The Value Of TWA, Hrt And HRV In Predicting Malignant Arrhythmia In AMI Patients

Objective:To investigate the value of microvolt T wave alternans （MTWA）. heart rate turbulence （HRT） and heart rate variability （HRV） basing on dynamic electrocardiogram in predicting malignant arrhythmia during hospitalization in patients with acute myocardial infarction （AMI）.Methods:A total of117AMI patients （male86, female31. aged32—84years old, mean aged61years old （±11years old））and38normal controls（male25, female13, aged41—79years old, mean aged59years old （±10years old）） were inrolled. The results of24-hour ambulatory ECG data in117AMI patients and38normal controls were analysed.117AMI patients were divided into ventricular tachycardia （VT）/ven-tricular fibrillation （VF） arm （37cases） and Non-VT/VF arm （80cases） basing on weather they had experienced an episode of VT/VF during their hospitalization. The24-hour ambulatory ECG data were performed and the following parameters were m-easured or calculated in the control group and all the patients:1. Time-domain HRV parameters:SDNN.SDANN,MSSD and PNN50. Requency-domain HRV parameters: VLF, LF,HF and LF/HF.2. HRT parameters:Turbulence onset（TO） and Turbulence slope （TS）.3.MTWA parameters:maximum MTWA.MTWA at Maximum Heart Rate.MTWA at8:00A.M. and MTWA during Maximum ST Segment Deviation.Results:1.LVEF was lower in AMI group than healhty group（P<0.01）. and also lower in VT/VF group than Non-VT/VF group（P<0.05）.2. SDNN. SDANN. PNN50and VLF were lower in AMI group compared to healthy group（P<0.05）, but there was no difference in TO and TS between the two groups（P>0.05）.MTWA in lead V₁was higher in patients with AMI compared to those healthy controls（P<0.05）. Heart rate at maximum TWA in V] was higher than healthy controls（P<0.05） and mean time of maximum TWA in V] was later compared to healthy controls（P<0.01）.3. SDNN and SDANN were lower in complete occlusion group significantly than steno-sis group（P<0.05）. but there was no difference in TS and MTWA between the two groups（P>0.05）. SDNN. SDANN. TS and MTWA were not different among single vessel stenosis group, double vessel stenosis group, and triple vessel stenosis group（P>0.05）.4.Significant differenc in TS. SDNN and SDANN were found between VT/VF group and Non-VT/VF group（P<0.01）. Positive rate of MTWA, SDNN and SDANN were different between VT/VF group and non-VT/VF group in AMI patients（P<0.05）. MTWA in lead V₁showed significant difference between VT/VF and Non-VT/VF group（P<0.01）. Heart rate at maximum TWA in V1of VT/VF group was higher than Non-VT/VF group （P<0.05）, and no significance was found in mean time of maximum TWA in V1between the two groups（P>0.05）.5.When MTWA≥25μV was used to predict VT/VF in patients with AMI, the sensitivity was50.00%. specificity was80.28%, positive predictive value was54.84%, and negative predictive value was77.03%.6.When MTWA, HRT and HRV were used to predict VT/VF in patients with AMI, the sensitivity was13.33%, specificity was98.21%. positive predictive value was80.00%. and negative predictive value was67.90%.Conclusions:MTWA, HRT and HRV of AMI patients could play the predictive role in malignant tachycardia arrhythmia during hospitalization. and could be used to identify high risk patients from AMI patients.