Hypoplastic Coronary Artery Disease Presenting with Ventricular Fibrillation Cardiac Arrest.

Hypoplastic coronary artery disease is a rare congenital anomaly that may present with ischaemic heart disease, heart failure or sudden cardiac death (SCD). We describe a case of cardiac arrest in a healthy young man. Work-up revealed a hypoplastic left anterior descending artery. The patient underwent cardioverter-defibrillator implantation for secondary prevention. LEARNING POINTS: Hypoplastic coronary artery disease (HCAD) is a rare cause of cardiac arrest and should be suspected in cases of sudden cardiac death (SCD) in young adults.The mechanism in HCAD leading to ventricular fibrillation cardiac arrest is not well understood.Implantable cardioverter-defibrillator (ICD) implantation is recommended for secondary prevention of ventricular fibrillation.

Cardiac Resynchronization Therapy and Clinical Outcomes in Continuous Flow Left Ventricular Assist Device Recipients.

BACKGROUND: Many patients with heart failure continue cardiac resynchronization therapy (CRT) after continuous flow left ventricular assist device (CF-LVAD) implant. We report the first multicenter study to assess the impact of CRT on clinical outcomes in CF-LVAD patients. METHODS AND RESULTS: Analysis was performed on 488 patients (58±13 years, 81% male) with an implantable cardioverter defibrillator (ICD) (n=223) or CRT-D (n=265) who underwent CF-LVAD implantation at 5 centers from 2007 to 2015. Effects of CRT on mortality, hospitalizations, and ventricular arrhythmia incidence were compared against CF-LVAD patients with an ICD alone. Baseline differences were noted between the 2 groups in age (60±12 versus 55±14, P<0.001) and QRS duration (159±29 versus 126±34, P=0.001). Median biventricular pacing in the CRT group was 96%. During a median follow-up of 478 days, Kaplan-Meier analysis showed no difference in survival between groups (log rank P=0.28). Multivariate Cox regression demonstrated no survival benefit with type of device (ICD versus CRT-D; P=0.16), whereas use of amiodarone was associated with increased mortality (hazard ratio 1.77, 95% confidence interval 1.1-2.8, P=0.01). No differences were noted between CRT and ICD groups in all-cause (P=0.06) and heart failure (P=0.9) hospitalizations, ventricular arrhythmia incidence (43% versus 39%, P=0.3), or ICD shocks (35% versus 29%, P=0.2). During follow-up, 69 (26%) patients underwent pulse generator replacement in the CRT-D group compared with 36 (15.5%) in the ICD group (P=0.003). CONCLUSIONS: In this large, multicenter CF-LVAD cohort, continued CRT was not associated with improved survival, hospitalizations, incidence of ventricular arrhythmia and ICD therapies, and was related to a significantly higher number of pulse generator changes.

Implantable Cardiac Monitors: Evolution Through Disruption.

Syncope and stroke are commonly seen in clinical practice, and the diagnostic workup is often time-consuming and costly and may increase resource utilization in the health-care system. The use of implantable cardiac monitors (ICMs) in syncope evaluation has been well studied, but their use in cryptogenic stroke evaluation and anticoagulation management in patients with atrial fibrillation (AF) is still emerging. The standard workup of the syncope patient or those at risk for a possible cardioembolic stroke includes the utilization of external cardiac monitors; however, these devices cannot provide long-term arrhythmia assessment, whereas ICMs can now last up to three years, increasing the possibility of arriving at a diagnosis. Recent studies have shown that ICM use may shorten the time to diagnosis associated with AF, which may affect the prescribed treatment plan, thereby reducing the risks of further stroke. Long term and on a larger scale, this could potentially reduce overall health-care costs, but more studies are needed to confirm whether ICMs can positively decrease such costs and improve patient care. Still, these devices have become smaller and more reliable; additionally, they are now equipped with enhanced diagnostic capabilities, reducing the likelihood of physicians being confronted with an overwhelming amount of data, and supplying them with actionable items to improve patient care. With this growth, ICMs have in effect become a disruptive technology, as their applications in clinical practice continue to grow. Additional studies are warranted to investigate the safety and efficacy of their potential uses.

A Randomized, Placebo-Controlled Trial of Omega-3 Fatty Acids for Inhibition of Supraventricular Arrhythmias After Cardiac Surgery: The FISH Trial.

