Delineation of intracavitary electrograms for the automatic quantification of decrement-evoked potentials in the coronary sinus with deep-learning techniques.

Cardiac arrhythmias cause depolarization waves to conduct unevenly on the myocardial surface, potentially delaying local components with respect to a previous beat when stimulated at faster frequencies. Despite the diagnostic value of localizing the distinct local electrocardiogram (EGM) components for identifying regions with decrement-evoked potentials (DEEPs), current software solutions do not perform automatic signal quantification. Electrophysiologists must manually measure distances on the EGM signals to assess the existence of DEEPs during pacing or extra-stimuli protocols. In this work, we present a deep learning (DL)-based algorithm to identify decrement in atrial components (measured in the coronary sinus) with respect to their ventricular counterparts from EGM signals, for disambiguating between accessory pathways (APs) and atrioventricular re-entrant tachycardias (AVRTs). Several U-Net and W-Net neural networks with different configurations were trained on a private dataset of signals from the coronary sinus (312 EGM recordings from 77 patients who underwent AP or AVRT ablation). A second, separate dataset was annotated for clinical validation, with clinical labels associated to EGM fragments in which decremental conduction was elucidated. To alleviate data scarcity, a synthetic data augmentation method was developed for generating EGM recordings. Moreover, two novel loss functions were developed to minimize false negatives and delineation errors. Finally, the addition of self-attention mechanisms and their effect on model performance was explored. The best performing model was a W-Net model with 6 levels, optimized solely with the Dice loss. The model obtained precisions of 91.28%, 77.78% and of 100.0%, and recalls of 94.86%, 95.25% and 100.0% for localizing local field, far field activations, and extra-stimuli, respectively. The clinical validation model demonstrated good overall agreement with respect to the evaluation of decremental properties. When compared to the criteria of electrophysiologists, the automatic exclusion step reached a sensitivity of 87.06% and a specificity of 97.03%. Out of the non-excluded signals, a sensitivity of 96.77% and a specificity of 95.24% was obtained for classifying them into decremental and non-decremental potentials. Current results show great promise while being, to the best of our knowledge, the first tool in the literature allowing the delineation of all local components present in an EGM recording. This is of capital importance at advancing processing for cardiac electrophysiological procedures and reducing intervention times, as many diagnosis procedures are performed by comparing segments or late potentials in subsequent cardiac cycles.

Automated isochronal late activation mapping for substrate characterization in patients with repaired tetralogy of Fallot.

AIMS: Slow conduction (SC) anatomical isthmuses (AIs) are the dominant substrate for monomorphic ventricular tachycardia (VT) in patients with repaired tetralogy of Fallot (rTF). This study aimed to evaluate the utility of automated propagational analysis for the identification of SC-AI in patients with rTF. METHODS AND RESULTS: Consecutive rTF patients undergoing VT substrate characterization were included. Automated isochronal late activation maps (ILAM) were obtained with multielectrode HD Grid Catheter. Identified deceleration zones (DZs) were compared with both SC-AI defined by conduction velocity (CV) (<0.5 m/s) and isthmuses of induced VT for mechanistic correlation. Fourteen patients were included (age 48; p25-75 35-52 years; 57% male), 2 with spontaneous VT and 12 for risk stratification. Nine VTs were inducible in seven patients. Procedure time was 140 (p25-75 133-180) min and mapping time 29.5 (p25-75 20-37.7) min, using a median of 2167 points. All the patients had at least one AI by substrate mapping, identifying a total of 27 (11 SC-AIs). Isochronal late activation maps detected 10 DZs mostly in the AI between ventricular septal defect and pulmonary valve (80%). Five patients had no DZs. A significant negative correlation between number of isochrones/cm and CV was observed (rho -0.87; P < 0.001). Deceleration zones correctly identified SC-AI (90% sensitivity; 100% specificity; 0.94 accuracy) and was related to VT inducibility (P = 0.006). Deceleration zones co-localized to the critical isthmus of induced VTs in 88% of cases. No complications were observed. CONCLUSION: Deceleration zones displayed by ILAM during sinus rhythm accurately identify SC-AIs in rTF patients allowing a safe and short-time VT substrate characterization procedure.

Long-Term Survival After Implantable Cardiac Defibrillator Therapy According to Sex: A Propensity Matched Study.

