1.

1. The latent period between the onset of the electrical and mechanical systoles, the length of the electrical and mechanical systoles and the height of the systolic and diastolic pressures were measured by simultaneous recording of right ventricular pressure and electrocardiogram in twenty-two patients suffering from congential or acquired heart disease, and compared in normal and abnormal beats.

2.

2. Ectopic beats appearing in the ejection phase caused a broadening of the mechanical systole of the antecedent beat and maintained its diastolic pressure at a level higher than normal.

3.

3. Ectopic beats appearing in the isometric ventricular relaxation phase usually had a high initial pressure, prolonged electrical-mechanical latent period, decreased systolic pressure, and shortened mechanical systole.

4.

4. Ectopic beats appearing in the rapid ventricular filling phase had a normal or elevated initial pressure, normal or prolonged electrical-mechanical latent period, normal or decreased systolic pressure and, frequently, shortened mechanical systole.

5.

5. Ectopic beats appearing in the diastase of the antecedent beat had a normal initial pressure, usually a normal electrical-mechanical latent period and systolic pressure, and a short, normal, or prolonged mechanical systole.

6.

6. Successive ectopic beats produced a lowering of systolic pressure and a rise in diastolic pressure in the ventricle, thus interfering with heart performance.

7.

7. Data on cases with ventricular alternans, fusion beats, wandering pacemaker with aberrant ventricular conduction, and auricular fibrillation are presented and discussed.