Arrhythmic Patterns Research Articles

Conduction patterns of idiopathic arrhythmias from the endocardium and epicardium of outflow tracts: New insights with noninvasive electroanatomic mapping

Idiopathic arrhythmias commonly arise from the septal right ventricular outflow tract (RVOT), sinuses of Valsalva (SoV), and great cardiac vein (GCV). Predicting the exact site of origin is important for preparation for catheter ablation. The purpose of this study was to examine the diagnostic value of noninvasive electroanatomic mapping (NIEAM) to differentiate between septal RVOT, SoV, and GCV origin and compare it to that of 12-lead electrocardiography (ECG). NIEAM maps (CardioInsight, Medtronic) were generated during spontaneous ventricular premature depolarizations (VPDs) and threshold pacing from septal RVOT, SoV, and GCV. Origin prediction using NIEAM was compared to algorithmic ECG criteria (maximal deflection index; V2 transition ratio) and subjective ECG evaluation. Sixty NIEAMs (18 spontaneous VPDs and 42 pace-maps) from 31 patients (age 56 ± 16 years) were analyzed. NIEAM showed distinct conduction patterns, best visualized at the base of the heart: septal RVOT VPDs propagate toward the tricuspid annulus, depolarizing the septum from inferior to superior; SoV VPDs engage the superior septum early; and GCV VPDs move laterally along the mitral annulus, depolarizing the heart from left to right. Activation of the lateral mitral annulus >60.50 ms and the superior basal septum <22.5 ms from onset predicts RVOT and SoV origin, respectively, in 100% of cases. NIEAM was superior to maximum deflection index in predicting GCV origin (100% vs 42.2% accuracy) and superior to V2 transition ratio in predicting SoV origin (100% vs 75.9% accuracy). Arrhythmias arising from the outflow tracts follow distinct propagation patterns depending on the origin. A 2-step algorithm using activation timing by NIEAM yields 100% diagnostic accuracy in predicting origin.

Atrial Fibrillation, Ventricular Arrhythmia, and Left Ventricular Remodeling in the ICU – First Results of the Single- Center RHYTHM-ACC Registry

Abstract The aim of this study was to investigate the association between left ventricular remodeling, atrial fibrillation (AF), and the severity of ventricular tachycardia (VT) in patients with ventricular rhythm disturbances admitted in a level 3 facility of acute cardiac care. Material and Methods: The RHYTHM-ACC registry was a single-center observational study, including 150 consecutive patients with sustained or non-sustained ventricular tachycardia (sVT and nsVT, respectively) admitted in an intensive cardiac care unit (ICCU), separated in: group 1 - 29 patients (21.01%) with dilated cardiomyopathy (DCM), and group 2 - 109 patients (78.99%) with normal ventricular performance. We investigated the difference between clinical characteristics of patients with sVT versus those with nsVT in each study group, and the association between AF and different forms of ventricular arrhythmia in 38 (25.33%) patients with AF and 112 (74.66%) patients in sinus rhythm. Results: There were no significant differences between the study groups with respect to type of ventricular arrhythmia: sVT (46.87% vs. 36.44%, p = 0.2), nsVT (43.75% vs. 55.93%, p = 0.2), or ventricular fibrillation (VF) (9.37% vs. 7.62%, p = 0.7). However, patients with DCM presented a significantly higher incidence of AF (43.75% vs. 20.33%, p = 0.01) and bundle branch block (37.5% vs. 11.86%, p = 0.0007). VF occurred more frequently in patients with AF compared to those in sinus rhythm (18.42% vs. 4.46%, p = 0.006). Multivariate analysis identified the co-existence of AF (OR = 4.8, p = 0.01) and the presence of a bundle branch block (BBB) (OR = 3.9, p = 0.03) as the most powerful predictors for the degeneration of VT into VF in patients admitted with sVT or nsVT in an ICCU unit. Conclusions: In patients with any type of VT admitted in an ICCU, the presence of ventricular remodeling is associated with a higher incidence of AF and conduction abnormalities, but not with a more severe pattern of ventricular arrhythmia. At the same time, AF and BBB seem to represent the most powerful predictors for degeneration of VT into VF, independent of the type of VT.

