Reliability of a Holter-based methodology for evaluation of sleep apnoea syndrome.

AIMS: Sleep apnoea has significant medical implications. A reliable non-invasive method (as a regular Holter system with a specific software) would be valuable for the screening of this condition in ambulatory patients. METHODS AND RESULTS: A total of 40 patients were divided into two groups: Group I, 20 patients with clinical suspicion of obstructive sleep apnoea (OSA) and Epworth sleepiness score >or= 10 and Group II, 20 controls. In Group I, polysomnography was performed simultaneously with Holter (specific software to detect sleep apnoea). In Group II, Holter-based detection was utilized. A cutoff value of 10 for the apnoea-hypopnoea index (for polysomnography) or for the respiratory disturbance index (RDI) (for Holter) was considered abnormal. Sleep apnoea was confirmed by polysomnography in 14 patients (70%) in Group I. Holter recordings correctly identified OSA in 11 patients (r = 0.74 with polysomnography; P = 0.0002). Holter showed 78.5% sensitivity, 83.3% specificity, 91.6% positive predictive value, and 62.5% negative predictive value (with polysomnography as the gold standard). The RDI measured by Holter was 19.5 +/- 20 in Group I and 3.9 +/- 4.4 in controls (P < 0.005). The measurement between Holter and polysomnography (Bland and Altman method) showed good correlation (mean 4.7 with 39.4 and -30.1 SD) and a Pearson correlation coefficient (r) of 0.74 (P = 0.0002, 95% CI: 0.44-0.89). CONCLUSION: Holter-based software may constitute an accessible tool on initial suspicion of OSA.

Circadian pattern of ventricular tachycardia episodes in patients with Chagas heart disease.

Chronic Chagas' cardiomyopathy (CCM) causes ventricular arrhythmias and sudden death, and constitutes the most frequent cause of death in many endemic areas. The circadian variation in the incidence of ventricular arrhythmias and sudden death differs according to the substrate (e.g., morning and evening peaks in ischemic heart disease and non-Chagasic dilated cardiomyopathy). Third generation implantable cardioverter defibrillators (ICDs) have the ability to store the time and date of each ventricular tachycardia (VT) episode, enabling the patterns of ventricular tachyarrhythmia occurrence to be analyzed. The aim of our study was to evaluate the circadian variation of spontaneous VT in recipients of an ICD with CCM.

Padrão circadiano dos episódios de taquicardia ventricular em portadores de cardiopatia chagásica / Circadian pattern of ventricular tachycardia episodes in patients with chagas heart disease

Cardiomiopatia chagásica crônica (CCC) causa arritmias ventriculares e morte súbita, sendo a mais freqüente causa de óbito em muitas áreas endêmicas1,2. A variação circadiana na incidência de arritmias ventriculares e morte súbita difere de acordo com o substrato (p. ex: picos matinais e noturnos na cardiopatia isquêmica e na cardiomiopatia dilatada não-chagásica). Cardioversores-desfibriladores implantáveis de terceira geração (CDI) conseguem registrar o dia e a hora de cada episódio de taquicardia ventricular (TV), permitindo uma análise dos padrões de ocorrência de taquiarritmias. O objetivo deste estudo foi avaliar a variação circadiana da TV espontânea em portadores de CCC tratados com CDI.

Chronic Chagas' cardiomyopathy (CCM) causes ventricular arrhythmias and sudden death, and constitutes the most frequent cause of death in many endemic areas1,2. The circadian variation in the incidence of ventricular arrhythmias and sudden death differs according to the substrate (e.g., morning and evening peaks in ischemic heart disease and non-Chagasic dilated cardiomyopathy). Third generation implantable cardioverter defibrillators (ICDs) have the ability to store the time and date of each ventricular tachycardia (VT) episode, enabling the patterns of ventricular tachyarrhythmia occurrence to be analyzed. The aim of our study was to evaluate the circadian variation of spontaneous VT in recipients of an ICD with CCM.

Importance of early combined N-terminal pro-brain natriuretic peptide and cardiac troponin T measurements for long-term risk stratification of patients with decompensated heart failure.

BACKGROUND: Markers of myocardial necrosis and natriuretic peptides are risk predictors in decompensated heart failure (DHF). We prospectively studied the optimal timing of combined cardiac troponin T (cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP) measurements for long-term risk stratification. METHODS: cTnT and NT-proBNP were measured upon admission, and before discharge in 76 patients hospitalized for DHF (mean age 62.3 +/- 15 years; 71% men). RESULTS: During a mean follow-up of 252 +/- 120 days, 39.5% of patients died or were re-hospitalized for DHF. From receiver-operator-characteristic (ROC) curves, the selected cut-off values for cTnT and NT-proBNP were 0.026 ng/ml and 3,700 pg/ml on admission, and 0.030 ng/ml and 3,200 pg/ml, respectively, at discharge. Depending upon measurements above vs below cut-off, the population was distributed on admission and before discharge for three groups: both negative (24% and 30% of patients); one positive (43% and 42%); and both positive (33% and 28%). For the admission groups, the 1-year DHF-free re-hospitalization survival rates were 85%, 60% and 34%, respectively (p = 0.0047). One-year survival rates for DHF-free re-hospitalization were 63%, 71% and 26% (p = 0.0029), respectively, for the discharge groups. In the Cox proportional hazards model, systolic blood pressure (hazard ratio [HR]: 0.98; 95% confidence interval [CI]: 0.96 to 0.99), heart rate (HR: 0.97; 95% CI: 0.94 to 0.98), one positive biomarker on admission (HR: 10.5; 95% CI: 1.3 to 83.7) and two positive biomarkers on admission (HR: 13.9; 95% CI: 1.8 to 98.5) were independent predictors of long-term outcomes. However, NT-proBNP on admission was the most important predictor of long-term prognosis (HR: 5.1; 95% CI: 2.3 to 12.2). CONCLUSIONS: The combined measurements of cTnT and NT-proBNP on hospital admission were more reliable than their measurements before discharge in the long-term risk stratification of DHF. A single positive measurement on admission predicted a poor long-term outcome.

