Prognostic impact of thyroid stimulating hormone levels in patients with cardiomyopathy.

Background: Thyroid stimulating hormone (TSH) abnormalities have been associated with various cardiac arrhythmias. Effect of TSH abnormalities on mortality and implantable cardioverter defibrillators (ICD) behavior in patients with cardiomyopathy has not been investigated.

Methods: Our ICD database includes 1,445 patients between December 1997 and January 2008.

Association between myocardial substrate, implantable cardioverter defibrillator shocks and mortality in MADIT-CRT.

Objective: The aim of the present study was to assess a possible association between myocardial substrate, implantable cardioverter defibrillator (ICD) shocks, and subsequent mortality.

Methods: Within the multicentre automatic defibrillator implantation trial-cardiac resynchronization therapy (MADIT-CRT) population (n = 1790), we investigated the association between myocardial substrate, ICD shocks and subsequent mortality using multivariate Cox regression analyses and landmark analyses at 1-year follow-up.

Results: The 4-year cumulative probability of ICD shocks was 13% for appropriate shock and 6% for inappropriate shock.

The prognostic impact of pre-implantation hyponatremia on morbidity and mortality among patients with left ventricular dysfunction and implantable cardioverter-defibrillators.

Aims: Hyponatremia is commonly observed among patients with left ventricular (LV) dysfunction and is a marker for adverse outcomes. We aimed to determine the prognostic significance of pre-implant hyponatremia on the outcomes of death, acute decompensated heart failure (ADHF) and appropriate implantable cardioverter-defibrillator (ICD) therapy for ventricular arrhythmias among patients with ICDs.

Methods And Results: The study population consisted of patients with an ejection fraction ≤40% undergoing ICD implantation (n = 911) for the primary or secondary prevention of sudden cardiac death from 1997 to 2007.

Evaluation of the Charlson comorbidity index to predict early mortality in implantable cardioverter defibrillator patients.

Background: Current guidelines consider the implantation of an implantable cardioverter defibrillator (ICD) a class III indication in patients with a life expectancy of <1 year. An evaluation of concomitant noncardiac conditions may identify patients whom may not derive benefit with ICD therapy. We sought to evaluate the association of the Charlson comorbidity index (CCI) on the prediction of early mortality (EM), death <1 year after ICD implant.

Predictors of pacemaker dependence and pacemaker dependence as a predictor of mortality in patients with implantable cardioverter defibrillator.

Background: The prevalence, predictors, and survival for the development of pacemaker dependence (PD) in patients implanted with an implantable cardioverter defibrillator (ICD) are unknown.

Methods: This was a retrospective analysis of 1,550 consecutive patients with ICD implantation at a single center from 1996 to 2008 with a mean of 4.2 ± 3.

The gender-paradox among patients with implantable cardioverter-defibrillators: a propensity-matched study.

Background: Several meta-analyses of the implantable cardioverter-defibrillator (ICD) clinical trials have demonstrated that while men derived a mortality reduction with prophylactic ICD implantation, women did not. These trials also observed that women receive less appropriate ICD shock therapy compared to men. We aimed to investigate this "gender-paradox" among a heterogeneous community cohort of patients receiving ICDs.

Frequency of inappropriate therapy in patients implanted with dual- versus single-chamber ICD devices in the ICD arm of MADIT-CRT.

Background: The majority of implantable cardioverter defibrillators (ICDs) are dual-chamber devices, but studies on the frequency of inappropriate therapy in dual- versus single-chamber devices have shown conflicting results. The aim of this study is to determine whether implantation of dual-chamber ICD devices decrease the incidence of inappropriate therapy without an unacceptable increase in complications.

Methods: In the ICD arm of the MADIT-CRT study (N = 704), comparisons of single- versus dual-chamber ICD devices were investigated on the endpoints of inappropriate therapy (antitachycardia pacing [ATP] and shocks) and device- and procedure-related complications by use of multivariate Cox proportional hazard regression analysis (hazard ratio dual:single chamber) adjusting for relevant covariates.

Bidirectional ventricular tachycardia due to coronary allograft vasculopathy a unique presentation.

