Ripple mapping in ventricular tachycardia substrate mapping and ablation of nonischemic ventricular tachycardia.

INTRODUCTION: Substrate-based ablation for ventricular tachycardia (VT) using Ripple map (RM) is an effective treatment strategy for patients with ischemic cardiomyopathy but has yet to be evaluated in patients with nonischemic cardiomyopathy (NICMO). The aim of this study is to determine the feasibility and effectiveness of an RM-based ablation for NICMO patients. METHODS AND RESULTS: This was a single-center, retrospective study including all NICMO patients undergoing VT ablation at St Vincent Hospital between January 1, 2018 and January 12, 2019. Retrospective RM analysis was performed on those that had a substrate-based ablation to identify the location and number of Ripple channels as well as their proximity to ablation lesions. Thirty-three patients met the inclusion criteria and had a median age of 65 (58, 73.5) with 15.2% of the population being female, and were followed for a median duration of 451 (217.5, 586.5) days. Of these patients, 23 (69.7%) had a substrate-based ablation with a median procedural duration of 196.4 (186.8, 339) min, 1946 (517, 2750) points collected per map, and 277 (141, 554) points were within the scar. Two (8.6%) procedural complications occurred, and 7 (30.4%) patients had VT recurrence during follow-up. RM analysis revealed an average of two Ripple channels and the patients without VT recurrence had ablation performed closer to the Ripple channels: 0 (0, 4.7) versus 14.3 (0, 23.5) cm; p = .02. CONCLUSION: An RM-based substrate ablation can be performed in NICMO patients and ablation within Ripple channels is a predictor of VT freedom.

Rapid detection of isthmus block and rhythm change using local electrogram changes during complex atrial flutter ablation.

AIMS: Multiple re-entry circuits may operate simultaneously in the atria in the form of dual loop re-entry using a common isthmus, or multiple re-entrant loops without a common isthmus. When two or more re-entrant circuits coexist, ablation of an individual isthmus may lead to a seamless transition (without significant changes in surface electrocardiogram, coronary sinus activation or tachycardia cycle length) to a second rhythm, and the isthmus block can go unnoticed. METHODS AND RESULTS: We hypothesize and subsequently illustrate in three patient cases, methods to rapidly identify a transition in the rhythm and isthmus block using local electrogram changes at the ablation site. CONCLUSION: Local activation sequence changes, electrogram timing, and the behaviour of pre-existing double potentials can reveal isthmus block promptly when rhythm transitions occur during ablation of multiloop re-entry tachycardias.

Diagnostic utility of early premature ventricular complexes in differentiating atrioventricular reentrant and atrioventricular nodal reentrant tachycardias.

BACKGROUND: His-refractory premature ventricular complexes perturbing a supraventricular tachycardia (SVT) establish the presence of an accessory pathway (AP). Earlier premature ventricular complexes (ErPVCs) may perturb SVTs but are considered nondiagnostic. OBJECTIVE: The purpose of this study was to test the hypothesis that an ErPVC will always show a difference >35 ms in its advancement of the next atrial activation during atrioventricular nodal reentrant tachycardia (AVNRT). During atrioventricular reentrant tachycardia (AVRT), a PVC delivered close to the circuit can result in greater advancement of atrial activation due to retrograde conduction via an AP. Thus, an AP response, defined as ErPVC (H1S2) advancing the subsequent atrial activation (A1-A2) more than this minimum difference (A1A2 ≤ H1S2+35 ms), establishes the presence of an AP. METHODS: Sixty-five consecutive patients with SVT were retrospectively evaluated. ErPVCs were defined when the ventricular pacing stimulus was >35 ms ahead of the His during tachycardia. RESULTS: Among the 65 cases, 43 were AVNRT and 22 AVRT. Fourteen AVRT cases had an AP response with a mean H1S2+35 ms of 336 ± 58 ms and A1A2 of 309 ± 51ms. No AVNRT cases had an AP response. The specificity of an AP response to ErPVC in predicting AVRT was 100%. CONCLUSION: An AP response to PVCs (A1A2 ≤ H1S2+35 ms) is 100% specific for the presence of an AP.

Left atrial hypertension and the risk of early incident heart failure after atrial fibrillation ablation.

