Anterior Right Ventricular Outflow Tract Research Articles

Similarly high success and low complication rates of catheter ablation for idiopathic premature ventricular contractions from the left and right ventricular outflow tract

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation is the first line treatment for idiopathic premature ventricular contractions (PVCs) from the right ventricular outflow tract (RVOT) but not from the left ventricular outflow tract (LVOT), due to presumed lower success and higher complication rates in the LVOT. In this observational single center study we analyzed success rates and complication rates in patients undergoing catheter ablation for idiopathic PVCs with an inferior axis. Methods Patients undergoing catheter ablation for idiopathic PVCs with an inferior axis at Hannover Heart Rhythm Center between 2012 and 2020 were included. Patients were excluded if no activation mapping could be performed because of low PVC activity. Ablation success was defined as complete suppression of the index PVC at the end of the procedure. Results 108 patients (53% male, age 53 ± 17 years) with predominantly symptomatic (94%) PVCs with one (72%), two (20%) or more (8%) morphologies and a PVC count of 22063 ± 14426 /24h were included. 47 PVCs (44%) were located in the RVOT (21 anterior RVOT and 26 septal RVOT) and 39 PVCs (36%) in the LVOT (11 lateral LVOT, 5 septal LVOT, 8 RCC, 2 ACC, 13 LCC). 14 PVCs (13%) had the origin close to the CS/LV summit and 8 PVCs (7%) in the parahisian region. Overall success rate was 82%. Success rates for RVOT and LVOT origin were 98% (46/47 cases) and 97% (38/39 cases) respectively. No significant differences in procedure time (145 ± 68 vs. 158 ± 72 min), ablation time (441 ± 328 vs. 462 ± 307 sec), fluoroscopy time (496 ± 521 vs. 519 ± 473 sec) or minor complications (5 vs. 8) were observed for outflow tract PVCs, and no major complications occurred in this group. However, 3 major complications and significantly lower success rates were observed for non-outflow tract PVCs (0/8 for parahisian origin, 4/14 (29%) for CS/LV summit origin). 2 patients with a parahisian focus experienced higher degree AV block and 1 patient with an LV summit focus had a pericardial tamponade. Conclusion Catheter ablation of PVCs with LVOT origin can be performed with similarly high success and low complication rates compared to PVCs with RVOT origin, and therefore could be considered as first-line therapy like RVOT PVCs. On the other hand, identification of PVCs with a parahisian or CS/LV summit focus should be aspired before an ablation procedure, as these localizations are associated with poorer ablation outcome and higher complication rates.

Radiofrequency ablation in Brugada syndrome.

Radiofrequency ablation in Brugada syndrome.

Inadequacy of fluoroscopy and electrocardiogram in predicting septal position in RVOT pacing – Validation with cardiac computed tomography

BackgroundElectrocardiographic (ECG) and fluoroscopic criteria, which are the only available guides to achieve a true septal position during right ventricular outflow tract (RVOT) pacing, have been infrequently validated. We sought to validate these using cardiac computed tomographic angiography (CTA) to confirm lead position within the RVOT septum. MethodsForty-four patients with permanent pacemaker leads in the RVOT position underwent CTA. Lead positions in RVOT were classified as anterior, free wall, or septal location. Fluoroscopic images were obtained in 4 standard views. ResultsOnly 19 (43%) patients had lead in true septal position within the RVOT in CTA while 25 patients (57%) were found to have an anterior lead location. Mean QRS axis, QRS duration, negative QRS in lead I, and notching in inferior leads were not significantly different between the two groups. The standard fluoroscopic LAO view showed a rightward-directed lead not only in all 19 patients with septal location, but also in 14/25 patients in the anterior location (p=0.22), and thus had a sensitivity of 100% but specificity of only 16% in predicting true septal position. The posteriorly directed lead in left lateral view was more accurate in predicting true septal position with good sensitivity (73.7%) and excellent specificity (80%). ConclusionsThis study, using validation with CTA, showed that conventional ECG criteria and fluoroscopy are inaccurate in differentiating septal from anterior RVOT pacing. The fluoroscopic lateral view, as corroborated by CTA, is more reliable than the LAO view in predicting septal lead placement.

