Intracardiac echocardiography in paediatric and congenital cardiac ablation shortens procedure duration and improves success without complications.

AIMS: Common to adult electrophysiology studies (EPSs), intracardiac echocardiography (ICE) use in paediatric and congenital heart disease (CHD) EPS is limited. The purpose of this study was to assess the efficacy of ICE use and incidence of associated complications in paediatric and CHD EPS. METHODS AND RESULTS: This single-centre retrospective matched cohort study reviewed EPS between 2013 and 2022. Demographics, CHD type, and EPS data were collected. Intracardiac echocardiography cases were matched 1:1 to no ICE controls to assess differences in complications, ablation success, fluoroscopy exposure, procedure duration, and arrhythmia recurrence. Cases and controls with preceding EPS within 5 years were excluded. Intracardiac echocardiography cases without an appropriate match were excluded from comparative analyses but included in the descriptive cohort. We performed univariable and multivariable logistic regression to assess associations between variables and outcomes. A total of 335 EPS were reviewed, with ICE used in 196. The median age of ICE cases was 15 [interquartile range (IQR) 12-17; range 3-47] years, and median weight 57 [IQR 45-71; range 15-134] kg. There were no ICE-related acute or post-procedural complications. There were 139 ICE cases matched to no ICE controls. Baseline demographics and anthropometrics were similar between cases and controls. Fluoroscopy exposure (P = 0.02), procedure duration (P = 0.01), and arrhythmia recurrence (P = 0.01) were significantly lower in ICE cases. CONCLUSION: Intracardiac echocardiography in paediatric and CHD ablations is safe and reduces procedure duration, fluoroscopy exposure, and arrhythmia recurrence. However, not every arrhythmia substrate requires ICE use. Thoughtful selection will ensure the judicious and strategic application of ICE to enhance outcomes.

Clinical profile and electrophysiological characteristics of atypical atrioventricular nodal reentrant tachycardia: A decade's experience.

OBJECTIVE: To assess the clinical features and inducibility characteristics of atypical atrioventricular nodal reentrant tachycardia (AVNRT) and compare it with typical AVNRT. BACKGROUND: AVNRT is the commonest form of paroxysmal supraventricular tachycardia. The mechanism of AVNRT is very varied. Several classification systems evolved with better understanding but a simplified approach of classification into typical and atypical AVNRT is justifiable and clinically more relevant. In our study, we have assessed the epidemiological profile of atypical AVNRT in a single institute over 10 years and analysed pertinent electrophysiological characteristics. METHOD: In this retrospective observational single center study we analysed data of all AVNRT cases from January 2011 to June 2021. In our study we classified atypical AVNRT and typical AVNRT based on the HA interval; HA≤70 ms in the His bundle region during tachycardia was considered as typical AVNRT. Other parameters were also analysed during tachycardia, such as: induction by atrial or ventricular pacing, AH/HA ratio, tachycardia cycle length and site of the earliest atrial activation. The demographic profile of the patients were also compared between 2 groups. RESULTS: Atypical AVNRT was found in 75/1431 patients (5.2%) of all cases of AVNRT. The age of patients with atypical AVNRT was 52.4 ± 15.2 years (range 9-82 years) while that for typical AVNRT it was 48.2 ± 15.7 years (2-89 years), p = 0.023. There was no gender difference. Atypical AVNRT was induced by only ventricular extrastimuli (VES) in 17/75 (22.6%) while in typical AVNRT this was seen in only 12/1356 patients (0.9%, p < 0.001). Induction of atypical AVNRT was seen by both atrial extrastimuli (AES) and VES in 17/75 patients (22.6%) while in typical AVNRT this was seen in 64/1356 patients (4.8%, p < 0.001). Atypical AVNRT was induced by only AES in 40/75 patients (53.3%) while in typical AVNRT this was seen in 1280/1356 patients (94.3%, p < 0.001). An AH >200 ms during tachycardia was seen in all patients with typical AVNRT and in only 31/75 patients (41.3%) of atypical AVNRT (p < 0.00001). An interesting finding in atypical AVNRT was the earliest atrial activation at the His bundle region in 10/75 (13.3%) patients. CONCLUSION: Atypical AVNRT prevalence depends on the way it is classified; this was 5.2% of all AVNRT cases in our study. Typical AVNRT was seen more frequently in comparatively younger age group and was more often induced by AES. Atypical AVNRT was much more commonly induced by only VES compared to typical AVNRT. It was not so unusual in atypical AVNRT to find the earliest atrial activation in the His bundle region.

