Biventricular Implantable Cardioverter-defibrillator Research Articles

Traumatic Tension Pneumothorax as a Cause of ICD Failure: A Case Report and Review of the Literature.

Background. Tension pneumothorax can infrequently cause ventricular arrhythmias and increase the threshold of defibrillation. It should be suspected whenever there is difficulty in defibrillation for a ventricular arrhythmia. Purpose. To report a case of traumatic tension pneumothorax leading to ventricular tachycardia and causing defibrillator failure. Case. A 65-year-old African-American female was brought in to our emergency department complaining of dyspnea after being forced down by cops. She had history of mitral valve replacement for severe mitral regurgitation and biventricular implantable cardioverter defibrillator inserted for nonischemic cardiomyopathy. Shortly after arrival, she developed sustained ventricular tachycardia, causing repetitive unsuccessful ICD shocks. She was intubated and ventricular tachycardia resolved with amiodarone. Chest radiograph revealed large left sided tension pneumothorax which was promptly drained. The patient was treated for congestive heart failure; she was extubated on the third day of admission, and the chest tube was removed. Conclusion. Prompt recognition of tension pneumothorax is essential, by maintaining a high index of suspicion in patients with an increased defibrillation threshold causing ineffective defibrillations.

Wide QRS Complex Tachycardia in a Patient with a Biventricular Implantable Cardioverter Defibrillator: What is the Mechanism?

Wide QRS Complex Tachycardia in a Patient with a Biventricular Implantable Cardioverter Defibrillator: What is the Mechanism?

Hyperkalemia and Rhabdomyolysis With Succinylcholine Used for Rapid Sequence Intubation

Objective: Succinylcholine, a depolarizing neuromuscular blocker used during intubation, has a black box warning for use in pediatric patients due to the risk of rhabdomyolysis, hyperkalemia, ventricular arrhythmias, and cardiac arrest in patients with skeletal muscle myopathy. Though the warning does not exist for adult patients, succinylcholine is commonly used in adults, who may still be at risk for the same complications. Our objective is to present the case of an adult patient experiencing rhabdomyolysis, hyperkalemia, and cardiac arrest after the administration of succinylcholine for rapid sequence intubation. Case Summary: We describe the hospital course of a 58-year-old patient admitted for the placement of a biventricular implantable cardioverter defibrillator. The patient received etomidate, fentanyl, isoflurane, midazolam, and succinylcholine during rapid sequence intubation. During intubation for the procedure and shortly after the administration of succinylcholine, the patient went into asystole and arrested. After several arrhythmias and periods of cardiac arrest, the patient was stabilized, and the procedure completed. Shortly after the procedure, the patient developed hyperkalemia, rhabdomyolysis, and acute kidney injury and ultimately expired. Discussion: Though reports of adverse reactions to succinylcholine are less common in adults without underlying muscular disorders, this phenomenon has been reported in the literature. There is the potential that this patient may have had an underlying myopathy that was previously undiagnosed or could have experienced malignant hyperthermia. The Naranjo adverse drug reaction probability scale for this case is 5, which is considered probable. Conclusions: Though uncommon, succinylcholine is a potential cause of hyperkalemia, rhabdomyolysis, and cardiac arrest in susceptible adult patients.

The pacemaker and implantable cardioverter-defibrillator registry of the Italian Association of Arrhythmology and Cardiac Pacing - Annual Report 2012

The pacemaker (PM) and implantable cardioverter-defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) monitors the main epidemiological data in real-world practice. The survey for the 2012 activity collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the Italian collaborating centers. The Registry collects prospectively national PM and ICD implantation activity on the basis of European cards. PM Registry: data about 25 611 PM implantations were collected (18 870 first implant and 6741 replacements). The number of collaborating centers was 245. Median age of treated patients was 80 years (74 quartile I; 86 quartile III). ECG indications included atrioventricular conduction disorders in 41.9% of first PM implants, sick sinus syndrome in 26.0%, atrial fibrillation plus bradycardia in 13.7%, other in 18.4%. Among atrioventricular conduction defects, third-degree atrioventricular block was the most common type (21.7% of first implants). Use of single-chamber PMs was reported in 29.0% of first implants, of dual-chamber PMs in 61.3%, of PMs with cardiac resynchronization therapy (CRT) in 1.7%, and of single lead atrial-synchronized ventricular stimulation (VDD/R PMs) in 8.0%. ICD REGISTRY: data about 16 606 ICD implantations were collected (11 393 first implants and 5213 replacements). The number of collaborating centers was 427. Median age of treated patients was 71 years (62 quartile I; 77 quartile III). Primary prevention indication was reported in 68.6% of first implants, secondary prevention in 31.4% (cardiac arrest in 9.0%). A single-chamber ICD was used in 29.4% of first implants, dual-chamber in 37.6% and biventricular in 32.9%. The PM and ICD Registry appears fundamental for monitoring PM and ICD utilization on a large national scale with rigorous examination of demographics and clinical indications. The PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The use of CRT-PM regards a very limited number of patients. The ICD Registry documented a constant increase in prophylactic and biventricular ICD use, reflecting a favorable adherence to trials and guidelines in clinical practice.

