23/09/2021
Frederick's syndrome (phenomenon), a symptom complex that combines complete AV blockade and atrial fibrillation, is not an independent nosology, but arises as a complication of various diseases of the cardiovascular system. Frederick's syndrome develops in 0.6-1.5% of patients with atrial fibrillation. The average age of patients suffering from this syndrome is from 65 to 75 years. In men, the disorder is more common than in women.
The pathophysiological basis of the syndrome is a complete blockade of the passage of electrical impulses in the atrioventricular node, as well as the occurrence of an ectopic focus in the myofibrils of the atria. This leads to a sharp decrease in the contractility of the heart and a violation of systemic hemodynamics, as a result of which the fraction of cardiac output decreases.
Reasons:
❗Acute myocardial infarction;
❗Chronic ischemia of the heart (angina pectoris) in a state of tension and rest;
❗Cardiosclerotic changes arising after a heart attack;
❗Myocarditis and other inflammatory lesions of the heart muscle;
❗Congenital or severe acquired heart defects;
❗Cardiomyopathies.
Against the background of the above diseases, coronary artery sclerosis occurs, which leads to the proliferation of connective tissue in the heart muscle. Also, myocardial sclerosis is affected by inflammatory and dystrophic changes, as a result of which pacemaker cells are replaced by typical cardiomyocytes, which contributes to a change in functional conductivity and the manifestation of AV blockade.
Risk factors that may contribute to the development of Frederick's syndrome:
🔴Taking certain drugs that reduce heart rate: M-cholinomimetics, β-adrenergic blockers, sodium channel blockers, cardiac glycosides;
🔴Hereditary factor (familial hyperlipidemia);
🔴Significant physical activity;
🔴Electrolyte imbalance.
Symptoms :
The clinical picture of Frederick's syndrome consists of symptoms of the underlying disease and symptoms of arrhythmia.
✔️growing weakness;
✔️Morgany-Adams-Stokes attacks;
✔️decreased exercise tolerance;
✔️dizziness;
✔️darkening of the eyes;
✔️fainting;
✔️shortness of breath on minimal exertion;
✔️seizures;
✔️аcrocyanosis.
The most serious complication of Frederick's syndrome is sudden cardiac arrest associated with asystole, preceded by increased attacks of fainting.
3-5% of patients have arrhythmic cardiogenic shock and pulmonary edema. With a prolonged course of the syndrome, heart failure develops.
Diagnostics:
The main diagnostic method is an electrocardiogram.
ECG signs:
🔸heart rate 40-60 beats. per minute;
🔸absence of P waves;
🔸presence of waves (f) of atrial flutter or waves (F) of atrial flutter;
🔸the RR interval is constant, the rhythm is correct.
🔸the ventricular rhythm of a non-sinus nature is nodular or idioventricular;
🔸the RR complex is expanded and deformed in idioventricular rhythm, similar to an ECG in BNPG.
Holter monitoring, transesophageal ECHO-KG, electrophysiological examination are used as additional instrumental research methods.
Treatment:
Etiotropic therapy: treatment of the underlying disease.
Symptomatic treatment: life-threatening conditions.
Surgical treatment: installation of a single- (VVI or VVIR) or dual-chamber stimulator ventricles (WIR).