Energy-Reduced Arrhythmia Termination Using Global Photostimulation in Optogenetic Murine Hearts.

Complex spatiotemporal non-linearity as observed during cardiac arrhythmia strongly correlates with vortex-like excitation wavelengths and tissue characteristics. Therefore, the control of arrhythmic patterns requires fundamental understanding of dependencies between onset and perpetuation of arrhythmia and substrate instabilities. Available treatments, such as drug application or high-energy electrical shocks, are discussed for potential side effects resulting in prognosis worsening due to the lack of specificity and spatiotemporal precision. In contrast, cardiac optogenetics relies on light sensitive ion channels stimulated to trigger excitation of cardiomyocytes solely making use of the inner cell mechanisms. This enables low-energy, non-damaging optical control of cardiac excitation with high resolution. Recently, the capability of optogenetic cardioversion was shown in Channelrhodopsin-2 (ChR2) transgenic mice. But these studies used mainly structured and local illumination for cardiac stimulation. In addition, since optogenetic and electrical stimulus work on different principles to control the electrical activity of cardiac tissue, a better understanding of the phenomena behind optogenetic cardioversion is still needed. The present study aims to investigate global illumination with regard to parameter characterization and its potential for cardioversion. Our results show that by tuning the light intensity without exceeding 1.10 mW mm-2, a single pulse in the range of 10–1,000 ms is sufficient to reliably reset the heart into sinus rhythm. The combination of our panoramic low-intensity photostimulation with optical mapping techniques visualized wave collision resulting in annihilation as well as propagation perturbations as mechanisms leading to optogenetic cardioversion, which seem to base on other processes than electrical defibrillation. This study contributes to the understanding of the roles played by epicardial illumination, pulse duration and light intensity in optogenetic cardioversion, which are the main variables influencing cardiac optogenetic control, highlighting the advantages and insights of global stimulation. Therefore, the presented results can be modules in the design of novel illumination technologies with specific energy requirements on the way toward tissue-protective defibrillation techniques.

PO334 Cardioprotective Effects of Testosterone Suggested by Ultra High-Resolution Electrophysiological Measurements of iPSC-Derived Cardiomyocyte Activity

Coronavirus infection is the cause of the current world-wide pandemic. Cardiovascular complications occur in 20–30% of patients with COVID-19 infection including myocardial injury and arrhythmias. Current understanding of specific arrhythmia type and frequency is limited.We aimed to analyze arrhythmia type and frequency in patients with COVID infection, identifying arrhythmia patterns over time during hospitalization and post discharge utilizing a patch based mobile cardiac telemetry system.A prospective cohort study during the COVID-19 pandemic was performed. We included in our study patients hospitalized with COVID-19 infection who had a patch-based mobile telemetry device placed for cardiac monitoring.Quantitative reports for 59 patients were available for analysis. Arrhythmias were detected in 72.9% of patients and at a consistent frequency throughout the monitoring period in 52.9%–89.5% of patients daily. The majority of arrhythmias were SVT (59.3% of patients) and AF (22.0%). New onset AF was noted in 15.0% of all patients and was significantly associated with older age (OR 1.4 for 5 yrs. difference; 95% CI 1.03–2.13). Of 9 patients who were discharged with continued patch monitoring, 7 (78%) had arrhythmic events during their outpatient monitoring period.In COVID-19 patients arrhythmias were observed throughout hospitalization with a consistent daily frequency. Patients continued to exhibit cardiac arrhythmias after hospital discharge of a type and frequency similar to that seen during hospitalization. These findings suggest that the risk of arrhythmia associated with COVID infection remains elevated throughout the hospital course as well as following hospital discharge.

