Endocardial repolarization dispersion in BrS: A novel automatic algorithm for mapping activation recovery interval.

INTRODUCTION: Repolarization dispersion in the right ventricular outflow tract (RVOT) contributes to the type-1 electrocardiographic (ECG) phenotype of Brugada syndrome (BrS), while data on the significance and feasibility of mapping repolarization dispersion in BrS patients are scarce. Moreover, the role of endocardial repolarization dispersion in BrS is poorly investigated. We aimed to assess endocardial repolarization patterns through an automated calculation of activation recovery interval (ARI) estimated on unipolar electrograms (UEGs) in spontaneous type-1 BrS patients and controls; we also investigated the relation between ARI and right ventricle activation time (RVAT), and T-wave peak-to-end interval (Tpe) in BrS patients. METHODS: Patients underwent endocardial high-density electroanatomical mapping (HDEAM); BrS showing an overt type-1 ECG were defined as OType1, while those without (latent type-1 ECG and LType1) received ajmaline infusion. BrS patients only underwent programmed ventricular stimulation (PVS). Data were elaborated to obtain ARI corrected with the Bazett formula (ARIc), while RVAT was derived from activation maps. RESULTS: 39 BrS subjects (24 OType1 and 15 LTtype1) and 4 controls were enrolled. OType1 and post-ajmaline LType1 showed longer mean ARIc than controls (306 ± 27.3 ms and 333.3 ± 16.3 ms vs. 281.7 ± 10.3 ms, p = .05 and p < .001, respectively). Ajmaline induced a significant prolongation of ARIc compared to pre-ajmaline LTtype1 (333.3 ± 16.3 vs. 303.4 ± 20.7 ms, p < .001) and OType1 (306 ± 27.3 ms, p < .001). In patients with type-1 ECG (OTtype1 and post-ajmaline LType1) ARIc correlated with RVAT (r = .34, p = .04) and Tpec (r = .60, p < .001), especially in OType1 subjects (r = .55, p = .008 and r = .65 p < .001, respectively). CONCLUSION: ARIc mapping demonstrates increased endocardial repolarization dispersion in RVOT in BrS. Endocardial ARIc positively correlates with RVAT and Tpec, especially in OType1.

Prolonged care delivery time and reduced rate of electrophysiological procedures during the lockdown period due to Covid-19 outbreak.

OBJECTIVES: The aim of this study is to demonstrate how Electrophysiology activity has been impacted by the pandemic Coronavirus disease 2019 (COVID-19). METHODS: In this multicenter retrospective study, we analyze all consecutive patients admitted for electrophysiological procedures during the COVID-19 lockdown in the Tuscany region of Italy, comparing them to patients hospitalized in the corresponding period of the previous year. RESULTS: The impact of COVID-19 on cardiac arrhythmia management was impressive, with a reduction of more than 50% in all kinds of procedures. A gender gap was observed, with a more relevant reduction for female patients. Arrhythmic urgencies requiring a device implant showed a reduced time from symptoms to first medical contact but the time from first medical contact to procedure was significantly prolonged. CONCLUSION: Hospitals need to consider how outbreaks may affect health systems beyond the immediate infection. Routine activity should be based on a risk assessment between the prompt performance of procedure and its postponement. Retrospective observational analysis such as this study could be decisive in evidence-based medicine of any future pathogen outbreak.Nonstandard Abbreviations and Acronyms PM= pacemakerICD= implantable cardioverter defibrillatorECV= electrical cardioversionEPS= electrophysiological studyAP= ablations proceduresCIED= cardiac implantable electronic devicesWCD= wearable cardioverter defibrillatorEP Lab= Electrophysiology LaboratoriesAVNRT =atrioventricular nodal reentry tachycardiaAVRT= atrioventricular reentry tachycardiaAFL= atrial flutterAF= atrial fibrillationVT= ventricular tachycardiaAT= atrial tachycardia.

Nationwide survey on the current practice of ventricular tachycardia ablation.

