Evolution of the heart rate variability, QT interval dispersion and T peak-tend interval in patients on longterm hormone therapy for advanced prostate cancer

Objective: To evaluate the effects of luteinizing hormo-ne-releasing hormone (LHRH) antagonists in advan-ced prostate cancer on the cardiac electrical parameters in patients (pts.) in sinus rhythm (SR)

Methods: We evaluated 40 men (pts.) with advanced prostate cancer treated by orchiectomy and LHRH an-tagonist degarelix. We noted clinical history and exclu-ded pts with atrial fibrillation, NYHA III and IV class heart failure (HF), acute myocardial infarction (AMI) within the last 6 months, chronic renal disease stages IV-V. We performed echocardiography, ECG, Hol-ter ECG and evaluated QT interval dispersion (QTd), Tpeak-Tend interval (Tpe) in V5 lead, heart rate vari-ability (HRV) using standard deviation of normal-to-normal interval over 24 hours (SDNN-24h), the square root of the mean squared differences of successive NN intervals (rMMSD) and the rate low frequency/high frequency (LF/HF) at the beginning of the treatment (V1) and 6 months later (V2). We noted in each pts the variations of the QTc, QTd, Tpe, SDNN 24 h, rMS-SD, LF/HF between V1 and V2 and Lown class of ventricu-lar premature beats (VPB) on Holter ECG. Statistical analysis was performed using Epi Info 8: paired t-test for comparing the differences and correlation test.

Results: Patients were 71.8 +/- 10 years old. 77.5% pa-tients had arterial hypertension, 52.5% stable angina, 25% old myocardial infarction, 22.5% diabetes melli-tus, 20% chronic renal disease grade I-IIIb. They were stable throughout the study. Mean LVEF was 60 +/- 5% and did not vary. Between V1 and V2 67.5% patients had a statistical significant increase of the QTd (+ QTd) and 25% patients a non significant increase of Tpe (ΔTpe). Mean +ΔQTd was 93 +/- 10 ms, mean +ΔTpe was 11 +/- 6 ms. 60% patients had a significant decrease of SDNN-24. 50% of them having concomitant incre-ase of QTd. There was no change of the rMMSD and LF/HF ratio between V1 and V2. We did not note an increase in the number or severity of VPB between V1 and V2.

Conclusions: 67.5% patients with advanced prostate cancer receiving LHRH antagonist for 6 months had significant prolongation of QTd and 60% a signifi-cant decrease of SDNN-24 suggesting an increase of the myocardial electrical instability. During this period there was no change in the number or severity of VPB.

ISSN – online: 2734 – 6382
ISSN-L 1220-658X
ISSN – print: 1220-658X
The Romanian Journal of Cardiology is indexed by:
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CODE: 379
CME Credits: 10 (Romanian College of Physicians)