Electromechanical Window and Spontaneous Ventricular Tachyarrhythmias in Takotsubo Syndrome.

QT interval prolongation is common in patients hospitalized with Takotsubo syndrome (TTS), however, only a minority experience ventricular tachyarrhythmias. Our aim was to characterize the electromechanical window (EMW) in patients with TTS and to evaluate its association with ventricular tachyarrhythmias. We preformed aretrospective analysis of 84 patients hospitalized with TTS in the Tel-Aviv Medical Center between 2013 and 2022. All patients underwent a comprehensive echocardiographic evaluation and the EMW was calculated by subtracting the QT interval from the QRS onset to the aortic valve closure obtained from a continuous-wave Doppler for the same beat. Of the 84 patients with TTS, 74 (88%) were female and the mean age was 70 ± 11 years. The mean left ventricular ejection fraction was 42 ± 8%. The EMW was negative in 81 patients (96%), and the mean EMW was -69 ± 50 ms. Ventricular tachyarrhythmias occurred in 7 patients (8%). The EMW of patients who experienced ventricular tachyarrhythmias was more negative than patients who did not (-133 ± 23 ms vs -63 ± 48 ms, p = 0.001). In the univariate analysis, EMW and QT were associated with ventricular tachyarrhythmias (univariate odds ratio [OR]EMW 1.03, 95% confidence interval [CI] 1.01 to 1.05, p = 0.003 and univariate ORQTc 1.02, 95% CI 1.01 to 1.03, p = 0.02); however, only EMW remained significant in the multivariate analysis (OREMW 1.03 95% CI 1.03 to 1.05, p = 0.023). EMW was more effective than corrected QT interval in identifying patients who had ventricular tachyarrhythmias (AUCEMW: 0.89, 95% CI 0.82 to 0.97 vs AUCQTc 0.77, 95% CI 0.61 to 0.93, p = 0.02), and a cut-off value of -108 ms was predictive of ventricular tachyarrhythmias with a sensitivity of 86% and a specificity of 79%. In conclusion, EMW is negative in patients with TTS and is associated with increased risk for ventricular tachyarrhythmias. The role of EMW in the risk stratification of patients with TTS warrants further investigation.

Safety of Sports for Patients with Subcutaneous Implantable Cardioverter Defibrillator (SPORT S-ICD): study rationale and protocol.

Background: Recent studies suggest that participation in recreational and even competitive sports is generally safe for patients with implantable cardioverter-defibrillators (ICDs). However, these studies included only patients with implanted transvenous ICD (TV-ICD). Nowadays, subcutaneous ICD (S-ICD) is a safe and effective alternative and is increasingly implanted in younger ICD candidates. Data on the safety of sport participation for patients with implanted S-ICD systems is urgently needed. Objectives: The goal of the study is to quantify the risks (or determine the safety) of sports participation for athletes with an S-ICD, which will guide shared decision making for athletes requiring an ICD and/or wishing to return to sports after implantation. Methods: The SPORT S-ICD (Sports for Patients with Subcutaneous Implantable Cardioverter Defibrillator) study is an international, multicenter, prospective, noninterventional, observational study, designed specifically to collect data on the safety of sports participation among patients with implanted S-ICD systems who regularly engage in sports activities. Results: A total of 450 patients will undergo baseline assessment including baseline characteristics, indication for S-ICD implantation, arrhythmic history, S-ICD data and programming, and data regarding sports activities. LATITUDE Home Monitoring information will be regularly transferred to the study coordinator for analysis. Conclusion: The results of the study will aid in shaping clinical decision making, and if the tested hypothesis will be proven, it will allow the safe continuation of sports for patients with an implanted S-ICD.

Regional Antibiotic Delivery for Implanted Cardiovascular Electronic Device Infections.