Efecto aditivo de los incrementos de urea y creatinina a la admisión sobre el pronóstico a largo plazo en pacientes con insuficiencia cardíaca descompensada / Additive effect of increased urea and creatinine levels at admission on long-term prognosis in patients with decompensated heart failure

Introducción y objetivos: La elevación de la creatinina es un marcador de riesgo en la insuficiencia cardíaca descompensada (ICD). Nuestro objetivo fue evaluar el rol pronóstico a largo plazo de la detección temprana de deterioro renal (DR), definido por elevación en los niveles de urea y/o creatinina, en pacientes con ICD. Material y métodos: Se incluyeron en forma prospectiva 241 individuos admitidos por ICD. Se seleccionaron los puntos de corte para urea y creatinina al ingreso a través de curva ROC, para la detección de eventos combinados (muerte o rehospitalización por ICD). El seguimiento medio fue de 366 ± 482 días. Resultados: La edad media fue 65,4 ± 11,6 años (63,8% hombres, 42,3% etiología isquémica) y la incidencia de eventos fue de 107. El área bajo curva ROC de urea y creatinina para la predicción de eventos fue de 0,59 y 0,57. Los puntos de corte, sensibilidad y especificidad fueron: urea 55 mg/dL, 57% y 63%; y creatinina 1,17 mg/dL, 58% y 62%, respectivamente. El DR se identificó en 144 (60,4%) sujetos, 82 con ambos marcadores elevados, 29 sólo con creatinina elevada y 33 sólo con urea elevada. En el grupo con DR fue más frecuente el diagnóstico previo de ICD (89 vs 78%, p=0,041) y la hipoperfusión periférica (12,5 y 4,1%, p=0,020), tuvieron menor fracción de eyección del ventrículo izquierdo (FEVI) (36,4±17,2% y 41,1±19,6%, p=0,05) y mayor nivel de pro-BNP (8681±9010 pg/l y 2943±269 pg/l, p<0,001). La supervivencia libre de rehospitalización por ICD a 18 meses en aquellos con y sin DR fue 35 y 60% (p=0,0086), y las variables asociadas con evolución adversa fueron DR (HR=1,8; IC 95% 1,1-2,7) y diagnóstico previo de ICD (HR=1,9; p<0,001; IC 95% 1,1-3,5). Conclusión: El uso combinado de urea y creatinina permite incrementar la detección temprana de DR en pacientes con ICD. Este hallazgo fue un fuerte predictor de eventos a largo plazo.

Background: Increased level of creatinine is a powerful risk marker in decompensated heart failure (DHF). Our objective was to evaluate the long-term prognostic role of early detection of renal dysfunction (RD), defined by abnormal levels of urea and/or creatinine, in patients with DHF. Patients and methods: Two hundred and forty-one patients admitted for DHF were prospectively included. The cut-off of urea and creatinine were selected using ROC curves for predicting combined events (death or rehospitalization for DHF). The mean follow-up was 366±482 days. Results: The mean age were 65.4±11.6 years (64% male, 42.3% ischemic etiology), and 44.4% had events. The area under ROC curves to predicting events for urea and creatinine was 0.59 and 0.57, respectively. The cut-off, sensitivity and specificity were: urea 55 mg/dL, 57% and 63%; creatinine 117 mg/dL, 58% and 62%, respectively. RD was identified in 144 (60.4%) subjects, 82 had elevated both markers, 29 with only increased levels of creatinine, and 33 with only abnormal levels of urea. RD groups had more frequently a previous diagnosis of HF (89 vs 78%, p=0.041) and peripheral hypoperfusion (12.5 vs 4.1%, p=0.020), and they showed lower LVEF (36.4±17.2% vs 41.1±19.6%, p=0.05) and higher pro-BNP (8.681±9010 pg/mL vs 2943±2690 pg/ mL, p<0.001) than those without RD. Eighteen-month free-DHF rehospitalization survival in patients with and without RD was 35% and 60% (p=0.0086). The variables significantly associated with events were RD (1.8, p<0.001; CI 95%=1.1-2.7) and previous diagnosis of HF (HR=1.9, CI 95%=1.1-3.5). Conclusion: The combined use of urea and creatinine improve the early detection of RD in patients with DHF. This finding was a strong long-term prognostic predictor.