Pattern of Arrhythmias in Patients of Acute ST Elevation Myocardial Infarction with Impaired Renal Function

Pattern of Arrhythmias in Patients of Acute ST Elevation Myocardial Infarction with Impaired Renal Function

College females with maltreatment histories have atypical autonomic regulation and poor psychological wellbeing.

This study uniquely examined the impact of maltreatment (without a diagnosis of posttraumatic stress disorder [PTSD]) on physiological responses to a physical and an emotional stressor. The study sample was composed exclusively of women, because men may differ in maltreatment experience and neural regulation of physiological reactivity. Participants were 60 female college students. A significant proportion of the participants reported experiencing childhood maltreatment without a history of PTSD. Participants completed measures assessing psychological and PTSD symptomatology. Heart rate was monitored before, during, and after riding a stationary bike (physical stressor) and viewing a video of a child being maltreated (emotional stressor). Baseline and stressor related patterns of heart rate and respiratory sinus arrhythmia (RSA) were quantified from the beat-to-beat heart rate. Women with maltreatment histories reported more psychological distress and PTSD symptomatology, had lower levels of RSA and faster heart rate, and reacted to the stressors with atypical vagal regulation of RSA and heart rate. Accompanying psychological difficulties, women with maltreatment histories exhibit atypical physiological regulation to stressors consistent with clinical observations of lower thresholds to defensiveness and other manifestations of compromised resilience. The findings are consistent with polyvagal theory, which emphasizes the role of the "vagal brake" in social engagement and coregulation behaviors-features frequently compromised in survivors of emotional and physical abuse. Future research should investigate whether these features of atypical autonomic regulation are lead indicators of mental and physical health risks and whether these features can be reversed. (PsycINFO Database Record

Thirty-Second Gold Standard Definition of Atrial Fibrillation and Its Relationship With Subsequent Arrhythmia Patterns: Analysis of a Large Prospective Device Database.

The Heart Rhythm Society consensus statement arbitrarily defines atrial fibrillation (AF) ablation failure as any episode ≥30 seconds. However, if brief AF events are not correlated to longer events, the rationale for this end point is questionable. We determined the impact of AF episode duration threshold on AF incidence and burden. Patients with a pacemaker in a prospective registry with device-detected AF and follow-up >30 days were analyzed. AF patterns were calculated for various AF duration thresholds (30 s; 2 and 6 minutes; 3.8, 5.5, and 24 hours) selected based on published consensus statements, established evidence of stroke risk, and device capabilities. Freedom from AF postdevice implant at each AF episode duration threshold was assessed, as was overall AF burden. Among 615 patients with pacemaker (aged 72.0±11.8 years, 54.2% male, follow-up 3.7±2.2 years) with device-detected AF, 599 had ≥1 AF episode of ≥30 seconds duration (median, 22 episodes). At 12 months, freedom from AF was 25.5%, 30.1%, 34.6%, 52.6%, 56.5%, and 73.1% for duration thresholds of 30 seconds, 2 minutes, 6 minutes, 3.8 hours, 5.5 hours, and 24 hours, respectively. Of patients with a first episode of 30 seconds to 2 minutes, 35.8% were free from subsequent episode >2 minutes at 180 days. Median AF burden was significantly less for patients with first episodes between 30 seconds and 3.8 hours versus >3.8 hours (0.2% versus 9.5%, respectively; P<0.0001). Small differences in AF episode duration definition can significantly affect the perceived incidence of AF and impact reported outcomes, including AF ablation success. An initial AF episode of 30 seconds does not predict clinically meaningful AF patterns.

