Automatic Implantable Cardioverter Defibrillator Research Articles

Catheter ablation of well tolerated ventricular tachycardia in patients with structural heart disease: long term follow-up of 62 cases without automatic defibrillator implantation

Abstract Funding Acknowledgements Type of funding sources: None. Background The occurrence of a sustained monomorphic ventricular tachycardias (SMVT) in patients with underlying structural heart disease (SHD) is considered correlated to a poor prognosis, based on historical data in patients with heterogeneous heart disease and clinical presentation; therefore the recommendation for implantation of automatic implantable cardioverter defibrillator (AICD) is strong. Information about prognosis of patients with SMVT is still limited, but recent studies have established that these patients represent a low-risk subgroup for sudden death that could benefit from radiofrequency (RF) ablation of the arrhythmic substrate and the AICD implantation could be deferred during the follow up. Purpose Patients with well-tolerated SMVT, SHD and left ventricular ejection fraction (LVEF) over 30% can benefit from a primary VT ablation strategy without the immediate need for AICD implantation. Methods We reviewed consecutive SHD patients with LVEF over 30% admitted for the occurrence of SMVT and who were treated by RF ablation as a first-choice therapy in a single Italian center, between 2009 and 2020 and who were discharged without AICD implantation. The primary outcome of the study was a composite of all-cause death and recurrence of VT. The secondary outcome was death from all causes. Patients with similar characteristics but who underwent AICD implantation during the same period served as control group. Results Clinical and electrophysiological features of 62 patients were analyzed (Table 1). In the study group, 88% were male; the median age was 72 years (IQR 55-81) and the median LVEF was 50.0% (IQR 40.0-55.0). The estimated success rate of ablative procedures (defined as VT no longer inducible) was around 82%. After a median follow-up of 38.8 months (IQR 15.6-76.1), the primary outcome occurred in 24 patients and the secondary outcome in 11 patients. All-cause mortality was 17%, corresponding to an annual mortality rate of 4.3%. Ten patients died for non-cardiovascular causes and one for advanced heart failure. No patient in the study died from sudden death. During the follow-up, 10 patients (16.1%) underwent AICD implantation due to VT relapse. At 36 months, between study and control groups, there was no difference in either the primary composite outcome (HR 1.03, 95% CI 0.45-2.21, p = 0.98) or in the secondary outcome (HR 1.4, 95% CI 0.48-4.54, p = 0.49). Conclusions Patients with well-tolerated SMVT, SHD and LVEF over 30% represent a subgroup of patients at lower risk that can benefit of RF ablation as a first-choice therapy. Delay in AICD implantation, after a possible VT relapse or clinical worsening, appears to represent a safe therapeutic strategy. Therefore, it is ethical and desirable to start a prospective randomized clinical trial to evaluate the benefit and cost-effectiveness of this strategy, as an alternative to AICD implantation.

P168 A RARE CASE OF HYPERTROPHIC CARDIOMYOPATHY WITH HIGH RISK OF SUDDEN CARDIAC DEATH: WHAT CAN WE DO UNTIL MIECTOMY?

