90 vs 50-Watt Radiofrequency Applications for Pulmonary Vein Isolation: Experimental and Clinical Findings.

BACKGROUND: Fifty-watt radiofrequency applications have proven to be safe and efficient for pulmonary vein isolation (PVI). However, as PV reconnection still occurs and ablation catheter instability significantly contributes to suboptimal lesion formation, a new ablation catheter capable of delivering 90 W for 4 seconds only has been developed with the aim of improving PVI outcomes. In this setting, we sought to determine whether 90 W applications create transmural lesions without collateral damage experimentally and whether they can safely improve PVI procedures clinically compared with 50 W settings. METHODS: Experimentally, individual lesions were created in vivo in the right atrium of 6 swine with 90 W-4 seconds applications using the SmartTouch-SF catheter in a power-controlled mode (3 animals) or the QDOT-MICRO catheter in a temperature-controlled mode (3 animals). Clinically, PVI was performed in a homogenous population of 150 consecutive paroxysmal atrial fibrillation patients using CARTO and the QDOT-MICRO catheter in a temperature-controlled mode (75 patients 50 W-ablation index-guided and 75 patients 90 W-4 seconds). RESULTS: Mostly, (94.9%) experimental lesions were transmural in the thin-walled right atrium of swine. However, collateral damage was observed with both catheters in 17.9% of lesions. Clinically, 90 W procedures had a lower first-pass PVI rate (49% versus 81%, P<10-4) and a higher acute PV reconnection rate (21% versus 5%, P=0.004) than 50 W procedures, whereas total procedural duration (62 versus 66 minutes, P=0.09), 1-year sinus rhythm maintenance (88% versus 90%, P=0.6) and safety (1 tamponade per group) were similar in both groups. CONCLUSIONS: Experimentally, using the QDOT-MICRO catheter, 90 W-4 seconds lesions are mostly transmural in the thin-walled right atrium of swine (median depth 1.87 mm) with a moderate lesion diameter of 6.62 mm but retain the potential for collateral damage. Clinically, 90 W-4 seconds applications are associated with a lower first-pass PVI rate and a higher acute PV reconnection rate than 50 W applications but similar safety outcomes and effectiveness at 1 year.

Elimination of the negative component of the unipolar atrial electrogram as an in vivo marker of transmural lesion creation: acute study in canines.

BACKGROUND: It has been experimentally shown that elimination of the negative component of the unipolar atrial electrogram (R morphology completion) during radiofrequency applications reflects transmural lesions creation. Subsequently, it has been clinically suggested that such a transmurality can be either irreversible or reversible. The present study is aimed to determine, at the histological level, whether transmural lesions, assessed by R morphology completion, might indeed be reversible in some circumstances or not. METHODS AND RESULTS: In 6 Mongrel hound dogs, superior and inferior vena cavae were isolated and individual lesions were created in the right atrium using radiofrequency energy (30 W/48°C/17 mL/min as presettings and 10g of force in average) under CARTO guidance. Five types of lesions were created; R+0: termination of ablation at the time of R morphology completion; R+5, R+10, or R+20: extension of ablation for 5, 10, or 20 seconds, respectively, after R morphology achievement; and conventional: radiofrequency applications lasting 30 seconds irrespective of the atrial electrogram modification. All conventional, R+5, R+10, and R+20 lesions were necrotic and transmural, whereas some R+0 lesions were not (comprising a part of necrosis and a part of reversible cell damage). Interestingly, surrounding organ injuries were observed after conventional, R+10, and R+20 radiofrequency applications but were not observed after R+0 and R+5 applications. CONCLUSIONS: Elimination of the negative component of the unipolar atrial electrogram reflects, in general, irreversible transmural necrosis creation. In some cases, however, it translates transmural lesion only (with potential reversibility) likely related to transient cell damage creation.

Age should be considered in the decision making of prophylactic splenic angioembolization in nonoperative management of blunt splenic trauma: a study of 208 consecutive civilian trauma patients.

BACKGROUND: A strategy of prophylactic splenic angioembolization using observation failure risk (OFR) computed tomographic (CT) scan criteria has been proposed recently. The main aim of the present study was to evaluate the relevance of the criteria in terms of delayed splenic rupture in patients with blunt splenic injury. METHODS: All patients with blunt splenic injuries admitted consecutively between January 2005 and January 2010 to our institution were included. Clinical, CT scan, and angiographic data, initial management, and outcome were noted. Patients managed expectantly were classified according to OFR CT scan criteria (high OFR was defined by at least one of the following CT scan signs: blush, pseudoaneurysm, Organ Injury Scale [OIS] grade III with a large hemoperitoneum, and OIS grade IV or 5). Initial management success was especially studied. RESULTS: Among the 208 patients included, 161 (77%) were treated by observation (35 OIS grade I, 64 OIS grade II, 33 OIS grade III, 18 OIS grade IV, and 11 OIS grade V) and 129 (80%) were men, with a mean (SD) age of 36.1 (18.7) years and a mean (SD) Injury Severity Score of 20.8 (15.4). Forty-nine patients (30%) had high OFR CT scan criteria. Thirteen patients (8%) experienced observation failure. High OFR CT scan criteria (odds ratio, 11; 95% confidence interval, 2.5-47.5) and patients 50 years and older (odds ratio, 33.9; 95% confidence interval, 6.2-185.5) were independent factors related to observation failure. The positive predictive value of OFR CT scan criteria for observation failure was 18%, and the negative predictive value was 96%. The corresponding values were 67% and 90%, respectively, in patients 50 years and older and 3% and 99%, respectively, in patients younger than 50 years. CONCLUSION: OFR CT scan criteria lack specificity to predict observation failure, mainly in patients younger than 50 years. Age should be considered when identifying patients requiring prophylactic splenic angioembolization. LEVEL OF EVIDENCE: Diagnostic study, level III.