Patients With Ventricular Tachycardia Of Right Ventricular Domain T-wave Alternans Characteristics And Clinical Follow-up Study

PartⅠThe features and clinical significance of microvolt T-wave alternans in patients with right ventricular tachycardia【Objective】To explore the features and clinical significance of microvolt T-wave alternans (MTWA) using modified moving average analyses in patients with right ventricular tachycardia.【Methods】MTWA voltages were detected using modified moving average analyses with exercise treadmill test in 35 patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) tachycardia, in 10 patients with idiopathic right ventricular tachycardia (IRVT), and in 60 healthy persons as control. MTWA voltages in precordial lead V1~V6 were recorded. The maximal MTWA voltages were expressed as MaxValt. The MTWA voltages were compared among ARVC group, IRVT group, and control group.【Results】The voltages of MTWA in all precordial leads were higher in ARVC group than those in control group (P<0.01). There was no significant difference between IRVT and control group(P>0.05). The voltages of MTWA in Lead V4 and MaxValt were higher in ARVC group than those in IRVT group (P<0.05). The receiver-operating characteristics (ROC) curves for MTWA showed that the sensitivity and specificity for diagnosing ARVC was 74.3% and 80.0% , respectively, when the 11.5μV was chosen as cutpoint value of MaxValt. In ARVC group, the voltages of MTWA in lead V2,V3,V4,V6 and MaxValt were greater in those with occurrence of sustained ventricular tachycardia during the previous one year than in those without ventricular tachycardia occurrence (P<0.05).【Conclusion】The voltages of MTWA detected with modified moving average method are significantly higher in ARVC patients. MTWA might be related to the late occurrence of ventricular tachycardia in ARVC patients. PartⅡUtility of modified moving average analyses of T-wave alternans to predict ventricular arrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy【Objective】To explore the predictive value of microvolt T-wave alternans (MTWA) using modified moving average analyses for ventricular arrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC).【Methods】MTWA voltages were detected using modified moving average analyses with exercise treadmill test in 35 patients with arrhythmogenic right ventricular cardiomyopathy and in 60 healthy controled people. MTWA voltages in precordial lead V1~V6 were recorded. The maximal MTWA voltages were expressed as MaxValt. The ARVC patients were followed up. The end point was the combination of cardiac death, sustained ventricular tachycardia/fibrillation, or appropriate ICD discharge.【Results】There was significant difference between ARVC patients and healthy people in lead V1~V6 and the greatest voltage of each individual in all precordial leads (MaxValt). The 75th percentile value of MaxValt in healthy people is 9.75μV. On 12-16 months'follow-up, there were 6 patients with cardic events. Differences in event rates were not found between MTWA-negative and positive subjects. The negative predictive value (NPV) and positive predictive value (PPV) of the MTWA test for the prediction of events at 12 months were 100% and 20.6% , respectively.【Conclusion】MTWA using modified moving average analyses with exercise has a high 1-year NPV for ventricular arrhythmias in ARVC patients. MMA-MTWA might play an important role in ventricular arrhythmias prediction in ARVC patients.