Chemoreflexsensitivity in patients with survived sudden cardiac arrest andprior myocardial infarction

For evaluation of patients with an increased risk of sudden cardiac death, the analyses of ventricular late potentials, heart rate variability, and ba roreflexsensitivity are helpful. But so far, the prediction of a malignant arrhythmic event is not possible with sufficient accuracy. For a better ris k stratification other methods are necessary. In this study the importance of the ChRS for the identification of patients at risk for ventricular tach yarrhythmic events should be investigated. Of 41 patients included in the s tudy, 26 were survivors of sudden cardiac arrest. Fifteen patients were not resuscitated, of whom 6 patients had documented monomorphic ventricular ta chycardia and 9 hard no ventricular tachyarrhythmias in their prior history . All patients had a history of an old myocardial infarction (>1 year ago). For determination of the ChRS the ratio between the difference of the RR i ntervals in the ECG and the venous pO(2) before and after a 5-minute oxygen inhalation via a nose mask was measured (ms/mmHg). The 26 patients with su rvived sudden cardiac death showed a significantly decreased ChRS compared to those patients without a tachyarrhythmic event (1.74 +/- 1.02 vs 6.97 +/ - 7.14 ms/mmHg, P < 0.0001). The sensitivity concerning a survived sudden c ardiac death amounted to 88% for a ChRS below 3.0 ms/mmHg. During a 12-mont h follow-up period, the ChRS was significantly different between patients w ith and without an arrhythmic event (1.64 +/- 1.06 vs 4.82 +/- 5.83 ms/mmHg , P < 0.01). As a further method for evaluation of patients with increased risk of sudden cardiac death after myocardial infarction the analysis of Ch RS seems to be suitable and predicts arrhythmias possibly more sensitive th an other tests of neurovegetative imbalance. The predictive importance has to be examined by prospective investigations in larger patient populations.