Typical atrial flutter (TP) is a common arrhythmia caused by the movement of the excitation wave along the re-entry circuit (re-entree) within the PT (usually counterclockwise). TP can be paroxysmal or stable. Atrial activity is represented on the ECG by regular F waves, following with a frequency of about 300 beats / min.
Usually, F waves are alternately carried out on the ventricles (alternating AV-conduction), as a result of which their frequency of contraction is about 150 bpm. In many ECG leads, the isoelectric line between F waves is absent, which gives rise to a characteristic sawtooth curve, which is best manifested in leads II, III and aVF.
At the same time, in the lead V1, atrial activity is recorded, as a rule, in the form of discrete waves. The etiological factors of TP are similar to the causes of AF. Often observed idiopathic TP. Antiarrhythmic drugs are often ineffective and in some cases can cause an increase in the frequency of ventricular contractions. First-line treatment methods are cardioversion and catheter ablation. The risk of systemic emboli should be monitored in the same way as with AF.
Arrhythmia is caused by the repeated circulation of an electrical impulse in the right atrium (PP). Usually the impulse moves upwards along the interatrial septum and returns down the side wall of the PT. LP is activated by pulses arising in the PP. TP can be paroxysmal or stable.
In the typical form of atrial flutter, the frequency of regular electrical activity of the atria is approximately 300 bpm. In many leads between the waves of atrial activation, called F waves, there is no isoelectric line, which leads to the formation of a characteristic saw-like curve, which is best manifested in leads II, III and aVF. However, in some leads, especially in lead V1, atrial activity is manifested by discrete waves.
In the typical form of atrial flutter (TP), the impulse circulates within the PC, as a rule, in the counterclockwise direction, and therefore the F waves in leads II, III and aVF are mostly negative, in lead I – very low amplitude, and in lead V1 – positive. Less commonly, the impulse circulates in a clockwise direction; in this case, the F waves will be positive in the lower leads and negative in the V1 lead.
Atypical flutter. In atypical atrial flutter (TF), the frequency of atrial contractions is higher (350-450 beats / min). It cannot be eliminated by ablation of the isthmus (see below) and is not stopped by frequent atrial stimulation.
Atrioventricular conduction during atrial flutter (TP). As with AF, the ventricular response to atrial flutter (TP) is determined by the conductive ability of the AV junction. Often, waves F are carried out alternately on the ventricles (i.e., alternating conduction with blockade or AV-conduction ratio of 2: 1 is observed), as a result of which the frequency of their contractions approaches 150 beats / min.
Drugs that block the AV node, dysfunction of the AV node, or increase the tone of the vagus nerve at night can lead to an increase in the degree of AV block. A high level of sympathetic nervous system activity, which can be observed during physical exertion, on the contrary, can cause an increase in AV conduction to a level of 1: 1, which is accompanied by an increase in the frequency of ventricular contractions up to 300 beats / min.