Prolonged QTc Dispersion Correlates with Coronary Artery Disease in Acute ST Elevated Myocardial Infarction (STEMI)

Abstract

Background: It has been found that there is strong association of QT dispersion and QT dispersion ratio with extent and severity of coronary artery disease. Qualitative importance of QTc dispersion on the base line ECG in patients with MI is recognized clinically but quantification of this phenomenon is less commonly used in clinical practice, which might be a better independent risk predictor of this group of patients. Methods: A total of 100 patients were selected, Study populations sub-divided into two groups on the basis of QTc dispersion. In group I (comparison group): QTc dispersion is <60 milliseconds (msec) in group II (study group) : QTc dispersion e”60milliseconds(msec). 50 patients in each group. QT dispersion was calculated on standard resting 12 lead ECGs. QT interval was measured from the beginning of the inscription of the QRS complex to the point at which the T wave returned to the isoelectric line. Angiographic severity of coronary artery disease was assessed by- Vessel score, Friesinger score and Leaman score. Interpretation of coronary angiogram was reviewed by at least two cardiologists. . Results: The mean vessel score for group I patients was 1.16±0.68 and that of group II patients was 2.30±0.64 and the mean difference was statistically significant (p<0.05). Patients those had single vessel involvement had mean QTc dispersion 57.05, patients those had double vessel disease mean QTc dispersion was 102.00 and patients those had triple vessel involvement had mean QTc dispersion 177.60. There was a strong positive correlation with the QTc dispersion and increasing number of vessel involvement (Pearson’s correlation coefficient). The mean Friesinger score for group I patients was 4.84±2.56 and that of group II patients was 9.80±2.60. The mean difference was significantly (p<0.05) higher in group II patients. There was a strong positive correlation between the QTc dispersion and Leaman score (Pearson’s correlation coefficient). In group I patients 56% had insignificant coronary artery disease and 44% had significant coronary artery disease defined by Friesinger index (n=100). In group II patients 6% had Insignificant coronary artery disease & had 94% significant coronary artery disease. Conclusion: QTc dispersion>60 ms had independent predictive value for the severity of coronary artery disease. The greater the QTc dispersion the higher the number of coronary artery involvement. We observed that there is a positive correlation between prolonged QT dispersion and coronary artery disease severity in terms of Vessel score, Friesinger score, Leaman score. DOI: http://dx.doi.org/10.3329/cardio.v5i2.14322 Cardiovasc. j. 2013; 5(2): 173-181

Effect of PCI on QTC Dispersion in Patients with Angina

“…Maximum frequency was found in the age group of 41-60 years.Almost similar mean age was observed by Yilmaz,et al 18 ,Tikiz,et al 19 , which are comparable with the current study.In this study it was observed that among 100 patients 76(76%) patients were male and 24(24%) patients were female which was almost similar 72/28 as observed by observed by Zhang Y et al 15 The common risk factors for coronary artery disease in the present study were smoking(73%) , the highest one followed by hypertension(50%), diabetes mellitus (49%), family history of CAD(23%), and dislipidemia(13%). Almost similar distribution of risk factors were observed by Sharafat et al 10 and Uddin et al 20 found smoking as the highest prevalent risk factor. This finding of the risk factors was similar regarding smoking habit & dyslipidemia with the study conducted by Tikiz et al 15…”

“…9 Prolonged QTc dispersion correlates with coronary artery disease severity in acute ST elevation myocardial infarction. 10 It is well established that ischemia can increase QT dispersion. Percutaneous coronary intervention is widely performed to manage ischemia in patients with coronary artery disease.…”

Correlation of corrected QT dispersion with the severity of coronary artery disease detected by SYNTAX score in non-diabetic patients with STEMI

“…Several studies documented the relationship between severity of coronary artery disease and QTc dispersion. 9 , 12 , 13 However, these studies used different scoring systems to assess severity of coronary artery disease such as vessel score, Friesinger score and Leaman score in Sharafat et al 14 , and vessel score, diffuse score and Gensini score in Yilmaz et al 4 . However, in 2005, a rather recent score was introduced as SYNTAX score based on the well-known SYNTAX trial.…”

“…We didn't state that 60 ms is the cutoff for prolonged QTc rather being an arbitrary value to subdivide our study population into two groups for statistical purpose. This value was derived from previous studies such as Yunus et al 5 and Sharafat et al 14 . Moreover, in correlation studies, we used QTc as a continuous variable.…”

A clinical study of hemodynamically significant arrhythmias and QTc interval associated with thrombolysed and non thrombolysed acute myocardial infarction patients

“…Increased QTd can cause ventricular arrhythmia, such as torsade de pointes. 5 Thrombolytic therapy improves survival and preserves myocardial function. Successfully perfused patients have demonstrated lower incidence of early and late mortality, as well as a higher left ventricular ejection fraction with early therapy, compared with conventionally treated patients.…”