Background: Whether the sex factor influences the benefit of the implantable cardioverter-defibrillator (ICD) for the prevention of sudden death remains a subject of debate. Using a prospective registry, we sought to analyze the survival and time to first ICD therapy according to sex. Materials and Methods: Retrospective analysis of a prospective cohort of patients undergoing an ICD implant from 2008 to 2019. Data about time to first appropriate therapy, type of therapy administered, and incidence and causes of mortality were collected. Results: Among 756 ICD patients, 150 (19.8%) were women. Women were younger (51 ± 15 years vs. 61 ± 14 years; p < 0.001) and showed a lower rate of ischemic cardiomyopathy (23% vs. 54%; p < 0.001) and atrial fibrillation (12% vs. 19%; p = 0.05). Women had higher left ventricular ejection fraction (39% ± 17% vs. 35% ± 13%) and showed more frequently left bundle branch block (39% vs. 28%, p = 0.027). The rate of primary prevention (68% vs. 59.6%; p = 0.058) and cardiac resynchronization therapy (27% vs. 19%, p = 0.02) were higher in women. After a median follow-up of 46 months (3382 patient-years), the incidence of both the primary combined endpoint of mortality/transplant (20% vs. 29%; logrank = 0.031) and ICD therapies (27% vs. 34%; p = 0.138) were lower in women. According to the propensity score-matching analysis, no differences were observed between both sexes with respect to the incidence of mortality/transplant (24.8% vs. 28.6%; logrank = 0.88), ICD therapies (28% vs. 27%; logrank = 0.17), and main cause of death (heart failure [HF]). Conclusions: The clinical characteristics at the moment of ICD implant are different between sexes. After adjusting them, both sexes equally benefit from the ICD. HF is the main cause of mortality both in men and women.

Intracoronary tenecteplase versus abciximab as adjunctive treatment during primary percutaneous coronary intervention in patients with anterior myocardial infarction.

AIMS: We sought to compare the effects of intracoronary administration of a fibrinolytic drug (tenecteplase) to those of a glycoprotein IIb/IIIa inhibitor (abciximab) in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). METHODS AND RESULTS: In this pilot trial, 76 patients (59 male) with anterior STEMI were randomised to intracoronary infusion of reduced-dose tenecteplase or abciximab during PPCI. Angiography was repeated at 48 hours to assess corrected TIMI frame count (cTFC) and TIMI myocardial perfusion grade (TMPG). The primary endpoint was infarct size as assessed by cardiac MRI. The abciximab group showed lower cTFC (median 14.1 [IQR 9.4-17.1]) than the tenecteplase group (18.2 [10.0-28.2]) (p=0.02), and the proportion of patients with TMPG grade 2/3 was higher in the abciximab group (90.3% vs. 67.7%; p=0.03). Major cardiac and cerebrovascular event rates did not differ; however, notably, 2/38 patients in the tenecteplase group experienced subacute stent thrombosis. At four months, there were no significant differences in infarct size between the tenecteplase and abciximab groups (17.0 g [9.6-27.5] vs. 21.1 g [11.3-35.0], p=0.33). CONCLUSIONS: Intracoronary administration of tenecteplase did not reduce infarct size compared to abciximab in STEMI patients undergoing PPCI. Tenecteplase exhibited poorer myocardial reperfusion and might be associated with increased subacute stent thrombosis.

Repeated procedures at the generator pocket are a determinant of implantable cardioverter-defibrillator infection.

BACKGROUND: Rates of cardiac-device infections have increased in recent years, but the current incidence and risk factors for infection in patients with implantable cardioverter-defibrillators (ICDs) are not well known. HYPOTHESIS: The increasing number of ICD infections is related to accumulated pocket manipulations over time. METHODS: This single-center, prospective study included patients that underwent ICD implantation from 2008 to 2015. The endpoint was time to infection. Multivariate analysis was performed to identify independent risk factors related to infection. RESULTS: The study included a total of 570 patients, of whom 419 (73.5%) underwent a first implantation. Mean age was 59 ± 14 years, and 80% were male. During a median follow-up of 36 months (interquartile range, 18-61 months; 1887 patient-years), infection was identified in 26 patients (4.56%), an incidence of 14.9 × 1000 patient-years. Median time to infection was 9.7 months (interquartile range, 1.35-23.4 months), and 38.5% were late infections (beyond 12 months of follow-up). In patients with replacement implants, the incidence was 3-fold higher than in first implantations (27.7 vs 9.1 × 1000 patient-years; P = 0.002). Cox regression identified 2 independent predictors of ICD infection: cumulative number of interventions at the generator pocket (hazard ratio: 1.92, 95% confidence interval: 1.42-2.6, P < 0.001) and pocket hematoma (hazard ratio: 7.0, 95% confidence interval: 2.7-17.9, P < 0.0001). CONCLUSIONS: The incidence of infection in ICD patients is greater than previously reported, largely due to late infections. Each new cumulative intervention at the same generator pocket nearly doubles the risk of infection.