Abstract A 43–year–old Indian man with obstructive hypertrophic cardiomyopathy (HCMO) and a family history of sudden death presented with heart palpitations associated with chest discomfort and syncope during moderate physical activity despite beta–blocker therapy at maximum dose (New York Heart Association–NYHA III). Transthoracic echocardiography demonstrated ejection fraction 55% and ventricular septum (SIV) (23 mm) and posterior wall hypertrophy (12 mm). There was evidence of dynamic left ventricular outflow tract obstruction (maximum LVOT gradient 30 mmHg at baseline and 45 mmHg after Valsalva) and systolic anterior movement of the amterior mitral flap responsible of moderate regurgitation. It also showed a bicuspid aortic valve with fusion of the right and left cusps and mild regurgitation. ECG Holter showed sporadic supraventricular premature ectopic beats and abnormality of the ventricular repolarization that were accentuated during exercise. Exercise stress test showed 3 mm ST depression in V4–V5 leads. Cardiac magnetic resonance (CMR) and Cardio–CT confirmed HCMO diagnosis and showed a junctional origin of the coronaries, a bifurcated interventricular artery, coronaries free from significant stenosis, intramural late gadolinium enhancement (LGE) of the mid–ventricular SIV and sub–endocardium LGE of the basal SIV. The high HCM– Sudden Cardiac Death Risk score and the presence of LGE on CMR identified a high–risk status and prompt consideration for primary prevention automatic implantable cardioverter defibrillator (AICD) therapy. Thus, in order to treat major life–threatening ventricular arrhythmias, AICD was placed (ESC guidelines 2014 Class IIa). Invasive treatment is indicated for symptomatic patients, NYHA class III and IV refractory to optimized medication and who have gradients in the LVOT. Aortic transvalvular–myectomy is the procedure with the longest experience and considered the gold standard. However, in this case surgical treatment was temporarily postponed. So a sequential rhythm pacing with reduced A–V delay was set up in order to induce a left bundle branch block and a “paradoxical” movement of the SIV with reduction of LVOT gradient. After 2 weeks the LVOT gradient was 20 mmHg and the symptoms were improved. This case suggests the usefulness of a single device for the treatment of different aspects in HCMO waiting to undergo surgical treatment: prevention of sudden cardiac death and improvement of symptoms refractory to medical therapy.

Psychiatric Disorder Induced By Twiddler's Syndrome May Pose Treatment Challenges In Clinical Practice

Twiddler’s syndrome is a rare condition caused by coiling of the leads, leading to a malfunction in the pacemaker or automated implantable cardioverter-defibrillator (AICD). It was first described by Bayliss in 1968 as a rare, but potentially fatal complication of pacemaker treatment1. Inappropriate shocks due to malfunctioning of the AICD can be devastating, traumatic, or fatal to the patient.

QRS micro-fragmentation as a mortality predictor.

AimsFragmented QRS complex with visible notching on standard 12-lead electrocardiogram (ECG) is understood to represent depolarization abnormalities and to signify risk of cardiac events. Depolarization abnormalities with similar prognostic implications likely exist beyond visual recognition but no technology is presently suitable for quantification of such invisible ECG abnormalities. We present such a technology.Methods and resultsA signal processing method projects all ECG leads of the QRS complex into optimized three perpendicular dimensions, reconstructs the ECG back from this three-dimensional projection, and quantifies the difference (QRS ‘micro’-fragmentation, QRS-μf) between the original and reconstructed signals. QRS ‘micro’-fragmentation was assessed in three different populations: cardiac patients with automatic implantable cardioverter-defibrillators, cardiac patients with severe abnormalities, and general public. The predictive value of QRS-μf for mortality was investigated both univariably and in multivariable comparisons with other risk factors including visible QRS ‘macro’-fragmentation, QRS-Mf. The analysis was made in a total of 7779 subjects of whom 504 have not survived the first 5 years of follow-up. In all three populations, QRS-μf was strongly predictive of survival (P < 0.001 univariably, and P < 0.001 to P = 0.024 in multivariable regression analyses). A similar strong association with outcome was found when dichotomizing QRS-μf prospectively at 3.5%. When QRS-μf was used in multivariable analyses, QRS-Mf and QRS duration lost their predictive value.ConclusionIn three populations with different clinical characteristics, QRS-μf was a powerful mortality risk factor independent of several previously established risk indices. Electrophysiologic abnormalities that contribute to increased QRS-μf values are likely responsible for the predictive power of visible QRS-Mf.

Upfront endoscopic band ligation for symptomatic gastric angioectasias to reduce peri‐endoscopic complexity with an automated implantable cardioverter defibrillator in situ

Argon plasma coagulation (APC) remains the mainstay endoscopic treatment of gastrointestinal angioectasia. Vis‐a‐vis automated implanted cardioverter defibrillators (AICD) endoscopic band ligation (EBL) represents an alternative without need for heart‐rhythm specialty support.

