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.

Multidetector cardiac tomography: a useful tool before cardiac resynchronization therapy.

BACKGROUND: Left ventricular lead placement in a suitable coronary vein is a key determi-nant of responsiveness to cardiac resynchronization therapy (CRT). Multidetector cardiac tomography (MDCT) is a non-invasive alternative to depict cardiac venous anatomy although coronary sinus (CS) retrograde venography (RV) is the gold standard. The aim of this study was to evaluate the accuracy of MDCT to determine the presence of CS tributaries before CRT. METHODS: A retrospective analysis of 41 consecutive patients eligible to CRT was performed. MDCT was assessed in all patients before CRT and RV was achieved in 39 patients. Both methods evaluated the presence of the inferior interventricular vein (IIV), posterior vein (PV) and lateral main vein (LMV). CS ostium diameter and distance between the CS ostium and right atrium (RA) lateral wall were also measured. RESULTS: The IIV was identified in 100% of MDCT and in 43.6% of RV. In comparison to RV, the MDCT's sensitivity to identify PV and LMV was 100% for both, kappa coefficient of 0.792 (CI 95% 0.46-0.93) and 0.69 (CI 95% 0.46-0.91), respectively. There was no significant difference between ischemic and non-ischemic patients regarding the presence of PV or LMV. Median CS antero-posterior diameter was 10.3 mm (IQR 7.5-13) and supero-inferior was 14.1 mm (IQR 11.5-17) (p < 0.01). A positive correlation (p < 0.001) between echocardiographic RA area and the distance from CS ostium to the RA lateral wall in the MDCT was observed. CONCLUSIONS: MDCT is as accurate as RV to depict CS and its tributaries (IIV, PV, LMV), and it could be useful as a non-invasive technique before CRT.

Cardiac magnetic resonance versus transthoracic echocardiography for the assessment and quantification of aortic regurgitation in patients undergoing transcatheter aortic valve implantation.

BACKGROUND: The transthoracic echocardiographic (TTE) evaluation of the severity of residual aortic regurgitation (AR) following transcatheter aortic valve implantation (TAVI) has been controversial and lacks validation. OBJECTIVES: This study sought to compare TTE and cardiac magnetic resonance (CMR) for assessment of AR in patients undergoing TAVI with a balloon-expandable valve. METHODS: TTE and CMR exams were performed pre-TAVI in 50 patients and were repeated postprocedure in 42 patients. All imaging data were analysed in centralised core laboratories. RESULTS: The severity of native AR as determined by multiparametric TTE approach correlated well with the regurgitant volume and regurgitant fraction determined by CMR prior to TAVI (Rs=0.79 and 0.80, respectively; p<0.001 for both). However, after TAVI, the correlation between the prosthetic AR severity assessed by TTE and regurgitant volume and fraction measured by CMR was only modest (Rs=0.59 and 0.59, respectively; p<0.001 for both), with an underestimation of AR severity by TTE in 61.9% of patients (1 grade in 59.5%). The TTE jet diameter in parasternal view and the multiparametric approach (Rs=0.62 and 0.59, respectively; both with p<0.001) showed the best correlation with CMR regurgitant fraction post-TAVI. The circumferential extent of prosthetic paravalvular regurgitation showed a poor correlation with CMR regurgitant volume and fraction (Rs=0.32, p=0.084; Rs=0.36, p=0.054, respectively). CONCLUSIONS: The severity of AR following TAVI with a balloon-expandable valve was underestimated by echocardiography as compared with CMR. The jet diameter, but not the circumferential extent of the leaks, and the multiparametric echocardiography integrative approach best correlated with CMR findings. These results provide important insight into the evaluation of AR severity post-TAVI.