In-vivo evaluation of catheter integrity with the use of a novel catheter torque tool.

INTRODUCTION: Electrophysiology studies and ablation procedures require strength, steadiness, and dexterity to manipulate catheters. We have previously described a novel catheter torque tool (Peritorq) that improves torqueability and stability and decreases user muscle fatigue. The objective was to evaluate measures of catheter integrity with and without the torque tool in place using multiple diagnostic and ablation catheters in an adult porcine model. METHODS: Diagnostic and ablation catheters were inserted through the femoral or jugular vein into areas of the right atrium, coronary sinus (CS), and right ventricle. Electrical measurements including impedance, sensing, and capture thresholds were obtained with and without the torque tool. Ablation lesions (30 s) were given at different locations using both irrigated and nonirrigated catheters and measurements were recorded with and without the torque tool. RESULTS: Procedures were performed in eight adult pigs. Measurements with and without the torque tool in all locations did not differ significantly using any of the catheters. With the nonirrigated ablation catheter there was a significant difference in maximum (mean 1.7 W, p = .03) and average power (mean 9.1 W, p = .04) delivery at the PS tricuspid valve, but there were no other differences with the irrigated or nonirrigated catheters. Subjective assessment by the operator revealed a substantial improvement in maneuverability, ability to transfer torque, and stability within the cardiac space. CONCLUSION: In an in-vivo environment, a novel catheter torque tool subjectively improved catheter manipulation and did not have a significant impact on the integrity of electrophysiologic catheters. Further study including additional catheters and in-vivo human testing is indicated.

Optimizing electrophysiology studies to prevent sudden cardiac death after myocardial infarction.

AIMS: This study assessed associations of minimum final extrastimulus coupling interval utilized within electrophysiology study (EPS) after myocardial infarction (MI) and possible site of origin of induced ventricular tachycardia (VT) with long-term occurrence of spontaneous ventricular tachyarrhythmia and long-term survival. METHODS AND RESULTS: This prospective study recruited consecutive patients with left ventricular ejection fraction (LVEF) ≤ 40% who underwent EPS days 3-5 after MI between 2004 and 2017. Positive EPS was defined as sustained monomorphic VT cycle length ≥200 ms for ≥10 s or shorter duration if haemodynamic compromise occurred. Each of the four extrastimuli was shortened by 10 ms at a time, until it failed to capture the ventricle (ventricular refractoriness) or induced ventricular tachyarrhythmia. Outcomes included spontaneous ventricular tachyarrhythmia occurrence and all-cause mortality. Shorter coupling interval length of final extrastimulus that induced VT was associated with higher risk of spontaneous ventricular tachyarrhythmia (P < 0.001). Significantly higher rates of spontaneous ventricular tachyarrhythmia (65.2% vs. 23.2%; P < 0.001) were observed for final coupling interval at EPS <200 ms vs. >200 ms. Right bundle branch block (RBBB) morphology of induced VT, with possible site of origin from the left ventricle, was associated with all-cause mortality [hazard ratio (HR) 3.2, P = 0.044] and a composite of spontaneous ventricular tachyarrhythmia recurrence or mortality (HR 1.8, P = 0.043). CONCLUSION: Ventricular tachycardia induced with shorter coupling intervals was associated with higher risk of spontaneous ventricular tachyarrhythymia on follow-up, indicating that the final extrastimulus coupling interval at EPS early after MI should be determined by ventricular refractoriness. Induced VT with possible origin from left ventricle was associated with increased risk of spontaneous ventricular tachyarrhythmia recurrence or death.

An interesting case of infra-hisian block.

