Atrial Fibrillation – Types, Causes, Symptoms, Diagnosis
DEFINITION
Atrial Fibrillation (AF) is one of the most common and important cardiac arrhythmias.
It is a supraventricular tachyarrhythmia in which the excitation of the atria is uncoordinated, resulting in ineffective atrial contraction.
EPIDEMIOLOGY
AF is the most common arrhythmia. One in three middle-aged people in Europe or the USA will develop AF at some point in their lives.
Its frequency increases with age.
In 10-15% of cases it occurs without the coexistence of other diseases.
However, in the majority of cases, it is combined with other cardiovascular diseases, such as Hypertension, Heart Failure, Coronary Heart Disease, Valvular Diseases, Cardiomyopathies, etc.
It often coexists with Diabetes Mellitus and Chronic Renal Failure.
FORMS
Newly Diagnosed AF.
Paroxysmal AF. Reversible, in most cases within 48 hours. Some AF paroxysms may continue for up to 7 days.
Persistent AF. AF Lasts more than 7 days. Includes episodes that terminate with cardioversion after 7 days or more.
Long-standing AF. Continuous AF for more than 1 year
Permanent AF. Continuous AF in which the patient and physician have decided to reject any attempt to restore sinus rhythm.
CAUSES
- Conditions that increase pressure within the atria:Valvular diseases, Arterial hypertension, Pulmonary hypertension, Cardiomyopathies, Intracardiac tumors or thrombi, Congenital heart diseases, Heart failure.
- Coronary artery disease
- Inflammatory or Infiltrative disease of the sinuses: Myocarditis or Pericarditis, Amyloidosis.
- Respiratory diseases: COPD, pulmonary embolism, respiratory infections, Obstructive sleep apnea.
- Use of alcohol and other substances: Stimulants, Alcohol [Chronic or acute use (e.g. “holiday or weekend syndrome”)], Caffeine, Cocaine.
- Endocrine diseases: Hyperthyroidism, Diabetes
- Surgical procedures: Heart, Thoracic, Esophageal
- Idiopathic: “Familial” MS, “Lone MS”
- Old age
- Chronic renal failure
- Anemia
- Obesity
IMPACTS
- increases total mortality (X 1.5 – 3.5 times)
- increases the likelihood of Vascular Stroke (STROKE) and embolic episodes in general: because the heart does not work in a synchronized manner, opportunities are provided within the heart chambers, especially in the left atrium, for clots to form that at some point can detach, enter the general circulation and cause an embolic episode either in the brain, in which case we have a stroke, or in another artery, e.g. in the leg, in which case they cause acute arterial occlusion.
- Increases the need for hospitalization in the hospital (1/3 of patients need to be hospitalized at least once a year)
- Adversely affects the quality of life of patients.
- In the long term, it is associated with deterioration of the functionality of the left ventricle (“tachycardia”), decline in mental functions (dementia) and depression
CLINICAL PRESENTATION
Varies widely. Many patients are asymptomatic.
The most common symptoms are palpitations, fatigue, dyspnea, chest discomfort, or syncope.
AF is found in 20-30% of patients admitted to hospitals with stroke.
Some patients present in a critical condition (hemodynamic instability) and require immediate electrical (DC) conversion.
DIAGNOSTIC CHECK
The Diagnostic Protocol that is followed is detailed as follows.
History – Physical examination: to determine the type of AF (paroxysmal, persistent, long-term persistent, permanent), to detect factors that predispose to AF (e.g. caffeine, alcohol, etc.) and to investigate the possibility of underlying heart disease.
Laboratory test: Complete blood count, complete biochemical test, thyroid function test.
Electrocardiogram: when it comes to a permanent chronic condition, it usually establishes the diagnosis (“absolutely” dissimilar RR intervals, absence of distinct P waves. It also serves to determine the ventricular response (heart rate), to investigate the presence of evidence of organic heart disease and to monitor the action of drugs (PR, QT intervals, etc.)
Functional Test(Exercise Test, Myocardial Scintigraphy, StressEcho): for investigation of the presence of ischemia.
Echocardiogram: to determine the presence of valvular disease, assessment of atrial and ventricular dimensions and left ventricular function, calculation of systolic pulmonary pressure and detection of thrombi. In the left atrium (if suspected, Transesophageal echocardiography is recommended)
Transesophageal echocardiogram: to determine the presence of a thrombus. In the left atrial appendage (high resolution) and more detailed study of patients with valvular disease.
Holter Rhythm: to diagnose paroxysmal AF and study the effect of treatment.
