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Updated: Aug 19, 2026
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
QT dispersion and viable myocardium in patients with prior myocardial infarction and severe left ventricular
Vuy Hun Li1, Sharmila Dorbala, Dhiraj Narula
1Division of Cardiology, St. Luke's-Roosevelt Hospital Center, 1111 Amsterdam Ave., New York, NY 10025, USA. jss7@columbia.edu
Insights
QT dispersion (QTd) does not correlate with myocardial viability in patients suffering from severe left ventricular dysfunction after myocardial infarction. This finding suggests QTd is not a reliable indicator in this specific patient group.
Area of Science:
- Cardiology
- Nuclear Medicine
- Electrophysiology
Background:
- QT dispersion (QTd) correlates with myocardial viability in Q-wave myocardial infarction patients with preserved LV function.
- The relationship between QTd and myocardial viability is not established in patients with severe left ventricular dysfunction.
Purpose of the Study:
- To investigate the relationship between QT dispersion and myocardial viability in patients with severe left ventricular dysfunction post-myocardial infarction.
Main Methods:
- 34 patients with myocardial infarction and severe LV dysfunction underwent Tc-99m sestamibi and F-18 FDG SPECT.
- Myocardial viability was defined by F-18 FDG SPECT criteria (DCD ≥ 20%).
- QTd, QTcd, and QTcv were compared between patients with and without viable myocardium.
Main Results:
- 10 out of 21 analyzed patients (48%) showed myocardial viability.
- No significant difference in QTd, QTcd, or QTcv was observed between patients with and without viability.
- FDG defect size and LVEF did not correlate with QTd.
Conclusions:
- This study found no relationship between QT dispersion and myocardial viability in patients with myocardial infarction and severe left ventricular dysfunction.
- QTd is not a reliable marker for assessing myocardial viability in this patient population.
Background:
QT dispersion (QTd) has been found to correlate to the amount of viable myocardium in patients with Q-wave myocardial infarction and well-preserved LV function. However, this relationship is unknown in patients with severe left ventricular dysfunction.
Methods:
Thirty-four patients with prior large myocardial infarction and severe left ventricular dysfunction underwent Tc-99m sestamibi single photon emission cardiac tomography (SPECT) and F-18 fluorodeoxyglucose (FDG) SPECT. Viability was defined as a defect relative count density (DCD) of at least 20% greater on FDG SPECT. QTd, corrected QT dispersion (QTcd), and QT coefficient of variation (cv) in patients with viable myocardium was compared to those without viable myocardium in the infarct area.
Results:
Thirteen patients were excluded from analysis for poor FDG images or inadequate ECG tracings. Of the remaining patients, 10 (48%) were found to have viability on FDG SPECT. QTd, QTcd, and QTcv in patients with viability were: 58 +/- 22 ms, 61 +/- 23 ms, and 4.81 +/- 1.76%, respectively, which did not differ significantly from those in patients without viability (QTd = 56 +/- 14 ms, QTcd = 70 +/- 16 ms and Qtcv = 5.06 +/- 1.20% [P = NS]). Moreover, neither FDG defect size, nor LVEF correlated with QTd.
Conclusions:
This study indicates no relationship between QTd and viability in patients with myocardial infarction and severe left ventricular dysfunction.
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