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BACKGROUND: The evolution of myocardial scar and its arrhythmogenic potential postinfarct is incompletely understood. OBJECTIVES: This study sought to investigate scar and border zone (BZ) channels evolution in an animal ischemia-reperfusion injury model using late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). METHODS: Five swine underwent 90-minute balloon occlusion of the mid-left anterior descending artery, followed by LGE-CMR at day (d) 3, d30, and d58 postinfarct. Invasive electroanatomic mapping (EAM) was performed at 2 months. Topographical reconstructions of LGE-CMR were analyzed for left ventricular core and BZ scar, BZ channel geometry, and complexity, including transmurality, orientation, and number of entrances/exits. RESULTS: LVEF reduced from 48.0% ± 1.8% to 41.3% ± 2.3% postinfarct. Total scar mass reduced over time (P = 0.008), including BZ (P = 0.002) and core scar (P = 0.05). A total of 72 BZ channels were analyzed across all animals and timepoints. Channel length (P = 0.05) and complexity (P = 0.02) reduced progressively from d3 to d58. However, at d58, 64% of channels were newly formed and 36% were midmyocardial. Conserved channels were initially longer and more complex. All LGE-CMR channels colocalized to regions of maximal decrement on EAM, with significantly greater decrement (115 ± 31 ms vs 83 ± 29 ms; P < 0.001) and uncovering of split potentials (24.8% vs 2.6%; P < 0.001) within channels. In total, 3 of 5 animals had inducible VT and tended to have more channels with greater midmyocardial involvement and functional decrement than those without VT. CONCLUSIONS: BZ channels form early postinfarct and demonstrate evolutionary complexity and functional conduction slowing on EAM, highlighting their arrhythmogenic potential. Some channels regress in complexity and length, but new channels form at 2 months' postinfarct, which may be midmyocardial, reflecting an evolving, 3-dimensional substrate for VT. LGE-CMR may help identify BZ channels that may support VT early postinfarct and lead to sudden death.
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BACKGROUND: Single-lead electrocardiogram (ECG) devices may allow detection and diagnosis of cardiac rhythms. However, data on their accuracy for detecting cardiac arrhythmias beyond atrial fibrillation are limited. We aimed to determine the accuracy of the AliveCor KardiaMobile (AC) (AliveCor Inc, Mountain View, CA, USA) for the diagnosis of arrhythmias against gold standard cardiac electrophysiology study (EPS). METHOD: Patients undergoing clinically indicated EPS underwent simultaneous rhythm recording with an AC, standard 12-lead ECG, and EP catheters for intracardiac electrograms. Rhythms recorded during EPS were classified based on electrogram, 12-lead ECG, and clinical findings. Blinded reviewers provided differential diagnoses for the single-lead AC tracings; a separate reviewer compared diagnoses made between the AC tracings and EPS findings. RESULTS: In 49 patients, 843 cardiac rhythms were captured during 502 AC recordings. Analysis of tracings containing sinus rhythm (n=273) returned an overall accuracy of 92%, with sensitivity and specificity values of 93% and 92%, respectively. Accuracy for tracings per rhythm was atrial fibrillation 91% (n=51); supraventricular tachycardia accuracy was 89% (n=191), ventricular tachycardia 91% (n=198), ventricular fibrillation 98% (n=11), and asystole 100% (n=5). Accuracy for supraventricular ectopy was 93% (n=28) and for premature ventricular complexes was 91% (n=86). Overall accuracy was 94% for solitary rhythms and 93% in tracings from patients with baseline bundle branch block. CONCLUSIONS: When compared against the gold standard EPS diagnosis, the interpretation of arrhythmias recorded by an AliveCor single-lead ECG device had reasonable diagnostic accuracy.
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BACKGROUND: Although there are evolving techniques and technologies for treating ventricular tachycardia (VT), the current landscape of clinical trials for managing VT remains understudied. OBJECTIVE: The objective of this study was to provide a systematic characterisation of the interventional management of VT through an analysis of the ClinicalTrials.gov, clinicaltrialsregister.eu, anzctr.org.au and chictr.org.cn databases. METHODS: We queried all phase II to IV interventional trials registered up to November 2023 that enrolled patients with VT. Published, completed but unpublished, terminated, or ongoing trials were included for final analysis. RESULTS: Of the 698 registered studies, 135 were related to VT, with 123 trials included in the final analysis. Among these trials, 25 (20%) have been published, enrolling a median of 35 patients (interquartile range [IQR] 20-132) over a median of 43 months (IQR 19-62). Out of the published trials, 14 (56%) were randomised, and 12 (48%) focused on catheter ablation. Twenty-two (18%) have been completed but remain unpublished, even after a median of 36 months (IQR 15-60). Furthermore, 27 (22%) trials were terminated or withdrawn, with the most common cause being poor enrolment. Currently, 49 (40%) trials are ongoing and novel non-ablative technologies, such as radioablation and autonomic modulation, account for 35% and 8% of ongoing trials, respectively. CONCLUSIONS: Our analysis revealed that many registered trials remain unpublished or incomplete, and randomised controlled trial evidence is limited to only a few studies. Furthermore, many ongoing trials are focused on non-catheter ablation-based strategies. Therefore, larger pragmatic trials are needed to create stronger evidence in the future.