Mazda Biria

Radiofrequency Ablation of Premature Ventricular Ectopy Improves the Efficacy of Cardiac Resynchronization Therapy in Nonresponders

OBJECTIVES This study sought to examine whether suppressing premature ventricular contractions (PVC) using radiofrequency ablation improves effectiveness of the cardiac resynchronization therapy (CRT) in nonresponders. BACKGROUND CRT is an effective strategy for drug refractory congestive heart failure. However, one-third of patients with CRT do not respond clinically, and the causes for nonresponse are poorly understood. Whether frequent PVC contribute to CRT nonresponse remains unknown. METHODS In this multicenter study, CRT nonresponders with >10,000 PVC in 24 h who underwent PVC ablation were enrolled from a prospective database. RESULTS Sixty-five subjects (age 66.6 ± 12.4 years, 78% men, QRS duration of 155 ± 18 ms) had radiofrequency ablation of PVC from 76 foci. Acute and long-term success rates of ablation were 91% and 88% in 12 ± 4 months of follow-up. There was significant improvement in left ventricular (LV) ejection fraction (26.2 ± 5.5% to 32.7 ± 6.7 %, p < 0.001), LV end-systolic diameter (5.93 ± 0.55 cm to 5.62 ± 0.32 cm, p < 0.001), LV end-diastolic diameter (6.83 ± 0.83 cm to 6.51 ± 0.91 cm, p < 0.001), LV end-systolic volume (178 ± 72 to 145 ± 23 ml, p < 0.001), LV end-diastolic volume (242 ± 85 ml to 212 ± 63 ml, p < 0.001), and median New York Heart Association functional class (3.0 to 2.0, p < 0.001). Modeling of pre-ablation PVC burden revealed an improvement in ejection fraction when the pre-ablation PVC burden was >22% in 24 h. CONCLUSIONS Frequent PVC is an uncommon yet significant cause of CRT nonresponse. Radiofrequency ablation of PVC foci improves LV function and New York Heart Association class and promotes reverse remodeling in CRT nonresponders. PVC ablation may be used to enhance CRT efficacy in nonresponders with significant PVC burden.

Intracardiac echo-guided radiofrequency catheter ablation of atrial fibrillation in patients with atrial septal defect or patent foramen ovale repair: a feasibility, safety, and efficacy study.

Introduction: Patients with atrial septal defect (ASD) are at higher risk for atrial fibrillation (AF) even after repair. Transseptal access in these patients is perceived to be difficult. We describe the feasibility, safety, and efficacy of pulmonary vein antral isolation (PVAI) in these patients.

Safety and efficacy of transvenous high-voltage implantable cardioverter-defibrillator leads in high-risk hypertrophic cardiomyopathy patients

BACKGROUND The implantable cardioverter-defibrillator (ICD) prevents sudden cardiac death in high-risk patients with hypertrophic cardiomyopathy (HCM). However, recently concerns have been raised regarding the performance of transvenous high-voltage ICD leads (HVL) in this population. OBJECTIVE The purpose of this retrospective, multicenter study was to assess the safety and efficacy of HVL in high-risk HCM patients. METHODS The study population consisted of HCM patients who received HVL ICDs and were subsequently followed at seven centers in the United States. Kaplan-Meier survival rates were calculated for HVL and patients. HVL failure was a malfunction caused by a noniatrogenic defect. RESULTS Between 1992 and 2007, 324 HCM patients (mean age 47 +/- 16 years) received 343 HVL from three major manufacturers. The average HVL implant duration was 3.3 +/- 2.8 years. Overall, the HVL failure rate was 1.4%/year. However, two models (Sprint Fidelis and Transvene, Medtronic, Inc.) accounted for 60% of HVL failures. Survival probabilities for HVL and patients at 10 years were 93% and 91%, respectively. No deaths or serious injuries were reported, although inappropriate shocks occurred in 12% of cases. CONCLUSIONS This multicenter experience shows that HVLs are safe and effective in high-risk HCM patients. However, differences in failure rates were found between lead models.

Clinical Utility and Prognostic Significance of Measuring Troponin I Levels in Patients Presenting to the Emergency Room With Atrial Fibrillation

The clinical significance of mildly elevated troponins in patients presenting to the emergency room (ER) with atrial fibrillation (AF) is not well understood.

