Luiz Guilherme Grossi Porto

Comparison of Time‐Domain Short‐Term Heart Interval Variability Analysis Using a Wrist‐Worn Heart Rate Monitor and the Conventional Electrocardiogram

Background: Wrist‐worn heart rate monitors have not been extensively validated for heart rate variability analysis. The purpose of this study was to compare time‐domain variability of heart interval series (R‐Ri) recorded by the Polar S810 monitor (Polar Electro Oy, Kempele, Finland) and the conventional electrocardiogram (ECG).

Risk factors for prolonged hospital stay after isolated coronary artery bypass grafting

INTRODUCTION Characteristics of the patient and the coronary artery bypass grafting may predispose individuals to prolonged hospitalization, increasing costs and morbidity and mortality. OBJECTIVE The objective of this study was to evaluate individual and perioperative risk factors of prolonged hospitalization in intensive care units and wards. METHODS We conducted a case-control study of 104 patients undergoing isolated coronary artery bypass grafting with cardiopulmonary bypass. Patients hospitalized >3 days in the intensive care unit or >7 days in the ward were considered for the study. The association between variables was estimated by the chi-square test, odds ratio and logistic regression; P <0.05 was considered statistically significant. RESULTS Hospital stay >3 days in the intensive care unit occurred for 22.1% of patients and >7 days in the ward for 27.9%. Among preoperative factors, diabetes (OR=3.17) and smoking (OR=4.07) were predictors of prolonged intensive care unit stay. Combining the pre-, intra-and postoperative variables, only mechanical ventilation for more than 24 hours (OR=6.10) was predictive of intensive care unit outcome. For the ward outcome, the preoperative predictor was left ventricular ejection fraction <50% (OR=3.04). Combining pre- and intraoperative factors, diabetes (OR=2.81), and including postoperative factors, presence of infection (OR=4.54) were predictors of prolonged hospitalization in the ward. CONCLUSION Diabetes and smoking were predictors of intensive care unit outcome, and ejection fraction <50% of ward outcome. For the set of perioperative factors, prolonged hospitalization after isolated coronary artery bypass grafting was associated with mechanical ventilation >24 hours for the intensive care unit and presence of infection for the ward.

Resting Bradycardia, Enhanced Postexercise Heart Rate Recovery and Cardiorespiratory Fitness in Recreational Ballroom Dancers

ABSTRACT Purpose: In a cross-sectional study design, we evaluated the resting heart rate (HRbaseline) and exercise and postexercise stress test-related chronotropic responses in male practitioners of recreational ballroom dancing (BD; n = 25, Mage = 26.6 ± 6.1 years) compared to a control group of insufficiently active nondancers (CG; n = 25, Mage = 25.9 ± 4.5 years). Method: All participants underwent a submaximal exercise test. At 85% of the maximal predicted HR, the recovery protocol was started, and heart rate recovery (HRR) was recorded during 1-min intervals for 5 min. Results: Compared with CG, BD showed lower HRbaseline (70 beats per minute [bpm] vs. 62 bpm, respectively, U = 143, p < .05, ES = .46), lower preexercise HR (94 bpm vs. 86 bpm, U = 157, p < .05, ES = .42), longer exercise test duration (346 s vs. 420 s, U = 95.5, p < .05, ES = .59), and higher HRR for 5 min postexercise (U = 1.29–1.89, p < .05, ES = .33–.50) as follows: 1st min (32 bpm vs. 40 bpm), 2nd min (45 bpm vs. 53 bpm), 3rd min (51 bpm vs. 58 bpm), 4th min (55 bpm vs. 59 bpm), and 5th min (59 bpm vs. 63 bpm). The coefficient of HRR from the 1st min to the 5th min postexercise was similar in both groups (U = 229–311, p > .05, ES = < .10–.22). Conclusion: Heightened cardiovascular functional status characterized by favorable enhanced chronotropic dynamics appears to occur in practitioners of recreational ballroom dancing, which suggests that this modality of exercise may result in health benefits.

EFEITO DE DIFERENTES PROTOCOLOS DE RECUPERAÇÃO SOBRE A FUNÇÃO AUTONÔMICA CARDÍACA

Introduccion: La evaluacion de la funcion autonomica cardiaca (FAC) despues de la prueba de esfuerzo (PE) se considera un predictor potente e independiente del riesgo cardiovascular. Es escaso el conocimiento de la influencia de los diferentes protocolos de recuperacion sobre la FAC despues de la PE en la cinta rodante con voluntarios en la posicion de pie. Objetivo: Comparar la reactivacion vagal y el grado de la modulacion general de la FAC en dos diferentes protocolos de recuperacion, pasiva (RP) vs. activa (RA) inmediatamente despues de la PE submaxima en la cinta rodante. Metodos: Se evaluaron 24 hombres fisicamente activos con edades (promedio ± DE) de 27,2 ± 4,4 anos y IMC de 24,8 ± 1,8 kg/m2. El orden de los protocolos de recuperacion se definio al azar. Las pruebas se realizaron en un intervalo de siete dias. Ambas recuperaciones se realizaron en la posicion de pie durante cinco minutos inmediatamente despues de la PE. Los indices temporales de la variabilidad de la frecuencia cardiaca fueron utilizados para evaluar la reactivacion vagal y el grado de modulacion general de la FAC, rMSSD y SDNN, respectivamente, en RP y RA. Despues del analisis de la distribucion de los datos, se utilizaron la prueba de Mann-Whitney y la de Friedman con post-hoc de Dum, a un nivel de significacion de p ≤ 0,05. Resultados: Se observo una mayor reactivacion vagal en el primer minuto de la PR comparada a la RA [4,1 (4,9-3,4) ms vs. 3,4 (4,0-2,9) ms, p = 0,03] y un mayor grado de modulacion general de la FAC del tercer al quinto minuto y una tendencia a la diferencia estadistica en el segundo minuto de RP comparada a RA (p = 0,09-0,005). Conclusion: Los resultados muestran que el esfuerzo fisico minimo, como caminar lentamente sobre la cinta rodante, disminuyo la reactivacion vagal y el grado de modulacion general de la FAC despues de la PE submaxima en hombres fisicamente activos.

Response to the letter by Anthony S. Leicht.: Bradycardia-changes in intrinsic rate rather than cardiac autonomic modulation. doi:10.1007/s10286-013-0208-8

We thank Prof. Leicht for the interesting and opportune comments about our paper [1] and the possible mechanisms related to exercise-induced bradycardia (EIB). Although we have not addressed the cardiac intrinsic rate, we agree that modifications on sino-atrial function (SAF) may play an important role on EIB. Further research should be conducted in order to discuss the possible limitations of the usual HRV analysis associated with EIB, based on the evaluation of HRV in different training season periods [2] or employing non-linear methods that allow the use of HRV analysis on dynamic and non-stationary conditions, as the post-exercise recovery period. Our findings are consistent with several studies [3, 4] but different results should also be taken into account [5, 6]. The modality of exercise should also be discriminated. Even though we do agree with Leicht’s suggestion about the necessity to examine SAF as a key mechanism, current data indicate that the precise characterization of the EIB is still an open question. References