Is the mechanism of supraventricular tachycardia in pediatrics influenced by age, gender or ethnicity?

BACKGROUND: The mechanism of supraventricular tachycardia (SVT) in adults is influenced by age and gender. The purpose of this study was to determine whether age, gender, or ethnicity impact the mechanism of SVT in pediatric patients. METHODS: A search of the Pediatric Electrophysiology Registry identified patients who had undergone a radiofrequency ablation for SVT from 1999 to 2004. Patients were grouped into categories based on the mechanism of tachycardia, age, gender, and ethnicity. US Census data from 2000 served as a benchmark for expected race and gender distributions. RESULTS: The study looked at 3556 patients (< or =7 years, n = 378; 7-12 years, n = 964; 12-21 years, n = 2214), with 1948 males, 2916 whites, 266 blacks, 248 Hispanics, 63 Asians, and 63 of another ethnicity. For accessory pathways (APs), there were 2418 patients (1405 male), and for atrioventricular node reentry tachycardia (AVNRT), there were 1138 patients (544 male). The APs decreased in proportion with increasing age; conversely, AVNRT increased with increasing age (P < .001). Significant differences were found in gender distribution between APs and AVNRT in the 12-21 years age group, with females more likely to have AVNRT than AP (P < .0001). No significant gender differences were present at younger ages. With respect to ethnicity, APs were more common than AVNRT in the white, black, and Hispanic ethnic groups (P < .02). When comparisons were made between ethnic groups from our registry and US Census data, whites had a much higher frequency of SVT than their representation in the US population (85% vs. 68.7%), while blacks (8.7% vs. 15%) and Hispanics (5.6% vs. 17.0%) had a lower frequency of SVT than their representation in the US population (P < .0001). CONCLUSION: The mechanism of SVT in pediatric patients is associated with age, gender, and ethnicity. The proportion of SVT due to APs decreases as age increases. Among children older than 12 years, females are more likely than males to have AVNRT as the mechanism of tachycardia. The racial distribution of patients in the registry differs from that of the US population, with a greater proportion of whites seen in the registry.

Usefulness of heart rate as an independent predictor for survival after heart transplantation.

It was unclear whether increased heart rate (HR) increased long-term mortality after heart transplantation (HT). The aim of this study was to evaluate whether HR predicted survival after HT. A retrospective analysis of patients who underwent HT at our institution was performed. Ethnicity, gender, date of birth, age at transplantation, length of follow-up after transplantation, cardiac rhythm within 3 months after transplantation, age at death, reason for transplantation, cause of death, and baseline medications after transplantation were recorded. Continuous variables, such as HR, blood pressure, cardiac ejection fraction, presence of allograft vasculopathy, and serum creatinine, were recorded at <3 months, 6 months, and 1 year after HT, then annually to 10 years after HT. Seventy-eight patients with a mean age of 50 +/- 13 years were identified. Mean survival was 8.5 +/- 6.5 years. Of 78 patients, 32 patients had an HR 90 beats/min within 3 months after HT. There was a mean decrease in HR of 6 beats/min during 10 years (p <0.03). Multivariate survival analysis showed that HR >90 beats/min was a significant predictor of early mortality (hazard ratio 2.8, 95% confidence interval 1.5 to 5.1, p <0.0013). Patients with a net increase in HR during 10 years had an increased risk of death compared with patients with no change or a net decrease in HR (hazard ratio 4.7, 95% confidence interval 1.9 to 12.0, p <0.002). No significant differences in cause of death between patients with an HR 90 beats/min existed. In conclusion, HT patients with an HR >90 beats/min within the first 3 months after HT were 2.8 times more likely to die than patients with an HR

Obesity and dysrhythmias.

In the United States, obesity has reached epidemic proportions. Results from the 2003-2004 National Health and Nutrition Examination Survey estimated that 66% of US adults are either overweight (body mass index [BMI] 25-30 kg/m(2)) or obese (BMI>30 kg/m(2)) as defined by the BMI cutoffs established by the World Health Organization. In the 1970s, only 15% of the US population between the ages of 20 and 74 years was categorized as obese. In 2003, approximately 32% of the adult population was obese. Obesity plays an important role in the evolution of cardiovascular disease. This article reviews the histopathophysiologic changes that occur in cardiac structure and function in response to obesity, explores the relationship between obesity and arrhythmias such as atrial fibrillation and sudden cardiac death, and analyzes electrocardiographic changes in an obese patient.

