This study was supported by an American Heart Association fellowship Grant to Dr. Cao; a NASPE Michel Mirowski International Fellowship and a grant from Jiangsu Provincial Government and Suzhou Children's Hospital, China, to Dr. Zhou; a Cedars-Sinai Electrocardiographic Heartbeat Organization Award to Dr. Karagueuzian; and a Pauline and Harold Price Endowment to Dr. Chen; and was supported in part by NIH Grants P50-HL52319 and R01-HL66389, AHA National Center Grant-in-Aid (9750623N, 9950464N), University of California Tobacco-Related Diseases Research Program 9RT-0041, Guidant Corporation, and the Ralph M. Parsons Foundation, Los Angeles, California.
T Wave Alternans as a Predictor of Spontaneous Ventricular Tachycardia in a Canine Model of Sudden Cardiac Death
Version of Record online: 12 AUG 2003
© Futura Publishing Company, Inc. 2002
Journal of Cardiovascular Electrophysiology
Volume 13, Issue 1, pages 51–55, January 2002
How to Cite
TSAI, J., CAO, J.-M., ZHOU, S., SWISSA, M., CATES, A. W., KENKNIGHT, B. H., CHEN, L. S., KARAGUEUZIAN, H. S. and CHEN, P.-S. (2002), T Wave Alternans as a Predictor of Spontaneous Ventricular Tachycardia in a Canine Model of Sudden Cardiac Death. Journal of Cardiovascular Electrophysiology, 13: 51–55. doi: 10.1046/j.1540-8167.2002.00051.x
- Issue online: 12 AUG 2003
- Version of Record online: 12 AUG 2003
- Manuscript received 12 September 2001; Accepted for publication 30 October 2001.
- Cited By
- myocardial infarction;
- long QT syndrome;
- heart block
T Wave Alternans as Predictor of Spontaneous VT.Introduction: We recently developed an ambulatory canine model of spontaneous ventricular tachycardia (VT) and sudden cardiac death by creating myocardial infarction, complete AV block, and infusion of nerve growth factor to the left stellate ganglion. Whether or not T wave alternans is associated with the spontaneously occurring episodes of VT in our model was unclear.
Methods and Results: Through intracardiac electrograms obtained from an implantable cardioverter defibrillator, we manually measured T wave amplitudes prior to VT and while the dogs were at rest (baseline, no VT). Of the 79 VT episodes analyzed, 28 (35.4%) exhibited repolarization alternans. In contrast, only 3 (4.7%) of 64 baseline data cases displayed alternans (P < 0.0001). The magnitude of T wave alternans for dogs that died of sudden cardiac death, dogs that did not die suddenly, and for the total 28 episodes that exhibited repolarization alternans were 4.8 ± 2.8 mm, 4.9 ± 3.5 mm, and 4.9 ± 3.3 mm, respectively (P = NS). We also found the sensitivity, specificity, positive predictive value, negative predictive value, and relative risk of repolarization alternans in predicting VT to be 35.4%, 95.3%, 90.3%, 54.5%, and 1.98, respectively. The ventricular rate prior to VT (65 ± 11 beats/min) was significantly higher than that at rest (49 ± 12 beats/min; P < 0.0001).
Conclusion: T wave alternans often occurred immediately before the onset of VT in dogs with myocardial infarction, complete AV block, and nerve growth factor infusion to the left stellate ganglion. Increased sympathetic activity might be responsible for the occurrence of the T wave alternans.