Kardiologia polska 2017 12 01() doi 10.5603/KP.a2017.0228
Cardionhibitory syncope is related with excessive bradycardia or asystole due to parasympathetic response.
We investigated whether patients with cardioinhibitory syncope have higher heart rate recovery index (HRRi) considered as an parasympathetic system activation in exercises stress testing (EST) than other those with other neurogenic syncope forms METHODS: A total of 262 patients who had neurogenic syncope documented by head-up tilt test (HUTT) and 199 healthy control individuals were examined. A maximal EST was applied to all patients after the HUTT. The HRRi was obtained by subtracting the heart rate that was measured at the first (HRRi-1), second (HRRi-2) and third minute (HRRi-3) of the recovery period from the maximal heart rate that was measured during the test.
80 patients had cardioinhibitory syncope, 118 patients had vasodepressor syncope, and 64 patients had mixed type syncope. The HRRi-1 was higher in patients with syncope (43.3±7.7) compared to the control group (34.5±4.8) (p<0.001). Among the syncope groups, there was no difference between patients with vasodepressor syncope (42.2±7.6) and patients with mixed type syncope (40.7±4.1) in terms of HRRi-1 according to post hoc analysis (p=0.420). However, patients with cardioinhibitory syncope (47±8.7) had a higher HRRi-1 than vasodepressor and mixed type syncope groups (p<0.05). The threshold value of the HRRi-1, which can be used for the prediction of cardioinhbitory syncope development, was determined to be 41 with 75% sensitivity and 72% specificity. CONCLUSIONS
The HRRi-1 was higher in patients with cardioinhibitory syncope compared to the controls. The HRRi-1 has the predictive feature of differentiating cardioinhibitory syncope from other syncope types.