Radiofrequency ablation of drug refractory ventricular tachycardia related to cocaine use: A feasibility, safety, and efficacy study

Cocaine use is a known but rare cause of cardiac arrhythmias. Ventricular arrhythmias related to cocaine may not respond to antiarrhythmic drugs and may need treatment with radiofrequency ablation.

Do Statins Have a Role in the Management of Diastolic Dysfunction

Diastolic dysfunction of the left ventricle is an increasingly recognized clinical entity that may in some cases cause overt congestive heart failure. Currently, treatment of these patients is based on limited studies in patients with symptomatic heart failure. HMG-CoA reductase inhibitor (statin) drugs, which are primarily used for the treatment of hyperlipidemia, have been shown to have additional pharmacologic properties that may be beneficial in other disease states such as heart failure. Here, we wish to review the current knowledge of the mechanism of action of statins and the probable implications for asymptomatic patients with diastolic dysfunction. We discuss the causes and settings of diastolic dysfunction, the potential role of statin therapy in the treatment of diastolic dysfunction, and potential mechanisms by which statins may show benefit. The use of statins in the setting of diastolic dysfunction, both for treatment of established heart failure as well as to prevent progression of subclinical disease to overt symptomatic expression, is an area of substantial research interest with direct clinical application.

Under-Utilization of Implantable Cardioverter Defibrillators in Patients with Heart Failure - The Current State of Sudden Cardiac Death Prophylaxis.

Background Despite ACC/AHA guidelines indicating implantable cardioverter defibrillator (ICD) as class I therapy for primary prevention of sudden cardiac death in patients with EF≤35%, ICD utilization rates in real world practice have been low. Objective To determine the rate of ICD implantation at a tertiary care academic center and to assess the reasons for under-utilization of the same. Methods Review of a prospectively collected database which included all patients diagnosed with an EF≤35% was performed to assess the rate of ICD implantation and mortality. Reasons for non-implantation of ICD were then assessed from detailed chart review. Results A total of 707 patients (age 69.4 ± 14.1 years) with mean EF of 26±7% were analyzed. Only 28% (200/707) of patients had ICDs implanted. Mortality was lower in the group with ICD (25% vs 37%, p=0.004). When patients who either died or were lost to follow-up prior to 2005 were excluded, ICD utilization rate was still low at 37.6%. The most common reason for non-implantation of ICD was physicians not discussing this option with their patients. Patient refusal was the second most common reason. Conclusions ICD Implantation rates for primary prevention of SCD in patients with EF≤35% is low. Physician and patient education should be addressed to improve the utilization rates.BACKGROUND Despite ACC/AHA guidelines indicating implantable cardioverter defibrillator (ICD) as class I therapy for primary prevention of sudden cardiac death in patients with EF≤35%, ICD utilization rates in real world practice have been low. OBJECTIVE To determine the rate of ICD implantation at a tertiary care academic center and to assess the reasons for under-utilization of the same. METHODS Review of a prospectively collected database which included all patients diagnosed with an EF≤35% was performed to assess the rate of ICD implantation and mortality. Reasons for non-implantation of ICD were then assessed from detailed chart review. RESULTS A total of 707 patients (age 69.4 ± 14.1 years) with mean EF of 26±7% were analyzed. Only 28% (200/707) of patients had ICDs implanted. Mortality was lower in the group with ICD (25% vs 37%, p=0.004). When patients who either died or were lost to follow-up prior to 2005 were excluded, ICD utilization rate was still low at 37.6%. The most common reason for non-implantation of ICD was physicians not discussing this option with their patients. Patient refusal was the second most common reason. CONCLUSIONS ICD Implantation rates for primary prevention of SCD in patients with EF≤35% is low. Physician and patient education should be addressed to improve the utilization rates.

Multi-organ effects of Conducted Electrical Weapons (CEW) — A review

Since the introduction of the Conducted Electrical Weapons (CEW) several studies have been conducted and multiple reports have been published on safety of these devices from a medical point of view. Use of these devices in different situations and reported deaths attracts media attention and causes general anxiety around these devices. These devices have several limitations- such as rate of fire or maximum effective range in comparison to fire arms. Here we wish to review medical publications regarding the safety of these devices based on different systems.

