Reduction in new cardiac electronic device implantations in Catalonia during COVID-19.

AIMS: During the COVID-19 pandemic, concern regarding its effect on the management of non-communicable diseases has been raised. However, there are no data on the impact on cardiac implantable electronic devices (CIED) implantation rates. We aimed to determine the impact of SARS-CoV2 on the monthly incidence rates and type of pacemaker (PM) and implantable cardiac defibrillator (ICD) implantations in Catalonia before and after the declaration of the state of alarm in Spain on 14 March 2020. METHODS AND RESULTS: Data on new CIED implantations for 2017-20 were prospectively collected by nine hospitals in Catalonia. A mixed model with random intercepts corrected for time was used to estimate the change in monthly CIED implantations. Compared to the pre-COVID-19 period, an absolute decrease of 56.5% was observed (54.7% in PM and 63.7% in ICD) in CIED implantation rates. Total CIED implantations for 2017-19 and January and February 2020 was 250/month (>195 PM and >55 ICD), decreasing to 207 (161 PM and 46 ICD) in March and 131 (108 PM and 23 ICD) in April 2020. In April 2020, there was a significant fall of 185.25 CIED implantations compared to 2018 [95% confidence interval (CI) 129.6-240.9; P < 0.001] and of 188 CIED compared to 2019 (95% CI 132.3-243.7; P < 0.001). No significant differences in the type of PM or ICD were observed, nor in the indication for primary or secondary prevention. CONCLUSIONS: During the first wave of the COVID-19 pandemic, a substantial decrease in CIED implantations was observed in Catalonia. Our findings call for measures to avoid long-term social impact.

Unexpected impairment of INa underpins reentrant arrhythmias in a knock-in swine model of Timothy syndrome.

Timothy syndrome 1 (TS1) is a multi-organ form of long QT syndrome associated with life-threatening cardiac arrhythmias, the organ-level dynamics of which remain unclear. In this study, we developed and characterized a novel porcine model of TS1 carrying the causative p.Gly406Arg mutation in CACNA1C, known to impair CaV1.2 channel inactivation. Our model fully recapitulated the human disease with prolonged QT interval and arrhythmic mortality. Electroanatomical mapping revealed the presence of a functional substrate vulnerable to reentry, stemming from an unforeseen constitutional slowing of cardiac activation. This signature substrate of TS1 was reliably identified using the reentry vulnerability index, which, we further demonstrate, can be used as a benchmark for assessing treatment efficacy, as shown by testing of multiple clinical and preclinical anti-arrhythmic compounds. Notably, in vitro experiments showed that TS1 cardiomyocytes display Ca2+ overload and decreased peak INa current, providing a rationale for the arrhythmogenic slowing of impulse propagation in vivo.

Multicenter prospective comparison of conventional and high-power short duration radiofrequency application for pulmonary vein isolation: the high-power short-duration radiofrequency application for faster and safer pulmonary vein ablation (POWER FAST III) trial.

BACKGROUND: Electrical isolation of pulmonary veins (PV) with high-power short-duration (HPSD) radiofrequency application (RFa) may reduce the duration of atrial fibrillation (AF) ablation, without compromising the procedural efficacy and safety in comparison with the conventional approach. This hypothesis has been generated in several observational studies; the POWER FAST III will test it in a randomized multicenter clinical trial. METHODS: It is a multicenter randomized, open-label and non-inferiority clinical trial with two parallel groups. AF ablation using 70 W and 9-10 s RFa is compared with the conventional technique using 25-40 W RFa guided by numerical lesion indexes. The main efficacy objective is the incidence of atrial arrhythmia recurrences electrocardiographically documented during 1-year follow-up. The main safety objective is the incidence of endoscopically detected esophageal thermal lesions (EDEL). This trial includes a substudy of incidence of asymptomatic cerebral lesions detected by magnetic resonance imaging (MRI) after ablation. RESULTS: A randomized clinical trial compares for the first time high-power short-duration and conventional ablation in order to obtain data about the efficacy and safety of the high-power technique in an adequate methodological context. CONCLUSIONS: The results of the POWER FAST III could support the use of the high-power short-duration ablation in clinical practice. REGISTRATION: ClinicalTrials.gov: NTC04153747.

