The American journal of cardiology
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Randomized Controlled Trial Comparative Study
Relation of systemic venous return, pulmonary vascular resistance, and diastolic dysfunction to exercise capacity in patients with single ventricle receiving fontan palliation.
Fontan patients have a reduced exercise capacity, primarily owing to limitations in the ability to augment pulmonary blood flow and stroke volume. To date, the mechanism of peak exercise pulmonary blood flow restriction has not been elucidated. We performed a single-center, prospective, crossover trial of supine and upright exercise in Fontan patients and healthy controls to determine the mechanisms of exercise limitation in the Fontan-palliated patient. ⋯ Six Fontan patients who underwent supine exercise with indwelling catheters failed to demonstrate the expected decrease in pulmonary vascular resistance characteristically seen with peak exercise (at rest, 2.8 + or - 0.7 mm Hg/L/min/m(2) vs at peak, 2.8 + or - 0.9 mm Hg/L/min/m(2); p = 0.9). In conclusion, supine exercise in Fontan patients does not result in an increased VO(2) or oxygen pulse, suggesting that inadequate venous return might not be the primary limitation of exercise capacity in this population. Diastolic dysfunction and relatively excessive peak exercise pulmonary vascular resistance might be more important factors in Fontan exercise limitation.
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Comparative Study
Usefulness of right-to-left shunting and poor exercise gas exchange for predicting prognosis in patients with pulmonary arterial hypertension.
We hypothesized that the longitudinal changes in peak oxygen uptake, ventilatory efficiency, and exercise-induced right-to-left shunting in patients with pulmonary arterial hypertension (PAH) would predict outcomes better than baseline measurements alone. Patients with PAH die prematurely. Identifying prognostic markers is critical for treating patients with PAH; however, longitudinal prognostic information of PAH is limited. ⋯ The absence of a shunt at baseline was associated with a 20% rate of nonsurvival, which decreased to 7% at follow-up. A poorer ventilatory efficiency appeared to be associated with a poor outcome in patients without a shunt. In conclusion, a persistent exercise-induced right-to-left shunt and poor ventilatory efficiency were highly predictive of poor outcomes in patients with pulmonary arterial hypertension.
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Comparative Study
Characteristics and predictors of obstructive sleep apnea in patients with systemic hypertension.
Obstructive sleep apnea (OSA) is a secondary cause of hypertension and independently associated with target-organ damage in hypertensive patients. However, OSA remains largely underdiagnosed and undertreated. The aim of the present study was to evaluate the characteristics and clinical predictors of OSA in a consecutive series of patients followed up in a hypertension unit. ⋯ Metabolic syndrome was associated with high sensitivity and specificity for OSA (0.86 and 0.85, respectively). Multiple regression analysis showed that age of 40 to 70 years (odds ratio 1.09, 95% confidence interval 1.03 to 1.16), a high risk of OSA on the Berlin Questionnaire (odds ratio 8.36, 95% confidence interval 1.67 to 41.85), and metabolic syndrome (odds ratio 19.04, 95% confidence interval 5.25 to 69.03) were independent variables associated with OSA. In conclusion, more important than the typical clinical features that characterize OSA, including snoring and excessive daytime sleepiness, the presence of the metabolic syndrome is as an important marker of OSA among patients with hypertension.
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Comparative Study
Long-term outcomes for cryoablation of pediatric patients with atrioventricular nodal reentrant tachycardia.
The long-term efficacy and complications of cryoablation for pediatric atrioventricular nodal reentrant tachycardia (AVNRT) have not been completely defined. We performed a retrospective review of pediatric patients diagnosed with AVNRT and treated with cryoablation therapy. A total of 73 patients underwent cryoablation for AVNRT from 2003 to 2008. ⋯ Procedural complications consisting of transient atrioventricular block developed in 10 patients, and 2 patients were diagnosed with new arrhythmias after AVNRT ablation (1 with junctional ectopic tachycardia and 1 with left ventricular outflow tract tachycardia originating near the region of the atrioventricular node 3 months after ablation). In conclusion, cryoablation is a safe and effective therapy for AVNRT. Recurrences can develop late, up to 2 years after initially successful ablation.
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Randomized Controlled Trial Multicenter Study Comparative Study
Comparison of usefulness of N-terminal pro-brain natriuretic peptide as an independent predictor of cardiac function among admission cardiac serum biomarkers in patients with anterior wall versus nonanterior wall ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention.
The purpose of the present study was to determine the prognostic value of N-terminal pro-brain natriuretic peptide (NT-pro-BNP), among other serum biomarkers, on cardiac magnetic resonance (CMR) imaging parameters of cardiac function and infarct size in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention. We measured NT-pro-BNP, cardiac troponin T, creatinine kinase-MB fraction, high-sensitivity C-reactive protein, and creatinine on the patients' arrival at the catheterization laboratory in 206 patients with ST-segment elevation myocardial infarction. The NT-pro-BNP levels were divided into quartiles and correlated with left ventricular function and infarct size measured by CMR imaging at 4 to 6 months. ⋯ Multivariate analysis revealed that a NT-pro-BNP level of > or = 260 pg/ml was the strongest independent predictor of left ventricular ejection fraction in patients with nonanterior wall myocardial infarction compared to the other serum biomarkers (beta = -5.8; p = 0.019). In conclusion, in patients with nonanterior wall myocardial infarction undergoing primary percutaneous coronary intervention, an admission NT-pro-BNP level of > or = 260 pg/ml was a strong, independent predictor of left ventricular function assessed by CMR imaging at follow-up. Our findings suggest that NT-pro-BNP, a widely available biomarker, might be helpful in the early risk stratification of patients with nonanterior wall myocardial infarction.