INTRODUCTION: The management of patients with conduction disease and supraventricular arrhythmias presents a multitude of clinical challenges.Intra-Hisian block, a condition characterized by delayed or blocked electrical conduction within the His bundle, can result in debilitating symptoms, such as syncope or presyncope. This case report aims to elucidate the diagnostic and therapeutic considerations that were taken in a patient who presented with recurrent syncopal episodes that corresponded to atrial flutter (AFL) and subsequently underwent cavotricuspid isthmus ablation. CASE PRESENTATION: A 65-year-old male with paroxysmal AFL and a pre-existing right bundle branch block and left anterior fascicular block (RBBB+LAFB) experienced recurrent syncopal episodes that were found to be correlated with AFL episodes. Following CTI ablation, an electrophysiology study (EPS) revealed a prolonged HV interval of 101ms, which indicated potential conduction abnormalities. With coronary sinus pacing, an intra-Hisian delay of 211ms was observed. During instances of atrioventricular block, intra-Hisian delay was evident on conducted beats, followed by intra-Hisian block on non-conducted beats. Ultimately, the patient's syncopal episodes prompted the placement of a dual-chamber pacemaker, which resulted in the resolution of symptoms. CONCLUSION: Intra-Hisian block is a condition that is often associated with delayed or blocked electrical conduction within the His bundle. When symptomatic, patients often present with syncope or presyncope. Etiologies of this condition include degenerative changes, myocardial infarction, autoimmune disorders, infections, medications, and more. This case emphasizes the importance of electrophysiology studies (EPS) in the diagnosis and management of patients with intra-Hisian block. Prompt intervention, such as the placement of a dual-chamber pacemaker, can alleviate symptoms and improve patient outcomes. Thus, clinical awareness and utilization of EPS can aid in accurate diagnosis and appropriate treatment selection for patients with conduction abnormalities and supraventricular arrhythmias.cuspid isthmus (CTI) ablation.

Risk Stratification in Pediatric Wolff-Parkinson-White: Practice Variation Among Pediatric Cardiologists and Electrophysiologists.

BACKGROUND: Published guidelines provide recommendations for risk stratification in pediatric Wolff-Parkinson-White (WPW). There are no data on provider concordance with these guidelines. We hypothesized that significant practice variation exists between pediatric cardiologists (PC) and electrophysiologists (EP). METHOD: The records of all patients, age 8 to 21 years, with a new ECG diagnosis of WPW between 1/1/2013 and 12/31/2018, from a single center, were retrospectively reviewed. Subjects were categorized on the basis of symptoms and resting ECG findings as one of the following: asymptomatic intermittent WPW, asymptomatic persistent WPW, or symptomatic WPW. The performance and results of diagnostic testing, including Holter monitor, event monitor, exercise stress test (EST), and electrophysiology study (EPS), were recorded. The primary outcome was concordance with published guidelines. A secondary outcome was documentation of a discussion of sudden cardiac death (SCD) risk. RESULTS: 615 patient encounters were analyzed in 231 patients with newly diagnosed WPW pattern on ECG (56% male; mean age at diagnosis 13.9 ± 2.5 years). EP were observed to have a significantly higher rate of guideline concordance than PC (95% vs. 71%, p < 0.001). There was significant practice variation between PC and EP in the documentation of a discussion of SCD risk: 96% in EP vs. 39% in PC (p < 0.001). CONCLUSION: Significant practice variation exists in the non-invasive and invasive risk stratification of pediatric WPW, with lower concordance to published guidelines amongst PC, when compared to EP. This report highlights the need to promote awareness of current WPW guidelines in the pediatric cardiology community at large.

Catheter ablation of atrial tachycardia originated from the left atrial epicardium.

A patient was referred with frequent atrial tachycardia (AT) attacks. Activation mapping showed that the left atrium (LA) roof was earlier activated with a broad region, and right atrial activation was delayed. The far-field A wave corresponding to the pulmonary artery area was advanced with failed ablation. Therefore, the AT could be left atrial epicardial origin, which was further confirmed by the successful ablation at earliest activated site at the epicardium.

Nonreentrant atrioventricular nodal tachycardia: The great simulator.

