- The recognition that paroxysmal atrial fibrillation (AF) is predominantly triggered by ectopic beats arising from the vicinity of pulmonary veins (PVs) has spurred the establishment of percutaneous procedures specifically designed to electrically sequestrate the arrhythmogenic PV from the vulnerable left atrium (LA) substrate.1 Recently, the procedure has evolved with the development of purpose-built pulmonary vein isolation (PVI) tools, such as the cryoballoon catheter. This article discusses the anatomic and electrophysiologic bases for the interpretation of pulmonary vein potentials (PVPs) using a small-caliber circular mapping catheter (CMC) and provides an expanded discussion on the pacing maneuvers relevant to cryoballoon-based PVI procedures.
- Advances in cardiac care of the young have given rise to a growing and aging population of patients with congenital heart disease. Despite remarkable improvements in overall survival, sudden cardiac death remains the most common cause of late mortality. As a result, implantable cardioverter-defibrillators (ICDs) are increasingly used in this heterogeneous patient population. Tetralogy of Fallot and transposition of the great arteries are the most prevalent subtypes of congenital heart disease in ICD recipients.
- Tetralogy of Fallot is the most common form of cyanotic heart disease, accounting for approximately 10% of congenital heart defects. Corrective surgery involves atrial and/or ventricular incisions and patches that, when combined with altered hemodynamics, predispose to the late onset of arrhythmias.1,2 In a multicenter cohort followed up for 35 years after corrective surgery, sustained atrial and ventricular tachyarrhythmias occurred in 10% and 12% of patients, respectively.1 Macroreentrant right atrial tachycardia is the most common atrial arrhythmia.
- Complete transposition of the great arteries (D-TGA) accounts for 5% to 7% of congenital heart defects. Although the arterial switch procedure has now replaced atrial redirection as the surgical procedure of choice, most adults today with D-TGA have had Mustard or Senning baffles. These surgeries involve extensive atrial reconstruction and predispose to sinus node dysfunction and atrial tachyarrhythmias.1,2 By 20 years after surgery, the prevalence of atrial tachyarrhythmias is approximately 25%, continues to increase with time, and is similar among patients with Mustard or Senning baffles.