Calcium and cAMP directly modulate the speed of the Drosophila circadian clock

Circadian clocks impose daily periodicities to animal behavior and physiology. At their core, circadian rhythms are produced by intracellular transcriptional/translational feedback loops (TTFL). TTFLs may be altered by extracellular signals whose actions are mediated intracellularly by calcium and cAMP. In mammals these messengers act directly on TTFLs via the calcium/cAMP-dependent transcription factor, CREB. In the fruit fly, Drosophila melanogaster, calcium and cAMP also regulate the periodicity of circadian locomotor activity rhythmicity, but whether this is due to direct actions on the TTFLs themselves or are a consequence of changes induced to the complex interrelationship between different classes of central pacemaker neurons is unclear. Here we investigated this question focusing on the peripheral clock housed in the non-neuronal prothoracic gland (PG), which, together with the central pacemaker in the brain, controls the timing of adult emergence. We show that genetic manipulations that increased and decreased the levels of calcium and cAMP in the PG caused, respectively, a shortening and a lengthening of the periodicity of emergence. Importantly, knockdown of CREB in the PG caused an arrhythmic pattern of eclosion. Interestingly, the same manipulations directed at central pacemaker neurons caused arrhythmicity of eclosion and of adult locomotor activity, suggesting a common mechanism. Our results reveal that the calcium and cAMP pathways can alter the functioning of the clock itself. In the PG, these messengers, acting as outputs of the clock or as second messengers for stimuli external to the PG, could also contribute to the circadian gating of adult emergence.

Increasing prevalence of atrial fibrillation and permanent atrial tachyarrhythmias in the aging population with congenital heart disease: A multicenter study

Atrial arrhythmias are the most common complication encountered in the growing and aging population with congenital heart disease (CHD). We assessed the types and patterns of atrial arrhythmias, associated factors, and age-related trends. A multicenter cohort study enrolled 482 patients with CHD and atrial arrhythmias, age 32.0 ± 18.0 years, 45.2% female, from 12 North American centers. Qualifying arrhythmias were classified by a blinded adjudicating committee. The most common presenting arrhythmia was intra-atrial reentrant tachycardia (IART; 61.6%), followed by atrial fibrillation (AF; 28.8%), and focal atrial tachycardia (FAT; 9.5%). Patients with FAT were the youngest at presentation (23.6 ± 18.5 years) followed by IART (28.8 ± 16.8 years) and AF (41.0 ± 17.2 years), P < 0.0001. The proportion of arrhythmias due to IART increased with CHD complexity from 47.2% to 62.1% to 67.0% in patients with simple, moderate, and complex defects, respectively ( P = 0.0013). AF comprised 9.3% of arrhythmias in patients < 20 years and increased with age to surpass IART as the most common arrhythmia in those ≥ 50 years (51.2% versus 44.2%, P < 0.0001). Older age [odd ratio (OR) 1.024 per year, 95% confidence interval (CI; 1.010, 1.039), P = 0.001] and hypertension [OR 2.00, 95% CI (1.08, 3.71), P = 0.029] were independently associated with AF. During a mean follow-up of 11.3 ± 9.4 years, the predominant arrhythmia pattern was paroxysmal in 62.3%, persistent in 28.2%, and permanent in 9.5%. Permanent atrial arrhythmias increased with age from 3.1% in patients < 20 years to 5.5%, 12.9%, and 22.6% in ages 20–35, 35–50, and ≥ 50 years, respectively ( P < 0.0001). IART is the most common presenting atrial arrhythmia in patients with CHD, with a predominantly paroxysmal pattern. However, as the population ages, atrial arrhythmias become increasingly permanent. AF surpasses IART as the most prevalent type of atrial arrhythmia over the age of 50 years.

Educational Software Applied in Teaching Electrocardiogram: A Systematic Review.

Background The electrocardiogram (ECG) is the most used diagnostic tool in medicine; in this sense, it is essential that medical undergraduates learn how to interpret it correctly while they are still on training. Naturally, they go through classic learning (e.g., lectures and speeches). However, they are not often efficiently trained in analyzing ECG results. In this regard, methodologies such as other educational support tools in medical practice, such as educational software, should be considered a valuable approach for medical training purposes. Methods We performed a literature review in six electronic databases, considering studies published before April 2017. The resulting set comprises 2,467 studies. From this collection, 12 studies have been selected, initially, whereby we carried out a snowballing process to identify other relevant studies through the reference lists of these studies, resulting in five relevant studies, making up a total of 17 articles that passed all stages and criteria. Results The results show that 52.9% of software types were tutorial and 58.8% were designed to be run locally on a computer. The subjects were discussed together with a greater focus on the teaching of electrophysiology and/or cardiac physiology, identifying patterns of ECG and/or arrhythmias. Conclusions We found positive results with the introduction of educational software for ECG teaching. However, there is a clear need for using higher quality research methodologies and the inclusion of appropriate controls, in order to obtain more precise conclusions about how beneficial the inclusion of such tools can be for the practices of ECG interpretation.