We present the case of a healthy 12-year-old boy without structural heart disease who was followed for several years for an arrhythmia with diverse and incorrect initial diagnoses, refractory to flecainide, metoprolol and verapamil. Thorough reevaluation of the electrocardiographic recordings led to a presumptive diagnosis of a non-reentrant atrioventricular nodal tachycardia, subsequently confirmed with electrophysiology study. Radiofrequency ablation was performed during the procedure and the arrhythmia resolved. Double conduction through the atrioventricular node often simulates other arrhythmias, leading to misdiagnosis.

Entrapment of diagnostic catheter within Advisor HD grid mapping catheter.

The potential for catheter entanglement with the HD Grid mapping catheter is explicitly stated in the manufacturer's product manual. A case of an entrapped 6 French quadripolar diagnostic catheter within an HD Grid mapping catheter is presented. We discuss the diagnosis, management, and resolution of this complication in our patient. The patient's arrhythmia was successfully eliminated, and no vascular complication in the postprocedural setting nor arrhythmia recurrence at follow-up were observed. Strategies to prevent and safely manage this complication, while salvaging access, are also discussed.

Electrophysiologic and electroanatomic characterization of ventricular arrhythmias in non-compaction cardiomyopathy: A systematic review.

BACKGROUND: Non-compaction cardiomyopathy (NCCM) is a form of structural heart disease prone to ventricular arrhythmias (VAs) and sudden cardiac death. Non-compacted myocardium may harbor VA substrate, though some reports suggest otherwise. OBJECTIVE: This study aimed to characterize the electrophysiologic (EP) features of VA in NCCM. METHODS: We performed a systematic review of case reports, case series, and observational studies. RESULTS: One hundred and thirty-five cases of NCCM from studies between 2000 and 2020 were included. Mean age was 34 ± 20 years, mean left ventricular (LV) ejection fraction was 42 ± 15% with two cases having late gadolinium enhancement on magnetic resonance imaging. The LV apex was the most common non-compacted segment (86%); 10% involved the right ventricle (RV). Antiarrhythmic failure was documented in 16 cases, of which 50% failed more than one agent. Only 23% of monomorphic VAs localized to regions of non-compaction on electrocardiogram. Most frequently, VAs localized to the RV outflow tract (n = 21), posterior fascicle (n = 19), and anterolateral LV apex (n = 9). All cases with apical exits arose from the non-compacted myocardium. On EPS, 83% of sustained VTs were due to re-entry, 17% due to focal mechanism. Catheter ablation was performed in 39 cases, with 7 requiring more than 1 procedure. Acute VA non-inducibility was achieved in 82% and VA-free survival was reported in 85% over a mean follow-up of 24 months. CONCLUSION: The majority of VAs in NCCM arise remotely from non-compacted myocardium, and non-re-entrant mechanism seen in ~1/5th of sustained VTs. Catheter ablation outcomes appear favorable. Further study is needed to understand the pathophysiology of VA in NCCM.

Predictors of high-degree conduction disturbances and pacemaker implantation after transcatheter aortic valve replacement: Prognostic role of the electrophysiological study.

BACKGROUND: Predictors of high-degree atrioventricular block (HAVB) after transcatheter aortic valve replacement (TAVR) are recognized, but the electrophysiological study's (EPS) role is still a subject to debate. The objective of our study was to determine factors associated with PPM implantation including the potential role of EPS before and/or after TAVR. METHODS AND RESULTS: Seventy four consecutive patients (pts) were included and 21 pts (28.4%) received a PPM during the immediate postoperative follow-ups (until Day 5): HAVB in 15 pts (71.4%), prophylactic implantation due to a documented increased HV interval ≥ 95-100 ms plus LBBB in 2 pts (9.5%), a high-degree HV block evidenced at the EPS plus LBBB in 3 pts (14.3%) and one additional patient was implanted for AV-block in presence of AFib (4.8%). In the multivariate model 1 including parameters before TAVR, both prosthesis diameter and PR lengthening remained significantly associated with PPM as well RBBB. In the multivariate model 2 including parameters after TAVR, only HV remained significantly associated with the risk of PPM (OR = 1.15 (1.05-1.26), p = .004). When all the significant variables in models 1 and 2 were analyzed together in model 3, only HV after TAVR remained significantly associated with an increased risk of PPM. CONCLUSIONS: In this prospective observational study, it was revealed that a Day 4-5 EPS is likely to more precisely stratify the risk of PPM implantation regarding its ability to discover asymptomatic severe infra-hisian conduction disturbances particularly in presence of LBBB. Multivariate analysis confirmed the prognostic value of HV alteration.