Near Zero Fluoroscopic Implantation of BIV ICD Using Electro‐anatomical Mapping

Biventricular (BIV) implantable cardioverter defibrillator (ICD) implantations are traditionally performed using fluoroscopic guidance, exposing both patients and laboratory staff to the risks of radiation. Three-dimensional (3D) electro-anatomical mapping (EAM) has been used in limited reports with modest decrease in fluoroscopy time in adjunct to standard use of contrast. The purpose of this study was to evaluate the feasibility of EAM in BIV ICD implantation with near zero use of fluoroscopy and contrast. Retrospective analysis was performed in two patient groups (both n = 10): (1) the near zero fluoroscopy (NZF) group consisting of consecutive adult patients, in which BIV implantation was accomplished by EAM; and (2) the fluoroscopy (F) group, in which BIV implantation was additionally guided by fluoroscopy and contrast use. The same operator performed all procedures with a step-by-step approach detailed below. Complications were limited to one patient in the standard (F) group who had a pneumothorax related to difficult access with occluded collateralized subclavian vein and small hematoma with no intervention required. Another patient in the NZF group had lead revision with an extra 0.5 minutes of fluoroscopy related to microdislodgement secondary to body habitus and postural changes. This NZF technique was feasible and effective in near elimination of contrast use, as well as in decreasing fluoroscopy exposure to as low as 0.1 minutes or near zero exposure. We also highlighted the technique in detailed step-by-step approach. It was also discovered that 3D mapping does not increase procedure time. In fact there was a tendency toward shortening the procedure time, further demonstrating the feasibility of this technique for the implantation of BIV ICD. Acute procedural success, complications, and clinical outcome were comparable in both groups.

Ventricular Arrhythmias After Left Ventricular Assist Device

Despite advances in medical therapy, heart failure remains one of the major causes of hospitalizations and deaths in the United States. Approximately 5.7 million patients have heart failure, and it is the direct cause of death for 57 000 individuals annually.1 Although the combination of optimal medical therapy, implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy has reduced mortality rates, an estimated 50% of patients with heart failure still die within 5 years of diagnosis.1 Heart transplant is often the best therapeutic option for patients with end-stage heart failure; however, there has been a stable plateau of ≈2200 transplants/y in the United States due largely to limitations in organ availability.1 For patients who are facing unfavorably long wait times for heart transplantation, left ventricular assist devices (LVAD) have become a lifesaving option as a bridge to transplant. Currently, one quarter to one third of all heart transplant recipients are bridged with mechanical circulatory support before transplantation.2 Much of this support is in the form of permanent LVADs—surgically implanted mechanical assist devices that unload the left ventricle and can function in ambulatory patients (Figure 1). The use of permanent LVADs as destination therapy has increased dramatically, with evidence that they benefit patients with end-stage heart failure, despite noncandidacy for heart transplantation. Since the seminal Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure destination therapy trial in 2001, ≈1578 destination therapy LVADs have been implanted, with implant rates increasing rapidly.3,4 Figure 1. Examples of implantable cardioverter-defibrillators (ICDs) with 2 different types of left ventricular assist devices (LVADs). Posterior-anterior chest x-ray projections of biventricular ICDs in the presence of HVAD ( A ) and Heartmate II ( B ) models of LVAD. Development of LVADs dates to 1969 when the world’s first total artificial heart was implanted by Dr …

An Unusual Case of Combined Classic and Reverse Twiddler's Syndrome

In recent years the phenomenon of reverse twiddler's syndrome has been described, characterized by pulse generator manipulation resulting in lead advancement rather than retraction. We describe what we believe to be the first reported case of both classic and reverse twiddler's syndrome occurring simultaneously in a patient with a biventricular implantable cardioverter-defibrillator.

