Prognostic factors of the results of cardiopulmonary resuscitation in a cardiology hospital

OBJECTIVE: To analyze the early and late results of cardiopulmonary resuscitation in a cardiology hospital and to try to detect prognostic determinants of both short- and long-term survival. METHODS: A series of 557 patients who suffered cardiorespiratory arrest (CRA) at the Dante Pazzanese Cardiology Institute over a period of 5 years was analyzed to examine factors predicting successful resuscitation and long-term survival. RESULTS: Ressuscitation maneuvers were tried in 536 patients; 281 patients (52.4%) died immediately, and 164 patients (30.6%) survived for than 24 hours. The 87 patients who survived for more than 1 month after CRA were compared with nonsurvivors. Coronary disease, cardiomyopathy, and valvular disease had a better prognosis. Primary arrhythmia occurred in 73.5% of the >1-month survivor group and heart failure occurred in 12.6% of this group. In those patients in whom the initial mechanism of CRA was ventricular fibrillation, 33.3% survived for more than 1 month, but of those with ventricular asystole only 4.3% survived. None of the 10 patients with electromechanical dissociation survived. There was worse prognosis in patients included in the extreme age groups (zero to 10 years and 70 years or more). The best results occurred when the cardiac arrest took place in the catheterization laboratories. The worst results occurred in the intensive care unit and the hemodialysis room. CONCLUSION: The results in our series may serve as a helpful guide to physicians with the difficult task of deciding when not to resuscitate or when to stop resuscitation efforts.

Prevalence of systemic hypertension in students aged 7 to 14 years in the municipality of Barbacena, in the State of Minas Gerais, in 1999

OBJECTIVE: To detect the prevalence of systemic hypertension in children and to establish the relation between blood pressure levels and sex, age, ethnicity, weight, and height. METHODS: The prevalence of systemic hypertension and its relation to sex, age, ethnicity, weight, and height were studied in 611 students aged 7 to 14 years out of 19.928 students classified according to age, ethnicity, and sex, who underwent anthropometric evaluation and blood pressure measurement. Hypertensive individuals were considered those whose blood pressure level was > the 95th percentile for age and sex, confirmed on 3 examinations. RESULTS: The prevalence of hypertension was 16.6% in the first evaluation, and 4.6% and 2.5% in the subsequent evaluations. The mean blood pressure levels increased with age. Weight was important, not only to determine blood pressure in healthy children, but also to determine systemic hypertension in children, which was not observed with height despite the different studies. The prevalence of systemic hypertension in the different ethnic groups and the mean blood pressure levels according to sex were similar. CONCLUSION: In addition to routine physical examinations, age, weight, and appropriate cuff size should be considered when assessing blood pressure in children to prevent hypertension, morbidity and mortality, and to avoid placing a financial burden on health care providers.

An Equation for the Prediction of Oxygen Consumption in a Brazilian Population

Background: The equations predicting maximal oxygen uptake (VO2max or peak) presently in use in cardiopulmonary exercise testing (CPET) softwares in Brazil have not been adequately validated. These equations are very important for the diagnostic capacity of this method. Objective: Build and validate a Brazilian Equation (BE) for prediction of VO2peak in comparison to the equation cited by Jones (JE) and the Wasserman algorithm (WA). Methods: Treadmill evaluation was performed on 3119 individuals with CPET (breath by breath). The construction group (CG) of the equation consisted of 2495 healthy participants. The other 624 individuals were allocated to the external validation group (EVG). At the BE (derived from a multivariate regression model), age, gender, body mass index (BMI) and physical activity level were considered. The same equation was also tested in the EVG. Dispersion graphs and Bland-Altman analyses were built. Results: In the CG, the mean age was 42.6 years, 51.5% were male, the average BMI was 27.2, and the physical activity distribution level was: 51.3% sedentary, 44.4% active and 4.3% athletes. An optimal correlation between the BE and the CPET measured VO2peak was observed (0.807). On the other hand, difference came up between the average VO2peak expected by the JE and WA and the CPET measured VO2peak, as well as the one gotten from the BE (p = 0.001). Conclusion: BE presents VO2peak values close to those directly measured by CPET, while Jones and Wasserman differ significantly from the real VO2peak.

