FIG. 46:  Following the high afterload the heart experiences following an episode of apnea, illustrated in the previous Figure, it is reasonable to assume that the heart will likely experience ischemia during an obstructive apneic event, particularly if there is underlying disease of the coronary arteries.  This Figure shows the results from a patient reported by Franklin and colleagues^[34] which found a fall in oxygen saturation during an obstructive apneic event, associated chronologically and very closely with changes in the ST segment of the electrocardigram, all suggestive of cardiac ischemia.  In other words, this is a patient who is fast asleep, has an apneic event, shows ST changes on the electrocardiogram suggesting cardiac ischemia, and then the patient wakes from sleep because of angina.   

In other words, this Figure illustrates data that reasonably suggest that obstructive apnea occurring during sleep can elicit cardiac ischemia, causing the patient to wake from sleep with episodes of angina.