Evaluation of serial QT dispersion in patients with first non‐Q‐wave myocardial infarction: Relation to the severity of underlying coronary artery disease

Background: Increased QT dispersion (QTD) has been correlated with ventricular arrhythmias. Recent reports suggest that it may serve as a marker of the severity of underlying coronary artery disease (CAD). Hypothesis: The aim of this study was to examine in-hospital changes of QTD and their possible correlation with the severity of underlying CAD in patients with first non-Q-wave myocardial infarction. Methods: In 62 patients we estimated QTD, precordial QTD, as well as their values corrected for heart rate on Days 3 and 7 after admission. The severity of underlying ischemic burden was estimated by means of the number of diseased vessels as well as by the jeopardy score. Results: On Day 3, patients with jeopardy score ≥ 6 exhibited greater QTD, corrected QTD, precordial QTD, and corrected precordial QTD (p = 0.001, p = 0.003, p = 0.02, p = 0.036, respectively); patients with multivessel disease had greater QTD (p = 0.007). On Day 7, patients with jeopardy score ≥6 and multivessel disease exhibited greater QTD, corrected QTD, precordial QTD, and corrected precordial QTD (p < 0.001 for all). Multiple regression analysis revealed a jeopardy score of ≥ 6 as the most significant independent predictor for QTD variables. From Days 3 to 7, only patients with none or one diseased vessel or jeopardy score < 6 had shortened QTD (p = 0.01 and p = 0.015, respectively) and corrected QTD (p < 0.001 for both). Conclusions: In patients with first non-Q-wave myocardial infarction, QTD variables and their in-hospital changes reflect the severity of underlying CAD.