Bidirectional ventricular tachycardia (BVT) is an uncommon type of polymorphic ventricular tachycardia (PVT) with alternating polarity of the QRS complex most commonly described digitalis toxicity. Recent data has demonstrated the possible molecular basis of this electrocardiographic phenomenon. To our knowledge this is the first reported case of BVT in a patient with orthotopic cardiac transplantation and coronary allograft vasculopathy.

CRT-D Therapy in Patients with Decompensated NYHA Class-Four CHF.

Background. ACC-HRS Guidelines for Cardiac Resynchronization Therapy ICD implantation (CRT-D) do not include patients with advanced nonambulatory NYHA class-four CHF due to an expectation of limited survival. There is little data available from these large multicenter randomized studies to support or refute this claim.

Pharmacologic and nonpharmacologic thromboprophylactic strategies in atrial fibrillation.

Stroke prevention in atrial fibrillation (SPAF) has traditionally been confined to aspirin and warfarin therapy. Based on CHADS2 scoring it was clearly delineated when aspirin and warfarin would be used in individual patients, but many patients had to forgo recommended therapy due to contraindications or adverse events. There has recently been a paradigm shift in SPAF, with new and promising options on the horizon.

IntravenousCorticosteroid Use Is Associated With Reduced Early Recurrence of Atrial Fibrillation Immediately Following Radiofrequency Catheter Ablation.

Early recurrence of atrial fibrillation (ERAF) occurs in up to 40% of patients after radiofrequency catheter ablation for atrial fibrillation (RFCA), increasing hospital stay, need for anti-arrhythmic medications (AADs) and cardioversion, and, possibly, the risk of future AF. It has been postulated that inflammation plays a key role in developing ERAF. Short term postoperative use of corticosteroids to reduce ERAF post-RFCA has not been vigorously studied.

Coronary sinus shocking lead as salvage in patients with advanced CHF and high defibrillation thresholds.

Background: We report a series of three patients whose implantable cardioverter-defibrillators (ICD) implants were unsuccessful due to inability to achieve defibrillation thresholds (DFT) at maximum available energy after failure of standard modification and enhancement procedures. All patients had advanced cardiomyopathy.

Methods: Use of the coronary sinus (CS) for left ventricular (LV) shocking electrode placement resulted in acceptable DFTs in each patient.

The prognostic impact of shocks for clinical and induced arrhythmias on morbidity and mortality among patients with implantable cardioverter-defibrillators.

Background: Recent investigations have demonstrated that the occurrence of implantable cardioverter-defibrillator (ICD) shocks is associated with adverse long-term outcomes. These studies have emphasized that the risk is most reasonably due to arrhythmias rather than to the shock itself. We sought to compare the impact of shock delivery for induced ventricular arrhythmias during implantation defibrillation threshold testing and noninvasive electrophysiology study (NIPS) to clinical shocks on long-term outcomes among patients with ICDs.

Comparison of single and double vein approaches for His bundle ablation and pacemaker placement for symptomatic rapid atrial fibrillation.

Background: His Bundle ablation (HBA) with permanent pacemaker (PPM) implantation is an effective strategy for controlling heart rate in symptomatic patients with rapid atrial fibrillation (AF), resistant to pharmacologic therapy. The standard double vein (DV) approach involves mapping and HBA from a femoral approach to achieve complete heart block (CHB), while single chamber (SC), dual chamber (DC), or biventricular (BiV) PPM is then placed via a subclavian approach.

Methods: We compared 7 patients with drug-resistant rapid AF who underwent the standard DV approach to 8 patients who underwent a single vein (SV) approach, in which HBA and PPM implantation were performed through the subclavian vein.

A comparison of outcomes for patients receiving implantable cardioverter defibrillators for primary vs secondary-prevention.

Objective: Compare characteristics and outcomes of patients receiving implantable cardioverter defibrillators (ICDs) for primary vs secondary cardiac arrest prevention.

Methods: Patients in this cohort study were identified from a prospectively collected ICD database from June 1999 to August 2003 and divided into groups based on whether they received their ICD for primary or secondary-prevention of cardiac arrest. Patient follow-up continued until August of 2006 and the occurrence of appropriate ICD shocks, inappropriate ICD shocks, and mortality were compared between groups.

Impact of magnesium sulfate on serum magnesium concentrations and intracellular electrolyte concentrations among patients undergoing radio frequency catheter ablation.

