Optimized workflow for pulmonary vein isolation using 90-W radiofrequency applications: a comparative study.

BACKGROUND: Ninety-watt applications are more sensitive to catheter instability and produce lesions that are shallower and smaller in diameter than 50-W applications. These characteristics were considered for the development of a combined (90-50 W) pulmonary vein isolation (PVI) strategy which was prospectively compared to a 50 W-only ablation index (AI)-guided PVI strategy. METHODS: One hundred fifty consecutive paroxysmal AF patients underwent PVI under general anesthesia using CARTO. In the first 75 patients, PVI was performed with a combined (90-50 W) strategy using the QDOT-MICRO catheter in a temperature-controlled mode. This strategy consisted of 90 W-4 s applications on the posterior LA wall (at sites of catheter stability and expectedly thin atrial tissue) with an interlesion distance (ILD) ≤ 4 mm and 50-W applications elsewhere (at sites of catheter instability or expectedly thick atrial tissue) with ILD < 6 mm. In the subsequent 75 patients, PVI was performed with a 50 W-only AI-guided strategy using the SmartTouch-SF catheter in a power-controlled mode. RESULTS: Both groups of patients had similar clinical characteristics and LA dimensions (123.1 ± 24.9 ml vs 119 ± 26.8 ml, P = 0.33). Total procedural times (61 [56-70] vs 65 [60-75] min, P = 0.12), first-pass PVI (82.6 vs 80%, P = 0.81), acute PV reconnection (0 vs 6.6%, P = 0.05), and 1-year SR maintenance (93.3 vs 90.6%, P = 0.57) rates were also similar in both groups of patients. There were no complications in the combined (90-50 W) group while only 2 groin hematomas were reported in the 50 W group. CONCLUSIONS: In paroxysmal AF patients, a combined (90-50 W) strategy for PVI did not improve safety, efficiency, or effectiveness compared to a 50 W-only AI-guided strategy.

Left ventricular summit premature ventricular contractions treated by venous ethanol infusion: Scar assessment by magnetic resonance imaging.

Left ventricular (LV) summit premature ventricular contractions (PVCs) are often unresponsive to radiofrequency (RF) ablation. Retrograde venous ethanol infusion (RVEI) can be a valuable alternative in this scenario. A 43-year-old woman without structural heart disease presented with LV summit PVCs unresponsive to RF ablation because of their deep-seated origin. Unipolar pace mapping performed through a wire inserted into a branch of the distal great cardiac vein (GCV) demonstrated 12/12 concordance with the clinical PVCs thus indicating close proximity to PVCs' origin. RVEI abolished the PVCs without complications. Subsequently, magnetic resonance imaging (MRI) evidenced an intramural myocardial scar produced by ethanol ablation. In conclusion, RVEI effectively and safely treated PVC arising from a deep site in the LVS. The scar provoked by chemical damage was well characterized by MRI imaging.

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.

Duration of hospital admission, need of on-demand analgesia and other peri-procedural and short-term outcomes in sub-cutaneous vs. transvenous implantable cardioverter-defibrillators.

BACKGROUND: Post-procedural recovery following sub-cutaneous ICD (S-ICD) implantation is feared to be more painful and to require more prolonged hospital admission. The purpose of this study was to compare peri-procedural and short clinical outcomes of the S-ICD vs. the Transvenous ICD (TV-ICD). METHODS: We conducted a single-center cross-sectional study including all consecutive patients who underwent S-ICD implantation by the same operator since January 2016 and a gender and age-matched control group with all single chamber TV-ICD implanted patients over a contemporary time period. RESULTS: Thirty-one patients (sex ratio 1/5; mean age 58.7±13.2years) with S-ICD were compared to 31 matched TV-ICD patients. Duration of the implant procedure was significantly longer for the S-ICD (58.0±24.4min vs 41.7±20.8min TV-ICD, p<0.01). Mean fluoroscopy time for the TV-ICD was 3.5±3.6min vs 0.1±0.01min for all S-ICD patients (p<0.01). Requirement of on-demand analgesia administration, and duration of hospitalization (1.5days for both groups; p=NS) were similar in the two groups. No peri-procedural events were reported, and after a mean follow-up of 6months, the only complication was a pocket infection requiring reintervention in the TV-ICD group. CONCLUSIONS: The S-ICD appears to be as effective and safe as the conventional single chamber TV-ICD. Duration of hospital admission and need of on-demand analgesia are also comparable for S-ICD patients.

