RESUMO
AIMS: Data on long-term follow-up of patients with Chagas' heart disease (ChHD) receiving a secondary prevention implantable cardioverter-defibrillator (ICD) are limited and its benefit is controversial. The aim of this study was to evaluate the long-term outcomes of ChHD patients who received a secondary prevention ICD. METHODS AND RESULTS: We assessed the outcomes of consecutive ChHD patients referred to our Institution from 2006 to 2014 for a secondary prevention ICD [89 patients; 58 men; mean age 56 ± 11 years; left ventricular ejection fraction (LVEF), 42 ± 12%]. The primary outcome included a composite of death from any cause or heart transplantation. After a mean follow-up of 59 ± 27 months, the primary outcome occurred in 23 patients (5.3% per year). Multivariate analysis showed that LVEF < 35% [hazard ratio (HR) 4.64; P < 0.01] and age ≥ 65 years (HR 3.19; P < 0.01) were independent predictors of the primary outcome. Using these two risk factors, a risk score was developed, and lower- (no risk factors), intermediate- (one risk factor), and higher-risk (two risk factors) groups were recognized with an annual rate of primary outcome of 1.4%, 7.4%, and 20.4%, respectively. A high burden of appropriate ICD therapies (16% per year) and electrical storms were documented, however, ICD interventions did not impact on the primary outcome. CONCLUSION: Among ChHD patients receiving a secondary prevention ICD, older age (≥65 years) and left ventricular dysfunction (LVEF < 35%) portend a poor outcome and were associated with increased risk of death or heart transplantation. Most patients received appropriate ICD therapies, however, ICD interventions did not impact on the primary outcome.
Assuntos
Cardiomiopatia Chagásica/mortalidade , Cardiomiopatia Chagásica/terapia , Desfibriladores Implantáveis , Transplante de Coração , Taquicardia Ventricular/mortalidade , Taquicardia Ventricular/terapia , Idoso , Feminino , Seguimentos , Transplante de Coração/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Prevenção Secundária , Volume SistólicoRESUMO
AIMS: Evidence is inconclusive concerning the benefit of implantable cardioverter-defibrillators (ICDs) for secondary prevention of mortality in patients with Chagas' heart disease (ChHD). The aim of this study was to compare the outcomes of ChHD patients with life-threatening ventricular arrhythmias (VAs), who were treated either with ICD implantation plus amiodarone or with amiodarone alone. METHODS AND RESULTS: The ICD group [76 patients; 48 men; age, 57 ± 11 years; left ventricular ejection fraction (LVEF), 39 ± 12%] and the historical control group treated with amiodarone alone (28 patients; 18 men; age, 54 ± 10 years; LVEF, 41 ± 10%) had comparable baseline characteristics, except for a higher use of beta-blockers in the ICD group (P < 0.0001). Amiodarone was also used in 90% of the ICD group. Therapy with ICD plus amiodarone resulted in a 72% reduced risk of all-cause mortality (P = 0.007) and a 95% reduced risk of sudden death (P = 0.006) compared with amiodarone-only therapy. The survival benefit of ICD was greatest in patients with LVEF < 40% (P = 0.01) and was not significant in those with LVEF ≥ 40% (P = 0.15). Appropriate ICD therapies occurred in 72% of patients and the rates of interventions were similar across patients with LVEF < 40% and ≥40%. CONCLUSION: Compared with amiodarone-only therapy, ICD implantation plus amiodarone reduced the risk of all-cause mortality and sudden death in ChHD patients with life-threatening VAs. Patients with LVEF < 40% derived significantly more survival benefit from ICD therapy. The majority of ICD-treated patients received appropriate therapies regardless of the LV systolic function.
