Cardiac Arrhythmias and ECG
Stimulation of the pacemaker of the heart causes tachycardia. Tachycardia >100 bpm Increased body temperature Sympathetic stimulation of the heart - 150 to 180 bpm Toxic conditions - digitalis toxicity Vagal stimulation of the heart causes a decrease in heart rate. Bradycardia <60 bpm. Parasympathetic system - acetylcholine. Carotid sinus syndrome - an atherosclerotic process causes excessive sensitivity of the baroreceptors in the atrial wall. External pressure to the neck causes the atherosclerotic plaque in the carotid sinus to stimulate the baroreceptors, which then stimulate the vagus nerve and cause bradycardia. Abnormal cardiac Rhythms that result from impulse conduction block. Rarely - Sinoatrial block - P waves are obsured by the QRS complex, and the ventricles pick up the rhythm originating from the atrioventricular node AV node AV block inhibits or completely blocks impulses originating in the SA node. Ischemia of the AV node or AV bundle...