Prognosis Value Of Non-invasive Cardiac Mark On Patients With Acute Coronary Syndrome

Part I: Prognosis Value of Ventricular Late Potential on Patients withAcute Coronary SyndromeObjectiveEvaluate the prognostic value of ventricular late potentials on patients with acute coronarysyndrome.Methods134patients with ACS who were undergone coronary angiography and percutaneouscoronary intervention were included in this prospective study. VLP detection was givenfor each patient in2-4weeks after the onset of ACS. ECG workstation provided by GECompany was used to detect when the patients were in resting state. Parameters of VLP(fQRSd, RMS(40), LAS(40))were obtained from high frequency signal-averagedelectrocardiograms(ECG). The follow up was continued for at least half a year to observethe occurrence of MACE.ResultsAmong the134patients, VLP was positive in13cases and negative in121cases, with thepositive rate of9.7%. The medium of follow up was7.3months.18cases occurred MACE,where5cases were VLP positive and13cases were VLP negative. The sensitivity andspecificity of VLP were27.8%and93.1%, respectively, which had an important predictivevalue for MACE (P<0.05). LAS(40) with the positive predictive value and negativepredictive value of27.8%and97.4%had independent predictive value for the prognosisof ACS patients (P<0.05). Positive predictive value and negative predictive value offQRSd were33.3%and90.5%, while LAS(40) were16.7%and91.4%, respectively.ConclusionACS patients with positive VLP or abnormal LAS(40) had increased risks in MACEduring the recovery period. Part II: Prognosis Value of Heart Rate Turbulence and Heart RateVariability on Patients withAcute Coronary SyndromeObjectiveEvaluate the prognostic value of heart rate turbulence and heart rate variability on patientswith acute coronary syndrome.Methods167patients with ACS who were undergone coronary angiography and percutaneouscoronary intervention were included in this prospective study. DELMAR dynamic ECGdetection system was used to give24h-holter for each patient in2-4weeks after the onsetof ACS. HRT analysis system and HRV analysis system were applied for analysis, thenturbulence onset (TO) and turbulence slope (TS) were obtained to evaluate HRT; SDNNwas used to evaluate HRV. The follow up was continued for at least half a year to observethe occurrence of MACE.ResultsAbnormal HRT were detected in51cases in which7cases (13.73%) MACE occurred.7cases (11.85%) MACE occurred in normal HRT group. No significance in the two group(P>0.05). The sensitivity and specificity of HRT were50%and54.17%while the accuracywere53.63%. The positive predictive value and negative predictive value of HRV topredict MACE were9.1%and92.4%, respectively. Decreased SDNN had importantclinical significance in prediction of MACE of the patients withACS (P <0.05).ConclusionThe24h-holter examination is very necessary during the perioperative. Reduced HRV isimportant for prediction of the prognosis of patients with ACS, whereas predictive valueof HRT is limited.Part III: Factors Influencing Measurement of T-wave alternansWhether the T-wave alternans (TWA) is negative or positive on the electrocardiogram(ECG) is mainly based on the T wave amplitude, no matter with the spectrum method ortime domain method. In this paper, some cardiac or non cardiac factors that influence theTWA determination are discussed. For example, myocardial edema and peripheral edemaare two of these influence factors, which influence the T wave amplitude, thus affecting the determination of TWA. Another situation that influences TWA determination result isthat during3to6months after an acute myocardial infarction (AMI), with the changes ofthe human pathological and physiological state, T wave amplitude will also besubsequently changed, and the amplitude change is likely to bias the final determination ofTWA value. Sensitivity and specificity of TWA after AMI should be considered andevaluated from several aspects. So some factors influencing T wave amplitude will beconsidered in TWA measurement, so as to improve the credibility of TWA to predictsudden cardiac death (SCD).