Comparison of epicardial cryoablation and irrigated radiofrequency ablation in a Swine infarct model.

UNLABELLED: Epicardial Cryoablation in Swine. INTRODUCTION: Cryoablation is an alternative to radiofrequency (RF) energy used in some ablation procedures. Its role and effectiveness compared to irrigated RF in epicardial tissue and epicardial substrates is not yet fully established. METHODS AND RESULTS: Using a swine chronic infarct model, we compared RF lesions produced by an open-irrigated 3.5 mm tip catheter with those produced by an 8 mm tip cryocatheter in epicardial infarct border zone, epicardial normal tissue, and normal endocardium. In the infarct border zone, cryolesions were larger than RF lesions in maximum diameter (9.3 ± 2.9 mm vs 6.2 ± 2 mm, P < 0.001) and volume (171.7 ± 173.1 mm(3) vs 77 ± 53.5 mm(3) , P = 0.021). In normal epicardial tissue, cryolesions were larger in maximum diameter (11.2 ± 4.3 mm vs 7.7 ± 3.1 mm, P = 0.012), depth (5.8 ± 1.6 mm vs 4.7 ± 1.4 mm, P = 0.034), and volume (274.7 ± 242.2 mm(3) vs 112 ± 102.9 mm(3) , P = 0.002). In normal endocardium, no significant differences were found. CONCLUSIONS: Epicardial cryoablation with an 8 mm tip cryocatheter led to larger lesion volume in infarcted myocardium compared to a 3.5 mm irrigated RF catheter. This is likely related to a combination of cryoadherence, more efficient energy delivery with horizontal orientation, and lack of warming by circulating blood. Cryoablation merits further investigation as a modality for treating ventricular tachycardia of epicardial origin in humans. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1016-1023, September 2012).

Characterization of the nodal slow pathway in patients with nodal reentrant tachycardia: clinical implications for guiding ablation.

INTRODUCTION AND OBJECTIVES: Nodal slow pathway ablation is the treatment of choice for nodal reentrant tachycardia. No demographic, anatomic, or electrophysiologic variables have been reported to predict an exact location of the slow pathway in the atrioventricular node or its proximity to the fast pathway. The purpose of this study was to analyze these variables. METHODS: The study prospectively included 54 patients (17 men; mean age, 55 [16] years) who had undergone successful slow pathway ablation. The refractory periods of both pathways and their differential conduction time were measured, and calculations were performed to obtain the distance from the His-bundle region (location of the fast pathway) to the coronary sinus ostium (to estimate the anteroposterior length of the triangle of Koch) and to the slow pathway area. RESULTS: The differential conduction time (139 [98] ms) did not correlate with the His-coronary sinus distance (19 [6] mm; P=.6) or the His-slow pathway distance (14 [4] mm; P=.4). When the His-coronary sinus distance was larger, the His-slow pathway distance was also larger (r=0.652; P<.01) and the anatomic correlation between the triangle dimensions and the separation between the two pathways was confirmed. In patients older than 70 years, smaller triangle sizes and a shorter distance between both pathways were observed (P<.001). CONCLUSIONS: A greater anteroposterior dimension of the triangle of Koch is associated with a slow-pathway location farther from the fast pathway. In elderly patients the two pathways are closer together (higher risk of atrioventricular block).

Pulmonary hemorrhage after cryoballoon ablation for pulmonary vein isolation in the treatment of atrial fibrillation.