Pacing alternans during broad complex tachycardia

Case summary A 56-year-old man with a history of myocardial infarction, left bundle branch block, and severe left ventricular systolic dysfunction (ejection fraction of 30%) underwent implantation of a biventricular implantable cardioverter-defibrillator (Medtronic Protecta D364TRG, Minneapolis, MN). The patient was referred to our institution for the implantation of a left ventricular lead following an unsuccessful attempt. Device check revealed a P wave of 2.4 mV, R wave of 11 mV, and satisfactory pacing thresholds and lead impedance. Shortly after presentation, the patient complained of palpitations and breathlessness. Electrocardiogram showed a regular broad complex tachycardia at a cycle length of 480 ms with intermittent pacing spikes (Figure 1). The programmed parameters were as follows: Pacing mode: DDD; Lower rate: 80 beats/min; Upper track rate: 130 beats/min; Paced/sensed atrioventricular (AV) delay: 350 ms; Mode switch: 171 beats/min; Ventricular safety pacing (VSP): ON; Noncompetitive atrial pacing: ON; Ventricular fibrillation detection: 188 beats/min; Ventricular tachycardia detection: 150 beats/min (monitor); What is the cause of the intermittent pacing stimuli?

Refractory ventricular fibrillation during bi-ventricular implantable cardioverter defibrillator implantation: a case report of successful cardioversion only with a left ventricular defibrillator lead

A 63-year-old male with ischaemic cardiomyopathy, New York Heart Association III and an ejection fraction of 25% had a bi-ventricular implantable cardioverter defibrillator (CRT-D) implant. The procedure was performed under general anaesthesia and during the placement of the defibrillator lead he went into spontaneous ventricular fibrillation …

Significance of Leukocytosis After Cardiac Device Implantation

Infection remains a feared complication after cardiac device implantation. Whether early postprocedural leukocytosis, a recognized marker of infection, is an indicator of impending infection is unclear and was the focus of this study. A retrospective chart review of consecutive patients who underwent implantable cardioverter defibrillator or pacemaker implantation was performed. The association between change in white blood cell (WBC) count and development of infection after device implantation was assessed. Infection was defined as pocket or lead infection or as bacteremia or sepsis <60 days after implantation. Pre- and postprocedural WBC counts were obtained within 48 hours of the procedure. Significant leukocytosis was defined as a ≥50% increase in WBC count; 1,245 device implantations met inclusion criteria. Device-related infections occurred in 8 cases (0.6%). A modest 17.6 ± 30.2% increase in WBC count was observed for the entire cohort. Cases resulting in infection demonstrated minimal change in WBC count (mean+5.5 ± 26.5%). No infections occurred in patients with ≥50% increases in WBC count or postprocedural WBC counts >15,000/μl. Subjects with significant leukocytosis were younger (mean age 61.9 ± 16.5 vs 65.6 ± 15.1 years, p <0.01), had longer procedure times (mean 198 ± 97 vs 170 ± 77 minutes, p <0.001), and received biventricular implantable cardioverter-defibrillators (25% vs 13.9%, p <0.001). In conclusion, after device implantation, a ≥50% increase in WBC count occurred in about 10% to 15% of patients. Age, race, type of device, and procedure time influenced the development of significant leukocytosis. Elevation in WBC count after cardiac device implantation was not associated with an increased risk for early infection.

Mycobacterium fortuitum causing infection of a biventricular pacemaker/implantable cardioverter defibrillator

Increased utilization of cardiovascular implantable electronic devices (CIED) has seen a corresponding rise in related infections. Non-tuberculosis mycobacteria (NTM) are rarely the cause. Treatment involves susceptibilities, antimicrobials, and device removal. This study presents a patient who underwent a biventricular implantable cardioverter defibrillator upgrade with a multi-drug resistant Mycobacterium fortuitum located at the pocket site and a lead infection.