Impact of Contact Force Monitoring in Acute Pulmonary Vein Isolation Using an Anatomic Approach. A Randomized Study.

BACKGROUND: The impact of contact force (CF) monitoring in pulmonary vein (PV) isolation after a circumferential anatomic ablation (CAA) is unknown. We analyze the usefulness of CF monitoring in acute PV isolation and procedure parameters using a CAA. METHODS: Fifty patients with paroxysmal atrial fibrillation were randomized into CF-on (CF >10 grams; n = 25) or CF-off (CF blinded; n = 25) groups. We performed a first round of CAA with a ThermoCool(®) SmartTouch(®) catheter blinded to the LASSO(®) catheter (Biosense Webster, Diamond Bar, CA, USA), with radiofrequency (RF) lesions tagged with the VisiTag(™) Module. After the CAA, each PV was reviewed with the LASSO(®) catheter recording the segments with gaps. RESULTS: All the PVs were isolated with a CAA in 20 patients of the CF-on versus eight of the CF-off (P = 0.001). Of the 45 segments with gaps in the left PVs, 38 were from the CF-off (P = 0.0001). Of the eight segments with gaps in the right PVs, seven were from the CF-off (P = 0.06). The CF in the left PVs was higher in the CF-on (16.3 ± 3.2 grams vs 10.5 ± 4.3 grams; P = 0.0001) and similar in the right PVs (17.6 ± 3.6 grams vs 15.2 ± 5.3 grams; P = 0.08). All of the gaps were closed with additional RF LASSO(®) -guided touch-up. Procedure and fluoroscopy times were shorter in the CF-on (139 ± 24 minutes vs 157 ± 32 minutes and 20 ± 6 minutes vs 24 ± 7 minutes; both P = 0.039). At 12 months the patients free of AF recurrence was 84% CF-on versus 75% CF-off (log-rank P = 0.4) [corrected]. CONCLUSIONS: In paroxysmal atrial fibrillation, a CAA guided by CF reduces PV gaps and shortens the procedure parameters at the expense of the left PVs.

Reverse atrial remodeling following pulmonary vein isolation: the importance of the body mass index.

BACKGROUND: Pulmonary vein isolation (PVI) causes a reduction in left atrium size that is attributable to reverse atrial remodeling (RAR). The objective of this study was to identify predictors of RAR and determine its association with other parameters of improvement in cardiac function. METHODS: It is a prospective study with 74 patients (52 ± 9 years old, 81% male), and 51% of patients had paroxysmal atrial fibrillation. Patients were serially assessed with transthoracic echocardiography; plasma N-terminal B-type natriuretic peptide (NT-proBNP); and high-sensitivity C-reactive protein levels at baseline and 3, 6, and 12 months following the PVI. RAR was defined as a reduction in the left atrial volume index (LAV-index) >10% from baseline at the end of follow-up. A multivariate analysis was conducted to identify predictors of RAR. RESULTS: The LAV-index decreased significantly during follow-up in the entire population (P = 0.0005). RAR (experienced by 63.5% of the patients) was more frequent (76% vs. 42%; P = 0.004) and pronounced (reduction 16.65 ± 14% vs. 8 ± 14%; P = 0.015) in patients with a successful ablation (46 of 74 patients, 62.2%). Only patients with RAR showed significant improvement in NT-proBNP levels (P = 0.0001), systolic function (P = 0.035), and diastolic function (P = 0.005). Multivariable analysis revealed that a successful ablation (odds ratio [OR] = 4.6; 95% confidence interval [CI] 1.46-14.68; P = 0.009), LAV-index (OR = 1.15; 95% CI 1.03-1.2; P = 0.021), and patient's body mass index (OR = 0.84; 95% CI 0.74-0.96; P = 0.012) were independent predictors of RAR. CONCLUSIONS: Successful PVI ablation is the main predictor of RAR that is associated with other parameters of improvement in cardiac function. The patient's body mass index may have a negative effect on RAR.

Paroxysmal atrial fibrillation burden before and after pulmonary veins isolation: an observational study through a subcutaneous leadless cardiac monitor.

