BIOC33H3 Lecture Notes - Aortic Valve, Artificial Cardiac Pacemaker, Obstructive Lung Disease
Document Summary
Ecg: standard limb leads: have p wave: atrial depolarization, qrs complex: ventricular contraction, t wave - repolarization of ventricles, pr distance. = time it takes to conduct electrical activity from sa node to av node: arrhythmias - wandering atrial pacemaker - get electrical activity of pacemaker potentials from other areas of atria. Arrhythmias: heart beat originating from the ventricle: can come from other areas than sa node, or can come from sa node and be faster or slower, can also have abnormal rhythms from the ventricles. Litmus test of looking at pacemaker activity is whether the qrs complex is narrow or wide. Narrow (but normal) qrs complex = electrical activity is probably arising from the atria. Abnormally wide/m-tooth/saw-tooth shape = electrical activity that caused this is from the ventricle: problematic; requires artificial pacemakers. Overdrive: increased pump activity - hyperpolarization -- suppression. Termed ectopic pacemaker because it is being generated not at sa node.
