I. Sinus Node.- The Sinoatrial Node Function.- Clinical Aspects of the Sick Sinus Syndrome.- The Significance of the Sinus Node Recovery Time in the Sick Sinus Syndrome.- Premature Atrial Stimulation for Evaluation of Sinoatrial Conduction in Man.- Sinus Node Recovery Time and Sinoatrial Conduction Time.- The Influence of Drugs on Sinoatrial Conduction Time in Man.- Evaluation of Suction Electrode Recording.- The Recording of the Human Right Atrial Monophasic Action Potential.- II. Atrioventricular Conduction.- Contributions of Intracardiac Electrography to the Understanding of Normal and Disturbed AV Conduction.- Clinical Significance of AV Conduction Disturbances.- Fascicular Block Patterns - Observations on Differential Diagnosis.- AV Nodal Tachycardias.- Drug Effects on AV Conduction.- Split His.- Atrioventricular (AV) and Ventriculoatrial (VA) Conduction Pattern in Patients with Short P - R Interval and Normal QRS Complex.- The Wolff-Parkinson-White Syndrome.- III. Supraventricular and Ventricular Tachycardias.- An in Vitro Model of Circulating Excitation in the Absence of an Anatomic Obstacle.- Clinical and Electrocardiographic Features of Supraventricular and Ventricular Tachycardias.- Reentry-Mechanism within the His-Purkinje-System in Man During Extrasystolic Stimulation of the Right Ventricle.- Patient Initiated Rapid Atrial Pacing to Manage Supraventricular Tachycardia.- Fundamentals of Orthorhythmic Pacing.- Orthorhythmic Stimulation and Endocardial Detection as a Diagnostic Tool.- The Use of Programmed Rate-Related Premature Stimulation in Managing Tachyarrhythmias.- Future Aspects of Cardiac Pacing.