BACKGROUND: Omega-3 polyunsaturated fatty acids (n3-PUFAs) might have antiarrhythmic properties, but data conflict on whether n3-PUFAs reduce rates of atrial fibrillation (AF) after coronary artery bypass graft surgery (CABG). We hypothesized that n3-PUFAs would reduce post-CABG AF, and we tested this hypothesis in a well-powered, randomized, double-blind, placebo-controlled, multicenter clinical trial. METHODS AND RESULTS: Patients undergoing CABG were randomized to pharmaceutical-grade n3-PUFAs 2 g orally twice daily (minimum of 6 g) or a matched placebo ≥24 hours before surgery. Gas chromatography was used to assess plasma fatty acid composition of samples collected on the day of screening, day of surgery, and postoperative day 4. Treatment continued either until the primary end point, clinically significant AF requiring treatment, occurred or for a maximum of 2 weeks after surgery. Two hundred sixty patients were enrolled and randomized. Before surgery, n3-PUFA dosing increased plasma n3-PUFA levels from 2.9% to 4% and reduced the n6:n3-PUFA ratio from 9.1 to 6.4 (both P<0.001). Similar changes were noted on postoperative day 4. There were no lipid changes in the placebo group. The rate of post-CABG AF was similar in both groups (30% n3-PUFAs versus 33% placebo, P=0.67). The post-CABG AF odds ratio for n3-PUFAs relative to placebo was 0.89 (95% confidence interval 0.52-1.53). There were no differences in any secondary end points. CONCLUSIONS: Oral n3-PUFA supplementation begun 2 days before CABG did not reduce AF or other complications after surgery. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov Unique identifier: NCT00446966. (J Am Heart Assoc. 2012;1:e000547 doi: 10.1161/JAHA.111.000547.).

Older persons with diabetes receive fewer inappropriate ICD shocks: results from the INTRINSIC RV trial.

In patients with heart disease, diabetes and age predict adverse outcomes. It remains unclear whether persons with diabetes who have implantable cardioverter defibrillators (ICDs) have fewer appropriate and inappropriate ICD shocks. The objective of this study is to determine if persons with diabetes who have ICDs receive a similar amount of appropriate and inappropriate shocks compared to persons without diabetes. In a post hoc analysis of 1,528 patients enrolled in the INTRINSIC RV trial, all-cause mortality and ICD shocks between persons with and without diabetes, stratified by age, was compared. The relationship between shock and mortality was also assessed. Mortality 1 year after ICD implant was lower for persons without diabetes vs. persons with diabetes (3.5% vs. 7.9%, p < 0.001). Young and old persons with diabetes received a similar number of total and appropriate ICD shocks. However, older persons with diabetes were less likely to receive inappropriate ICD shocks vs. older persons without diabetes (1.9% vs. 6.9%, p < 0.01). ICD shocks were not temporally related to mortality regardless of diabetes status. In the INTRINSIC RV trial, persons with diabetes and older persons without diabetes undergoing ICD implant were at a higher risk of death. Older persons with diabetes received less inappropriate shocks and still had a similar amount of appropriate shocks compared to persons without diabetes of similar age.

The dual role of implantable loop recorder in patients with potentially arrhythmic symptoms: a retrospective single-center study.

BACKGROUND: Unexplained and potentially arrhythmic symptoms often lead to electrophysiology referral for evaluation. Implantable loop recorder (ILR) correlation of the symptom to the rhythm can secure a definitive arrhythmic diagnosis after a standard, yet nondiagnostic workup. METHODS: This large single-center retrospective study sought to assess the role of ILR in the evaluation of potentially arrhythmic symptoms, both in terms of diagnosis of an arrhythmia as well as to rule out an arrhythmic cause. Clinical data, indications for ILR, interrogation reports, and further management strategies were collected in all 86 patients who received ILR from June 1999 to April 2008 at the University of Iowa Hospitals and Clinics. The indications for ILR were unexplained syncope (76%), palpitations (14%), and presyncope or dizziness (10%). RESULTS: During a mean follow-up period of 10 +/- 7 months, 53 patients (62%) had recurrent symptoms after ILR placement with the mean time to recurrence of 12 +/- 17 weeks. Of these, an arrhythmic diagnosis was established in 12 patients (14%). Forty-one patients (48%) did not have any arrhythmia during their symptoms. These patients were discharged from the electrophysiology clinic. Thirty-three patients (38%) did not have any symptoms following ILR placement. Out of these, device was explanted in 10 patients, while the rest are still being followed. CONCLUSIONS: In patients with potentially arrhythmic symptoms, ILR plays an important role not only in diagnosing an arrhythmia, but also to rule out an arrhythmic cause.

Not so innocent bystander(s).

A patient with atrial flutter, intermittent non-sustained wide complex tachycardia and 1:1 AV conduction is reported. Electrophysiology testing showed counterclockwise isthmus-dependent right atrial flutter with conduction via the AV node and an innocent bystander left lateral accessory pathway. This explained the observed intermittent wide complex tachycardia. After successful bidirectional cavotricuspid isthmus conduction block, a sustained wide complex tachycardia with identical counterclockwise right atrial activation and rate occurred. This was due to antidromic AV re-entrant tachycardia with innocent bystander activation of the right atrium mimicking atrial flutter. Accessory pathway ablation effectively stopped tachycardia.

Antiarrhythmic effects of statins in heart failure.

In vitro heart failure models indicate that statins may be antiarrhythmic, but the mechanisms by which statins are antiarrhythmic are not completely understood. Several retrospective and post hoc analysis studies also indicate that statins can be antiarrhythmic in heart failure populations, but this was not confirmed by a recent large prospective randomized controlled clinical trial. Ongoing and future clinical trials will likely resolve the discrepancies between studies and further the understanding of how pleiotropic properties of statins can be antiarrhythmic in patients who have heart failure.