Autonomic dysfunction is highly prevalent in hemodialysis patients and has been implicated in their increased risk of cardiovascular mortality.ObjectiveTo evaluate the ability of different parameters of exercise treadmill test to detect autonomic dysfunction in hemodialysis patients.MethodsCross-sectional study involving hemodialysis patients and a control group. Clinical examination, blood sampling, echocardiogram, 24-hour Holter, and exercise treadmill test were performed. A ramp treadmill protocol symptom-limited with active recovery was employed.ResultsForty-one hemodialysis patients and 41 controls concluded the study. There was significant difference between hemodialysis patients and controls in autonomic function parameters in 24h-Holter and exercise treadmill test. Probability of having autonomic dysfunction in hemodialysis patients compared to controls was 29.7 at the exercise treadmill test and 13.0 in the 24-hour Holter. Chronotropic index, heart rate recovery at the 1st min, and SDNN at exercise were used to develop an autonomic dysfunction score to grade autonomic dysfunction, in which, 83% of hemodialysis patients reached a scoring ≥2 in contrast to 20% of controls. Hemodialysis was independently associated with either altered chronotropic index or autonomic dysfunction scoring ≥2 in every tested model (OR=50.1, P=0.003; and OR=270.9, P=0.002, respectively, model 5).ConclusionThe exercise treadmill test was feasible and useful to diagnose of the autonomic dysfunction in hemodialysis patients. Chronotropic index and autonomic dysfunction scoring ≥2 were the most effective parameters to differentiate between hemodialysis patients and controls suggesting that these variables portrays the best ability to detect autonomic dysfunction in this setting.
BackgroundAutonomic dysfunction (AD) is highly prevalent in hemodialysis (HD) patients and
has been implicated in their increased risk of cardiovascular mortality.ObjectiveTo correlate heart rate variability (HRV) during exercise treadmill test (ETT)
with the values obtained when measuring functional aerobic impairment (FAI) in HD
patients and controls.MethodsCross-sectional study involving HD patients and a control group. Clinical
examination, blood sampling, transthoracic echocardiogram, 24-hour Holter, and ETT
were performed. A symptom-limited ramp treadmill protocol with active recovery was
employed. Heart rate variability was evaluated in time domain at exercise and
recovery periods.ResultsForty-one HD patients and 41 controls concluded the study. HD patients had higher
FAI and lower HRV than controls (p<0.001 for both). A correlation was found
between exercise HRV (SDNN) and FAI in both groups. This association was
independent of age, sex, smoking, body mass index, diabetes, and clonidine or
beta-blocker use, but not of hemoglobin levels.ConclusionNo association was found between FAI and HRV on 24-hour Holter or at the recovery
period of ETT. Of note, exercise HRV was inversely correlated with FAI in HD
patients and controls.
Backgrounds: The exercise treadmill test can be used in ventricular dysfunction patients for functional capacity or predicting prognosis. The cardiac image with 123I MIBG shows cardiac sympathetic activation.
BackgroundThe association of autonomic activation, left ventricular ejection fraction (LVEF)
and heart failure functional class is poorly understood. ObjectiveOur aim was to correlate symptom severity with cardiac sympathetic activity,
through iodine-123-metaiodobenzylguanidine (123I-MIBG) scintigraphy and
with LVEF in systolic heart failure (HF) patients without previous beta-blocker
treatment. MethodsThirty-one patients with systolic HF, class I to IV of the New York Heart
Association (NYHA), without previous beta-blocker treatment, were enrolled and
submitted to 123I-MIBG scintigraphy and to radionuclide
ventriculography for LVEF determination. The early and delayed heart/mediastinum
(H/M) ratio and the washout rate (WR) were performed. ResultsAccording with symptom severity, patients were divided into group A, 13 patients
in NYHA class I/II, and group B, 18 patients in NYHA class III/IV. Compared with
group B patients, group A had a significantly higher LVEF (25% ± 12% in group B
vs. 32% ± 7% in group A, p = 0.04). Group B early and delayed H/M ratios were
lower than group A ratios (early H/M 1.49 ± 0.15 vs. 1.64 ± 0.14, p = 0.02;
delayed H/M 1.39 ± 0.13 vs. 1.58 ± 0.16, p = 0.001, respectively). WR was
significantly higher in group B (36% ± 17% vs. 30% ± 12%, p= 0.04). The variable
that showed the best correlation with NYHA class was the delayed H/M ratio (r=
-0.585; p=0.001), adjusted for age and sex. ConclusionThis study showed that cardiac 123I-MIBG correlates better than
ejection fraction with symptom severity in systolic heart failure patients without
previous beta-blocker treatment.
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