METHODS: We performed a nationwide survey on the current practice of ventricular tachycardia catheter ablation in Italy during the year 2016. RESULTS: Among 145 operators participating in the survey, 58 (40.0%) did not perform any ventricular tachycardia ablation in 2016. Among those performing ventricular tachycardia ablation, 9 operators (6.2%) performed only right ventricular endocardial catheter ablation, 52 (35.9%) performed endocardial catheter ablation both in the right and left ventricle (LV) and 26 (17.9%) performed both endocardial and epicardial LV catheter ablations. Seventy operators (89.7%) among the 78 performing LV and epicardial ablations treated patients with ischemic cardiomyopathy; ablations in the setting of other causes were less frequently performed. The following were considered as minimum requirements for ventricular tachycardia ablation: presence of a three-dimensional mapping system (120 operators, 82.8%), ICU in the hospital (118 operators, 81.4%), operator's training in high volume centers (93 operators, 64.1%). Twenty-eight operators (19.3%) performed catheter ablation in patients with electrical storm only after hemodynamic stabilization, 41 operators (28.3%) also during the acute phase and 9 operators (6.2%) never performed catheter ablation in electrical storm patients; the remaining 67 operators did not perform ventricular tachycardia ablation at all, or performed ablations only in the right ventricle. CONCLUSION: The present survey provides a snapshot of the current invasive treatment of ventricular tachycardia by catheter ablation. The procedure, especially in the setting of ischemic cardiomyopathy, is performed nationwide. Complex cases, including those with electrical storm, should be managed within a preestablished integrated network of regional referral centers able to transfer patients as soon as possible.

Feasibility of combined unipolar and bipolar voltage maps to improve sensitivity of endomyocardial biopsy.

BACKGROUND: Endomyocardial biopsy (EMB) has a low sensitivity. Electroanatomic voltage mapping (EVM) is effective in guiding EMB thanks to its ability in identifying and locating low-voltage regions. The analysis of unipolar EVM can correlate with epicardial pathological involvement. We evaluated the unipolar EVM in EMB areas to determine whether it can increase EMB sensitivity in diagnosing epicardial diseases. METHODS AND RESULTS: We performed endocardial bipolar EVM-guided EMBs in 29 patients and we analyzed unipolar EVM at withdrawal sites. Eighty myocardial samples were collected (mean, 2.8±0.9; median, 3 fragments per patient) and 60 were suitable for histological analysis. Ten specimens (17%) were collected from an area with discordant normal bipolar/low-voltage unipolar EVM and they were diagnostic or suggestive for arrhythmogenic right ventricular dysplasia/cardiomyopathy in 6 patients, for myocarditis and sarcoidosis in 1 patient each. Six samples (10%) were collected from an area with discordant low-voltage bipolar/normal unipolar EVM and they showed nonspecific features. The sensitivity of unipolar EVMs for a diagnostic biopsy finding EMB was significantly higher compared with bipolar EVMs analyzed according to samples (P<0.01) and patients (P=0.008). The specificity of unipolar EMB was better than bipolar EMB when analyzed for all samples (P=0.0014) but the difference did not reach statistical significance when analyzed by patient (P=0.083). The diagnostic yield was 63.3% for the bipolar and 83.3% for the unipolar EVM. CONCLUSIONS: These findings suggest that use of a combined bipolar/unipolar map may be able to improve the diagnostic yield of endomyocardial ventricular biopsy.

Noncontact mapping of left ventricle during CRT implant.

INTRODUCTION: Not all candidates for cardiac resynchronization therapy (CRT) are responders at follow-up. Echocardiographic parameters of dyssynchrony do not predict the response. Analysis of electrical properties of left ventricle (LV) by noncontact mapping (NCM) could be useful to better identify candidates for CRT. METHODS AND RESULTS: We studied nine consecutive patients undergoing CRT. An NCM was positioned in the LV via atrial transeptal puncture. LV activation was recorded during sinus rhythm (SR), pacing from RV, from different LV epicardial locations, and in biventricular (BIV) pacing. The corresponding invasive pressure was determined. Heparin, administered during NCM, was reversed and CRT implant was completed. An offline analysis of the data was performed in order to measure transeptal and total LV activation time, to evaluate the site of earliest and latest LV activation, and the pattern of activation. No complications occurred. Mean time of total NCM procedures was 24 + or - 7 minutes. During SR, RV, LV, and BIV pacing, respectively, a "U"-shaped LV activation pattern was found in three, seven, four, and and two patients; mean LV activation time was 58.1 + or - 7.0, 81.7 + or - 15.8, 71.1 + or - 12.4, and 65.6 + or - 7.7 ms; and mean systolic LV peak pressure was 114 + or - 21, 97 + or - 18, 103 + or - 17 and 110 + or - 15 mmHg, respectively. LV activation was influenced by a slow conduction area at the pacing site and by the duration of transeptal time. CONCLUSION: An NCM during CRT is safe and feasible. It provides an additional information on electrical activation in SR and in various modality of pacing. Further studies with larger populations are needed in order to correlate electrical to clinical outcomes.

