricular outflow tract : The road to septal pacing

Background: Pacing from the right ventricular apex is associated with long‐term adverse effects on left ventricular function. This has fuelled interest in alternative pacing sites, especially the septal aspect of the right ventricular outflow tract (RVOT). However, it is a common perception that septal RVOT pacing is difficult to achieve.

Right ventricular outflow tract pacing: radiographic and electrocardiographic correlates of lead position.

Objective: To characterize the pacing site in an unselected series of patients undergoing right ventricular outflow tract (RVOT) lead placement and investigate the role of the electrocardiogram (ECG) in predicting implantation.

Focal atrial tachycardias arising from the right atrial appendage: electrocardiographic and electrophysiologic characteristics and radiofrequency ablation.

Objective: To characterize the electrocardiographic and electrophysiological features and frequency of focal atrial tachycardia (AT) originating from the right atrial appendage (RAA).

Selective site ventricular pacing.

Purpose of review The traditional site for ventricular pacing, the right ventricular apex, produces an abnormal pattern of ventricular depolarization and there is growing evidence that pacing from this site is associated with adverse functional and structural changes in the left ventricle. This is manifest clinically as an increased morbidity and mortality. These observations have fuelled interest in pacing at sites alternative to the right ventricular apex. In this article, we review the evidence for selective site pacing, focusing mainly on the right ventricular outflow tract. Recent findings Data are conflicting on the acute and medium-term effects of right ventricular outflow tract pacing. Although a recent meta-analysis has suggested acute benefit from pacing at this site, the data are confounded by poor definition of the outflow tract and the non-randomized nature of most trials. There is a need for standardization of nomenclature and better definition of non-apical sites. Long-term data on chronic pacing are limited, with two studies showing equivalency between apical and outflow tract pacing. In another two studies, right ventricular outflow tract pacing was associated with improved ejection fraction. Summary Selective site pacing holds promise in attempting to reduce the problems associated with chronic ventricular pacing. Large, prospective, randomized control trials are needed.

Atrial Anatomy and Imaging in Atrial Fibrillation Ablation

Catheter ablation of atrial fibrillation (AF) can be a technically challenging procedure, requiring detailed knowledge of the anatomy of the atria and thoracic veins to achieve successful cure of AF with a low complication rate. In this article, we review the anatomy relevant to AF ablation: the intraatrial septum, the pulmonary veins and left atrial antral region, the left atrial vestibule, the right atrium and related veins, and the esophagus. We focus on normal variations of anatomy and the role of the available imaging modalities in facilitating safe and effective ablation of this common and complex arrhythmia.