We describe a series of investigations that used transesophageal echo-Doppler observations during cardiac arrest and cardiopulmonary resuscitation. Regular contractions of the left atrium persisted during the initial 7 mins of untreated ventricular fibrillation. Ventricular chamber deformation and mitral valve closing and opening followed precordial compression and relaxation. Stroke volumes computed from differences between diastolic and systolic areas of the left ventricle were predictive of the success of the resuscitation. Progressive decreases in left ventricular compliance were associated with decreases in left ventricular diastolic and stroke volumes and progressed to a stone heart.