Assessment of baroreflex sensitivity using phenylephrine test for prediction of haemodynamic tolerance of inducible ventricular tachycardia after myocardial infarction

Background. Assessment of arterial sympathetic part of baroreflex response to hypotension, provoked by sodium nitroprusside infusion, allows one to predict haemodynamic tolerance (HT) of induced ventricular tachycardia (VT). However, widespread use of this method is limited, since it requires performing of microneurography of the peroneal nerve, which is attainable only in a few research centres. Aim. To study the value of the simple method of baroreflex sensitivity (BRS) assessment by the phenylephrine test (BRS-Phe) in prediction of HT of inducible VT. Methods. Fifty two patients (mean age 62±8 years) with remote myocardial infarction (MI) and a history of spontaneous VT underwent BRS-Phe, programmed electrical stimulation (PES) and left ventricular ejection fraction (LVEF) assessment. On the basis of the PES outcome the patients were divided into two groups: patients with good haemodynamic tolerance of VT (GHT-VT group, n=20), and those with poor haemodynamic tolerance of VT (PHT-VT group, n=27 patients). The remaining five patients in whom VT was not induced, were excluded from further studies. The relationship between HT of induced VT, BRS-Phe, cycle length (CL) of induced VT, LVEF and age was examined. Results. The lnBRS-Phe values were significantly lower in the PHT-VT group than in the GHT-VT group (0.8±0.8 ms/mmHg versus 1.7±0.5 ms/mmHg; p2= 21.1; p