New Diagnostic and Therapeutic Approaches to Treat Ventricular Tachycardias Originating at the Summit of the Left Ventricle

Abstract

T he left ventricular (LV) summit is the most common site of idiopathic epicardial LV arrhythmias and frequently represents a diagnostic and a therapeutic challenge. 1 We present a case of sustained monomorphic ventricular tachycardia (SMVT) originating at the LV summit that underwent failed cryosurgical epicardial ablation and was successfully treated with the aid of merged hemodynamic and contrast-enhanced MRI (CE-MRI). Editor's Perspective see p e85Case A 67-year-old man was admitted in 2010 for heart failure with severe LV dysfunction (ejection fraction 20%) initially attributed to alcohol consumption, and during the diagnostic work-up, a severe lesion at the bifurcation of the proximal left anterior descending artery with the first diagonal was percutaneously revascularized using a bifurcated drug-eluting stent, and he was discharged with the diagnosis of dilated cardiomyopathy of mixed pathogenesis (alcoholic and ischemic). In April 2011, he presented with SMVT with left-bundle branch block morphology. He underwent CE-MRI followed by an electrophysiologic study using an endocardial LV retrograde access, where frequent premature ventricular contractions (PVCs) with similar morphology to the clinical VT were ablated at the mitroaortic continuity, with partial success (ie, reduction in PVC density). The patient underwent implantable cardioverter-defibrillator (ICD) insertion and was discharged on amiodarone treatment. He remained free of arrhythmias until September 2012, when he was readmitted for a SMVT with left-bundle branch block morphology, right inferior axis at 140 beats per minute (below ICD detection rate), and early precordial transition (Figure 1). At the time of the EP study, SMVT was not inducible with programmed stimulation during isoproterenol infusion, but the patient presented frequent PVCs with identical morphology to the clinical VT (Figure 2C). A combined endoepicardial electroanatomical mapping (NaviStar ThermoCool, 3.5-mm tip, 2-5-2 interelectrode distance, and Carto XP Navigation System; Biosense Webster, Inc, Diamond Bar, CA) followed by coronary angiography revealed the presence of a low-voltage (<1 mV) area at the epicardium of the superior LV aspect that during sinus rhythm was characterized by the presence of fragmented and late electrograms ( Figure 2B), whereas the endocardial voltage and the electrogram characteristics of both outflow tracts were normal. Endocardial activation mapping of PVCs showed late activation in the right and LV outflow tracts ( Figure 2A) and no QRS match with pace mapping. In contrast, activation mapping showed an earliest site at the epicardium, where an excellent pace mapping was obtained ( Figure 2B and 2C). Because of the close proximity (≈1 cm) of the left main arteries, a surgical epicardial approach using cryoenergy was indicated.2,3 The patient had constant ventricular bigeminy during the surgical procedure. Intraoperative electroanatomic epicardial mapping (NavX system; St Jude Medical, Minneapolis, MN) confirmed the observations of the percutan...

Retrograde Coronary Venous Ethanol Infusion for Ablation of Refractory Ventricular Tachycardia

“…Surgical cryoablation or TCEA have been reported. 31 Strategies such as ablation in the AIV 32 , or bipolar ablation 33 have been proposed, but catheter size, proximity to coronary arteries or impedance rises limit the former 34 and the latter is not universally available. Other approaches have been described, such as hot saline or direct ethanol injections.…”

“…More recently, intracoronary ethanol injection has become limited to arrhythmogenic foci that are not amenable to contact-based ablation 12, 41 . Non-inducibility of VT following intracoronary ethanol ablation is reported between 56 and 84%, with a recurrence rate of around 33- 64% 1, 31, 41, 42 . Unfortunately, adverse events are not uncommon, most notably coronary arterial dissection, thrombosis and myocardial infarction 13-15 .…”

Editor’s Perspective: Similia Similibus Curantur

“…For example, in the case presented by Atienza et al, one can deduce that the origin is high (cranial) and to the left of the body. 1 When understanding the anatomy of the region, 3,4 we know that structures that require detailed mapping will likely include the distal right ventricular outflow tract and proximal pulmonary artery, the left coronary cusp, the anterior anteromedial mitral annulus, the epimyocardium of the summit, the great cardiac vein and anterior interventricular vein, and associated arterial vessels. Beyond this information, directing energy delivery and identifying the best site for ablation will depend on detailed mapping of each of these sites and understanding the mechanism of arrhythmia.…”

Surgical cryoablation for ventricular tachyarrhythmia arising from the left ventricular outflow tract region

“…Surgical ablation has been described with subendocardial resection in ischemic cardiomyopathy and with surgical cryoablation in nonischemic cardiomyopathy with successful outcomes. 3,4 However, there are few reports of surgical cryoablation in patients who had failed percutaneous endocardial or epicardial catheter ablation for arrhythmias arising from the LVOT region. [3][4][5] Methods During the period from March 2009 to March 2014, 190 consecutive patients with focal ventricular arrhythmias (VAs) originating from the LVOT underwent ablation at Brigham and Women's Hospital, Boston.…”

“…3,4 However, there are few reports of surgical cryoablation in patients who had failed percutaneous endocardial or epicardial catheter ablation for arrhythmias arising from the LVOT region. [3][4][5] Methods During the period from March 2009 to March 2014, 190 consecutive patients with focal ventricular arrhythmias (VAs) originating from the LVOT underwent ablation at Brigham and Women's Hospital, Boston. In the present study, we describe 4 patients (2%) with drug-refractory, highly symptomatic VAs emanating from the LVOT region who underwent surgical cryoablation.…”