Sony Jacob

Significance of a Fragmented QRS Complex Versus a Q Wave in Patients With Coronary Artery Disease

Background— Q waves on a 12-lead ECG are markers of a prior myocardial infarction (MI). However, they may regress or even disappear over time, and there is no specific ECG sign of a non–Q-wave MI. Fragmented QRS complexes (fQRSs), which include various RSR′ patterns, without a typical bundle-branch block are markers of altered ventricular depolarization owing to a prior myocardial scar. We postulated that the presence of an fQRS might improve the ability to detect a prior MI compared with Q waves alone by ECG. Methods and Results— A cohort of 479 consecutive patients (mean±SD age, 58.2±13.2 years; 283 males) who were referred for nuclear stress tests was studied. The fQRS included various morphologies of the QRS (<120 ms), which included an additional R wave (R′) or notching in the nadir of the S wave, or >1 R′ (fragmentation) in 2 contiguous leads, corresponding to a major coronary artery territory. The Q wave was present in 71 (14.8%) patients, an fQRS was present in 191 (34.9%) patients, and an fQRS and/or a Q wave was present in 203 (42.3%) patients. Sensitivity, specificity, and the negative predictive value for myocardial scar as detected by single photon emission computed tomography analysis were 36.3%, 99.2%, and 70.8%, respectively, for the Q wave alone; 85.6%, 89%, and 92.7%, respectively, for the fQRS; and 91.4%, 89%, and 94.2%, respectively, for the Q wave and/or fQRS. Conclusions— The fQRS on a 12-lead ECG is a marker of a prior MI, defined by regional perfusion abnormalities, which has a substantially higher sensitivity and negative predictive value compared with the Q wave.

Relationship between Red Cell Distribution Width and Microalbuminuria: A Population-Based Study of Multiethnic Representative US Adults

Introduction: Microalbuminuria (MA), a renal marker of vascular injury, is an independent predictor of cardiovascular (CV) events. Red cell distribution width (RDW), an emerging CV risk predictor, has not been evaluated for its association with MA. Methods: We evaluated 8,499 participants of the National Health and Nutrition Examination Survey (NHANES) 1999–2006, where RDW was evaluated as a continuous variable and in quartiles (Q1 ≤12.1, Q2 12.2–12.5, Q3 12.6–13 and Q4 >13). Multivariate adjusted logistic regression analysis was performed to estimate the odds of having MA (n = 1,736; adjusted for traditional CV risk factors, race, BMI, estimated glomerular filtration rate, hemoglobin, mean corpuscular volume, high-sensitivity C-reactive protein and nutritional factors deficiencies of iron, folate and vitamin B12). Results: The prevalence of MA increased with increasing RDW (13.52% in Q1 vs. 30.02% in Q4, p < 0.001). The odds of having MA for those in Q4 was 2.49 (95% CI: 1.95–3.18, p < 0.001) compared to those in Q1 after the adjustments. No effect modification was observed by covariates on the association between RDW and MA. Conclusion: Elevated RDW is independently associated with a higher risk of MA. An interaction between chronic inflammation, oxidative stress, neurohumoral overactivity and endothelial dysfunction may explain this association and the attendant elevated CV/renal risk.

“Pseudo” Faraday cage: a solution for telemetry link interaction between a left ventricular assist device and an implantable cardioverter defibrillator

Patients implanted with left ventricular assist devices (LVAD) may have implantable cardioverter defibrillators (ICD) implanted for sudden cardiac death prevention. This opens the possibility of device–device communication interactions and thus interferences. We present a case of such interaction that led to ICD communication failure following the activation of an LVAD. In this paper, we describe a practical solution to circumvent the communication interference and review the communication links of ICDs and possible mechanisms of ICD–LVAD interactions.