Stratification of the Risk of Sudden Death in Nonischemic Heart Failure

Despite significant therapeutic advancements, heart failure remains a highly prevalent clinical condition associated with significant morbidity and mortality. In 30%-40% patients, the etiology of heart failure is nonischemic. The implantable cardioverter-defibrillator (ICD) is capable of preventing sudden death and decreasing total mortality in patients with nonischemic heart failure. However, a significant number of patients receiving ICD do not receive any kind of therapy during follow-up. Moreover, considering the situation in Brazil and several other countries, ICD cannot be implanted in all patients with nonischemic heart failure. Therefore, there is an urgent need to identify patients at an increased risk of sudden death because these would benefit more than patients at a lower risk, despite the presence of heart failure in both risk groups. In this study, the authors review the primary available methods for the stratification of the risk of sudden death in patients with nonischemic heart failure.

Value of the Qrs-T Angle in Predicting the Induction of Ventricular Tachyarrhythmias in Patients with Chagas Disease

Background:The QRS-T angle correlates with prognosis in patients with heart failure and coronary artery disease, reflected by an increase in mortality proportional to an increase in the difference between the axes of the QRS complex and T wave in the frontal plane. The value of this correlation in patients with Chagas heart disease is currently unknown.Objective:Determine the correlation of the QRS-T angle and the risk of induction of ventricular tachycardia / ventricular fibrillation (VT / VF) during electrophysiological study (EPS) in patients with Chagas disease.Methods:Case-control study at a tertiary center. Patients without induction of VT / VF on EPS were used as controls. The QRS-T angle was categorized as normal (0-105º), borderline (105-135º) or abnormal (135-180º). Differences between groups for continuous variables were analyzed with the t test or Mann-Whitney test, and for categorical variables with Fisher's exact test. P values < 0.05 were considered significant.Results:Of 116 patients undergoing EPS, 37.9% were excluded due to incomplete information / inactive records or due to the impossibility to correctly calculate the QRS-T angle (presence of left bundle branch block and atrial fibrillation). Of 72 patients included in the study, 31 induced VT / VF on EPS. Of these, the QRS-T angle was normal in 41.9%, borderline in 12.9% and abnormal in 45.2%. Among patients without induction of VT / VF on EPS, the QRS-T angle was normal in 63.4%, borderline in 14.6% and abnormal in 17.1% (p = 0.04). When compared with patients with normal QRS-T angle, those with abnormal angle had a fourfold higher risk of inducing ventricular tachycardia / ventricular fibrillation on EPS [odds ratio (OR) 4; confidence interval (CI) 1.298-12.325; p = 0.028]. After adjustment for other variables such as age, ejection fraction (EF) and QRS size, there was a trend for the abnormal QRS-T angle to identify patients with increased risk of inducing VT / VF during EPS (OR 3.95; CI 0.99-15.82; p = 0.052). The EF also emerged as a predictor of induction of VT / VF: for each point increase in EF, there was a 4% reduction in the rate of sustained ventricular arrhythmia on EPS.Conclusions:Changes in the QRS-T angle and decreases in EF were associated with an increased risk of induction of VT / VF on EPS.

Cost-Effectiveness of High, Moderate and Low-Dose Statins in the Prevention of Vascular Events in the Brazilian Public Health System

Background:Statins have proven efficacy in the reduction of cardiovascular events, but the financial impact of its widespread use can be substantial.Objective:To conduct a cost-effectiveness analysis of three statin dosing schemes in the Brazilian Unified National Health System (SUS) perspective.Methods:We developed a Markov model to evaluate the incremental cost-effectiveness ratios (ICERs) of low, intermediate and high intensity dose regimens in secondary and four primary scenarios (5%, 10%, 15% and 20% ten-year risk) of prevention of cardiovascular events. Regimens with expected low-density lipoprotein cholesterol reduction below 30% (e.g. simvastatin 10mg) were considered as low dose; between 30-40%, (atorvastatin 10mg, simvastatin 40mg), intermediate dose; and above 40% (atorvastatin 20-80mg, rosuvastatin 20mg), high-dose statins. Effectiveness data were obtained from a systematic review with 136,000 patients. National data were used to estimate utilities and costs (expressed as International Dollars - Int$). A willingness-to-pay (WTP) threshold equal to the Brazilian gross domestic product per capita (circa Int$11,770) was applied.Results:Low dose was dominated by extension in the primary prevention scenarios. In the five scenarios, the ICER of intermediate dose was below Int$10,000 per QALY. The ICER of the high versus intermediate dose comparison was above Int$27,000 per QALY in all scenarios. In the cost-effectiveness acceptability curves, intermediate dose had a probability above 50% of being cost-effective with ICERs between Int$ 9,000-20,000 per QALY in all scenarios.Conclusions:Considering a reasonable WTP threshold, intermediate dose statin therapy is economically attractive, and should be a priority intervention in prevention of cardiovascular events in Brazil.