Electrophysiologic Implications of Transcatheter Aortic Valve Replacement: Incidence, Outcomes, and Current Management Strategies.

PURPOSE OF REVIEW: Transcatheter aortic valve replacement (TAVR) has changed the paradigm for management of severe aortic stenosis. Despite substantial procedural advancements, conduction system abnormalities remain a common complication following TAVR. In this review, we describe (1) incidence and risk factors for the development of conduction disturbances following TAVR, along with their prognostic significance, (2) the incidence and prognostic significance of new-onset arrhythmias following TAVR, (3) approach to management of perioperative and post-procedural conduction disturbances and arrhythmias, and (4) novel areas of research. RECENT FINDINGS: Conduction disturbances including left bundle branch block (LBBB) and high-grade atrioventricular block (HAVB) remain common issues post-TAVR despite advancements in valve technology and improvements in procedural technique. Despite data showing most conduction abnormalities resolve over time, rates of post-procedural permanent pacemaker implantation remain high. Similarly, rates of new-onset or newly detected arrhythmia, particularly atrial fibrillation, have been widely reported post-implantation of all types of TAVR valves. Recent consensus statements and decision pathway documents have been helpful in standardizing an approach to post-TAVR conduction disturbances. New areas of research show promise both for predicting which patients will develop conduction disturbances post-TAVR and for management of HAVB with novel pacing techniques. On the other hand, management of new-onset or newly detected atrial fibrillation after TAVR remains a significant challenge without standardized treatment strategy.

Effectiveness of the Early Staged Hybrid Approach for Treatment of Symptomatic Atrial Fibrillation: the Electrophysiology Study Could Be Deferred?

BACKGROUND: The efficacy of catheter ablation for persistent atrial fibrillation (AF) remains suboptimal. A hybrid approach of catheter ablation combined with totally thoracoscopic surgical ablation can improve outcomes. In this study, we evaluated the efficacy of the early staged hybrid procedure in hospital stay after totally thoracoscopic ablation compared to the stand-alone totally thoracoscopic ablation. METHODS: Patients who underwent totally thoracoscopic ablation from February 2012 to December 2018 were included in this study. We compared the outcomes of the totally thoracoscopic ablation only group versus the early staged hybrid procedure group. The primary outcome was recurrence of atrial tachyarrhythmia after three months of blanking period. The secondary outcome was repeated unplanned additional electrophysiology study and catheter ablation due to atrial tachyarrhythmia recurrence. RESULTS: A total of 306 patients (mean age, 56.8 ± 8.5 years; 278 [90.8%] males) was included in the study, with 81 patients in the early staged hybrid group and 225 patients in the stand-alone totally thoracoscopic ablation only group. The mean follow-up duration was 30.0 months. Overall arrhythmia-free survival showed no significant difference between the two groups (log-rank P = 0.402). There was no significant difference in the rate of repeat procedure between the two groups (log-rank = 0.11). CONCLUSION: The early staged hybrid procedure after thoracoscopic ablation could not improve the outcome of recurrence of atrial tachyarrhythmia. The second stage of electrophysiology study could be deferred to patients with recurrence of atrial tachyarrhythmia during follow up after totally thoracoscopic ablation.

Electrophysiologic evidence of epicardial connections between low right atrium and remote right atrial region or coronary sinus musculature: Relevance for catheter ablation of typical atrial flutter.

