The stunned and hibernating myocardium: a brief review

DEFINITIONS

Stunned myocardium is viable myocardium salvaged by coronary reperfusion that exhibits prolonged postischemic dysfunction after reperfusion. Hibernating myocardium is ischemic myocardium supplied by a narrowed coronary artery in which ischemic cells remain viable but contraction is chronically depressed.

CLINICAL EVIDENCE

Stunned myocardium has been identified in the following patient groups: (1) thrombolysis or percutaneous transluminal coronary angiography (PTCA) in patients with acute evolving infarction; (2) unstable angina; (3) exercise-induced angina; (4) coronary artery spasm; (5) platelet aggregation or transient thrombosis of a coronary artery; (6) PTCA for chronic myocardial ischemia; and (7) immediately following coronary artery bypass graft (CABG). Evidence of hibernating myocardium (LV dysfunction) is found in the patient with severe coronary artery stenosis, even in asymptomatic patients at rest. Stunned myocardium returns to normal after a prolonged period of time (hours to weeks). Hibernating myocardium returns to normal function rather quickly if the cause is removed.

DIFFERENTIATION

Stunned myocardium can be differentiated from hibernating myocardium by three clinical parameters, namely, LV wall motion, myocardial perfusion, and myocardial metabolism. Stunned myocardium has abnormal wall motion that tends to normalize in response to inotropes and postextrasystolic potentiation. Perfusion is adequate and metabolism is also adequate. Hibernating myocardium also has abnormal wall motion, which normalizes after nitrates, inotropes, post extrasystolic potentiation (PESP), PTCA, or CABG. Myocardial perfusion is reduced but can be reversed with PTCA or CABG and metabolism is adequate.

Familial recurring cardiac myxoma

A 34-year-old woman presented with her fourth occurrence of an atrial myxoma and a right lower lung field mass. Her surgical history was extensive. In addition to resection of three previous atrial myxomas, she had undergone resection of her adrenal glands as a teenager because of Cushing's syndrome, and a hysterectomy at age 26 revealed a myxoid leiomyoma. Family history was remarkable as a maternal uncle and daughter died from embolic complications of left atrial myxomas and her sister previously had a left atrial myxoma resected. The patient underwent uncomplicated removal of the myxoma, and resection of the lung mass revealed a granuloma. A review of typical and atypical aspects of cardiac myxomas is provided including a rare and recently described syndrome of familial cardiac myxoma associated with Cushing's syndrome, spotty skin pigmentation and other myxoid tumors.

Cardiac catheterization laboratories: should every hospital have one?

It is obvious that times have changed. Cardiac catheterization laboratories are everywhere. The concerns that must be addressed continually are: 1. Patient safety and quality of patient care. 2. Access to emergency hospitalization. 3. The overseeing of these laboratories. 4. Physician conflict of interest. 5. Need for the laboratory in the region In order to add a new cardiac catheterization laboratory to any region, patient need must be documented. Patient need is the only justification for the development of a new laboratory. I fail to understand how the continuing development of new laboratories will decrease costs, and am concerned that more catheterization laboratories will mean more studies of patients with borderline indications for the procedure.

Why use a nitrate in 1990?

Nitrates are beneficial because they combine coronary and noncoronary effects. They have proven clinical efficacy, relieving symptoms and documented evidence of ischaemia. They can be given to patients by multiple routes and can be easily combined with other anti-ischaemic drugs including aspirin, heparin, calcium antagonists and beta-blockers.