Expression of the clock gene Rev-erbα in the brain controls the circadian organisation of food intake and locomotor activity, but not daily variations of energy metabolism.

The nuclear receptor REV-ERBα is part of the molecular clock mechanism and is considered to be involved in a variety of biological processes within metabolically active peripheral tissues as well. To investigate whether Rev-erbα (also known as Nr1d1) in the brain plays a role in the daily variations of energy metabolism, feeding behaviour and the sleep-wake cycle, we studied mice with global (GKO) or brain (BKO) deletion of Rev-erbα. Mice were studied both in a light/dark cycle and in constant darkness, and then 24-hour variations of Respiratory quotient (RQ) and energy expenditure, as well as the temporal patterns of rest-activity and feeding behaviour, were recorded. The RQ increase of GKO mice was not detected in BKO animals, indicating a peripheral origin for this metabolic alteration. Arrhythmic patterns of locomotor activity were only found in BKO mice. By contrast, the circadian rhythm of food intake was lost both in GKO and BKO mice, mostly by increasing the number of daytime meals. These changes in the circadian pattern of feeding behaviour were, to some extent, correlated with a loss of rhythmicity of hypothalamic Hcrt (also named Orx) mRNA levels. Taken together, these findings highlight that Rev-erbα in the brain is involved in the temporal partitioning of feeding and sleep, whereas its effects on energy metabolism are mainly exerted through its peripheral expression.

Mapping of ventricular arrhythmias using a novel noninvasive epicardial and endocardial electrophysiology system

IntroductionThe aim of this study was to assess the use of a novel noninvasive epicardial and endocardial electrophysiology system (NEEES) for mapping of ventricular arrhythmias. MethodsEight patients (2 females, mean age 50±17 years) with ischemic (n=3) and nonischemic (n=5) cardiomyopathy and inducible ventricular arrhythmias during electrophysiology study were enrolled. Noninvasive mapping of ventricular arrhythmias was performed using the NEEES based on body-surface electrocardiograms and computed tomography imaging data. Arrhythmia patterns were analyzed using noninvasive phase mapping. ResultsMacro-reentrant VT circuits were observed in 3 ischemic and 1 nonischemic cardiomyopathy patient, respectively. In the remaining 4 patients, phase mapping revealed relatively stable rotor activity and multiple wavelets. ConclusionsNoninvasive cardiac mapping was able to visualize the macro-reentrant circuits in patients with scar-related VT. In patients without myocardial scar only polymorphic VT or VF was inducible, and rotor activity and multiple wavelets were observed.

Increasing Prevalence of Atrial Fibrillation and Permanent Atrial Arrhythmias in Congenital Heart Disease

