Trends Favoring an Anatomical Approach to Radiofrequency Catheter Ablation of Idiopathic Ventricular Arrhythmias Originating From the Left Ventricular Summit.

BACKGROUND: Epicardial radiofrequency catheter ablation (RFCA) of idiopathic ventricular arrhythmias (VAs) originating from the left ventricular summit (LVS) is challenging because of the anatomic barriers. On the other hand, RFCA at the endocardial sites near the earliest epicardial activation site of LVS-VAs (anatomic approach) has proven successful. The evolving trends in the approaches and outcomes of RFCA of LVS-VAs at a single center were evaluated. METHODS: We studied 88 consecutive patients with idiopathic LVS-VAs at our institute from 2009 to 2019. These patients were divided into 3 periods: 2009 to 2012 (early), 2013 to 2015 (middle), and 2016 to 2019 (recent). The data were compared among the 3 periods. RESULTS: The RFCA success rate did not significantly change from the early to middle period but significantly increased from the middle to recent period (P=0.0315). The transpericardial approach usage significantly decreased over the 3 periods. The anatomic approach usage significantly increased over the 3 periods. The use of the transpericardial approach did not affect the RFCA outcomes over the 3 periods. The success rate of the anatomic RFCA tended to increase from the early to middle period and significantly increased from the middle to recent period (P=0.0412). The number of endocardial locations where RFCA was successful increased over the 3 periods. CONCLUSIONS: Over the 10-year period, the transpericardial approach became decreasingly performed, whereas the anatomic approach became increasingly performed with a satisfactory improvement in the RFCA outcomes of LVS-VAs. The anatomic RFCA became more successful by identifying more and various endocardial locations as target sites.

Typical atrial flutter mimicking a pacemaker-mediated tachycardia.

A 64-year-old man with a history of congestive heart failure secondary to nonischemic cardiomyopathy, mitral and aortic valve replacements, and biventricular cardioverter-defibrillator placement, developed a tachycardia. The tachycardia exhibited a biventricular paced rhythm with a short R-P interval and concentric atrial activation sequence within the coronary sinus, suggesting that the tachycardia might be a pacemaker-mediated tachycardia (PMT). However, the tachycardia was diagnosed as counterclockwise cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL), and linear ablation of the CTI eliminated the tachycardia. This case illustrated that typical AFL can mimic a PMT when there is a severe conduction delay through the CTI.

Focal ventricular arrhythmias originating from the left ventricle adjacent to the membranous septum.

AIMS: We report the features of focal ventricular arrhythmias (VAs) arising from the left ventricle (LV) adjacent to the membranous septum. METHODS AND RESULTS: We studied eight patients (five men, 65 ± 10 years) with (n = 2) or without structural heart disease (n = 6) who had ventricular tachycardia (n = 4) or premature ventricular contractions (n = 4) originating from the LV septum underneath the aorta. Ventricular arrhythmias exhibited a focal activation pattern, left (n = 4) or right bundle branch block (n = 4), respectively, left superior (n = 4) or inferior axis QRS morphology (n = 4), negative QRS polarity in lead III and early or no precordial transition in all. During all of these VAs, far-field electrograms in the His bundle (HB) region preceded the QRS onset. In all patients, ventricular pre-potentials were recorded during VAs while late potentials were recorded in sinus rhythm at the border of a localized low-voltage area underneath the aorta. Radiofrequency catheter ablation at the presumed sites of origin successfully eliminated VAs in five patients and was abandoned in the remaining three because the HB electrogram was recorded at that site. CONCLUSION: Focal VAs may arise from the LV adjacent to the membranous septum as a part of the LV ostium, and broadens the spectrum of LV ostium VAs.

QRS alternans during idiopathic ventricular tachycardia originating from the right coronary cusp of the aorta.

A 77-year-old man underwent electrophysiological testing for idiopathic ventricular tachycardia (VT) with QRS alternans exhibiting a left bundle branch block and left inferior axis QRS morphology. Successful radiofrequency catheter ablation was achieved at the site of the earliest ventricular activation in the right coronary cusp. Pacing at this site reproduced an excellent pace map with QRS alternans. Pacing from other sites in the ventricular outflow tracts reproduced neither an excellent pace map nor QRS alternans. This case demonstrates that VT with a single origin and multiple exits in the aortic root may exhibit QRS alternans.

Electroanatomic mapping in the catheter ablation of premature atrial contractions with a non-pulmonary vein origin.

Symptomatic premature atrial contractions (PACs) may be a target for catheter ablation. However, mapping of PACs with an atrial origin may not be easy because of erratic incidence and different sites of origin. Although the technique and efficacy of electroanatomic mapping has been established in stable arrhythmias, electroanatomic mapping of PACs in intermittent arrhythmias has not yet been reported. This article describes a manoeuvre for mapping PACs using an electroanatomic mapping system. Our experience has demonstrated that electroanatomic mapping using an auto-freeze map is feasible during PACs and may be an option for catheter ablation of PACs.

Successful catheter ablation of premature ventricular contractions originating from the tricuspid annulus using a Halo-type catheter.

A 31-year-old woman with idiopathic premature ventricular contractions originating from the tricuspid annulus (TA) underwent electrophysiological testing. Activation mapping with a 20-pole bipolar Halo-type catheter positioned along the TA revealed the earliest ventricular activation at a site between 7 and 8 o'clock along the TA. A reversal in the polarity of the local ventricular electrograms was observed between the two neighbouring electrode pairs of the TA catheter. Successful catheter ablation was achieved at the ventricular site between those electrode pairs. A Halo-type catheter may be effective for mapping and catheter ablation of ventricular arrhythmias originating from the TA.

Successful catheter ablation of atrial fibrillation in a patient with dextrocardia.

A 49-year-old woman with dextrocardia and situs inversus underwent catheter ablation of paroxysmal atrial fibrillation. A contrast injection into the left atrium revealed that the left atrial appendage (LAA) was adjacent to the right-sided (anatomic left) superior pulmonary vein (PV). After successful isolation of that PV, LAA potentials were recorded from several electrode pairs of a circular PV mapping catheter. LAA may cause similar difficulties during PVI of the right-sided superior PV in a dextrocardia patient, as during PVI of the left superior PV in a normal heart.

Duplicated coronary sinus with a connecting branch.

A 48-year-old woman with class III heart failure and left bundle branch block underwent an implantation for cardiac resynchronization therapy. Right anterior oblique (RAO) view coronary sinus (CS) venography suggested the antero- and postero-lateral branches appeared to arise from the same vessel of a duplicated CS, but the antero-lateral branch arising from a different vessel was visualized via a connecting branch by the contrast injected into the vessel with the postero-lateral branch, and the distal parts of the two vessels were superimposed in the RAO view. This unusual anomaly may have the potential risk for complications such as perforations.