Compatibility of a novel temperature-controlled, irrigated radiofrequency catheter with ultra-high-density mapping.

Background: Compatibility of DiamondTemp (DT) radiofrequency (RF) catheter with the Rhythmia mapping system has not been manufacturer-reported nor its tracking accuracy reported. Methods: Consecutive patients undergoing macroreentrant atrial tachycardia ablation guided by Rhythmia and ablated using DT were prospectively enrolled. Following catheter configuration, ablation lines were performed and remapped to measure the RF tag to effective-ablation-line-center (RFT-ALC) distance. Results: Among 20 consecutive patients (54 maps), 40 ablation lines were evaluated. Overall, the RFT-ALC distance was 3.88 ± 2.95 mm, and the operator assessment of accuracy was high. No complications occurred. Conclusion: The use of DT catheter guided by the Rhythmia mapping system is feasible and accurate.

Systematic Workflow and Electrogram guidance to reduce X-ray Exposure Time during cryoballoon ablation of atrial fibrillation: the SWEET-Cryo strategy.

AIMS: Cryoballoon pulmonary vein isolation (CB-PVI) offers similar efficacy to point-by-point radiofrequency PVI for patients with atrial fibrillation (AF), but generally with higher X-ray exposure. Strategies aimed at reducing fluoroscopy mostly rely on other costly imaging techniques, limiting their applicability. We designed a Systematic Workflow and Electrogram guidance to reduce X-ray Exposure Time during CB-PVI (SWEET-Cryo) strategy and analysed its impact on fluoroscopy use and acute procedural and clinical outcomes. METHODS AND RESULTS: We enrolled 100 patients with paroxysmal or persistent AF undergoing CB-PVI by two operators with different levels of expertise. Patients treated with the SWEET-Cryo strategy (prospective cohort; n = 50) or conventional fluoroscopy (retrospective control cohort; n = 50) were compared. When applied by the senior operator, the SWEET-Cryo strategy significantly reduced the mean fluoroscopy time (FT) (2.6 ± 1.25 vs. 20.3 ± 10.8 min) and mean dose area product (DAP) (5.1 ± 3.8 vs. 35.3 ± 22.3 Gy cm2) compared with those of the control group, respectively (P < 0.001). Significant reductions in FT (6.4 ± 2.5 min vs. 32.5 ± 10.05) and DAP (13.9 ± 7.7 vs. 92.3 ± 63.8) were also achieved by the less experienced operator (P < 0.001). No difference was observed in acute and long-term complications or freedom from AF between fluoroscopy strategies during a 33-month median follow-up. Mean FT was maintained below 3 min in randomly selected cases performed during the follow-up period. CONCLUSION: In contrast to conventional protocols and regardless of the operator's experience, the optimized SWEET-Cryo strategy dramatically reduced fluoroscopy exposure during CB-PVI. The efficacy, safety, or added costs of the ablation procedure were not compromised.

Impact of Coronavirus Disease 2019 on Cardiac Arrhythmia Care: Experience of a Spanish Tertiary Hospital During the Health Crisis Triggered by the First Wave of the Pandemic.

The coronavirus disease 2019 (COVID-19) pandemic has resulted in a deep restructuring of cardiovascular care, especially in the setting of cardiac arrhythmia units, which are characterized by a wide variety of clinical and interventional activities. We describe the experience of a large university hospital deeply hit during the COVID-19 health crisis (first outbreak of the pandemic), focusing on the exceptional measures implemented and their impact in terms of outcomes. We performed a retrospective study comparing the human and structural resources and the activity of a cardiac arrhythmia unit in a Spanish tertiary hospital for two consecutive periods: from January 12, 2020, to March 8, 2020 ("pre-COVID stage"), and from March 9, 2020, to May 2, 2020 ("COVID stage"). Data were contextualized within the number of confirmed COVID-19 cases in the region of Madrid. The measures implemented were promotion of non-face-to-face consultations, selection of urgent procedures, design of a "COVID-free" circuit for outpatient interventions, and protocolization for patients with COVID-19. A total of 3,526 consultations and 362 procedures were performed. During the COVID stage, the number of consultations remained stable, and the electrophysiology rooms' activity decreased by 55.2% with a relative increase in the number of urgent-hospitalized cases attended (11.8% COVID-19-positive patients). The electrophysiology rooms' activity returned to "normal" in the last week of the COVID stage, with no contagion being detected among patients or professionals. In conclusion, the measures implemented allowed us to respond safely and efficiently to the health care needs of patients with arrhythmias during the COVID-19 crisis and may be useful for other institutions facing similar situations.

Complete interatrial block in a left-atrial dependent atrioventricular node.

INTRODUCTION: A middle-age woman underwent an electrophysiologic study due to recurrent atypical atrial flutter. METHODS AND RESULT: Radiofrequency ablation of cavotricuspid isthmus and anterior mitral line was performed. During energy delivery on the anterior left atrial wall, interatrial dissociation and complete block of the sinus impulse to the atrioventricular (AV) node was observed. AV node activation became dependent on a subsidiary left atrial rhythm. CONCLUSION: Anatomical location of intra and inter-atrial connections must be taken into account when performing extensive ablation procedures, specially in cases with prior cardiac surgeries.

Lesion Index Titration Using Contact-Force Technology Enables Safe and Effective Radiofrequency Lesion Creation at the Root of the Aorta and Pulmonary Artery.

BACKGROUND: Ablation of some myocardial substrates requires catheter-based radiofrequency delivery at the root of a great artery. We studied the safety and efficacy parameters associated with catheter-based radiofrequency delivery at the root of the aorta and pulmonary artery. METHODS: Thirty-six pigs underwent in-vivo catheter-based ablation under continuous contact-force and lesion index (power, contact-force, and time) monitoring during 60-s radiofrequency delivery with an open-irrigated tip catheter. Twenty-eight animals were allocated to groups receiving 40 W (n=9), 50 W (n=10), or 60 W (n=9) radiofrequency energy, and acute (n=22) and chronic (n=6) arterial wall damage was quantified by multiphoton microscopy in ex vivo samples. Adjacent myocardial lesions were quantified in parallel samples. The remaining 8 pigs were used to validate safety and efficacy parameters. RESULTS: Acute collagen and elastin alterations were significantly associated with radiofrequency power, although chronic assessment revealed vascular wall recovery in lesions without steam pop. The main parameters associated with steam pops were median peak temperature >42°C and impedance falls >23 ohms. Unlike other parameters, lesion index values of 9.1 units (interquartile range, 8.7-9.8) were associated with the presence of adjacent myocardial lesions in both univariate ( P=0.03) and multivariate analyses ( P=0.049; odds ratio, 1.99; 95% CI, 1.02-3.98). In the validation group, lesion index values using 40 W over a range of contact-forces correlated with the size of radiofrequency lesions (R2=0.57; P=0.03), with no angiographic or histopathologic signs of coronary artery damage. CONCLUSIONS: Lesion index values obtained during 40 W radiofrequency applications reliably monitor safe and effective lesion creation at the root of the great arteries.