INTRODUCTION: Elevated left atrial pressure (LAP) during catheter ablation of atrial fibrillation (AF) is associated with an increased risk of AF recurrence, but it is unknown if this correlates with heart failure (HF). The objective of the study was to determine if elevated LAP after AF ablation correlates with HF events. METHODS: Prospective, single-center, cohort study measuring LAP and right atrial pressure (RAP) during AF ablation in 100 patients. The primary endpoint was clinical HF within 30 days of ablation. The secondary outcome was AF-free HF. RESULTS: One hundred patients (63% male, mean age 64.5) were enrolled and 20% had clinical HF within 30 days. Bivariate correlates included mitral valve (MV) disease, persistent AF, class III antiarrhythmics, LAP, and recurrent AF. Multivariate analysis revealed class III antiarrhythmics were protective (odds ratio [OR]: 0.24 [0.1-0.5], p = .04), while MV disease (OR: 8.7 [3.3-23], p = .03) and loop diuretics (OR: 4.8 [2.6-9.1], p = .01) were hazardous. AF-free HF occurred in 9% of patients and correlated with higher LAP and RAP, and chronic kidney disease. CONCLUSION: Patients with HF after AF ablation had higher LAP. MV disease, diuretic use, and class III antiarrhythmics also correlated to HF. These present opportunities to target future interventions to reduce a common complication of AF ablation.

Avoiding Bladder Catheters During Atrial Fibrillation Ablation.

OBJECTIVES: This study sought to determine if atrial fibrillation (AF) ablation can be performed safely without bladder catheterization. BACKGROUND: Patients undergoing AF ablation often receive bladder catheters. Catheterization is associated with potential complications. The ABCD-AF (Avoiding Bladder Catheters During Atrial Fibrillation) ablation study evaluates the advantages of performing AF ablation without routine catheterization. METHODS: In this single-center, prospective, randomized controlled trial, 80 patients received bladder catheterization (group A), and 80 patients received only as-needed catheterization (group B). The primary endpoint was a composite of cystitis, urethral injury, hematuria, dysuria, or urinary retention. RESULTS: The mean patient age was 63 ± 13 years, and 33% of patients were female. The primary outcome was reached in 45 patients in group A and 11 patients in group B (p < 0.001). Urinary tract infection occurred in 7 patients in group A and 2 patients in group B (p = 0.17). Urinary retention occurred in 12 patients in group A and 5 patients in group B (p = 0.07). Randomization to catheterization carried an odds ratio of 8.1 (95% confidence interval [CI]: 3.7 to 17.5; p < 0.001), and male sex carried an odds ratio of 3.8 (95% CI: 1.7 to 8.6; p = 0.001) for the primary endpoint. On subgroup analysis, randomization to undergo catheterization had no association with the primary outcome in female patients but had an odds ratio of 14.6 (95% CI: 5.6 to 38.1; p < 0.001) in male patients. In multivariable analysis, sex and catheter status remained independently associated with the primary outcome. CONCLUSIONS: Bladder catheterization can be safely avoided in patients undergoing AF ablation and is associated with a significant reduction in adverse outcomes, especially in men.

Predictors of successful ultrasound-guided lead implantation.

BACKGROUND: Technical advances have improved the safety of cardiac implantable electronic device (CIED) insertion, but periprocedural complications persist. Despite ultrasound (US) guidance for vascular access being feasible and exhibiting shorter fluoroscopy times, it is not widely adopted for insertion of CIEDs. Thus, we studied the use of US for CIED insertion to (1) quantify the success rate of venous cannulation, (2) identify predictors of failed cannulation, and (3) quantify the rate of complications using US guidance. METHODS: We studied 166 consecutive patients who underwent US-guided CIED implantation. Anatomic parameters of the axillary vein were measured. The primary outcome was success (group 1) or failure (group 2) to obtain vascular access utilizing US guidance. Secondary outcomes included pneumothorax and hematoma. RESULTS: Successful US-guided cannulation occurred in 154 of 166 patients (93%). No patient had a pneumothorax. Hematoma occurred in 1 of 166 patients (0.01%). Group 2 exhibited higher male proportion at 11 of 12 (92%) compared with 94 of 154 (61%) in group 1 (P = .03), increased vein depth at 3.84 versus 2.85 cm (P = .003), more right-sided implants (P = .03), higher weight at 104.6 versus 85.3 kg (P = .017), higher body mass index at 35.6 versus 29.2 kg/m2 (P = .049), and higher body surface area at 2.24 versus 1.99 m2 (P = .013). Other parameters were statistically nonsignificant. In multivariate analysis, vein depth remained significantly associated with failure. CONCLUSION: Using US guidance for CIED implantation is successful in the vast majority (93%) of patients. Rare cases of unsuccessful cannulation were associated with right-sided implants and increased venous depth.