Assuntos
Ritmo Idioventricular Acelerado/terapia , Amiodarona/uso terapêutico , Antiarrítmicos/uso terapêutico , Cardiomiopatia Chagásica/terapia , Morte Súbita Cardíaca/prevenção & controle , Desfibriladores Implantáveis , Fibrilação Ventricular/terapia , Ritmo Idioventricular Acelerado/etiologia , Adulto , Idoso , Cardiomiopatia Chagásica/complicações , Morte Súbita Cardíaca/etiologia , Feminino , Estudo Historicamente Controlado , Humanos , Masculino , Pessoa de Meia-Idade , Prevenção Secundária , Índice de Gravidade de Doença , Volume Sistólico , Taquicardia Ventricular/etiologia , Taquicardia Ventricular/terapia , Resultado do Tratamento , Fibrilação Ventricular/etiologiaRESUMO
PURPOSE: To test whether elite mountain bikers display a cardiac autonomic modulation pattern that is distinctive from that of active non-athletes. BACKGROUND: The relationship between autonomic adaptation and bradycardia during physical exercise, including high-performance sports such as the mountain biking, remains to be elucidated. METHODS: Twelve elite mountain bikers and 11 matched non-athletes controls were evaluated for time- and frequency-domain heart rate variability based on a 5-min ECG R-R intervals series obtained in both the supine and the orthostatic positions. Oxygen uptake and pulse rate were obtained at ventilatory thresholds and peak effort during an incremental cardiopulmonary exercise test. Significance of differences between medians (25th, 75th percentiles) from the two groups was evaluated by the Mann-Whitney test at p ≤ 0.05. RESULTS: Athletes had lower heart rate [50 (47, 59) versus 63 (60, 69) bpm; p = 0.0004] and higher cardiopulmonary performance than controls [70.9 (64.6, 74.4) versus 47.7 (41.0, 51.9) mL (kg min)(-1); p = 0.01]. No statistical difference was found in heart rate variability in the group of athletes (p = 0.17-0.97), except for trend toward having lower coefficient of variation and low-frequency absolute power indices both in supine position (p = 0.06). CONCLUSIONS: Bradycardia and higher oxygen uptake were found in association with unaltered cardiac autonomic modulation in elite mountain bikers athletes in supine and orthostatic positions, compared to active non-athletes. This bradycardia was not dependent on distinctive resting autonomic modulation. Intrinsic adaptation of sinus node and/or a peculiar state of autonomic adaptation to this exercise can be possible mechanisms.
Assuntos
Adaptação Fisiológica/fisiologia , Atletas , Sistema Nervoso Autônomo/fisiologia , Bradicardia , Frequência Cardíaca/fisiologia , Adulto , Ciclismo , Teste de Esforço , Feminino , Humanos , MasculinoRESUMO
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). METHODS: Agreement was verified between variability indices of 5-minute R-Ri simultaneously recorded by both devices and processed by unique software, from 33 subjects aged 18 to 42 years, normal or with different clinical conditions, in rest supine and active standing. ECG minus Polar differences were quantified by the Bland-Altman analysis, and tested by the one-sample t-test or Wilcoxon test. RESULTS: In the supine position, the Polar overestimates (P < 0.0001) the absolute and percentage mean or median of the number (-2.00; -0.49%) and mean of R-Ri (-1.85 ms; -0.20%) and pNN50 (-2.20%; -8.68%), and underestimates the standard deviation (SDNN) (0.32 ms; 0.59%) (P = 0.08; P = 0.02) and root mean square successive difference (RMSSD) (0.90 ms; 1.56%) (P = 0.0008; P < 0.0001). The coefficient of variation (CV) showed null difference. On standing, differences were overestimated for the number (-2.61 intervals; -0.64%) and mean of R-Ri (-0.70 ms; -0.09%), and underestimated for rMSSD (1.70 ms; 10.84%) (P < 0.0001 to < 0.02). The SDNN, CV, and pNN50 indices did not show differences (P = 0.12 to 0.73). CONCLUSIONS: The Polar S810 monitor was feasible and reliable for recording short-term R-R interval series, showing excellent agreement with the ECG in providing the time-domain indexes of heart interval variability with differences functionally not relevant. The CV showed the higher agreement in both postures, and the SDNN and pNN50 in the standing posture.