Arrhythmogenic Right Ventricular Dysplasia Diagnosed in a Patient with Long-term Undiagnosed Syncope

Arrhythmogenic Right Ventricular Dysplasia (ARVD) is an inherited cardiomyopathy which represents progressive replacement of right ventricular myocardium with fibrofatty tissue. In the present case, a 42-year-old male presented to the hospital as he fell down, due to syncope. He had a history of recurrent syncopal in past 4-5 years. His chest radiogram revealed cardiomegaly (CT ratio 0.64), repeat electrocardiogram showed symmetric T-wave inversions and epsilon waves in right precordial V1, V2 and V3 leads, and echocardiogram revealed mild left ventricular dysfunction (ejection fraction - 45%) and dilated right atrium and ventricle. Cardiac Magnetic Resonance Imaging (MRI) confirmed the diagnosis of ARVD.The patient was advised for the placement of an Automatic Implantable Cardioverter Defibrillator (AICD), but he denied for this treatment. Thus, he was managed with anti-arrhythmic drugs and was advised for regular follow-up. The patient was followed-up for six months where episodes of syncope had significantly reduced to one in six months but need of AICD implantation was still there to avoid sudden cardiac death.

9. The Skip Phenomenon in Staphylococcus aureus Bacteremia: Clinical Associations

BackgroundSerial blood cultures are integral in managing Staphylococcus aureus bacteremia (SAB) as clinicians rely on the results to determine infectious complication risks and antibiotic duration. Current IDSA guidelines suggest a single set of negative blood cultures is adequate evidence of SAB clearance. Several studies, however, have identified the skip phenomenon (SP), which is the occurrence of intermittent negative blood cultures, and have recommended obtaining additional blood cultures to document bacterial clearance (Table 1). We therefore examined patients who manifested the SP to determine its clinical significance and to study this, associations were tested for SP in relation to various baseline factors as well as clinical outcomes. MethodsWe performed a retrospective, multicenter study of all patients with a positive blood culture for S. aureus from January 2019 to December 2019 using data collected from electronic health records and the clinical microbiology laboratory. ResultsA total of 602 patients with SAB were identified and 495 patients were included in the investigation (Figure 1). Overall, 25 (5.1%) patients had the SP. Significant differences between those who did and did not manifest the SP included higher rates of injection drug use, automatic implantable cardioverter defibrillator, and community onset of infection in the SP cohort (Table 2). Moreover, the median duration of SAB was longer (3.2 [2.3-5.4] vs 1.90 [1.2-2.9] days, p=0.002), and high-grade SAB, (88.0% vs 58.7%, p=0.004), complicated bacteremia (92.0% vs 67.9%, p=0.011) and IE diagnosis (28.0% vs 11.3%, p=0.013) were all more common in the SP group. In unadjusted outcome analyses, association of SP with hospital length of stay was not significant, although a higher risk of in-hospital mortality among SP patients approached statistical significance (p=0.055). Analysis of 435 hospital survivors revealed no significant differences in rates of 1-year mortality or 90-day relapse between the two groups (Table 3). ConclusionFindings of the current investigation demonstrates an increased risk of SAB complications in patients with the SP and support the notion that serial negative blood cultures are needed to document clearance of SAB. Disclosures Larry M. Baddour, MD, Boston Scientific (Individual(s) Involved: Self): Consultant; Botanix Pharmaceuticals (Individual(s) Involved: Self): Consultant; Roivant Sciences (Individual(s) Involved: Self): Consultant Muhammad R. Sohail, MD, Medtronic (Consultant)Philips (Consultant)