Pulmonary vein isolation has evolved over the past years as an alternative for the treatment of symptomatic recurrences of atrial fibrillation refractory to antiarrhythmic drug treatment. Both radiofrequency energy and cryoballoon ablation have proven useful in this setting. We present the case of a 55-year-old male patient undergoing cryoballoon ablation complicated with pulmonary hemorrhage. The cause of this rare complication may be found in the damage of vascular venous structures near the ablation zone or, alternatively, in hemorrhagic damage of the pulmonary vein surrounding tissue (or less probably to direct injury of the lingular bronchus). The extremely low temperatures achieved in this case (which are often associated with deep balloon position inside the veins) are alarming and should alert the physician about the possibility of an excessively intrapulmonary vein deployment of the cryoablation balloon.

Obstructive sleep apnea in patients with typical atrial flutter: prevalence and impact on arrhythmia control outcome.

BACKGROUND: The clinical yield of cavotricuspid isthmus (CTI) radiofrequency ablation of atrial flutter (AF) is limited by a high incidence of atrial fibrillation (AFib) in the long term. Among other acknowledged variables, the association of obstructive sleep apnea (OSA) could favor incomplete arrhythmia control in this setting. We assessed the impact of CPAP in reducing the occurrence of AFib after CTI ablation. METHODS: Consecutive patients with AF who were undergoing CTI ablation were screened for OSA. Relationship of the following variables with the occurrence of AFib during follow-up (12 months) was investigated: CPAP initiation, hypertension, BMI, underlying structural heart disease, left atrial diameter, and AFib documentation prior to ablation. RESULTS: We prospectively included 56 patients (mean age: 66 (± 11) years; 12 female patients), of whom 46 (82%) had OSA and 25 (45%) had severe OSA. Twenty-one patients (38%) had AFib during follow-up after CTI ablation. Both freedom from AFib prior to ablation and CPAP initiation in those patients without previously documented AFib at inclusion were associated with a reduction of AFib episodes during follow-up (P = .019 and P = .025, respectively). Inversely, CPAP was not protective from AFib recurrence when this arrhythmia was documented prior to ablation (P = .25). CONCLUSIONS: OSA is a prevalent condition in patients with AF. Treatment with CPAP is associated with a lower incidence of newly diagnosed AFib after CTI ablation. Screening for OSA in patients with AF appears to be a reasonable clinical strategy.

Ablation of ventricular arrhythmias arising near the anterior epicardial veins from the left sinus of Valsalva region: ECG features, anatomic distance, and outcome.

BACKGROUND: Left ventricular outflow tract tachycardia/premature depolarizations (VT/VPDs) arising near the anterior epicardial veins may be difficult to eliminate through the coronary venous system. OBJECTIVE: To describe the characteristics of an alternative successful ablation strategy targeting the left sinus of Valsalva (LSV) and/or the adjacent left ventricular (LV) endocardium. METHODS: Of 276 patients undergoing mapping/ablation for outflow tract VT/VPDs, 16 consecutive patients (8 men; mean age 52 ± 17 years) had an ablation attempt from the LSV and/or the adjacent LV endocardium for VT/VPDs mapped marginally closer to the distal great cardiac vein (GCV) or anterior interventricular vein (AIV). RESULTS: Successful ablation was achieved in 9 of the 16 patients (56%) targeting the LSV (5 patients), adjacent LV endocardium (2 patients), or both (2 patients). The R-wave amplitude ratio in lead III/II and the Q-wave amplitude ratio in aVL/aVR were smaller in the successful group (1.05 ± 0.13 vs 1.34 ± 0.37 and 1.24 ± 0.42 vs 2.15 ± 1.05, respectively; P = .043 for both). The anatomical distance from the earliest GCV/AIV site to the closest point in the LSV region was shorter for the successful group (11.0 ± 6.5 mm vs 20.4 ± 12.1 mm; P = .048). A Q-wave ratio of <1.45 in aVL/aVR and an anatomical distance of <13.5 mm had sensitivity and specificity of 89%, 75% and 78%, 64%, respectively, for the identification of successful ablation. CONCLUSIONS: VT/VPDs originating near the GCV/AIV can be ablated from the LSV/adjacent LV endocardium. A Q-wave ratio of <1.45 in aVL/aVR and a close anatomical distance of <13.5 mm help identify appropriate candidates.