Dr. Jalife enjoys an international reputation as a leader in his field of research, which focuses on bringing sophisticated mathematical and biophysical concepts to increase the understanding of the mechanisms of life-threatening cardiac arrhythmias, from the molecule to the bedside. He and his associates have investigated the molecular mechanisms and nonlinear dynamics of heart rhythm and conduction disturbances. Their studies have provided important insight that has led to reevaluation of classical criteria for the diagnosis of complex arrhythmias, including atrial fibrillation and ventricular fibrillation. Other contributions include studies on the cellular mechanisms of dynamic vagal control of heart rate and atrioventricular conduction and the mechanisms of pacemaker synchronization in the sinoatrial node; non-linear dynamics of excitation and propagation in isolated cardiac tissues; application of video-imaging techniques and the use of transgenic and knockout mice to study wave propagation and spiral wave formation in cardiac muscle; and more recently, the study of the cellular and molecular mechanisms underlying sudden death in inherited arrhythmogenic diseases.