Cardiac sarcoidosis: a case report and review of the literature.

Massive pericardial effusion is rarely the sole clinical presenting symptom of sarcoidosis. Herein we report a case of recurrent pericardial effusions requiring surgical intervention secondary to sarcoidosis. A review of the literature regarding the prevalence/histopathology, the role of endomyocardial biopsy, the use of cardiac magnetic resonance imaging, and the utility of steroid based treatments in the management of cardiac sarcoidosis is discussed.

The role of fish oil in arrhythmia prevention.

Numerous epidemiological studies, case-control series, and randomized trials have demonstrated the ability of fish oil to reduce major cardiovascular events, particularly sudden cardiac death and all-cause mortality. We discuss the potential benefits of fish oil therapy to improve overall autonomic tone and potentially reduce the risk of major ventricular and atrial arrhythmias. Specifically, this review focuses on how fish oil therapy has performed in 3 primary prevention trials in patients with implantable cardioverter defibrillators, reviews the effects that fish oil has on the autonomic nervous system, focuses on the use of fish oil as a novel therapy for atrial fibrillation, and revisits other beneficial properties of fish oil (ie, ability to lower serum triglycerides, anti-inflammatory effects, and possible improvements in arterial pressure/diastolic function). We also discuss the safety profile of fish oil, including effects on bleeding time and bleeding complications as well as provide commentary regarding fish oil supplementation in light of increasing contaminants contained in fish. In summary, any patient with documented coronary heart disease and those with risk factors for sudden cardiac death, such as left ventricular dysfunction, left ventricular hypertrophy, prior myocardial infarction, or high-grade ventricular dysrhythmias, should consider fish oil supplementation. The American Heart Association recommends four 3-ounce servings of oily fish weekly. For those who cannot eat fish or do not have access to fish, as well as those who would prefer not to eat fish regularly, capsules of fish oil are readily available in various concentrations. At the present time, we recommend doses of eicosapentanoic acid and docosahexanoic acid in the combined range of 800 to 1000 mg/day for primary and secondary prevention of cardiovascular disease.

Fish oil in primary and secondary cardiovascular prevention.

Omega-3 fatty acid therapy shows great promise in both primary and secondary prevention of cardiovascular (CV) diseases, especially coronary heart disease (CHD). In this review, we discuss the evidence available from prospective and retrospective observational epidemiologic studies and controlled clinical trials demonstrating the effects of omega-3 fatty acids (fish oil) in primary and especially secondary prevention of major CV events, including CV mortality, fatal and nonfatal myocardial infarction (MI), and sudden cardiac death (SCD). Significant reductions in total mortality and SCD to the extent of 20% to 50% have been found in studies using doses ranging from 0.85 to 4.0 g/d. We review the compelling evidence that indicates all clinicians should strongly consider therapy with fish oil, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), for patients with known CV disease and for patients at increased risk for CV disease, particularly patients at increased risk for SCD. The target DHA + EPA consumption levels are about 800 to 1000 mg/d for individuals with known CHD and at least 500 mg/d for individuals without disease.

Is heart failure more prevalent in patients with peripheral arterial disease? A meta-analysis.

Because risk factors for heart failure (HF) cluster in persons with peripheral artery disease (PAD), the authors conducted a meta-analysis to examine the prevalence of HF in individuals with PAD. MEDLINE searches were performed to review all PAD clinical trials (1966-2003). Expected control population prevalence rates for HF were derived from the National Health and Nutrition Examination Survey (NHANES) database. In total, 11,304 patients were evaluated. The average age of the patients was 67+/-5 years. The prevalence of HF in patients with PAD was 7.9% (range, 5.3%-13.9%) compared with an expected prevalence of 4.1%(range, 3.7-4.5%). The relative risk for increased HF prevalence among those with PAD was 1.9 (range, 1.35-3.10; P<.001). Thirteen (range, 7-19) PAD patients needed to be screened to detect 1 case of HF. The presence of PAD is associated with a 2-fold increase in the prevalence of HF. The use of PAD as a risk marker for underlying HF may enhance the effectiveness of screening criteria for HF detection.