BACKGROUND: Present guidelines endorse complete removal of cardiovascular implantable electronic devices (pacemakers/defibrillators), including extraction of all intracardiac electrodes, not only for systemic infections, but also for localized pocket infections. OBJECTIVES: The authors evaluated the efficacy of delivering continuous, in situ-targeted, ultrahigh concentration of antibiotics (CITA) into the infected subcutaneous device pocket, obviating the need for device/lead extraction. METHODS: The CITA group consisted of 80 patients with pocket infection who were treated with CITA during 2007-2021. Of them, 9 patients declined lead extraction because of prohibitive operative risk, and 6 patients had questionable indications for extraction. The remaining 65 patients with pocket infection, who were eligible for extraction, but opted for CITA treatment, were compared with 81 patients with pocket infection and similar characteristics who underwent device/lead extraction as primary therapy. RESULTS: A total of 80 patients with pocket infection were treated with CITA during 2007-2021. CITA was curative in 85% (n = 68 of 80) of patients, who remained free of infection (median follow-up 3 years [IQR: 1.0-6.8 years]). In the case-control study of CITA vs device/lead extraction, cure rates were higher after device/lead extraction than after CITA (96.2% [n = 78 of 81] vs 84.6% [n = 55 of 65]; P = 0.027). However, rates of serious complications were also higher after extraction (n = 12 [14.8%] vs n = 1 [1.5%]; P = 0.005). All-cause 1-month and 1-year mortality were similar for CITA and device/lead extraction (0.0% vs 3.7%; P = 0.25 and 12.3% vs 13.6%; P = 1.00, respectively). Extraction was avoided in 90.8% (n = 59 of 65) of extraction-eligible patients treated with CITA. CONCLUSIONS: CITA is a safe and effective alternative for patients with pocket infection who are unsuitable or unwilling to undergo extraction. (Salvage of Infected Cardiovascular Implantable Electronic Devices [CIED] by Localized High-Dose Antibiotics; NCT01770067).

Arrhythmogenic Effects of Cardiac Memory.

Cardiac memory is the term used to describe an interesting electrocardiographic phenomenon. Whenever a QRS complex is wide and abnormal, such as during ventricular pacing, the T waves will also be abnormal and will point to the opposite direction of the wide QRS. If the QRS then normalizes, such as after cessation of ventricular pacing, the T waves will normalize as well, but at a later stage. The period of cardiac memory is the phase between the sudden normalization of the QRS and the eventual and gradual return of the T waves to their baseline morphology. Cardiac memory is assumed to be an innocent electrocardiographic curiosity. However, during cardiac memory, reduction of repolarizing potassium currents increases left ventricular repolarization gradients. Therefore, when cardiac memory occurs in patients who already have a prolonged QT interval (for whatever reason), it can lead to a frank long QT syndrome with QT-related ventricular arrhythmias (torsades de pointes). These arrhythmogenic effects of cardiac memory are not generally appreciated and are reviewed here for the first time.

Reconstruction of the left atrium for atrial fibrillation ablation using the machine learning CARTO 3 m-FAM software.

PURPOSE: Atrial fibrillation (AF) ablation requires a precise reconstruction of the left atrium (LA) and pulmonary veins (PV). Model-based FAM (m-FAM) is a novel module recently developed for the CARTO system which applies machine learning techniques to LA reconstruction. We aimed to evaluate the feasibility and safety of a m-FAM-guided AF ablation as well as the accuracy of LA reconstruction using the cardiac computed tomography angiography (CTA) of the same patient LA as the gold standard, in 32 patients referred for AF ablation. METHODS: Consecutive patients undergoing AF ablation. The m-FAM reconstruction was performed with the ablation catheter (group 1) or a Pentaray and ablation catheters (group 2). The reconstruction accuracy was confirmed prior to the ablation by verification of pre-specified landmarks of the LA and PVs by an intracardiac echocardiogram (ICE) visualization and fluoroscopy. A cardiac CTA performed before the ablation was used as the gold standard of LA anatomy. For each patient, the m-FAM reconstruction was compared to his/her cardiac CTA. RESULTS: The m-FAM reconstruction was accurate in all patients regardless of the catheter used for mapping. Twelve percent re-acquisition of the LA landmarks was necessary to improve the accuracy. m-FAM time was shorter in group 2 while the M-Fam fluoroscopy time was similar. Pulmonary vein isolation was achieved in 100% of patients without major complications. The m-FAM reconstructions accurately resemble the cardiac CTA of the same patients. CONCLUSIONS: The m-FAM module allows for rapid and precise reconstruction of the LA and PV anatomy, which can be safely used to guide AF ablation.