Radiofrequency ablation of atrial fibrillation: is the persistence of all intraprocedural targets necessary for long-term maintenance of sinus rhythm?

BACKGROUND: Several approaches have been developed for radiofrequency catheter ablation of atrial fibrillation, but the correct intraprocedural end point is still under debate, and few data exist about the destiny of ablation lesions over time. The aim of the present study was to evaluate the long-term maintenance of intraprocedural end points of ablation procedures. METHODS AND RESULTS: Inclusion criteria were (1) a previous ablation procedure of pulmonary vein (PV) encircling performed for drug-refractory persistent atrial fibrillation; (2) a "complete" intraprocedural end point, which consisted of voltage abatement inside the lesions, PV disconnection, and exit-block pacing from inside the lesions, attained in all PVs; and (3) stable sinus rhythm documented during a minimum follow-up of 2.5 years after the procedure. Twenty volunteers were selected (12 males, mean age 59+/-7 years) and underwent a repeat electrophysiological study. After a follow-up of 36.4+/-4.7 months, complete voltage abatement was maintained around 32 PVs (40.0%), PV disconnection persisted in 12 (37.5%) of the previously isolated PVs, and exit block was present in 39 PVs (48.7%). Ten patients who underwent a redo ablation procedure because of recurrences of atrial fibrillation were used as the control group. Differences in intraprocedural end-point maintenance between the 2 groups were not statistically significant. CONCLUSIONS: Common intraprocedural end points such as voltage abatement, PV disconnection, and exit block persist only in a limited number of patients, even when the outcome is favorable during follow-up. Further investigation will be required to determine whether such data will have implications for ablation strategies.

Feasibility of the transseptal approach for fast and unstable left ventricular tachycardia mapping and ablation with a non-contact mapping system.

BACKGROUND: Radiofrequency ablation of fast and unstable left ventricular tachycardia (VT) usually requires non-contact mapping. The procedure is usually performed by a retrograde-transaortic route, requiring a double femoral artery puncture, for the 9F multielectrode catheter and the 7F ablation catheter which are advanced through the aorta and aortic valve into the left ventricle (LV). Reported limitations of the procedure are due to the stiffness of the balloon catheter, particularly in patients with tortuous peripheral arteries, atherosclerotic aorta, or with aortic stenosis. The aim of our study was to test the feasibility and assess the safety of a transseptal approach for left VT non-contact mapping and ablation. MATERIALS AND METHODS: Ten patients with multiple cardiac defibrillator shocks because of fast and unstable VT were selected for non-contact mapping and ablation. After a double transseptal puncture the multielectrode catheter (Ensite Array, St. Jude Medical) was advanced through a standard 10F introducer to a stable position in the LV apex over a 260 cm length 0.035 J-tip guidewire. The ablation catheter (Celsius Thermo-cool, Biosense Webster) was then inserted through the second 8F introducer. Twenty-five monomorphic sustained ventricular tachycardia were induced and ablated at the level of the diastolic pathway or exit point revealed by unipolar isopotential mapping. The total procedural and fluoroscopy times were 209 +/- 32 min and 28.5 +/- 9.27 min, respectively, which were comparable to those described with the traditional retrograde-transaortic approach. No major complication related with the transseptal approach were reported. CONCLUSION: A transseptal approach can be a feasible and effective alternative approach for mapping and ablation of fast and unstable left VT with a non-contact mapping system.