Ingestion of a 500-kcal formula meal significantly increased the QTc interval above baseline at 15 minutes (P<0.007) compared to isovolumic water, persisting for 1 hour.
Does meal ingestion lengthen the QTc interval in healthy subjects compared to water ingestion?
Meal ingestion significantly prolongs the QTc interval in healthy subjects, suggesting that EKG screening for QTc prolongation should consider fasting status.
p-value: p=<0.007
Weight reduction, either by dietary or surgical means, is associated with prolongation of the heart rate corrected QT interval (QTc = QT/R-R0.5) and, on occasion, sudden death. Screening subjects with obesity before weight loss for prolonged QTc intervals is an accepted practice, although at present, there are no guidelines for whether subjects should be fasting before electrocardiogram (EKG) evaluation. The aim of this study was to test the hypothesis that EKG QTc interval duration is independent of meal ingestion. The hypothesis was tested in 11 healthy subjects who ingested a 500-kcal formula meal. A small decrease in absolute QT interval and a steady decline in R-R interval were observed for up to 60 minutes after formula ingestion. The QTc interval increased above baseline at 15 minutes (p < 0.007) after meal, a change that persisted for the 1-hour postmeal observation period. Spectral analysis of EKG R-R intervals (low-/high-frequency amplitude ratio) indicated a change in cardiac autonomic flow after meal ingestion. The QTc interval did not lengthen and R-R low-/high-frequency amplitude ratio remained unchanged in eight subjects evaluated in a similar manner but in whom isovolumic amounts of water replaced the meal. These observations suggest that (1) cardiac repolarization changes with fasting and feeding, (2) the QTc interval is influenced by meal intake, and (3) the autonomic nervous system may play a role in meal-related QTc changes. These findings have implications for the evaluation of patients with obesity before starting and during weight loss treatment.
Nagy et al. (Sat,) conducted a other in Healthy subjects (n=19). 500-kcal formula meal vs. Isovolumic amounts of water was evaluated on QTc interval duration (p=<0.007). Ingestion of a 500-kcal formula meal significantly increased the QTc interval above baseline at 15 minutes (P<0.007) compared to isovolumic water, persisting for 1 hour.