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Measurement of Heart Rate Variability (HRV) is a noninvasive approach based on ECG monitoring that allows an indirect evaluation of cardiovascular autonomic control. In this study, we aimed to compare HRV parameters between type 2B and other types of vasovagal syncope (VVS) to find parameters for predicting prolonged asystole risk before Tilt testing.
By examining past records, we scanned patients between 1 January 2009 - 1 December 2012 who applied our hospital with complaining syncope.We included one hundred patients with a diagnosis of VVS who examined by echocardiography and Holter ECG before Tilt table testing. Patient with type 2B VVS was called group 1 (n:43), VVS other than type 2B (type 1, type 2A, type 3 and POTS) were called group 2 (n:57).
In group 1 patients, starting asystole time was observed at 16.2±10.4 minute from beginning the test and duration asystole period was found 5.2±2.1 seconds during the test.
Between two groups, HRV parameters (SDNN, SDANN, SDNN indeks) were significantly longer in group 1 patients than group 2 patients (p:0.019, p:0.036, p:0.008; respectively).
The highest heart rate value which obtained by Holter ECG records were significantly lower in group 1 patients than group 2 patients (p:0.011).
Patients diagnosed with type 2B VVS were found prolonged HRV parameters. It considered these type of patients are more sensitive to the effects of autonomic nervous system than other types of VVS. The highest heart rate value in type 2B VVS was lower than the other group. It suggested that sinus node parasympathetic dominance inhibites reaching maximum heart rate values in those patients than other types of VVS patients. Our study is important to show predicting risk of asystole before Tilt testing by examaning HRV parameters and the maximum heart rate value