Implantation of cardioverter-defibrillator: Effects on shoulder function

BackgroundSubcutaneous almost substituted subpectoral approach of implantable cardioverter-defibrillator (ICD) implantation as a less invasive surgical technique. However, the impact of this change in placement site on procedure-related shoulder impairment is poorly understood. MethodsCandidates for ICD implantation were prospectively evaluated at baseline, 2-weeks and 3-months after the procedure. Assessment of shoulder function included: Constant Score, Numeric Rating Scale (NRS) for pain and the Disability of the Arm, Shoulder and Hand (DASH) scoring method. The Short Form-36 (SF-36) questionnaire was adopted for quality of life. ResultsFifty consecutive patients were enrolled (21 single-chamber, 5 dual-chamber and 24 biventricular ICD). Significant changes in the short term were observed: physical component summary (regarding SF-36) decreased from 44.5±9.1 to 41.8±11.4 (p=0.016), patients with NRS >1 increased from 14% to 44% (p<0.001), DASH score increased from 1.29 [interquartile range 0.00–10.34] to 30.60 [interquartile range 12.93–46.34] (p<0.001). Notably, only the shoulder ipsilateral to implantation site presented a decrease in Constant Score (76.00 [interquartile range 61.37–86.87] vs. 95.75 [interquartile range 91.37–98.00]; p<0.001). After three months most of the parameters seemed to have recovered, except for range of motion. Procedure-related increase in pain (i.e. NRS increase ≥1 point) was the most important independent predictor of shoulder impairment, in terms of Constant Score modification (r=0.570; p<0.001). ConclusionsICD implantation is frequently associated with ipsilateral shoulder impairment which tends to recover within 3-months. These data positively compare with the subpectoral approach and should be considered for future research regarding impact of ICD implant on physical well-being and quality of life.

The Implantable Cardioverter-Defibrillator Minimalist

The implantable cardioverter-defibrillator (ICD) was devised to satisfy the unmet need for an effective, instantaneous therapy to prevent sudden cardiac death (SCD) due to ventricular fibrillation (VF) in at-risk, ambulatory patients. That therapy was a high-voltage electric shock delivered directly into the heart muscle. More than 3 decades later, shocks are still the defining operating characteristic of ICDs, and no other instantaneously effective therapy for VF exists. This elite status was clinched by large randomized clinical trials1,2 which demonstrated that ICDs improved mortality in patients with reduced left ventricular ejection fraction, regardless of pathogenesis or accompanying symptoms of heart failure (HF), by primary prevention of SCD due to ventricular tachyarrhythmia (VTA). Like bradycardia pacemakers for asystole, the ICD resides as a therapy genre of one, with no peer, and no competitor on the horizon. These sibling therapies for lethal heart rhythm disturbances will stand prominently among the greatest medical achievements of the 20th century. The ICD is a mature technology, and neither the technique nor the tools have changed much for several decades. Despite a certain evolutionary elegance of the operating system, the ICD is still a blunt instrument. Although it is true that some innovation has occurred, it is still a matter of a shock delivered by insulated metal conductors residing somewhere in direct proximity to the heart. No innovation beyond the fundamental of a timed shock for VF has proven to enhance mortality benefit. The basic design persists simply because no one can think of a suitable alternative and the self-satisfying aphorism that “shocks save lives.” Yet there is a growing intellectual dissatisfaction with the unintended consequences of this powerful, irreplaceable therapy. The stimulus for this self-inspection is an awareness of the very high morbidity risk overhead borne by the primary prevention patient, in particular, …

Biventricular Defibrillator Patients Have Higher Complication Rates after Revision of Recalled Leads

Since the 2009 revised advisory statement regarding Sprint Fidelis® Defibrillator Lead failure rates (Medtronic Inc., Minneapolis, MN, USA), there has been a significant increase in revision of these leads. We sought to establish the frequency of major procedural complications and determine what patient characteristics were associated with these outcomes. We retrospectively reviewed the charts of 621 patients with Fidelis® leads being followed in the University of Pittsburgh Medical Center through January 1, 2010. The population was then examined for rates of lead malfunction, revision, and complication. The average time from implantation of Fidelis® lead to endpoint was 32 ± 16 months. Overall lead survival rates were 89% at 41 months and were lower in biventricular implantable cardioverter defibrillator (BiVICD) as compared to standard implantable cardioverter defibrillator patients (log rank P = 0.053). Prophylactic revisions increased dramatically during 2009 (9.4% vs 1.4%, P < 0.001). Among the 131 patients who underwent revision during the entire time of follow-up, 11 patients had postoperative complications (8.5%). The only significant variable found between patients who did and did not have complications was the presence of a BiVICD (81.8 vs 48.7%, P = 0.036). Of the 40 total patients who underwent lead extraction, all three complications occurred in patients with BiVICDs. The number of prophylactic Fidelis® lead revisions has increased dramatically since 2008, and procedure-related complications have been higher than anticipated. Major procedural complication rates are greater among patients with BiVICDs. Overall, lead extraction does not appear to increase procedural risk as compared to abandonment.

