MYOCARDIAC ULTRASTRUCTURE IN SYSTOLE AND DIASTOLE USING BALLISTIC CRYOFIXATION

A method is described whereby sections of myocardium were obtained for electron microscopy from an actively beating heart during specific phases of its contraction cycle. Small section were rapidly removed by hollow projectiles accelerated to supersonic velocities by an explosive. Cryofixation was achieved using a mixture of liquid and frozen propane as the coolant. The method employed is discussed in terms of its application, results, and limitations. © 1968 Academic Press Inc.