BACKGROUND: The coronary sinus (CS) is surrounded by a myocardial coat with extensive connections to the left and right atria that contributes to the interatrial electrical connection. Whereas epicardial connections between CS musculature and the left atrium have largely been demonstrated, clinically relevant epicardial connections from the CS musculature toward the low right atrium (LRA) and epicardial connections between two regions of the right atrium remain questionable. METHODS: Five patients underwent electrophysiology (EP) study for typical atrial flutter (AFl) using either conventional multipolar catheters (four patients) or three-dimensional high-density mapping system (one patient). RESULTS: All five patients had a similar sequence of events during the EP studies. After several cavotricuspid isthmus (CTI) radiofrequency (RF) applications, double potentials were recorded along the ablation line while tachycardia persisted. The right atrial activation pattern strongly suggested the presence of a complete endocardial CTI line of the block. Based on the detailed conventional atrial mapping, RF applications at the middle cardiac vein/CS ostium allowed sinus rhythm restoration in four patients. High-density mapping showed an early breakthrough site at the septal side of the ablation line, close to the CS ostium during counterclockwise AFl, in the fifth patient. RF applications at this site resulted in tachycardia termination. CONCLUSION: Our observations suggested the existence of epicardial fibers connecting the LRA with either the CS musculature or a remote right atrial region. When AFl ablation fails whereas evidence for the local endocardial block is observed, the operators should integrate this finding in the diagnosis and ablation strategy.

Synthesis, biological activities, and SAR studies of novel 1-(2-chloro-4,5-difluorophenyl)-1H-pyrazole derivatives.

In order to search for the new ryanodine receptor (RyR) regulator, a series of 35 novel fluoro-substituted compounds introduced 1-(2-chloro-4,5-difluorophenyl)-1H-pyrazole moiety containing modified pyrazole heterocycle were designed and synthesized. Then, they were tested for the insecticidal activities against Mythimna separata and Plutella xylostella in our greenhouse. After a systematic biological screening, it was found out that IVc showed 50% larvicidal activities against Mythimna separata at 0.1 mg L-1, equivalent to that of chlorantraniliprole (36%, 0.1 mg L-1). The activity of IVc against Plutella xylostella was 90% at 10-5 mg L-1, whereas the chlorantraniliprole was 70% at the same concentration. Then, insect electrophysiology experiments were conducted to study the pattern of action of IVc and IVe. It was confirmed by the experimental results that both compounds could lead to the release of calcium from the endoplasmic reticulum of neurons as classical anthranilic diamide insecticides.

Institutional experience of healthy pediatric patients presenting with atrial fibrillation who had an electrophysiology study.

INTRODUCTION: Atrial fibrillation (AF) is a very common tachyarrhythmia with increasing prevalence with age, but uncommon in the pediatric population. Understanding that AF increases comorbidities make the need for investigation and potential elimination of alternate etiologies in pediatric AF patients critical. The objective of this study was to review our institutional data and compare our findings with previously documented adult AF risk factors to pediatric patients while also identifying which patients had alternate electrophysiology diagnoses amenable to transcatheter ablation. METHODS: A retrospective chart review was performed identifying AF patients who were less than 21 years old, had no significant congenital cardiovascular anomalies, a documented episode of AF on electrocardiogram and underwent invasive electrophysiology study (EPS). RESULTS: Nineteen patients were identified over a 9-year period of time finding a male predominance (74%), the average age of 14.95 ± 4.17 years, the average weight of 78.5 ± 31.4 kg, and average body mass index of 26.8 ± 6.87 kg/m2 . Preprocedural left atrial volumes made on echocardiograms demonstrated a mean of 33.96 ± 16.35 mL/m2 (Z-scores -0.81 ± 1.50), indicating no dilation. Five of nineteen patients (26%) had additional electrophysiologic diagnoses during EPS, including atrioventricular reentrant tachycardia (n = 2, 10%) and atrioventricular nodal reentrant tachycardia (n = 3, 16%). Four patients underwent successful ablation with no documented or clinical AF recurrence. CONCLUSIONS: Adult risk factors of male predominance and obesity were seen in pediatric AF patients, while left atrial enlargement was not. Twenty-one percent of the pediatric AF patients who had additional electrophysiologic substrates and successful ablations resulted in no further clinical episodes of AF. This suggests that pediatric patients presenting with AF might benefit from an EPS as part of a complete evaluation.

Successful radio-frequency catheter ablation of two cases of supraventricular tachycardia via a left-sided inferior vena cava.