Glycosylated hemoglobin and prevalent metabolic syndrome in nondiabetic multiethnic U.S. adults

BACKGROUND Metabolic syndrome poses a significant risk for cardiovascular disease. Recently, glycosylated hemoglobin (HbA1c) has been included in the diagnostic criteria for diabetes mellitus and prediabetes. We sought to determine if HbA1c is associated with prevalent metabolic syndrome in nondiabetic U.S. adults. METHODS A total of 9,022 nondiabetic participants of National Health and Nutrition Examination Surveys 1999-2008 (age, 47.5 ± 18.3 years, 51% females) were divided into quintiles (Q) of HbA1c: Q1 (reference), ≤5%; Q2, 5.1%-5.3%; Q3, 5.4%-5.5%; Q4, 5.6%-5.7%; and Q5, ≥5.8%. Modified National Cholesterol Education Program Adult Treatment Panel III criteria were used to identify metabolic syndrome (n=2,821; 31.3%). Unadjusted and adjusted multivariate logistic regression analysis was performed to assess the risk of metabolic syndrome. RESULTS A graded increase in odds of having prevalent metabolic syndrome with increase from each quintile of HbA1c compared to Q1 was observed after adjusting for age, sex, race, body mass index (BMI), total cholesterol, lipid-lowering therapy, current smoking, family history of diabetes, C-reactive protein, and fasting insulin. Stratified analysis based on gender, ethnicity, and BMI showed similar results. The HbA1c value of ≥5.4% remained appropriate cutoff for predicting metabolic syndrome in Caucasians and Hispanics, whereas ≥5.6% provided the best accuracy for African Americans based on receiver operating characteristics analysis. CONCLUSION HbA1c much below the level for prediabetes was associated with prevalence of the metabolic syndrome in a cohort of nondiabetic U.S. adults. HbA1c can be considered as a surrogate marker for metabolic syndrome in nondiabetics.

Prognostic Importance of Defibrillator Shocks in Survivors of Sudden Cardiac Death

Implantable cardioverter-de fi brillator (ICD) implantation is standard of care for patients who have survived life threatening ventricular tachyarrhythmias (LTVA). ICD shocks predict future adverse events in patients with ICD implantation for primary prevention. However, the role of ICD shocks in prediction of adverse events in a secondary prevention population is unknown. The Antiarrhythmics Versus ICDs (AVID) Trial (n=1016) was a randomized controlled trial comparing ICD (n=507) and antiarrhythmic drugs (n=509) in the treatment of patients with LTVA. Mean follow-up duration was 916 ± 471 days. We analyzed the ICD arm of the AVID trial using the NHLBI limited access dataset. ICD shocks were categorized as appropriate if underlying rhythm triggering the shock was ventricular tachycardia or ventricular fibrillation. All other ICD shocks were considered as inappropriate. Data on ICD therapy was available for 420 patients. Any shock (n=380), any appropriate (n=296) or any inappropriate (n=72) shock was not associated with increased all cause, cardiac or arrhythmic mortality. However any appropriate shock was associated with increased LTVA. In conclusion, ICD shocks do not confer increased risk of death on follow up in LTVA survivors. Use of ICD shocks as surrogate marker for adverse outcomes is not viable in secondary prevention patients.

Pharmacotherapy of Atrial Fibrillation: A Pathophysiological Perspective and Review

Atrial fibrillation (AF) is one of the most common arrhythmia encountered in clinical practice. Although AF is due to the structural and electrophysiological alterations in the atria, its sustainability is multifactorial, and the actual mechanisms are still not clear. Despite the recent advances in catheter ablation technology and techniques, pharmacotherapy still remains the first-line therapy for the management of AF. Current pharmacotherapy targets ion channel alterations that in fact represent only one aspect of the management of this complex arrhythmia. Successful pharmacological treatment of AF and restoration of sinus rhythm is limited and is in part due to its potential deleterious side effects. Newer agents having diverse mechanisms acting on the recently uncovered pathophysiological processes are on the horizon. These include atrial repolarization delaying agents, newer class III agents, Na+-Ca2+ channel blockers, stretch receptor blockers, IKACH blockers, gap junction modifiers, upstream therapies, and agents targeting ischemia-induced AF. Gene- and cell-specific therapies including ‘tailored nanopharmacy,’ newer rate control medications with minimal side effects and the emergence of novel drugs targeting multiple areas of AF arrhythmogenesis in tandem with electrical therapy may be the future direction in the management of AF.

