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Hybrid surgical ventricular tachycardia (VT) ablation combines surgical epicardial access/exposure with contemporary mapping and ablation techniques adapted from percutaneous catheter ablation procedures. Patients considered for a hybrid surgical approach for VT are those who have had prior cardiac surgery or failed percutaneous epicardial access due to pericardial adhesions. They often represent the most challenging end of the spectrum of patients and usually have undergone multiple unsuccessful ablations. In this review, the indications, preprocedure work-up, ablation techniques, and outcomes from hybrid surgical access VT ablations are discussed as well as key technical details that present unique challenges to its success., Competing Interests: Disclosure The authors have no conflicts of interest to disclose., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Survival from in-hospital cardiac arrest (IHCA) due to pulseless electrical activity/asystole remains poor. We aimed to evaluate whether electrocardiographic changes provide predictive information for risk of IHCA from pulseless electrical activity/asystole. We conducted a retrospective case-control study, utilizing continuous electrocardiographic data from case and control patients. We selected 3 consecutive 3-hour blocks (block 3, 2, and 1 in that order); block 1 immediately preceded cardiac arrest in cases, whereas block 1 was chosen at random in controls. In each block, we measured dominant positive and negative trends in electrocardiographic parameters, evaluated for arrhythmias, and compared these between consecutive blocks. We created random forest and logistic regression models, and tested them on differentiating case versus control patients (case block 1 vs control block 1), and temporal relation to cardiac arrest (case block 2 vs case block 1). Ninety-one cases (age 63.0 ± 17.6, 58% male) and 1,783 control patients (age 63.5 ± 14.8, 67% male) were evaluated. We found significant differences in electrocardiographic trends between case and control block 1, particularly in QRS duration, QTc, RR, and ST. New episodes of atrial fibrillation and bradyarrhythmias were more common before IHCA. The optimal model was the random forest, achieving an area under the curve of 0.829, 63.2% sensitivity, 94.6% specificity at differentiating case versus control block 1 on a validation set, and area under the curve 0.954, 91.2% sensitivity, 83.5% specificity at differentiating case block 1 versus case block 2. In conclusion, trends in electrocardiographic parameters during the 3-hour window immediately preceding IHCA differ significantly from other time periods, and provide robust predictive information., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Magnetic resonance imaging (MRI) has been performed safely in patients without MRI-conditional cardiac implantable electronic devices (CIEDs), but experience specifically with cardiac magnetic resonance imaging (CMR) is limited in this patient population., Objective: Evaluate the safety of CMR in non-MRI-conditional CIEDs and the interpretability of images using wideband sequences., Methods: We performed 114 consecutive CMR studies in 111 patients (mean age 59 ± 14 years, with 12 pacemakers, 73 implantable cardioverter defibrillators, 29 biventricular defibrillators) using a wideband pulse sequence for late gadolinium enhancement (LGE) imaging. A standardized protocol for device management and patient monitoring was followed. Patients were evaluated for major clinical adverse events and device parameter changes immediately after CMR and at clinical follow-up., Results: In total, 111 CMR studies were completed successfully. There were no patient deaths, new arrhythmias, immediate generator or lead failures, electrical resets, or pacing capture failures in dependent patients. Right atrial, right ventricular, and left ventricular lead impedances were significantly lower post CMR, with median differences -7 Ω (interquartile range [IQR] -20 to 0 Ω; P < .0001), 0 Ω (IQR -19 to 0 Ω; P = .0001), and -10 Ω (IQR -30 to 0 Ω; P = .023), respectively. These changes persisted through the follow-up period, with median differences -18.5 Ω (IQR -41 to -66 Ω; P = .007), -19 Ω (IQR -44 to -7 Ω; P = .006), and -30 Ω (IQR -130 to 0 Ω; P = .003), respectively. Ninety-seven studies (87%) had no artifact limiting interpretation., Conclusions: CMR can be performed safely in non-MRI-conditional CIEDs using a standardized protocol. Use of a wideband