Atrial flutter - Cardiac abnormalities and signs

Published At: 17 January 2020 , 04:11 PM

Atrial flutter (TP) is one of the most common heart rhythm disturbances, accounting for about 10% of all paroxysmal supraventricular tachyarrhythmias. Atrial flutter characterized by the correct rhythm of the atria with a frequency of 250-350 beats/min.

TP is an “organic” arrhythmia, i.e. concomitant cardiopulmonary pathology. “Isolated” TP in the absence of arterial hypertension, lung disease, or structural heart disease is rare, except people involved in active sports or drinking alcohol daily, as well as in patients with hyperthyroidism. The incidence of this type of TA is increasing due to the progressive ageing of the population. Left-sided TP also becomes more common due to an increase in the number of the catheter and surgical ablation procedures for AF and increased survival of patients with mitral valve surgery.

As electrophysiological studies show, even with a characteristic ECG picture, tachycardia includes multiple re-entry circles. Re-entry loops often span large areas of the atrium and are therefore called macro re-entry.

Determining the type of atrial flutter, its dependence on cavotricuspid isthmus is an essential step in catheter ablation, but this does not change the primary approaches to treatment.

The clinical picture.

Although typical TP is usually paroxysmal, it has been found that some patients suffer from chronic TP without any symptoms. Conventional isthmus-dependent TP is 2.5 times more common in men than in women. Acutely rarely observed in patients under the age of 50 years, except people who are actively involved in sports. Prolonged intense exercise may predispose not only to atrial fibrillation (AF) but also to the development of isthmus-dependent TP. The incidence of TP increases with age in the presence of chronic obstructive pulmonary diseases, arterial hypertension, obesity, atrial septal defect (ASD) (even after surgery for ASD plastic surgery), mitral valve lesions, and systolic or diastolic dysfunction of the left ventricle of various etiologies.

Isolated TP without pathology from the cardiovascular or respiratory system is rare, amounting to less than 2. TP in adults tends to recur or becomes chronic. Patients with AF may develop TP, either spontaneously, or after therapy with IC class drugs or amiodarone. TP is extremely rare in infants, usually in connection with cardiorespiratory episodes, and does not tend to relapse, unless it is associated with congenital heart disease].

Patients with atrial flutter usually complain of sudden heartbeat, shortness of breath, weakness, or chest pain. With this arrhythmia, symptoms and conditions can also be observed, such as weakness caused by physical exertion, an increase in heart failure, or worsening of the course of lung diseases.

Electrocardiographic signs of atrial flutter counterclockwise are dominant-negative flutter waves F in the lower leads, positive flutter waves F in lead V1 with transformation into harmful waves in lead V6 at a frequency of atrial contraction of 250-350 per min. When fluttering clockwise, the opposite picture observed (i.e., positive flutter waves F in the lower leads, large harmful flutter waves in lead V1 with a transition to the positive phase in lead V6). However, characteristic ECG signs in patients may not always be; therefore, only during the endo-EFI, using the phenomenon of entering the tachycardia cycle, it is possible to prove the interest of the cavotricuspid isthmus.

Urgent care with an outbreak of atrial flutter depends on clinical manifestations. In patients with acute vascular collapse or with an increase in the expressions of congestive heart failure, emergency synchronized cardioversion indicated. Successful restoration of the sinus rhythm can be achieved by a discharge of less than 50 J using single-phase currents, and with biphasic currents, even lower energy. In most cases, with AV 2: 1 and higher, patients do not have hemodynamic disorders. In such a situation, the clinician may opt for drugs that slow down AV conduction. Adequate, although challenging to achieve, control of the rhythm frequency is especially essential if the restoration of sinus rhythm is delayed (for example, if anticoagulant therapy is necessary). Frequent atrial stimulation, like transesophageal, so and atrial, is the method of choice when restoring sinus rhythm. If atrial flutter lasts more than 48 hours, patients are shown anticoagulant therapy before electric or medical cardioversion. Moreover, if medical cardioversion planned, rhythm frequency control is necessary, since antiarrhythmic drugs, such as class Ic drugs, can reduce the rate of atrial contraction and cause a paradoxical increase in ventricular contraction rate due to a slowdown in intrinsic AV conduction.

In approximately 60% of patients, atrial flutter occurs as a result of acute processes in lung pathology, after heart and lung surgery, during acute myocardial infarction. If the symptoms of the underlying disease stopped and the sinus rhythm restored, continuous antiarrhythmic therapy, as a rule, is not required. So, emergency treatment of atrial flutter may include electrical stimulation, electrical or medical cardioversion, as well as drugs that slow AV conduction.

RFA of the cava-tricuspid isthmus with isthmus-dependent TP.

The goal of ablation is to create a bi-directional block line between the tricuspid valve ring and the inferior vena cava.

During catheter ablation, TP RF applications applied to the area between the inferior vena cava and the tricuspid valve, which creates a block re-entry in the circle. At first, it believed that the criterion of the effectiveness of the operation is the relief of TP. In the future, strict standards developed for achieving a bidirectional holding unit in the area of ​​the lower isthmus, which significantly increased the long-term RFA efficiency (90-100%). One prospective, randomized trial compared the efficacy of continuous oral antiarrhythmic therapy (61 patients with TA) and radiofrequency ablation. With a dynamic follow-up of 21 ± 11 months, sinus rhythm persisted only in 36% of patients receiving antiarrhythmic therapy, whereas after RFA in 80% of patients. Also, 63% of patients receiving ongoing drug therapy, one or more hospitalizations were required, compared with 22% of patients after ablation. Quality of life was significantly higher in patients after RFA.

The effectiveness of the RFA of the cava-tricuspid isthmus varies from 77 to 100% (according to different authors) with a relapse rate of less than 5%.