THICKEN, THICKEN, THICKEN, DROP: WENCKEBACH SECONDARY TO HYPERTROPHIC CARDIOMYOPATHY

TOPIC: Cardiovascular Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: Wenckebach is an atrioventricular conduction disorder leading to progressively lengthened PR interval followed by dropped beats. Hypertrophic cardiomyopathy (HCM) is a genetic cardiac muscle disease characterized by left ventricular hypertrophy that can cause symptoms that are typically categorized into those from heart failure, chest pain, or arrhythmias. HCM is rarely associated with AV blocks with few case reports describing a connection. We will present a case of second degree AV block Mobitz Type I known as Wenckebach block secondary to HCM. CASE PRESENTATION: The patient is a 63-year-old woman with no significant past medical history reporting to the hospital for substernal chest pressure and lightheadedness. She was found to have symptomatic second degree AV block Mobitz Type I and was scheduled for dual chamber pacemaker. Prior to pacemaker implantation, echocardiogram was obtained that was concerning for left ventricular outflow tract obstruction and takotsubo cardiomyopathy. Left and right heart catheterization was performed that showed no significant coronary artery disease or takotsubo cardiomyopathy. Cardiac MRI was performed that showed features concerning for HCM. The patient underwent successful implantation of automatic implantable cardioverter defibrillator (AICD) with improvement in symptoms. Unfortunately, due to COVID-19 related limitations, further work up of HCM has been delayed including genetic testing. DISCUSSION: Wenckebach block is typically caused by myocardial ischemia, myocarditis, iatrogenic or cardiomyopathy of amyloidosis or sarcoidosis etiology. There is sparse literature discussing HCM causing first degree and complete heart block. Wenckebach block caused by HCM is very rare with only one other significant case found discussing the association. Once Wenckebach is discovered, a thorough work up for the underlying cause must be completed. In our case further work up via echocardiogram and cardiac MRI revealed HCM allowing for appropriate intervention with implantation of an AICD. CONCLUSIONS: Wenckebach block is rarely caused by HCM, but if obvious causes have been ruled out including myocardial ischemia, myocarditis, or iatrogenic then further work up is required. Cardiac imaging including echocardiogram and possibly cardiac MRI may be warranted to determine the underlying cause of the heart block, allowing for appropriate treatment. HCM is a rare cause of Wenckebach block, but must be considered on the differential diagnosis. REFERENCE #1: Wong TC. First-Degree Atrioventricular Block and Hypertrophic Cardiomyopathy: "I Have a Bad Feeling About This". J Am Heart Assoc. 2020 Mar 17;9(6):e015911. doi: 10.1161/JAHA.120.015911. Epub 2020 Mar 9. PMID: 32146897; PMCID: PMC7335525. REFERENCE #2: Dubey L, Guruprasad S, Bhattacharya R, Subramanyam G. Complete Heart Block in Hypertrophic Cardiomyopathy: A Rare Association. Kathmandu Univ Med J (KUMJ). 2015 Oct-Dec;13(52):372-4. doi: 10.3126/kumj.v13i4.16841. PMID: 27423292. REFERENCE #3: Konishi E, Kawasaki T, Shiraishi H, Yamano M, Kamitani T. Additional heart sounds during early diastole in a patient with hypertrophic cardiomyopathy and atrioventricular block. J Cardiol Cases. 2015 Apr 1;11(6):171-174. doi: 10.1016/j.jccase.2015.02.010. PMID: 30546559; PMCID: PMC6281973. DISCLOSURES: No relevant relationships by Anas Ahmed, source=Web Response No relevant relationships by Rebekah Lantz, source=Web Response No relevant relationships by Mark Saling, source=Web Response No relevant relationships by Steven Young, source=Web Response

Microvolt T-Wave Alternans Is Modulated by Acute Low-Level Tragus Stimulation in Patients With Ischemic Cardiomyopathy and Heart Failure.

Aims: Microvolt T-wave alternans (TWA), an oscillation in T-wave morphology of the electrocardiogram (ECG), has been associated with increased susceptibility to ventricular tachy-arrhythmias, while vagus nerve stimulation has shown promising anti-arrhythmic effects in in vivo and ex vivo animal studies. We aimed to examine the effect of non-invasive, acute low-level tragus stimulation (LLTS) on TWA in patients with ischemic cardiomyopathy and heart failure.Methods: 26 patients with ischemic cardiomyopathy (left ventricular ejection fraction <35%) and chronic stable heart failure, previously implanted with an automatic implantable cardioverter defibrillator (ICD) device with an atrial lead (dual chamber ICD or cardiac resynchronization therapy defibrillator), were enrolled in the study. Each patient sequentially received, (1) Sham LLTS (electrode on tragus, but no stimulation delivered) for 5 min; (2) Active LLTS at two different frequencies (5 and 20 Hz, 15 min each); and (3) Active LLTS, during concomitant atrial pacing at 100 bpm at two different frequencies (5 and 20 Hz, 15 min each). LLTS was delivered through a transcutaneous electrical nerve stimulation device (pulse width 200 μs, frequency 5/20 Hz, amplitude 1 mA lower than the discomfort threshold). TWA burden was assessed using continuous ECG monitoring during sham and active LLTS in sinus rhythm, as well as during atrial pacing.Results: Right atrial pacing at 100 bpm led to significantly heightened TWA burden compared to sinus rhythm, with or without LLTS. Acute LLTS at both 5 and 20 Hz, during sinus rhythm led to a significant rise in TWA burden in the precordial leads (p < 0.05).Conclusion: Acute LLTS results in a heart-rate dependent increase in TWA burden.

