Effect of reperfusion strategy on QT dispersion in patients with acute myocardial infarction:Impact on in-hospital arrhythmia

BACKGROUND Myocardial ischemia and ST-elevation myocardial infarction(STEMI)increase QT dispersion(QTD)and corrected QT dispersion(QTcD),and are also associated with ventricular arrhythmia.AIM To evaluate the effects of reperfusion strategy[primary percutaneous coronary intervention(PPCI)or fibrinolytic therapy]on QTD and QTcD in STEMI patients and assess the impact of the chosen strategy on the occurrence of in-hospital arrhythmia.METHODS This prospective,observational,multicenter study included 240 patients admitted with STEMI who were treated with either PPCI(group I)or fibrinolytic therapy(group II).QTD and QTcD were measured on admission and 24 hr after reperfusion,and patients were observed to detect in-hospital arrhythmia.RESULTS There were significant reductions in QTD and QTcD from admission to 24 hr in both group I and group II patients.QTD and QTcD were found to be shorter in group I patients at 24 hr than those in group II(53±19 msec vs 60±18 msec,P=0.005 and 60±21 msec vs 69+22 msec,P=0.003,respectively).The occurrence of in-hospital arrhythmia was significantly more frequent in group II than in group I(25 patients,20.8%vs 8 patients,6.7%,P=0.001).Furthermore,QTD and QTcD were higher in patients with in-hospital arrhythmia than those without(P=0.001 and P=0.02,respectively).CONCLUSION In STEMI patients,PPCI and fibrinolytic therapy effectively reduced QTD and QTcD,with a higher observed reduction using PPCI.PPCI was associated with a lower incidence of in-hospital arrhythmia than fibrinolytic therapy.In addition,QTD and QTcD were shorter in patients not experiencing in-hospital arrhythmia than those with arrhythmia.

QT Dispersion Level and Its Clinical Significance in Dilated Cardiomyopathy

Objective To evaluate the clinical significance of QT dispersion (QTd, QTcd) in dilated cardiomyopathy (DCM). Methods QTd and QTcd were measured on simultaneously recording 12 lead electrocardiograms (ECGs) in 60 DCM patients and compared with 60 healthy subjects. Results The values of QTd and QTcd in DCM were significantly higher than those in control group (P<0 01). With subgroup analysis, QTd and QTcd in patients with cardiac sudden death (CSD) were longer than those in survivors and those died of progressive heart failure (P<0 05), patients with ventricular tachycardia (VT) or with severe heart failure than those without (compared with patients with ventricular premature beats [VPB], P<0 05, compared with patients without ventricular arrhythmia [VA], P<0 01) or with mild heart failure (P<0 01). The values of QTd and QTcd in patients with VPB were greater than those in patients without VA(P<0 05). There were significant differences in the rates of VT, CSD and heart failure between the groups of QTd>110 ms and QTd≤110 ms(P<0 01 or P<0 05), in contrast to ejection fraction(EF) and fractional shortening (FS)(P>0 05). Conclusion The values of QTd and QTcd increased in DCM patients were susceptive index for monitoring maligant VA in DCM, also important prognostic markers of CSD. QTd was correlated with NYHA functional class but not with EF and FS.

Electrocardiographic alterations in patients with chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease(COPD)have an increased risk for cardiovascular events,and electrocardiography has an important role in detecting cardiac side effects of COPD-related hypoxia.