Author + information
- Received May 12, 1994
- Revision received October 4, 1994
- Accepted October 12, 1994
- Published online March 1, 1995.
- Markus Zabel, MD,
- Stuart Portnoy, MD and
- Michael R. Franz, MD, PhD, FACC*
- ↵*Address for correspondence: Dr. Michael R. Franz, Division of Cardiology, Department of Veterans Affairs Medical Center, 50 Irving Street, NW, Washington, D.C. 20422.
Objectives. This study tested the correlation of QT and JT dispersion and other potentially useful electrocardiographic (ECG) indexes with dispersion of repolarization and recovery time.
Background. Dispersion of ventricular repolarization is currently being assessed noninvasively from the surface ECG by means of QT and JT dispersion, although their correlation with dispersion of repolarization as measured directly from the myocardium is not well established.
Methods. Multiple monophasic action potentials were recorded simultaneously with a 12-lead ECG from isolated Langendorff-perfused rabbit hearts. The QT and JT dispersion was compared with the dispersion of monophasic action potential duration at 90% repolarization (APD90) and with dispersion of recovery time. As new ECG indexes, total T wave area, T wave area after the peak (late T wave area) and T peak to T end interval were also tested.
Results. The QT and JT dispersion showed a significant correlation with the dispersion of APD90and the dispersion of recovery time (r values between 0.58 and 0.64, respectively, p < 0.001). However, total T wave area showed better correlation, respectively, with dispersion of APD90and recovery time (r = 0.79 and r = 0.82, p < 0.0001), as did late T wave area (r = 0.81 and r = 0.81, p < 0.0001) and T peak to T end interval (r = 0.81 and r = 0.82, p < 0.0001).
Conclusions. The JT and QT dispersion correlate significantly with dispersion of APD90and recovery time. The ECG assessment of dispersion of repolarization can be improved by three new ECG dispersion indexes: T peak to T end interval, total T wave area and late T wave area. These new indexes should be tested clinically.
This study was supported by a Merck International Fellowship in Clinical Pharmacology (Dr. Zabel) and by a Department of Veterans Affairs Merit Review Grant (Dr. Franz). It was presented at the 1994 North American Society of Pacing and Electrophysiology Young Investigator Award competition, Nashville, Tennessee, May 1994.
- Received May 12, 1994.
- Revision received October 4, 1994.
- Accepted October 12, 1994.
- American College of Cardiology