Response of narrow QRS tachycardia in a patient with surgical closure of atrial septal defect to atrial overdrive pacing: What is the mechanism?

A 57-year old woman who had pericardial patch closure of ostium secundum atrial septal defect (ASD) at the age of 23 years presented with shortness of breath. Her echocardiogram showed no residual ASD, good biventricular function and normal pulmonary artery pressures.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias.

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Classical response of antidromic atriofascicular tachycardia to premature atrial extrastimulus delivered during septal refractoriness.

A 23-year-old gentleman presented with a history of palpitations. The 12-lead electrocardiogram showed no manifest ventricular pre-excitation. Echocardiogram was within normal limits. A retrograde study showed concentric activation of the atrium with decremental conduction. Atrial pacing from right atrial free wall showed progressive pre-excitation. No anterograde nodal duality was documented.

Interesting case of dual tachycardia in a patient with surgical closure of atrial septal defect.

A 34-year-old gentleman, who had undergone pericardial patch closure of ostium secundum atrial septal defect (ASD) at 8 years of age, was evaluated for shortness of breath. Electrocardiogram revealed typical atrial flutter with varying atrioventricular conduction. Echocardiogram showed no residual ASD or pulmonary hypertension and good biventricular function. He was taken for an electrophysiological study with the intention of radiofrequency ablation of the typical flutter.