[Problems in carrying out baroreflex sensitivity measurements in clinical routine practice: practicability and...

Measurement of baroreflex sensitivity is a new method to identify patients after myocardial infarction with a high risk for sudden cardiac death, ventricular tachycardia or ventricular fibrillation. In this retrospective study the baroreflex sensitivity was obtained noninvasively by measuring the systolic blood pressure blood pressure with a FINAPRES-device and correlating this with the R-R intervals of the ECG after raising blood pressure with an intravenous dose of Norfenefrin-hydrochloride (Novadral). According to other investigators a correlation of > 0.7 with a significance of p < 0.05 was recommended for evaluable results with a baroreflex sensitivity < 3 ms/mm Hg being judged as decreased. We investigated 302 patients (mean age 59 +/- 17 years, 224 males, 78 females). 75% of the investigations showed acceptable results. In 77 cases (25%) reasonable results could not be achieved. We found premature ventricular beats to be responsible in 18 investigations (6% of all investigations). 41 (13.1%) of all investigations were not evaluable because of bad correlation for unknown reason. When we looked closely at these nonevaluable results, we found a significantly higher number of patients with impaired left ventricular ejection fraction (< 40%), diabetes or inducible sustained ventricular tachyarrhythmia in the electrophysiologic study in this group. During all investigations no severe side effects were observed. We conclude that the noninvasive measuring of the baroreflex sensitivity is a save method and leads to reasonable results in 75% of the investigations. In 13.1% it is not possible for unknown reason to achieve sufficiently correlating values. These measurements cannot be evaluated from nowadays' standards and have to be further investigated as they may indicate a population at high risk.