pulse sequence for LGE imaging yields a high rate of studies unaffected by artifact., (Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Ventricular arrhythmias remain a significant cause of sudden cardiac death (SCD), and knowledge of their cause and high-risk features is important. SCD occurs when the interaction between vulnerable substrates and acute triggers results in sustained ventricular tachycardia progressing to ventricular fibrillation. Here, the authors aim to review the role of ventricular arrhythmias in SCD, first by approaching the substrates that support ventricular arrhythmias, and then by exploring features of these substrates and the acute triggers that may lead to SCD., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: About 200,000 patients suffer from in-hospital cardiac arrest (IHCA) annually. Identification of at-risk patients is key to improving outcomes. The use of continuous ECG monitoring in identifying patients at risk for developing IHCA has not been studied., Objective: To describe the profile and timing of ECG changes prior to IHCA., Design: Retrospective, observational., Setting: Single 520-bed tertiary care hospital., Patients: IHCA in adults between April 2010 and March 2012 with at least 3 hours of continuous telemetry data immediately prior to IHCA., Measurements: We evaluated up to 24 hours of telemetry data preceding IHCA for changes in PR, QRS, ST segment, arrhythmias, and QTc in ventricular tachycardia cases. We determined mechanism and likely clinical cause of the arrest by chart and telemetry review., Results: We studied 81 IHCA patients, in whom the mechanism was ventricular tachycardia/fibrillation in 14 (18%), bradyasystolic in 21 (26%), and pulseless electrical activity (PEA) in 46 (56%). Preceding ECG changes were ST segment changes (31% of cases), atrial tachyarrhythmias (21%), bradyarrhythmias (28%), P wave axis change (21%),QRS prolongation (19%), PR prolongation (17%), isorhythmic dissociation (14%), nonsustained ventricular tachycardia (6%), and PR shortening (5%). At least one of these was present in 77% of all cases, and in 89% of IHCA caused by respiratory or multiorgan failure. Bradyarrhythmias were primarily seen with IHCA in the setting of respiratory or multiorgan failure, and PR and QRS prolongation with IHCA and concomitant multiorgan failure., Limitations: This is a retrospective study with a limited number of cases; each patient serves as their own control, and a separate control population has not yet been studied., Conclusions: ECG changes are commonly seen preceding IHCA, and have a pathophysiologic basis. Automated detection methods for ECG changes could potentially be used to better identify patients at risk for IHCA., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Aims: Cardiac resynchronization therapy (CRT) is associated with reverse left ventricular (LV) remodelling. However, the effects of CRT-induced mechanical remodelling on electrical remodelling, and the occurrence of ventricular arrhythmias have not been clearly established. We studied the relationship between mechanical remodelling, electrical remodelling, and the occurrence of appropriate implantable cardioverter-defibrillator (ICD) therapy 1 year after CRT., Methods and Results: We analysed data from 45 patients who underwent ICD-CRT implantation at our centre. Significant LV reverse remodelling was defined by a minimum 10% decrease in the LV end-diastolic diameter (LVEDd) at 1 year of follow-up. Electrocardiographic indices of dispersion of repolarization [QTc, Tpeak-Tend (Tp-e) and their dispersion] were measured immediately and 1 year post-CRT implantation. The occurrence of appropriate ICD therapy was noted for each patient. Patients with (n= 21) and without (n= 24) significant LV reverse remodelling had similar baseline characteristics. At 1 year of follow-up, patients with mechanical reverse LV remodelling exhibited a significant decrease in QTc (505 ± 42 vs. 485 ± 52 ms, P < 0.05) and Tp-e (107 ± 26 vs. 92 ± 22 ms, P < 0.0001). However, patients without mechanical LV reverse remodelling exhibited a significant increase in QT dispersion (29 ± 43 vs. 98 ± 47 ms, P = 0.002) and Tp-e dispersion (22 ± 21 vs. 54 ± 36 ms, P = 0.0001). Finally patients with mechanical LV reverse remodelling experienced a lower rate of ICD therapy (P = 0.0025) after a mean follow-up of 19 months., Conclusion: Reverse LV mechanical remodelling is associated with reversal of electrical remodelling and a lower rate of appropriate ICD therapy following CRT.