Surgery for Ventricular Tachycardia.

The treatment of drug-refractory chronic ventricular tachycardia (VT) has undergone a revolution over the last 50 years. We now have automatic implantable cardioverter defibrillator therapy with pace-terminating capabilities, and catheter ablation of VT has refined mapping and improved methods of lesion generation. Between 1980 and 1993, Houston Methodist Hospital became a leader in the diagnosis and surgical ablation of VT and other arrhythmias. This is a brief account of that period and some of the experiences and lessons that have led to significant advances used today.

A Rare Cause of Upper Gastrointestinal Bleeding: Pacemaker Lead Induced Superior Vena Cava Stenosis

Automatic implantable cardioverter-defibrillator (AICD) lead associated superior vena cava (SVC) syndrome is rare, with an incidence of <0.1% [1]. Aetiology is thought to result from mechanical irritation and lead-related foreign body reaction, resulting in fibrosis, thrombus and vessel stenosis. Most patients are asymptomatic, in cases with rapid thrombosis and stenosis, there may be signs of SVC obstruction such as upper limb, neck and facial oedema [2]. Upper gastrointestinal bleeding due to collateral circulation formation is rare [3].

Impact of COVID-19 Pandemic on Physical Activity in Patients With Implantable Cardioverter-Defibrillators.

The coronavirus disease-2019 (COVID-19) pandemic has been spreading rapidly worldwide since late January 2020. The strict lockdown strategy prompted by the Italian government, to hamper severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) spreading, has reduced the possibility of performing either outdoor or gym physical activity (PA). This study investigated and quantified the reduction of PA in patients with automatic implantable cardioverter-defibrillators (ICDs) for primary prevention of sudden death. Daily PA of 24 patients was estimated by processing recorded data from ICD-embedded accelerometric sensors used by the rate-responsive pacing systems. During the forced 40-d in-home confinement, a mean 25% reduction of PA was observed as compared with the 40-d confinement-free period (1.2 ± 0.3 vs 1.6 ± 0.5 hr/d, respectively, P = .0001). This objective quantification of the impact of the COVID-19 pandemic on PA determined by an ICD device showed an abrupt and statistically significant reduction of PA in primary prevention ICD patients, during the in-home confinement quarantine. To counteract the deleterious effects of physical inactivity during the COVID-19 outbreak, patients should be encouraged to perform indoor exercise-based personalized rehabilitative programs.

Challenging Transcatheter Treatment of a “Complex” Refractory Congestive Heart Failure

A 61-year-old man with a history of postischemic dilated cardiomyopathy was referred in advanced congestive heart failure to our department (Department of Cardiology). He had a history of acute inferolateral myocardial infarction complicated by left ventricular (LV) aneurysm treated elsewhere by coronary artery bypass grafts, aneurysm resection, and automatic implantable cardioverter defibrillator implantation a few years before. At the time of admission, he was in functional New York Heart Association class III-IV with signs and symptoms of congestive heart failure and low cardiac output.