Inverse Correlation of Venous Brain Natriuretic Peptide Levels with Body Mass Index Is due to Decreased Production

Objective: The aim of this paper was to study the association between body mass index (BMI) and coronary sinus (CS) brain natriuretic peptide (BNP) levels in patients with heart failure and reduced systolic function (HFrEF). Background: There is an inverse relationship between systemic venous BNP (V-BNP) levels and BMI in patients with HFrEF. It is unclear whether this finding is due to decreased production or due to an increased metabolism of BNP. Since CS-BNP levels reflect BNP production, we hypothesized that assessing the correlation of CS-BNP levels with BMI would provide insight into the mechanism of this inverse relationship of V-BNP and BMI. Methods: We prospectively enrolled 54 subjects with HFrEF who were to undergo cardiac resynchronization device implantation. CS-BNP, V-BNP, and arterial BNP (A-BNP) levels were measured during the implant procedure. Subjects were divided into 2 groups based on their BMI (group 1: BMI <30 and group 2: BMI ≥30). Results: The mean age of the overall study group was 64 ± 10 years. Average BMI for group 1 was 25.8 ± 2.8 and 36.8 ± 4.6 for group 2 (p < 0.03). A history of hypertension was present in 55% (n = 26) of the subjects, while diabetes was reported in 31% (n = 15). Serum creatinine was 1.0 ± 0.2 mg/dL and TSH 2.1 ± 1.4 mIU/L. 79% of the subjects were receiving β-blockers, while 94% were receiving angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. The mean CS-BNP, V-BNP, and A-BNP levels in group 2 were significantly lower than in group 1 (286.2 ± 170.5 vs. 417.5 ± 247.5 pg/mL, p = 0.04; 126.6 ± 32.5 vs. 228 ± 96.4 pg/mL, p = 0.01; and 151.9 ± 28.6 vs. 242 ± 88.8 pg/mL, p = 0.04, respectively). Univariate analysis and multivariate regression adjusted for age, diabetes mellitus, sex, glomerular filtration rate, and left atrial size confirmed BMI as an independent predictor of CS-BNP levels (β = -0.372, p = 0. 03) in our study. Conclusions: In this study, we demonstrate an inverse relationship between CS-BNP levels and BMI in patients with HFrEF. These findings suggest that the previously established inverse relationship between V-BNP and BMI is due to a decreased cardiac production of BNP in obese patients rather than from increased peripheral metabolism.

Age-Dependent Impact of Fluoroscopic Radiation on the Gender of Off-Spring: An International Survey of Cardiologists.

Background: Fluoroscopic radiation has been implicated in reducing the sex ratio (M:F) by potentially damaging the Y chromosome. We examined the effects of exposure to fluoroscopic radiation on gender of offspring of cardiologists across the world. Methods: An internet based survey was e-mailed worldwide to 8000 physicians who practice invasive electrophysiology and/or interventional cardiology. Survey questions included age, race, sub-specialty, hours of exposure to radiation, number of children, gender of off-spring, miscarriages and mutations and exposure to radiation prior to conception of each child. Logistic regression analyses were performed on years of exposure and gender of offspring born post radiation exposure. Results: Responses of 377 cardiologists (84% male and 16% female) were reviewed. With a total of 398 males and 402 females born to 377 cardiologists, although reduced, the overall sex ratio (0.99) was not significantly different from that observed in the general population (1.05). Univariate logistic regression analysis identified higher male births with increasing hours of radiation exposure (OR 1.034, CI 1.003-1.067 p=0.03) and increasing paternal age (OR 1.05, CI 1.01-1.08, p=0.002). Subgroup analysis of children of male cardiologists revealed higher incidence of male births with increasing age and radiation exposure and multivariate analysis only identified paternal age as predictor of higher incidence of male births (OR 1.05, CI 1.01-1.089, p=0.0027). Conclusion: Exposure to ionizing radiation leads to a decrease in the sex ratio (M/F) in younger male cardiologists, while this effect is reversed with greater number of male births in older male cardiologists.