Abrupt bradycardia and grouped beating during treadmill testing: A mimic of upper rate behavior

p t t Case summary A 67-year-old man with a biventricular implantable cardioverter-defibrillator (Medtronic Concerto C1540WK) presented for exercise treadmill testing. The patient had an ischemic cardiomyopathy and prior anterior infarction with a left ventricular ejection fraction of 25%. One year prior to this presentation, the patient presented with sustained monomorphic ventricular tachycardia and had catheter ablation for ventricular tachycardia, followed by implantation of the current device. An exercise treadmill test (ETT) was performed by using a ramp protocol. During the ETT, at peak exercise, his peak heart rate abruptly dropped and the ETT was stopped (data not shown). The device was again interrogated Programmed settings and measurements are shown in Table 1; the lower rate limit was 60 beats/min. No alerts or episodes were recorded during the ETT. To assess device function, the ETT was repeated with wireless device telemetry engaged. The preexercise 12-lead electrocardiogram and device rhythm strip at rest are shown in Figure 1A, demonstrating baseline atrial-paced and biventricular-paced rhythm. Figure 1B shows electrograms (EGMs) measured on the right ventricular channel of the device and the marker channel during early exercise. During the ETT, the abrupt bradycardia was again observed, this time with a drop from the peak heart rate of 107 to 56 beats/min (Figure 2). Stress testing was quickly terminated,

Abstract P110: Medicare/Medicaid Patients are at Increased Risk for Death after Prophylactic Implantable Cardioverter-Defibrillator Implantation

Background: If reliable predictors of mortality after prophylactic implantable cardioverter-defibrillator (ICD) implantation were identified, this information could be used to target this therapy to patients (pts) who are most likely to benefit. Methods: The study population consisted of 584 pts who received an ICD for primary prevention from 3/06 to 12/09 at a single center. Clinical and demographic variables were obtained from the ACC-NCDR ICD Registry data. Vital status was obtained from clinic records and the Social Security Death Index. Univariate and multivariable Cox analysis were used to identify significant predictors of mortality. Results: The pts were 76% male with mean age 69±13 yrs. There were 89 deaths after 590±400 days of follow-up. Insurance type was a significant predictor of mortality (p=0.015, figure). Pts with Medicare/Medicaid (M) had more high risk features such as older age, worse renal function, more advanced heart failure, prior stroke, prior bypass surgery, and were more likely to receive biventricular ICDs. After adjustment for these factors, M was independently associated with decreased survival as compared to Commercial (adjusted HR 0.26, p=0.005) but not Health Maintenance Organization (HMO, adjusted HR 0.69, p=0.24). Conclusions: M insurance is independently associated with increased mortality after prophylactic ICD implantation. Additional research is needed to determine if this finding is attributable to quality of care or decreased access to medical services.

Quantitative Assessment of Artifacts on Cardiac Magnetic Resonance Imaging of Patients With Pacemakers and Implantable Cardioverter-Defibrillators

The safety and clinical utility of MRI at 1.5 T in patients with cardiac implantable devices such as pacemakers (PM) and implantable cardioverter-defibrillators (ICD) have been reported. This study aims to evaluate the extent of artifacts on cardiac magnetic resonance (CMR) in patients with PM and ICD (PM/ICD). A total of 71 CMR studies were performed with an established safety protocol in patients with prepectoral PM/ICD. The artifact area around the PM/ICD generator was measured in all short-axis (SA), horizontal (HLA), and vertical long-axis (VLA) SSFP cine planes. The location and extent of artifacts were also assessed in all SA (20 sectors per plane), HLA, and VLA (6 sectors per plane) late gadolinium-enhanced CMR (LGE-CMR) planes. The artifact area on cine CMR was significantly larger with ICD versus PM generators in each plane (P<0.001, respectively). In patients with left-sided ICD or biventricular ICD systems, the percentages of sectors with any artifacts on LGE-CMR were 53.7%, 48.0%, and 49.2% in SA, HLA, and VLA planes, respectively. Patients with left-sided PM or right-sided PM/ICD had fewer artifacts. Anterior and apical regions were severely affected by artifact caused by left-sided PM/ICD generators. In contrast to patients with right-sided PM/ICD and left-sided PM, the anterior and apical left ventricle can be affected by susceptibility artifacts in patients with left-sided ICD. Artifact reduction methodologies will be necessary to improve the performance of CMR in patients with left sided ICD systems.