69 Treatment Variation of Stable Ventricular Tachycardia in the Emergency Department

Advanced cardiac life support (ACLS) guidelines allow various treatments for stable monomorphic ventricular tachycardia (VT). Research on this topic has been limited by the transient nature of this rhythm, hence most studies have small sample sizes and are difficult to reproduce. The purpose of this study is to compare the relative effectiveness and safety of initial therapies used to treat stable VT across 21 community emergency departments (EDs). This retrospective cohort study used structured chart review of all treated adults with ED presentations for prolonged (>2 min) monomorphic VT in 21 community EDs from 01/2010 through 12/2017. We defined monomorphic VT as a regular wide complex tachycardia (WCT) with QRS >120 ms and rate >120 beats/min. Supraventricular tachycardia with aberrancy was excluded based on Brugada criteria for VT and confirmed by the cardiology consult obtained during the patient encounter. We excluded unstable patients defined as those with an abnormal level of consciousness, dyspnea at rest, severe anginal symptoms, or physician documentation of instability. We used descriptive statistics and reported results at the patient encounter level. We described the incidence of initial treatments, successful termination (defined as VT termination within 20 minutes lasting >30 min), ED cardiac arrest following the initial intervention, and death. We compare outcomes using a two-tailed chi-square test. We analyzed 359 eligible ED presentations from 339 patients. Mean age was 70.0 years and 22.3% of cases were female: 125 (34.8%) had an automated implantable cardioverter-defibrillator (AICD), 185 (51.5%) had congestive heart failure, and 122 (34.0%) were taking chronic antiarrhythmic medications. WCT was evaluated with adenosine in 40 cases (11.1%). Initial VT treatments were intravenous amiodarone (n=196, 54.6%), external direct-current cardioversion [DCC] (n=88, 24.5%), lidocaine (n=30, 8.4%), AICD shock (n=14, 3.9%), procainamide (n=3, 0.8%), and other treatments (n=28, 7.8%). We report initial treatment success in the Table. DCC was significantly more effective than amiodarone (81.8% vs 37.2%; p<0.0001). Overall, 160 presentations (45.1%) required multiple treatments prior to ED disposition. Cardiac arrest was uncommon in this study (2.7%) and could not be associated with specific interventions due to small sample size. Five patients (1.5%) suffered cardiac arrest after the initial ED intervention, four others (1.2%) suffered cardiac arrest in the ED after subsequent interventions, one of whom died in the ED prior to disposition. Emergency physicians use a variety of treatments for stable monomorphic VT with differing rates of success. Amiodarone is the most common initial treatment, but it may be less effective than DCC. Because initial treatments are often ineffective, patients frequently require multiple interventions. Opportunities exist for improvements in care.

Defibrillator-Heart Pump: An Implantable Ventricular Assist Device With Integrated Defibrillator Component-The First In Vitro Testing.

Left ventricular assist devices (LVADs) are an important therapeutic option for patients with end-stage heart failure waiting for heart transplantation or in older patients as definite therapy for heart failure. Interestingly, about 62% of patients receiving LVADs do not have an automatic implantable cardioverter-defibrillator (AICD) at the time of implantation, although these patients have increased risk of being confronted with dangerous arrhythmia. Therefore, an LVAD system including AICD function is a reasonable alternative for such heart failure patients thereby avoiding a second surgical intervention for AICD implantation. In this article, a newly developed system including LVAD and AICD function is introduced, and we also report its first in vitro testing.

Enterobacter Cloacae Device Endocarditis: Case Report, Scoping Study, and Guidelines Review.

While traditionally an infection of the endocardial surface of heart valves, infective endocarditis (IE), can atypically present as infection of cardiac implantable electronic devices (CIED), including permanent pacemakers (PPM) or automatic implantable cardioverter-defibrillators (AICD). CIED endocarditis, similar to valvular IE, is generally caused by Gram-positive organisms such as Staphylococcus spp., most frequently S. Auerus, but is rarely caused by gram-negative bacteria, both HACEK and non-HACEK species. We present the case of Enterobacter cloacae CIED endocarditis. We also present a scoping study of previous case reports and case series highlighting the risk factors, surgical interventions, and mortality outcomes associated with E. Cloacae endocarditis. We also discuss the current guidelines and recommendations on antibiotic therapies for non-HACEK Gram-negative endocarditis and surgical management of infected CIED extraction and replacement.

Twiddler's Syndrome.

Twiddler’s syndrome refers to a rare condition in which a pacemaker or automatic implantable cardioverter-defibrillator (AICD) malfunctions due to coiling of the device in the skin pocket and resultant lead displacement. This image is the chest radiograph (CXR) of a 54-year-old male who presented to the emergency department with chest pain five months after his AICD was placed. The CXR shows AICD leads coiled around the device and the absence of leads in the ventricle consistent with Twiddler’s syndrome. Patients with twiddler’s syndrome should be admitted for operative intervention.