Congenital venous anomalies are uncommon, incidental findings encountered during adult interventional electrophysiology procedures. Femoral venous access is conventionally used during cardiac electrophysiology studies to gain access to the heart. The chance finding of an inferior vena cava anomaly may preclude the performance of these procedures from the femoral approach. We describe two cases in which we were able to successfully perform different radiofrequency catheter ablation procedures in the presence of an unusual venous anomaly, the left-sided IVC.

Ventricular Arrhythmias in Cardiac Sarcoidosis.

The diagnosis of cardiac sarcoidosis (CS), especially in cases where there is limited or no extracardiac involvement, is challenging. Patients with CS are at increased risk of ventricular arrhythmias and sudden cardiac death. Several techniques for risk stratification for sudden cardiac death have been proposed in this population, including advanced cardiac imaging and electrophysiology study. Clinical ventricular arrhythmias in patients with CS may be treated with immunosuppressant therapy, antiarrhythmic drugs, catheter ablation, or implantable cardioverter-defibrillator placement. This article will provide an update on techniques for diagnosing CS, risk stratifying patients with CS for sudden cardiac death, and treating patients with CS with ventricular arrhythmias, focusing on evidence that has become available since publication of the 2014 Heart Rhythm Society Expert Consensus Statement on the Diagnosis and Management of Arrhythmias Associated With Cardiac Sarcoidosis.

Systematic Review for the 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

BACKGROUND: Although large randomized clinical trials have found that primary prevention use of an implantable cardioverter-defibrillator (ICD) improves survival in patients with cardiomyopathy and heart failure symptoms, patients who receive ICDs in practice are often older and have more comorbidities than patients who were enrolled in the clinical trials. In addition, there is a debate among clinicians on the usefulness of electrophysiological study for risk stratification of asymptomatic patients with Brugada syndrome. AIM: Our analysis has 2 objectives. First, to evaluate whether ventricular arrhythmias (VAs) induced with programmed electrostimulation in asymptomatic patients with Brugada syndrome identify a higher risk group that may require additional testing or therapies. Second, to evaluate whether implantation of an ICD is associated with a clinical benefit in older patients and patients with comorbidities who would otherwise benefit on the basis of left ventricular ejection fraction and heart failure symptoms. METHODS: Traditional statistical approaches were used to address 1) whether programmed ventricular stimulation identifies a higher-risk group in asymptomatic patients with Brugada syndrome and 2) whether ICD implantation for primary prevention is associated with improved outcomes in older patients (>75 years of age) and patients with significant comorbidities who would otherwise meet criteria for ICD implantation on the basis of symptoms or left ventricular function. RESULTS: Evidence from 6 studies of 1138 asymptomatic patients were identified. Brugada syndrome with inducible VA on electrophysiological study was identified in 390 (34.3%) patients. To minimize patient overlap, the primary analysis used 5 of the 6 studies and found an odds ratio of 2.3 (95% CI: 0.63-8.66; P=0.2) for major arrhythmic events (sustained VAs, sudden cardiac death, or appropriate ICD therapy) in asymptomatic patients with Brugada syndrome and inducible VA on electrophysiological study versus those without inducible VA. Ten studies were reviewed that evaluated ICD use in older patients and 4 studies that evaluated unique patient populations were identified. In our analysis, ICD implantation was associated with improved survival (overall hazard ratio: 0.75; 95% confidence interval: 0.67-0.83; P<0.001). Ten studies were identified that evaluated ICD use in patients with various comorbidities including renal disease, chronic obstructive pulmonary disease, atrial fibrillation, heart disease, and others. A random effects model demonstrated that ICD use was associated with reduced all-cause mortality (overall hazard ratio: 0.72; 95% confidence interval: 0.65-0.79; P<0.0001), and a second "minimal overlap" analysis also found that ICD use was associated with reduced all-cause mortality (overall hazard ratio: 0.71; 95% confidence interval: 0.61-0.82; P<0.0001). In 5 studies that included data on renal dysfunction, ICD implantation was associated with reduced all-cause mortality (overall hazard ratio: 0.71; 95% confidence interval: 0.60-0.85; P<0.001).