Video-Assisted Implantation of a Left Ventricular Lead and Intrathoracic Tunneling to a Right-Sided CRT-D Device

We describe two cases in which a biventricular implantable cardioverter defibrillator for cardiac resynchronization therapy had to be placed on the right side due to unsuitability of the left subclavian vein. Endocardial implantation of a left ventricular lead through the coronary sinus was previously attempted but was unsuccessful. Implantation of the epicardial left ventricular pacing lead was performed through video-assisted thoracic surgery on the left side. The connector end of the left ventricular pacing lead was tunnelized through the anterior mediastinum into the right pleural space. The right-sided pocket was then opened. A tunnel was created from the pocket to the thoracic wall, and the pleural space was entered over the second rib. The lead was retrieved from the right pleural space and connected with the Cardiac resynchronization therapy-device (CRT-D). Both procedures and postoperative periods were uneventful. Intrathoracic left-to-right tunneling of an epicardial left ventricular lead by video-assisted thoracic surgery is feasible and safe. It provides an alternative to subcutaneous tunneling.

Implantation of a biventricular implantable cardioverter-defibrillator guided by an electroanatomic mapping system

AimsThe aim of this study is to show the feasibility of a biventricular implantable cardioverter-defibrillator [cardiac resynchronization therapy (CRT)–ICD] implantation using an electroanatomic navigation system and a low dose of fluoroscopy. Here four case reports of patients affected by dilated cardiomyopathy, who underwent cardiac resynchronization therapy, are described.Methods and resultsDuring 2010, four patients were admitted to our Cardiology Department for implantation of an CRT–ICD device in primary prevention. All had an ejection fraction of <35% and were in New York Heart Association class III despite optimal medical therapy. The implantations were performed using the EnSite NavX system. All the leads were positioned in the cardiac chambers utilizing the three-dimensional navigation system and only using X-ray to check that the leads had been positioned correctly. To our knowledge, these cases are the first use of an electroanatomic system for implantation of an CRT–ICD device and in all four cases the cannulation of the coronary sinus (CS) was performed only using the mapping system. Electroanatomic navigation made it possible to minimize X-ray exposure during the implantation of the CRT–ICD device; in addition, the mapping system was used to choose the optimum position of the CS catheter using as reference the maximum activation delay between the two ventricles.ConclusionsThe NavX system shows great potential during the implantation of an CRT–ICD device. It seems to be feasible, safe, and extremely beneficial in terms of a reduction in X-ray exposure. Furthermore, there is benefit of more detailed information and accuracy during the CS lead placement.

ICD Implantation May Increase Heart Failure Admissions in Patients with Left Ventricular Systolic Dysfunction Who Demonstrate Reverse Remodeling

In patients with an implantable cardioverter defibrillator (ICD), worsening heart failure (HF) is an important cause of death. Patients who demonstrate reverse remodeling (RR) have fewer admissions for HF, however, the effect of an ICD implant on HF outcomes in this group is not known. The aim of our study was to evaluate whether an ICD implant affects the likelihood of heart failure hospitalizations in patients who subsequently demonstrate RR compared to those who do not. Consecutive patients (n = 600) with newly documented LVEF ≤ 0.35 with at least one follow up echocardiogram ≥ 3 months later were identified. We excluded patients with ICDs implanted prior to enrollment and for secondary prevention (n=72), and those with a bi-ventricular ICD (n= 25). RR was defined as an increase in LVEF to > 0.35. Patients who demonstrated reverse remodeling (RR group) (n = 246) and those who did not (No-RR group) (n = 257) were evaluated. In each group, the subset with and without an ICD were compared for the likelihood of a future HF hospitalization using Cox-proportional hazard analysis. In patients who had an ICD, HF admissions prior to receiving the ICD were censored. Mean follow up period was 27 months. Overall, patients in the RR group compared to the No-RR group had fewer annualized HF admissions per patient (0.15 vs. 0.43, p< 0.001). In the No-RR group, survival free-from-HF admissions was similar between the ICD (n= 71) and No ICD (n = 186) subgroups (HR 1.0; 95% CI 0.7- 1.6; p NS). However, in the RR group, patients in the ICD subgroup (n= 13) had increased HF admissions demonstrated by a trend towards reduced survival-free-from-HF admissions (HR 0.54; 95% CI 0.2-1.4; p = 0.07) when compared to the No ICD subgroup (n = 233). In patients with LV systolic dysfunction without reverse remodeling, HF admissions were unaffected by ICD implantation. On the contrary, in patients who demonstrated reverse remodeling, there was an important trend towards increased HF admissions following ICD implantation. This trend is concerning and needs further evaluation in a larger population.