New concepts of digitalis.

The data presented in this review have substantiated the following ideas:* There is a direct relationship between digitalis dosage and myocardial contractile force. A small dose of digitalis produces a small increase of the contractile force of the heart and a large dose increases the force of the heart's contraction by a much greater amount, whether the heart is normal, has a poor reserve, or is in frank failure.* Digitalis is of benefit to the patient with cardiovascular disease whether his heart is in failure or not.