Overview: Join Dr. Faiza in this in-depth lecture on cardiac impulse and the rhythmical excitation of the heart. This presentation covers the intricate pathways and mechanisms that ensure the efficient conduction of electrical impulses through the heart, leading to coordinated myocardial contractions. Attendees will gain a comprehensive understanding of the normal sequence of cardiac depolarization, the specialized conductive pathways, and the ionic basis of pacemaker potentials. Learning Objectives: Trace the normal sequence of cardiac depolarization via specialized conductive pathways and cardiac myocytes. Illustrate the velocity of conduction of cardiac impulses through these pathways. Draw and label a typical pacemaker action potential. Describe the ionic basis of various phases of the pacemaker potential. Key Topics: Generation of Impulse: Mechanisms of rhythmical excitation in the heart. Conduction of Impulse: How impulses are transmitted and why atrial syncytium contracts ahead of ventricular syncytium. Specialized Excitatory & Conductive System: Detailed examination of the SA node, AV node, bundle branches, and Purkinje fibers. SA Nodal Action Potential: Phases of pacemaker potential, ionic movements, and self-excitation mechanisms. Transmission Pathways: Role of anterior and posterior fascicles, internodal, and interatrial pathways. Clinical Significance: Implications of delayed conduction and conditions like Stokes-Adams syndrome and ectopic pacemakers. Target Audience: This lecture is tailored for medical students, physiology scholars, healthcare professionals, and anyone interested in cardiac physiology and the mechanisms of cardiac impulse conduction. It is particularly beneficial for those preparing for exams or seeking to enhance their clinical knowledge in Applied physiology of cardiovascular system and internal medicine.