Updated results on catheter ablation of ventricular arrhythmias arising from the papillary muscles of the left ventricle

BACKGROUND

Catheter ablation of ventricular arrhythmias (VAs) arising from the left ventricle`s (LV) papillary muscles (PM) is challenging. In this study we present results of catheter ablation using multiple energy sources and image-based approaches.

METHODS

Fifty-three patients (49 ± 17 years old; 34% females; median LV ejection fraction 53 ± 11%) underwent catheter cryoablation or radiofrequency (RF) ablation with non-contact force sensing (Non-CFS) catheters and cardiac computed tomography integration (CTII) into the electroanatomical mapping system or contact force sensing RF (CFS RF) ablation catheters and intracardiac echo-facilitated 3D electroanatomical mapping. Ventricular arrhythmias foci were mapped at either the anterolateral (ALPM) or posteromedial papillary muscles (PMPM). Ablation was performed using an 8-mm cryoablation catheter (CRYO); a Non-CFS 4-mm open-irrigated RF catheter; or a CFS RF 3.5-mm open-irrigated tip catheter, via transmitral or transaortic approach.

RESULTS

Acute success rate was 83% for Non-CFS RF/CTII; 100% for CRYO/CTII (n = 16) and CFS RF/ICE3D (n = 14) (P = 0.03). Catheter stability was achieved in all patients treated with Cryo/CTII. VA recurrence at 12 months follow-up was 48% (n = 11) for Non-CFS RF/CTII; 19% (n = 3) for CRYO/CTII; and 7% (n = 1) for CFS RF/ICE3D (P = 0.02).

CONCLUSIONS

Non-CFS/CTII was associated with an increased risk of recurrence of the clinical arrhythmia. Ablation with either CFS RF/ICE3D or CRYO/CTII showed high acute success rates and low recurrence rates during follow-up. Cryoablation provided stable contact and was less arrhythmogenic.

Results of Cryoenergy and Radiofrequency-Based Catheter Ablation for Treating Ventricular Arrhythmias Arising From the Papillary Muscles of the Left Ventricle, Guided by Intracardiac Echocardiography and Image Integration

BACKGROUND

Catheter radiofrequency ablation of ventricular arrhythmias (VAs) arising from the left ventricle's papillary muscles has been associated with inconsistent results. The use of cryoenergy versus radiofrequency has not been compared yet. This study compares outcomes and complications of catheter ablation of VA from the papillary muscles of the left ventricle with either cryoenergy or radiofrequency.

METHODS AND RESULTS

Twenty-one patients (40±12 years old; 47% males; median ejection fraction 59±7.3%) with drug refractory premature ventricular contractions or ventricular tachycardia underwent catheter cryoablation or radiofrequency ablation. VAs were localized using 3-dimensional mapping, multidetector computed tomography, and intracardiac echocardiography, with arrhythmia foci being mapped at either the anterolateral papillary muscle or posteromedial papillary muscles of the left ventricle. Focal ablation was performed using an 8-mm cryoablation catheter or a 4-mm open-irrigated radiofrequency catheter, via transmitral approach. Acute success rate was 100% for cryoenergy (n=12) and 78% for radiofrequency (n=9; P=0.08). Catheter stability was achieved in all patients (100%) treated with cryoenergy, and only in 2 (25%) patients treated with radiofrequency (P=0.001). Incidence of multiple VA morphologies was observed in 7 patients treated with radiofrequency (77.7%), whereas none was observed in those treated with cryoenergy (P=0.001). VA recurrence at 6 months follow-up was 0% for cryoablation and 44% for radiofrequency (P=0.03).

CONCLUSIONS

Cryoablation was associated with higher success rates and lower recurrence rates than radiofrequency catheter ablation, better catheter stability, and lesser incidence of polymorphic arrhythmias.

Cryoablation for Ventricular Arrhythmias Arising From the Papillary Muscles of the Left Ventricle Guided by Intracardiac Echocardiography and Image Integration

OBJECTIVES

This case series reports outcomes and complications of catheter cryoablation at the papillary muscles (PM) of the left ventricle (LV).

BACKGROUND

Catheter radiofrequency ablation is an effective treatment for ventricular arrhythmias (VAs) arising from the PM of the LV. The use of cryoablation at PMs has not been described.

METHODS

Ten patients (70% men; median age: 38 years [range: 34 to 45 years]) with drug-refractory premature ventricular contractions or ventricular tachycardia underwent catheter cryoablation. VAs were localized using 3-dimensional (3D) mapping, multidetector computed tomography, and intracardiac echocardiography, with arrhythmia foci being mapped at either the anterolateral PM or posteromedial papillary muscle (PMPM) of the LV. Focal ablation, up to 240 s with freeze-thaw-freeze cycles was performed using an 8-mm cryoablation catheter via a transmitral approach.

RESULTS

Termination of ventricular arrhythmia was observed in all 10 patients during ablation. Median follow-up was 6 months after ablation. The PMPM had higher prevalence of clinical arrhythmias (100% PMPM VAs vs. 10% anterolateral PM VAs). The PM base was the most frequent site of origin of the arrhythmias (60% of patients). Pace-mapping showed ≥11/12 match in all treated PM at the site of effective lesion. All VAs arising from the base of the PM showed Purkinje potentials. There were no post-procedure complications. VA recurred in 1 patient.

CONCLUSIONS

Cryoablation for arrhythmias arising from the PMs of the LV can be performed, and is a safe and effective alternative energy source for ablation.

Runaway pacemaker: A forgotten phenomenon?

Runaway is an uncommon pacemaker dysfunction, characterized by fast and erratic spikes at non-physiological rates. This infrequent but potentially lethal failure mode may be related to low battery voltage. Four single chamber pacemaker patients were analyzed (Medtronic Minix ST 8330, Minneapolis, MN, had been implanted in two patients and two CPI Triumph VR 1124, St Paul, MN, in the other two). They had been admitted because of presyncopal episodes. Typical high rate stimuli at 2000 ppm alternating with pacing at 60-65 ppm were recorded in all ECGs. Lead system tests were normal. The pulse generators had to be replaced.