Atrial flutter is caused by a re-entrant rhythm. This usually occurs along the cavo-tricuspid isthmus of the right atrium though atrial flutter can originate in the left atrium as well. Typically initiated by a premature electrical impulse arising in the atria, atrial flutter is propagated due to differences in refractory periods of atrial tissue. This creates electrical activity that moves in a localized self-perpetuating loop, which usually lasts about 200 milliseconds for the complete circuit. For each cycle around the loop, an electric impulse results and propagates through the atria. The impact and symptoms of atrial flutter depend on the heart rate of the affected person. Heart rate is a measure of ventricular rather than atrial activity. Impulses from the atria are conducted to the ventricles through the atrio-ventricular node (AV node). In a person with atrial flutter, a 12-lead electrocardiogram (ECG) will demonstrate the atrial chambers of the heart contracting at a rate of 280–300 beats per minute whereas the ventricular chambers of the heart typically beat at a rate of 140–150 beats per minute. Due primarily to its longer refractory period, the AV node exerts a protective effect on heart rate by blocking atrial impulses in excess of about 180 beats/minute, for the example of a resting heart rate. (This block is dependent on the age of the patient, and can be calculated roughly by subtracting patient age from 220). If the flutter rate is 300/minute only half of these impulses will be conducted, giving a ventricular rate of 150/minute, or a 2:1 heart block. The addition of rate-controlling drugs or conduction system disease can increase this block substantially
types of Supraventricular tachycardia
medical cause of Ventricular tachycardia
medical cause of Ventricular fibrillation
symptoms of Brugada syndrome
medical cause of Supraventricular tachycardia
symptom of Brugada syndrome
complications of Atrial fibrillation
symptom of Catecholaminergic polymorphic ventricular tachycardia