BackgroundAtrial arrhythmias are the most common complication encountered in the growing and aging population with congenital heart disease. ObjectivesThis study sought to assess the types and patterns of atrial arrhythmias, associated factors, and age-related trends. MethodsA multicenter cohort study enrolled 482 patients with congenital heart disease and atrial arrhythmias, age 32.0 ± 18.0 years, 45.2% female, from 12 North American centers. Qualifying arrhythmias were classified by a blinded adjudicating committee. ResultsThe most common presenting arrhythmia was intra-atrial re-entrant tachycardia (IART) (61.6%), followed by atrial fibrillation (28.8%), and focal atrial tachycardia (9.5%). The proportion of arrhythmias due to IART increased with congenital heart disease complexity from 47.2% to 62.1% to 67.0% in patients with simple, moderate, and complex defects, respectively (p = 0.0013). Atrial fibrillation increased with age to surpass IART as the most common arrhythmia in those ≥50 years of age (51.2% vs. 44.2%; p < 0.0001). Older age (odds ratio [OR]: 1.024 per year; 95% confidence interval [CI]: 1.010 to 1.039; p = 0.001) and hypertension (OR: 2.00; 95% CI: 1.08 to 3.71; p = 0.029) were independently associated with atrial fibrillation. During a mean follow-up of 11.3 ± 9.4 years, the predominant arrhythmia pattern was paroxysmal in 62.3%, persistent in 28.2%, and permanent in 9.5%. Permanent atrial arrhythmias increased with age from 3.1% to 22.6% in patients <20 years to ≥50 years, respectively (p < 0.0001). ConclusionsIART is the most common presenting atrial arrhythmia in patients with congenital heart disease, with a predominantly paroxysmal pattern. However, atrial fibrillation increases in prevalence and atrial arrhythmias progressively become permanent as the population ages.

3880Correcting the PRKAG2 mutation in WPW patient's induced pluripotent stem cells using CRISPR/Cas9 eliminates arrhythmic firing patterns in the derived cardiomyocytes

3880Correcting the PRKAG2 mutation in WPW patient's induced pluripotent stem cells using CRISPR/Cas9 eliminates arrhythmic firing patterns in the derived cardiomyocytes

Young Children's Physiological Reactivity during Memory Recall: Associations with Posttraumatic Stress and Parent Physiological Synchrony.

Autonomic reactivity is implicated in stress response and social engagement - both key components of posttraumatic stress disorder (PTSD) - but few studies have examined autonomic reactivity in pediatric samples, and no known studies have examined physiological synchrony among children with PTSD and caregivers. In a sample of 247 young children (94 girls, 153 boys), most (85%) of whom had exposure to trauma and 40% who met criteria for PTSD, we examined children's patterns of respiratory sinus arrhythmia (RSA) at baseline and in response to a memory recall task, as well as correspondence between parents' and children's RSA. Children with PTSD demonstrated significantly higher reactivity than other groups during their recollection of a traumatic memory, but not during other memory tasks. Regarding synchrony, caregivers' and children's RSA were more significantly and positively correlated during the trauma recall task among children who had had exposure to a potentially traumatic event but did not meet PTSD criteria, suggesting physiological synchrony may be protective in contexts of trauma. Overall, findings demonstrate physiological reactivity differences among young children with PTSD. While more work is needed to understand the meaning of parent-child physiological synchrony, these data suggest that children's psychopathology is associated with physiological synchrony processes among young children with exposure to trauma.

Brugada Syndrome and Exercise Practice: Current Knowledge, Shortcomings and Open Questions.

Since its recognition as a clinical entity in 1992, the Brugada Syndrome (BrS), a hereditary disease characterized by a typical electrocardiogram (ECG) pattern potentially predisposing to sudden cardiac death (SCD), has attracted the attention of many physicians for its circadian pattern of ventricular arrhythmias (VA), mostly occurring at rest. Exercise may potentially worsen the ECG abnormalities in BrS patients, resulting in higher peak J-point amplitudes during the vasovagal reaction of the recovery period, possibly leading to an increased risk of cardiac events. Moreover, the enhanced vagal tone in athletes could be both a BrS risk factor and an exercise effect. Therefore, the true risk of a BrS patient during exercise is still unclear. This review summarizes current knowledge, shortcomings and open questions on BrS and exercise. The paper, in particular, underlines specific considerations including BrS diagnostic criteria and differential diagnosis in athletes, the genetic basis, the autonomic imbalance during exercise practice and the recommendations for athletic participation in this patient group.

Brugada Syndrome and Exercise Practice: Current Knowledge, Shortcomings and Open Questions.

