Early detection of cardiac dysfunction in thalassemic patients by radionuclide angiography and heart rate variability analysis.
BACKGROUND
Cardiac dysfunction remains the major cause of death in beta-thalassemia. Aim of this study was to assess early myocardial damage in thalassemic patients with no symptoms or echocardiographic evidence of dysfunction at routine monitoring.


METHODS
Twenty patients (seven females; median 25 yr [first quartile 22,third quartile 28]) with beta-thalassemia underwent radionuclide angiography (RNA) at rest and during low-dose dobutamine infusion (5-10 gamma/kg/min). Right and left ventricular ejection fractions (EF) were determined by first-pass method and gated equilibrium acquisition, respectively. Twenty-four-hour Holter monitoring with time-domain heart rate variability (HRV) assessment and echocardiographic follow-up (21 months [5,27]) were performed.


RESULTS
Eleven patients showed regional wall motion abnormalities at RNA; left ventricular EF, HR and diastolic measurements significantly increased after dobutamine infusion. Patients with abnormal RNA right ventricular EF (n = 8, <0.45) showed lower echocardiographic left ventricular EF at the enrollment (0.54 [0.50,0.61] vs. 0.62 [0.56,0.67], P = 0.02) than those with a normal right ventricular EF. Patients with reduced standard deviation of the averages of RR intervals in all 5-minute periods of entire recording (SDANN) (n = 6, <100 ms), a measure of HRV, had lower echocardiographic left ventricular EF (0.53 [0.49,0.62] vs. 0.62 [0.56,0.66], P = 0.03) and lower fractional shortening (0.28 [0.25,0.32] vs. 0.36 [0.30,0.39], P = 0.003) at the enrollment than those with normal SDANN. No significant association was found between RNA and HRV measurements and follow-up left ventricular function.


CONCLUSIONS
Right ventricular dysfunction and abnormal HRV may represent the early features of cardiac disease in thalassemic patients with no evidence of ventricular dysfunction at routine evaluation.
De Chiara
Benedetta
B
Section of Milan, CNR Clinical Physiology Institute, Niguarda Hospital, Milan, Italy.
Crivellaro
Wilma
W
Sara
Roberto
R
Ruffini
Livia
L
Parolini
Marina
M
Fesslovà
Vlasta
V
Carnelli
Vittorio
V
Fiorentini
Cesare
C
Parodi
Oberdan
O
D000328:Adult; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D011875:Radionuclide Angiography; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging* / Q000209:etiology / Q000401:mortality; D017086:beta-Thalassemia / Q000150:complications / Q000401:mortality