Performance of surface electrocardiographic vectors in differentiating ventricular arrhythmia originating from coronary cusp, peri-pulmonic valve and right ventricular outflow tract

Introduction: Symptomatic outflow tract ventricular arrhythmia (OTVA), including ventricular tachycardia and premature ventricular complexes, can be readily treated with catheter ablation. Outflow tract anatomy is complex and differentiating aortic, pulmonary and subvalvular origin is important for planning approach to mapping and ablation. We investigated whether surface ECG characteristics of OTVA can accurately discriminate between right coronary cusp (RCC), peri-pulmonic valve (PV) and right ventricular outflow tract (RVOT) origin. Methods: Thirty-six consecutive patients (mean age 41±14 years, 13 male) undergoing catheter ablation for OTVA were studied. Site of OTVA origin were determined from intracardiac electrogram tracings, electroanatomical maps and ablation reports. Observers blinded to these results manually measured PVC waveform amplitude and duration from standard 12-lead ECG tracings. Measurements with highest diagnostic performance were modelled into an algorithm designed to discriminate between predefined sites of origin within the outflow tract. Results: Sites of successful ablation were anterior RVOT (n=6), posterior RVOT (n=4), PV (≤1cm below, at or above pulmonary valve, n=18) and RCC (n=8). RCC origin was best discriminated by lead I R-wave ≥ 1.5 mV AND V1 R-wave ≥2.0mV (PPV 39%, NPV 94%, accuracy 67%). Posterior RVOT origin was best discriminated by lead I R/(R+S) ≥ 0.1 AND V1 R-wave > 0mV (PPV 33%, NPV 96%, accuracy 81%). Anterior RVOT origin was best discriminated by V1 R-wave = 0mV AND aVR/aVL S-wave ratio > 1 (PPV 100%, NPV 94%, accuracy 94%). Origin from PV was best discriminated by lead II/III R-wave ratio ≤0.95 OR lead I R/(R+S) < 0.08 (PPV 68%, NPV 86%, accuracy 75%). Sequential algorithmic application of these criteria resulted in an overall accuracy of 80% in predicting site of OTVA origin. Conclusions: Application of simple surface ECG criteria in sequential algorithmic fashion can discriminate between coronary cusp, peri-pulmonic and RVOT origin of outflow tract ventricular arrhythmia.

Inaccuracy of radiological and ECG criteria for right ventricular outflow tract implantation of pacemaker leads

We present three cases of active fixation pacemaker lead implantation, where the leads were believed to be inserted in the right ventricular outflow tract (RVOT) septal position, using established radiological criteria. However, when the exact location of the leads was documented by three-dimensional echocardiography, true septal RVOT position was achieved in only one patient. In the other two patients, the leads were, in fact, implanted into the RVOT anterior free wall. The electrocardiogram criteria were not able to identify the septal position from the anterior RVOT free wall position.

Supravalvular Arrhythmia

Supravalvar ablation has now been well documented to be the ideal mode for ablating specific forms of ventricular tachycardia, atrial tachycardia, and accessory pathways. A studied appreciation of the anatomy of the supravalvar region is a prerequisite for electrophysiologists to safely and effectively approach these arrhythmias. In addition, the consistent ability to correlate the recorded electrograms with fluoroscopic anatomy and intracardiac ultrasound images enhances the chance of successful elimination of supravalvar arrhythmias.

Right ventricular outflow tract resection for treatment of refractory ventricular tachycardia in a 2-year-old child

Ventricular tachycardia (VT) of right ventricular origin in young children might be due to Purkinje cell tumors, arrhythmogenic right ventricular dysplasia (ARVD), or Uhl’s anomaly, or it might be idiopathic. Surgical intervention has been used in adults when medical or catheter ablative therapy is ineffective. We describe a unique cause of VT of right ventricular outflow tract (RVOT) origin in a young child that was successfully managed with surgical resection. Clinical Summary A 2-year-old child presented with syncope and near-incessant VT at a rate of 270 beats/min. The tachycardia was notable for subtle irregularities in both cycle length and QRS morphology (Figure 1). However, all QRS complexes suggested an RVOT origin, with positive vectors in leads II, III, and aVF. Transthoracic echocardiography showed marked dilation of the RVOT, which was confirmed by means of cardiac magnetic resonance imaging. At electrophysiologic testing, the arrhythmia could not be terminated with overdrive pacing but did temporarily stop with adenosine. Activation mapping defined the onset of activation at the anterior RVOT immediately inferior to the pulmonary valve annulus. Catheter probing of this area resulted in marked acceleration of the arrhythmia and hypotension. Because of the marked dilation and attenuation of tissue in this region and hemodynamic instability with mapping, catheter ablation was not performed. Despite pharmacologic therapy with amiodarone, lidocaine, and class 1C agents, recurrences of sustained VT with hemodynamic compromise persisted. Thus surgical intervention was recommended, with anticipation that discrete myocardial tumors would be identified. At the time of the operation, the anterior free wall of the RVOT was dilated and visibly thin, and it collapsed when the patient was From the Department of Cardiothoracic Surgery, Children’s Hospital of Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, Calif.