Deep Pujara

Procedural and biophysical indicators of durable pulmonary vein isolation during cryoballoon ablation of atrial fibrillation

BACKGROUND Limited data exist on procedural and biophysical indicators of pulmonary vein (PV) isolation durability after the cryoballoon ablation of atrial fibrillation (AF). OBJECTIVE The aim of this study was to investigate the procedural and biophysical characteristics associated with late PV reconnection (PVR) and durable PV isolation (PVI) after cryoablation using the currently available second-generation cryoballoon. METHODS Data from 435 PVs targeted in 112 consecutive patients who underwent a repeat procedure 14 ± 3 months after an index cryoablation of AF were examined. RESULTS Altogether, 111 PVs (25.5%) in 71 patients (63.4%) demonstrated PVR, whereas 324 PVs (74.5%) exhibited PVI. The number and duration of cryoballoon applications did not differ between PVR and PVI. However, the time to PV isolation (time to effect) was considerably shorter (39.1 ± 11.7 seconds vs 67.6 ± 19.7 seconds; P < .001), the balloon temperature at time to effect was significantly warmer (-32.1°C ± 7.8°C vs -39.4°C ± 5.8°C; P < .001), the balloon nadir temperature was slightly cooler (-48.7°C ± 4.6°C vs -47.8°C ± 2.9°C; P = .034), and the total thaw time (56.5 ± 25.4 seconds vs 34.8 ± 9.1 seconds; P < .001) and interval thaw times at 0°C (iTT0; 14.8 ± 10.9 seconds vs 7.1 ± 2.0 seconds; P < .001) and 15°C (54.2 ± 25.4 seconds vs 33.3 ± 9.1 seconds; P < .001) were notably longer with PVI than with PVR. However, only a time to effect of ≤60 seconds and an iTT0 of ≥10 seconds emerged as significant predictors of PV isolation durability. Consequently, in a multivariate model, presence of both criteria predicted <1% and their mere absence ~75% likelihood of PVR. CONCLUSION A time to effect of ≤60 seconds and an iTT0 of ≥10 seconds significantly predict PV isolation durability after the cryoballoon ablation of AF. If both criteria are met, the likelihood of PV reconnection may be exceedingly low.

Impact of irrigation flow rate and intrapericardial fluid on cooled-tip epicardial radiofrequency ablation

BACKGROUND The optimal irrigation flow rate (IFR) during epicardial radiofrequency (RF) ablation has not been established. OBJECTIVE This study specifically examined the impact of IFR and intrapericardial fluid (IPF) accumulation during epicardial RF ablation. METHODS Altogether, 452 ex vivo RF applications (10 g for 60 seconds) delivered to the epicardial surface of bovine myocardium using 3 open-irrigated ablation catheters (ThermoCool SmartTouch, ThermoCool SmartTouch-SF, and FlexAbility) and 50 in vivo RF applications delivered (ThermoCool SmartTouch-SF) in 4 healthy adult swine in the presence or absence of IPF were examined. Ex vivo, RF was delivered at low (≤3 mL/min), reduced (5-7 mL/min), and high (≥10 mL/min) IFRs using intermediate (25-35 W) and high (35-45 W) power. In vivo, applications were delivered (at 9.3 ± 2.2 g for 60 seconds at 39 W) using reduced (5 mL/min) and high (15 mL/min) IFRs. RESULTS Ex vivo, surface lesion diameter inversely correlated with IFR, whereas maximum lesion diameter and depth did not differ. While steam pops occurred more frequently at low IFR using high power (ThermoCool SmartTouch and ThermoCool SmartTouch-SF), tissue disruption was rare and did not vary with IFR. In vivo, charring/steam pop was not detected. Although there were no discernible differences in lesion size with IFR, surface lesion diameter, maximum diameter, depth, and volume were all smaller in the presence of IPF at both IFRs. CONCLUSION Cooled-tip epicardial RF ablation created using reduced IFRs (5-7 mL/min) yields lesion sizes similar to those created using high IFRs (≥10 mL/min) without an increase in steam pop/tissue disruption, whereas the presence of IPF significantly reduces the lesion size.

The State of the Art in Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation has evolved in design, technology, patient selection, insertion techniques, adjunct devices, and management in the past 45 years since it began. Outcomes have improved and indications have expanded. It continues to be an expeditious, cost-effective tool for rapid resuscitation of patients with cardiorespiratory failure, whose outcomes without extracorporeal membrane oxygenation intervention are predominately fatal. However, results are still moderately satisfactory, and the ethical aspects of ongoing care need to be at the forefront of daily family discussions in patients for whom a bridge to transplant or definitive device is not possible.

5-YEAR OUTCOMES OF A STAGED HYBRID SURGICAL AND CATHETER-BASED ABLATION APPROACH FOR TREATMENT OF LONG-STANDING PERSISTENT ATRIAL FIBRILLATION

Background: Catheter ablation (CA) of long-standing persistent (LSP) atrial fibrillation (AF) is associated with reduced success rates. This analysis examines the acute/long-term outcomes of a staged hybrid surgical and catheter-based ablation strategy for treatment of LSP AF. Methods: In this

Complex Left Atrial Appendage Morphology Is an Independent Risk Factor for Cryptogenic Ischemic Stroke

Importance: Ischemic strokes pose a significant health burden. However, the etiology of between 20 and 40% of these events remains unknown. Left atrial appendage morphology may influence the occurrence of thromboembolic events. Design: A retrospective cross-sectional study was conducted to investigate the role of LAA morphology in patients with atrial fibrillation (AF) and cardioembolic-associated stroke and patients with cryptogenic stroke without atrial fibrillation. LAA morphology is classified into two groups: (1) simple (chicken-wing) vs. (2) complex (non-chicken wing) based on transesophageal echocardiography (TEE) findings. In addition to the LAA morphology, left atrial parameters, including orifice diameter, depth, emptying velocity, and filling velocity, were collected for both groups. Mathematical, computational models were constructed to investigate flow velocities in chicken-wing and non-chicken wing morphological patterns to assess LAA function further. Findings: TEE values for volume, size, emptying, and filling velocities were similar between simple and complex LAA morphology groups. Patients with cryptogenic stroke without coexisting AF were noted to have significantly higher rates of complex LAA morphology. Chicken-wing LAA morphology was associated with four-fold higher flow rate (kg/s) in computational simulations. Conclusions: Complex LAA morphology may be an independent contributing factor for cryptogenic strokes. Further studies are warranted to investigate the mechanism involved in LAA morphology and thromboembolic events.