Since its recognition as a clinical entity in 1992, the Brugada Syndrome (BrS), a hereditary disease characterized by a typical electrocardiogram (ECG) pattern potentially predisposing to sudden cardiac death (SCD), has attracted the attention of many physicians for its circadian pattern of ventricular arrhythmias (VA), mostly occurring at rest. Exercise may potentially worsen the ECG abnormalities in BrS patients, resulting in higher peak J-point amplitudes during the vasovagal reaction of the recovery period, possibly leading to an increased risk of cardiac events. Moreover, the enhanced vagal tone in athletes could be both a BrS risk factor and an exercise effect. Therefore, the true risk of a BrS patient during exercise is still unclear. This review summarizes current knowledge, shortcomings and open questions on BrS and exercise. The paper, in particular, underlines specific considerations including BrS diagnostic criteria and differential diagnosis in athletes, the genetic basis, the autonomic imbalance during exercise practice and the recommendations for athletic participation in this patient group.

Respiratory Sinus Arrhythmia Predicts Restricted Repetitive Behavior Severity.

In addition to social communication deficits, restricted repetitive behaviors (RRBs) are a key diagnostic feature of autism spectrum disorder (ASD). Dysfunction of the autonomic nervous system (ANS) in ASD has been posited as a mechanism of RRBs; however, most studies investigating ANS activity in ASD have focused on its relation to social functioning. This study used respiratory sinus arrhythmia (RSA) patterns to measure ANS functioning and analyze its relation to RRBs in children with and without an ASD diagnosis. Baseline RSA and RSA reactivity predicted RRB severity and exploratory analyses revealed these measures may be associated with RRB subgroups. These results are discussed in regards to the behavioral literature on RRBs and the benefits of finding biomarkers for these behaviors.

794Correcting PRKAG2 mutation in induced pluripotent stem cells using CRISPR/Cas9 eliminates arrhythmic firing patterns in the derived cardiomyocytes

794Correcting PRKAG2 mutation in induced pluripotent stem cells using CRISPR/Cas9 eliminates arrhythmic firing patterns in the derived cardiomyocytes

Impact of Chronic Total Coronary Occlusion on Recurrence of Ventricular Arrhythmias in Ischemic Secondary Prevention Implantable Cardioverter-Defibrillator Recipients (VACTO Secondary Study): Insights From Coronary Angiogram and Electrogram Analysis

ObjectivesThis study sought to evaluate the incidence and clinical effect of coronary chronic total occlusions (CTOs) in patients with ischemic cardiomyopathy receiving an implantable cardioverter-defibrillator (ICD) for secondary prevention of sudden cardiac death (SCD). BackgroundCTOs are common in patients with ischemic cardiomyopathy, which is the major cause of SCD. However, the impact of CTO in SCD survivors receiving an ICD is unknown. MethodsA total of 425 patients who had survived an episode of ventricular arrhythmias and underwent ICD implantation for secondary prevention in 8 centers were included. Coronary angiogram, CTO angiographic characteristics, and ventricular arrhythmia pattern were centrally analyzed. Primary and secondary endpoints were appropriate ICD therapies and mortality during a median follow-up of 4.1 years, according to the presence of CTO in the baseline angiogram. ResultsAppropriate ICD therapies were higher in patients with CTO (51.7% vs. 36.3%; p = 0.001 at 4 years). Left ventricular ejection fraction (LVEF) (p = 0.015) and CTO (p = 0.001) were independent predictors of appropriate ICD therapy. Ventricular arrhythmia onset was associated to a shorter coupling interval and lower prematurity index in CTO patients. Defibrillator therapies were independently associated with worse LVEF (p = 0.046) and renal dysfunction (p = 0.023) among patients with CTO, and a tendency was observed in patients with better collateral flow (p = 0.093). Patients with poorer renal function (p = 0.029), LVEF (p = 0.041), and CTO (p = 0.033) experienced higher mortality rate. ConclusionsAmong ICD recipients for secondary prevention of SCD, coronary CTO conferred a higher risk of VA recurrence and mortality in long-term follow-up. Angiographic and VA patterns could provide insights into the mechanisms of SCD and may have implications for the use of interventions designed to limit ICD shocks in this high-risk population.