The effects of distension of the small intestine on myocardial blood flow in anaesthetised cats: possible relevance to coronary vasospasm.

The haemodynamic effects of distending the small intestine (with a balloon in the lumen) were examined in cats anaesthetised with chloralose. Particular attention was paid to blood flow changes in localised areas of the left ventricular wall (as assessed using the heated thermocouple technique). Intestinal distension led to an increase in systemic blood pressure but usually to a reduction in myocardial blood flow; no cardiac dysrhythmias were observed. When the effect of increased systemic (perfusion) pressure on blood flow was eliminated (using partial correlation coefficients) flow then bore a negative relationship to intestinal pressure, probably indicating constriction of the myocardial blood vessles. This may indicate that distension of hollow organs can lead to a visceral-cardiac reflex. The resulting coronary vasospasm might be one cause of pain in certain patients with angina pectoris.