AIMS: Data on the success rate of ablation in atrial fibrillation (AF) are controversial. Our hypothesis is that the efficacy must be evaluated considering the AF burden (AFB) before the procedure. Moreover, the clinical significance of early recurrence (ERAT) of AF or atrial tachyarrhythmias (AT) is debatable. The aim is to describe the outcome of pulmonary vein isolation in paroxysmal AF through a subcutaneous cardiac monitor (ICM) implanted before the procedure. METHODS: Using CARTO 3, circumferential lesions around the pulmonary veins were placed. The study endpoint was the first documented recurrence of AF/AT by ICM after the blanking period (3 months). AFB (percentage of time in AF/AT) was collected every month before and after the procedure during the 12-month follow-up. RESULTS: The ICM was implanted 94 ± 23 days before the procedure in 35 patients with paroxysmal AF (54 ± 11 years, refractory to 1.8 ± 0.6 antiarrhythmic drugs). Cumulative AFB before the procedure and after the blanking period was 2.5% (1-5%) versus 0% (0-0.25%), P < 0.001. Twenty patients (57.1%) were free of documented AF/AT recurrence, 5 patients (14.2%) reduced the AFB 90%, 6 patients (17.1%) continued the same, and 4 patients (11.4%) increased the AFB 90% for AT. The success rate with second procedure was 71.4%. All 13 patients with ERAT had recurrence after the blanking period. CONCLUSIONS: The outcome of pulmonary vein isolation in patients with paroxysmal AF is well documented by an ICM. The success rate is dependent of the previous AFB that can be randomly variable and lower than expected. ERATs predict late recurrence.

Ablation of atrioventricular nodal reentrant tachycardia in a patient with tricuspid atresia guided by electroanatomic mapping.

We describe a case of ablation of atrioventricular nodal reentrant tachycardia in a patient with tricuspid atresia and L-malposition of great vessels using an electroanatomical mapping system integrated with cardiac magnetic resonance imaging. Atrial activation mapping during tachycardia identified the retrograde fast pathway proximal to the His bundle, observed in the left interatrial septum. Ablation was successfully completed below this area. Map integration with the patient's anatomy allowed a safe, individualized procedure.

T-wave Oversensing with Inappropriate Therapy in Remote Monitoring.

T-wave oversensing can cause inappropriate implantable cardioverter-defibrillator (ICD) therapies that are difficult to correct. Remote monitoring allows follow-up of ICD patients without visiting the hospital and can help in early detection of any malfunctions. We describe the case of a patient who experienced inappropriate antitachycardia pacing therapy due to T-wave oversensing; the problem was promptly detected by remote monitoring and corrected by device reprogramming.

Electroanatomical mapping of the esophagus in circumferential pulmonary vein isolation.

A virtual reconstruction of the geometry of the esophagus was produced using an electroanatomical mapping system and a specially designed catheter in 20 consecutive patients undergoing circumferential pulmonary vein isolation. The course of the esophagus, its motion and its proximity to the predicted lines of application of radiofrequency energy to the left atrium were evaluated. Thirteen (65%) were located centrally (i.e. >10 mm from the ostium), 69 (30%) laterally (i.e. <10 mm from the ostium) and 1 (5%) obliquely. No movements larger than 10 mm occurred during the procedure. Conventionally, the radiofrequency ablation lines are configured such that, in 50% of patients, radiofrequency energy is applied to areas adjacent to the esophagus. In order to decrease the potential risk associated with this procedure, either the position of the ablation lines was altered to bring them closer to the ostium (by 15%) or the power was reduced (by 35%). Although there was no significant movement of the esophagus during the ablation procedure, its course was variable. Consequently, the ablation strategy was altered in a substantial number of cases.

Unusual tachycardia association in a patient without structural heart disease.

We report an unusual association of persistent atrial flutter and bundle branch re-entrant ventricular tachycardia in a young patient without structural heart disease. Atrial flutter masked the infra-Hisian conduction disease, was fundamentally dependent on a long PR interval, and could be a possible trigger of ventricular tachycardia.

Three-dimensional impedance mapping as an aid to circumferential pulmonary vein isolation in paroxysmal atrial fibrillation.

During circumferential pulmonary vein isolation, radiofrequency lesions are created in the transition zone between the left atrium and the pulmonary veins, outside the ostia, to avoid stenosis. Three-dimensional impedance maps were constructed for 25 patients with paroxysmal atrial fibrillation. In the first 15 patients, impedance was measured inside the pulmonary veins (165.4 +/- 7.5 Omega), the ostium (141.6 +/- 7.3 Omega) and the left atrium (131.09 +/- 8.3 Omega). An impedance of 136 Omega identified the outer limit of the atrium (area under the receiver operating characteristic curve, 0.85). In the subsequent 10 patients, a single operator who was blinded to the anatomic position of the catheter tip was able to determine, by impedance measurement alone, whether the point targeted for radiofrequency ablation was in the left atrium or the ostium of the pulmonary vein. The positive predictive value for identifying the left atrium was 91% and the negative predictive value was 73%. In patients with paroxysmal atrial fibrillation, three-dimensional impedance mapping was helpful in guiding circumferential pulmonary vein isolation.