Polymorphic Ventricular Tachycardia: Terminology, Mechanism, Diagnosis, and Emergency Therapy.

Polymorphic ventricular tachyarrhythmias are highly lethal arrhythmias. Several types of polymorphic ventricular tachycardia have similar electrocardiographic characteristics but have different modes of therapy. In fact, medications considered the treatment of choice for one form of polymorphic ventricular tachycardia, are contraindicated for the other. Yet confusion about terminology, and thus diagnosis and therapy, continues. We present an in-depth review of the different forms of polymorphic ventricular tachycardia and propose a practical step-by-step approach for distinguishing these malignant arrhythmias.

Continuous Heart Rate Monitoring for Automatic Detection of Life-Threatening Arrhythmias With Novel Bio-Sensing Technology.

Aims: Assessing the effectiveness of novel bio-sensing technology (CardiacSense), for accuracy and reliability of automatic detection of life-threatening arrhythmias. Methods and Results: This prospective study consisted of Eighteen patients (13 males and 5 females, mean age 59.4 ± 21.3 years) undergoing induction of ventricular tachycardia/fibrillation or provocation of transient ventricular asystole. We tested the detection of provoked ventricular arrhythmias by a wrist-worn watch-like device which uses photoplethysmography (PPG) technology to detect the cardiac rhythm. We used simultaneous electrocardiographic (ECG) recordings as gold standard for arrhythmia definition and confirmation of beat-to-beat detection. A total of 1,527 QRS complexes were recorded simultaneously by ECG and PPG. The overall correlation between the ECG (R-R intervals) and the PPG (G-G intervals) was high, with a correlation coefficient of R = 0.949 (p < 0.001). The device accurately detected all events of mimicked life endangering arrhythmias, including five events of transient (adenosine-induced) ventricular asystole as well as seven episodes of monomorphic ventricular tachycardia and 6 events of ventricular fibrillation. Conclusion: This proof-of-concept study suggests that wearable devices using PPG technology, currently used to detect atrial fibrillation, may also have a role as automatic detectors of life-threatening arrhythmias.

Arrhythmic storm from ischemic ventricular fibrillation treated with intravenous quinidine.

We present a case who developed an acute right ventricular infarction. The leads demonstrating ST-segment elevation were different than those expected based on previous publications. We explain why this happened with the aid of 3-dimentional imaging. Our case then developed an arrhythmic storm caused by ischemic ventricular fibrillation (VF). Emergency revascularization failed and the VF-storm failed to respond to sedation, lidocaine and amiodarone but responded to intravenous quinidine.

Management of Congenital Long-QT Syndrome: Commentary From the Experts.

While published guidelines are useful in the care of patients with long-QT syndrome, it can be difficult to decide how to apply the guidelines to individual patients, particularly those with intermediate risk. We explored the diversity of opinion among 24 clinicians with expertise in long-QT syndrome. Experts from various regions and institutions were presented with 4 challenging clinical scenarios and asked to provide commentary emphasizing why they would make their treatment recommendations. All 24 authors were asked to vote on case-specific questions so as to demonstrate the degree of consensus or divergence of opinion. Of 24 authors, 23 voted and 1 abstained. Details of voting results with commentary are presented. There was consensus on several key points, particularly on the importance of the diagnostic evaluation and of ß-blocker use. There was diversity of opinion about the appropriate use of other therapeutic measures in intermediate-risk individuals. Significant gaps in knowledge were identified.