Outcomes and Risk Prediction Model for Peripheral Arterial Disease in Patients with Stable Coronary Artery Disease

We used the National Heart, Lung, and Blood Institute Limited Access Dataset of Prevention of Events with Angiotensin-Converting Enzyme Inhibition (PEACE) Trial (n = 8290) which included patients with stable coronary artery disease (CAD) and preserved ejection fraction (>40%). We identified risk factors for the development of critical peripheral arterial disease (PAD; those needing angioplasty, bypass grafting, or aneurysm repair) and formulated a risk score by multivariate analyses. A total of 220 patients (2.8%) developed critical PAD over a mean follow-up of 4.7 years. Significant predictors of critical PAD were history of intermittent claudication, smoking, hypertension (HTN), coronary-artery bypass grafting (CABG), diabetes, age, serum cholesterol, and body mass index (BMI). Incident critical PAD was associated with increased composite outcome of cardiovascular death, myocardial infarction, percutaneous transluminal coronary angioplasty, or CABG (hazard ratio 1.82, 95% CI 1.50-2.22, P < .001). Risk assessment using our score may identify CAD patients at risk for critical PAD events.

Renal disease and cardiac mortality in survivors of sudden cardiac death.

Objective - Renal disease is associated with increased all-cause mortality and cardiovascular mortality. However, the role of ICD implantation on cardiac mortality in patients with renal disease has not been well studied. Implantable cardioverter-defibrillator (ICD) implantation is protective against cardiac death in a secondary prevention population with renal disease. Methods - The Antiarrhythmics Versus Implantable Cardioverter Defibrillators (AVID) Trial (n??=??1016) was a multicentre trial comparing ICD (n = 507) and anti-arrhythmic drugs (AAD) (n = 509) for secondary prevention of life-threatening ventricular tachyarrhythmias.We performed a post-hoc analysis of the AVID trial using the National Heart, Lung, and Blood Institute limited access dataset. Individuals in the original AVID study with history of renal disease (n = 82) were included in this analysis. Outcomes of our analysis were cardiac death and all-cause mortality. Results- 41 patients had renal disease in both the ICD and AAD arms. A total of 116 patients died in the ICD arm, while 162 died in the AAD arm. Renal disease was an independent predictor (HR, 95% CI) of cardiac death (1.967, 1.09-3.57, P = 0.02) and all-cause mortality (2.04, 1.23-3.39, P = 0.01) in the AAD arm. Renal disease was also a predictor of all-cause mortality in the ICD arm (1.75, 1.01-3.01, P = 0.04). However, renal disease did not influence cardiac death in the ICD arm. Conclusions- Our study investigates the effect of ICD implantation in an entirely secondary prevention population with renal disease. ICD implantation appears to be equally protective against cardiac death in renal disease when compared to AAD.

Device Therapy in Heart Failure Patients With Chronic Kidney Disease

We read with great interest the recent article in the Journal by Cannizzaro et al. ([1][1]). The researchers provided a great overview of various trials in the use of implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy in patients with chronic kidney disease (CKD)

Role of Lipid Lowering Therapy and Renin Angiotensin Blockade in Outcomes of Patients With Atrial Fibrillation

Role of Lipid Lowering Therapy and Renin Angiotensin Blockade in Outcomes of Patients With Atrial Fibrillation We read the recently published report by Saksena et al comparing cariovascular outcomes of individual aniarrhythmic drugs versus rate-control rugs using propensity score–matched ubcohorts in the Atrial Fibrillation Folow-Up Investigation of Rhythm Mangement (AFFIRM) trial. The investiators reported increases in composite ortality and the frequency of cardioascular hospital stay with individual ntiarrhythmic drugs and noncardiovasular mortality and intensive care unit ospital stay with amiodarone comared to rate-control therapy. We analyzed the outcomes of atrial brillation (AF) in the National Heart, ung, and Blood Institute public-use, imited-access data set of the AFFIRM rial. We addressed the impact of lipidowering therapy (LLT) on outcomes of F and observed decreases in all-cause ortality (hazard ratio [HR] 0.77, 95% onfidence interval [CI] 0.62 to 0.95, 0.01), ischemic stroke (HR 0.56, 5% CI 0.36 to 0.89, p 0.01), cardioascular mortality (HR 0.71, 95% CI .53 to 0.95, p 0.02), and the comined end point (HR 0.81, 95% CI 0.69 o 0.96, p 0.01) in patients with AF ho were receiving LLT. Drug interacions and adverse effects have been reorted with concomitant use of statins and miodarone, especially rhabomyolysis.