Three-dimensional interlead distance predicts response and outcomes after cardiac resynchronization therapy.

BACKGROUND: Approximately one-third of patients do not respond favourably to cardiac resynchronization therapy (CRT). A longer distance between ventricular leads may improve response. AIM: To study the impact of the true three-dimensional interlead distance (ILD) on outcomes. METHODS: Consecutive patients undergoing CRT device implantation were included prospectively. Interlead separation was measured from postprocedural anterior-posterior and lateral chest X-rays. The three-dimensional ILD was calculated using the Pythagorean theorem. Response to CRT was defined using a composite clinical score at 6 months. RESULTS: Forty-two patients were included (mean age 70±9 years; QRS duration 154±31ms; left ventricular ejection fraction 26±7%; 50% ischaemic). At 6 months, 71% of patients were considered to be responders. Responders had a significantly longer ILD (108±17 vs. 87±21mm; P=0.002). When the ILD was corrected for cardiac size, the optimal cut-off value was ≥ 0.53 for predicting response (sensitivity 83%, specificity 75%, area under the curve 0.84; P=0.0002). Similar results were obtained in a historical retrospective cohort. The use of proximal electrodes on the left ventricular lead was associated with a longer ILD in 95% of patients, compared with more distal pacing configurations. In the total cohort of 74 patients (median follow-up, 420 days), those with an indexed ILD ≥ 0.53 had a 70% reduction in risk of hospitalization for heart failure (P=0.004). CONCLUSION: Longer three-dimensional ILD corrected for cardiac size measured on chest radiographs can accurately predict response to CRT and outcomes. This simple variable may be used to identify optimal lead placement and pacing configuration during CRT implantation.

Beta-blockers or Digoxin for Atrial Fibrillation and Heart Failure?

In patients with atrial fibrillation (AF) and heart failure (HF) with or without systolic dysfunction, either rhythm control or rate control is an acceptable primary therapeutic option. If a rate control strategy is chosen, treatment with a beta-blocker is almost always required to achieve rate control. Adequate ventricular rate control is usually a resting rate of less than 100 beats per minute, but lower resting rates may be appropriate. Non-dihydropyridine calcium channel blockers are often contraindicated when AF is associated with HF with systolic dysfunction. There have been recent debates on a possible reduced efficacy of beta-blockers as well as safety issues with digoxin when treating HF patients with AF. The benefit of beta-blockers on survival may be lower in patients with HF with reduced ejection fraction when AF is present. Digoxin does not improve survival but may help to obtain satisfactory rate control in combination with a beta-blocker. Digoxin may be useful in the presence of hypotension or an absolute contraindication to beta-blocker treatment.

PKR, a cognitive decline biomarker, can regulate translation via two consecutive molecular targets p53 and Redd1 in lymphocytes of AD patients.

In Alzheimer's disease (AD), the control of translation is dysregulated, precisely, two opposite pathways: double-stranded RNA-dependent protein kinase (PKR) is up-regulated and mammalian target of rapamycin (mTOR) is down-regulated. These biochemical alterations were found at the periphery in lymphocytes of AD patients and were significantly correlated with cognitive and memory test scores. However, the molecular crosslink between these two opposite signalling pathways remains unknown. The tumour suppressor p53 and Redd1 (regulated in development and DNA damage response) could be two downstream targets of active PKR to explain the breakdown of translation in AD patients. In this study, the protein and gene levels of p53 and Redd1 were assayed in lymphocytes of AD patients and in age-matched controls by Western blotting and RT-PCR. Furthermore, correlations were analysed with both the level of active PKR and the Mini Mental State Examination score (MMSE). The results show that the gene and protein levels of p53 and Redd1 were significantly increased about 1.5-fold for both gene and Redd1 protein and 2.3-fold for active p53 in AD lymphocytes compared to age-matched controls. Furthermore, statistical correlations between proteins and genes suggest that active PKR could phosphorylate p53 which could induce the transcription of Redd1 gene. No correlations were found between MMSE scores and levels of p53 or Redd1, contrary to active PKR levels. PKR represents a cognitive decline biomarker able to dysregulate translation via two consecutive targets p53 and Redd1 in AD lymphocytes.