Exercise-induced ST segment alternans

Ring, Michael E.; Fenster, Paul E.

doi:10.1016/0002-8703(86)90662-9

Cited by 18 publications

(1 citation statement)

References 9 publications

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“…The mechanism of ST segment and T-wave alternans is unclear. ST-T alternans on surface ECG has been associated with vasospastic angina [3,4], classical angina [ 5 ] , exercise testing [ 6 ] , and acute myocardial infarction [7]. Surawicz and Fisch [8] reported that this phenomenon is the failure of an ischemic area to depolarize on alternate beats because of variations in conduction and refractoriness between the ischemic and nonischemic areas.…”

Section: Discussionmentioning

confidence: 99%

Intracoronary ST‐T alternans during coronary balloon angioplasty

Kwan

Feit

Chadow

et al. 1995

Cathet. Cardiovasc. Diagn.

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To evaluate the presence and clinical significance of electrical alternans during PTCA, intracoronary electrocardiography (ic-ECG) was performed in 65 consecutive lesions. ST-T alternans, defined as a beat-to-beat difference in the ST elevation > or = 1 mm, was present in five lesions (7.7%), all in the proximal left anterior descending (LAD) coronary artery. The phenomenon was seen only after 130 sec (mean 174 +/- 57) of balloon inflation. Only two of the five showed ST-T alternans simultaneously on both surface and ic-ECG. One of five patients had premature ventricular contractions following ST-T alternans. Three of these five lesions required a second balloon inflation with duration of > or = 300 sec; there was no ST-T alternans on the second inflation in any of these lesions. We conclude: (1) the detection of ST-T alternans during PTCA is enhanced by use of ic-ECG, (2) electrical alternans during PTCA was seen only in proximal LAD lesions, implicating a large amount of ischemic myocardium as a requisite for the phenomenon, (3) electrical alternans is not immediate, requiring a certain duration of balloon occlusion and hence ischemia to occur, and (4) the absence of ST-T alternans during second balloon inflations suggests ischemic preconditioning may abolish this phenomenon.

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