Electrocardiographic response to ice water ingestion

To determine the necessity of restricting ice water for patients with acute myocardial infarction (MI) we performed studies in 89 patients who had been admitted to a coronary care unit with a diagnosis of acute MI or "rule out MI." Using a split-plot factorial repeated-measures design, we randomly assigned patients to position and sequence of volume. A Marquette Augmented Cardiograph was used to obtain 12-lead electrocardiogram (ECGs) at baseline and at 3, 10, and 25 minutes after ingestion of 200 or 400 ml ice water. Multivariate analysis of variance (MANOVA) was used to assess the significance of each factor alone and in interaction for both ST segments and T waves for 11 leads. The preliminary analysis of variance showed significant difference (p less than 0.10) in ST segments for position in several leads and in T waves for disease in several leads. Differences did not continue to be significant when they were considered across the four time periods (MANOVA); then time and volume were the significant variables for most leads. Mean change scores for ST segment (0.01 to 0.05) and T wave amplitude (0.01 to 0.88) were not clinically significant; however, a few patients had significant changes in ST segment of greater than 1 mm and T wave amplitude of greater than 10 mm. A few patients exhibited T wave inversion, suggesting a third level of significance: clinically detectable differences.(ABSTRACT TRUNCATED AT 250 WORDS)