Background: We evaluated the impact of intravenous magnesium on intracellular magnesium (iMg) and serum magnesium (sMg) in patients undergoing radio frequency catheter ablation (RFCA) for atrial fibrillation (AF).

Method: Patients with AF received 4g intravenous magnesium sulfate or normal saline in a randomized, double-blinded fashion. Venous blood and buccal cells were collected for evaluation of sMg and iMg at baseline, postinfusion, at the end of ablation procedure and six-hours posttherapy.

Association between statin therapy and reductions in atrial fibrillation or flutter and inappropriate shock therapy.

Aims: In patients without implantable cardioverter defibrillators (ICDs), statins have been shown to reduce the incidence of atrial fibrillation and atrial flutter (AF/AFL). We sought to determine if statin therapy could reduce the occurrence of AF/AFL with rapid ventricular rates with and without inappropriate shock therapy among a large heterogeneous ICD cohort.

Methods And Results: We prospectively followed 1445 consecutive patients receiving an ICD for the primary (n = 833) or secondary (n = 612) prevention from December 1997 through January 2007.

Association between statin use and mortality in patients with implantable cardioverter-defibrillators and left ventricular systolic dysfunction.

Background: A few previous nested cohort trials have evaluated the use of statins on survival and the occurrence of ventricular tachycardia or fibrillation (VT/VF). While the studies generally agreed on the survival effects, they disagreed on the magnitude of the mortality benefit and on the effect on VT/VF.

Objective: The purpose of this study was to determine in a large, long-term follow-up cohort whether statin therapy could reduce mortality and the occurrence of VT/VF in a mixed population receiving an implantable cardioverter-defibrillator (ICD) for primary or secondary prevention and either ischemic or nonischemic cardiomyopathy.

The impact of carvedilol on the defibrillation threshold.

Background: Defibrillation threshold (DFT) is the minimum energy required to successfully terminate ventricular fibrillation. Epinephrine has been shown to increase the DFT in the beta-blocker naïve, but using cardioselective beta-blockers leads to a reduction in the DFT on infusion of epinephrine and norepinephrine. We sought to determine the impact of carvedilol therapy on the DFT after infusion of epinephrine and norepinephrine.

Electromagnetic Interference (EMI) and arrhythmic events in ICD patients undergoing gastrointestinal procedures.

Background: The objective was to determine the effect of electromagnetic interference (EMI) in patients undergoing gastrointestinal endoscopy. The implantable cardioverter-defibrillator (ICD) is the primary therapeutic modality for patients at risk for sudden cardiac death. One potential problem with ICDs is interactions with electrical devices and medical procedures causing EMI or triggering arrhythmic events.

Thermal mapping of right ventricular outflow tract tachycardia.

Background: Acute and long-term success of catheter ablation of right ventricular outflow tract tachycardia (RVOT VT) may be limited by the inability to reproduce the arrhythmia at the time of activation (AM) and pace mapping (PM). We have observed early initiation of the clinical VT when subtherapeutic radiofrequency (RF) energy was applied to the target area (TA), defined as a 2-cm(2) area around a pace match. We describe a novel approach using thermal mapping (TM) to guide the ablation of RVOT VT.

The use of protamine after radiofrequency catheter ablation: a pilot study.

Objective: Evaluate the effect of administering intravenous protamine immediately post-radiofrequency catheter ablation (RFCA) on thrombotic and bleeding complications in heparinized patients.

Methods: Heparinized patients that had RFCA for atrial or ventricular arrhythmias at our institution between January 2001 and March 2006 and had a complete data set were included in this cohort evaluation. Patients receiving at least one dose of protamine within 15 min of RFCA were deemed the prophylactic group while those not receiving protamine within 15 min were the control group.

Implantation of a biventricular pacing and defibrillator device via a persistent left superior vena cava.

A persistent left superior vena cava was discovered in a 66-year-old man with heart failure undergoing implantation of a biventricular pacing and defibrillator device. An active fixation right ventricular defibrillator lead was placed through a curved guiding catheter. A sub-selection catheter and a guidewire allowed the engagement of a posterior-lateral branch of the coronary sinus, performance of an angiogram without an occlusive balloon, and optimal lead placement.