The Role of the Cardioversion Defibrillator in Post Myocardial Infarction Sudden Cardiac Death: A Systematic Review of Clinical Trials and Observational Studies.

Sudden cardiac death (SCD) accounts for approximately half of all the deaths attributed to cardiovascular disease in the United States. Survivors of an acute myocardial infarction (AMI) are at high risk of SCD, largely due to cardiac arrhythmias and severe left ventricular (LV) systolic dysfunction. The implantable cardioverter defibrillator (ICD) or automated implantable cardioverter defibrillator (AICD) is a device that is implantable inside the body, able to perform cardioversion, defibrillation, and (in modern versions) pacing of the heart. According to a study included in our review, patients who received an ICD contributed to an adjusted 44% reduction (hazard ratio [HR] 0.56, 95% CI: 0.32-1.01; P = 0.053) of all-cause mortality compared to those with a comparable baseline. Patients with an ICD implant three months after a myocardial infarction (MI) demonstrated a non-significantly higher mortality than patients who did not receive an ICD. The factors favoring ICD implantation were multiple MIs, increased resting heart rate, occurrence of non-sustained ventricular tachycardia, QRS duration = 120 ms, syncope events, anti-arrhythmic drug treatment (mostly Class III), and an index MI of more than one year. The likelihood of receiving an ICD diminished with the patient’s age. Increased periodic repolarization dynamics were a significant predictor of mortality. It can be concluded that cardioverter defibrillators help reduce not only all-cause mortality but also sudden cardiac death. It is important to note that ICDs are only significant if implanted after a sufficient time-gap post-MI.

Clinical profile, complications, and quality of life in patients undergoing automatic implantable cardioverter-defibrillator implantation in a tertiary care hospital of North India

Background: Despite better understanding of various aspects of Sudden Cardiac Death (SCD), mortality from the disease still remains very high. Coronary artery disease (CAD) is the most common cause of SCD in all parts of India. The American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society (ACC/AHA/HRS) guidelines recommend the use of implantable cardioverter-defibrillator (ICD) therapy as a primary prevention. Aim: The aim of our study was to assess the clinical and demographic profile, complications and quality of life (QOL) of patients undergoing ICD implantation as compared to controls at a tertiary care center of north India. Method: A total of 64 patients with mean age 54.39± 11.54 years were implanted ICD during a period of one year. During the same period, 51 patients in which ICD could not be implanted due to financial reasons were included as controls. Of the 64 patients, 43 (67.19%) patients received ICD for primary prevention whereas 21 (32.81%) patients received it for secondary prevention. Result: At a follow up of 6 months, mortality was 4 (7.84%) in ICD group as compared to 8 (15.69%) in control group. Mortality from SCD in ICD and control group was 2 and 5 respectively (P = 0.23). ICD interrogation data was collected for 37 cases of which 19 (51.35%) patients had records of ventricular tachycardia (VT) and 3 (8.1%) patients had records of ventricular fibrillation (VF) respectively. Total VT/VF episodes recorded in primary prevention group were 10, whereas 12 in secondary prevention group. Success rate of ATP and ICD shocks were 30.23% and 95.92% respectively. All 47 VT/VF episodes were terminated by shocks. Conclusion: The QOL of patients undergoing ICD implant was better in the domains of social relationship and environment though the difference was not significant statistically. Overall, there was a significant reduction in SCD mortality and no deterioration in QOL.

Double de novo mutations in dilated cardiomyopathy with cardiac arrest

Here we report the identification of two novel mutations in a previously asymptomatic young man who suffered an out-of-hospital sudden cardiac arrest. During following evaluation, diagnosis of early stage dilated cardiomyopathy was established, while electrocardiogram monitoring showed frequent complex ventricular arrhythmias, incomplete right bundle branch block and prolonged QT duration. No reversible causes explaining the clinical presentation were established and an automatic implantable cardioverter defibrillator was therefore implanted.Heterozygous mutations in human protein coding genes NKX2-5 and RBM20 are associated with a wide array of pathological phenotypes some of which are sudden cardiac death, unexplained syncope and either combined or isolated congenital heart diseases such as dilated cardiomyopathy.