Atrial Fibrillation

Majority of patients will not present with any symptoms at all. Only mild palpitations, chest discomfort, light headedness, dyspnea, and generalized weakness are subjectively felt by the patients. Upon physical examinations, pulses and auscultatory findings will reveal an irregularly regular rhythm. Pulses may not coincide with ventricular rates because the pumping may not generate sufficient blood or force to produce peripheral pressure.

Atrial fibrillations are effectively diagnosed by an accurate medical history and a thorough physical examination. The following diagnostic methods and tests may be implored in patients presenting signs and symptoms of atrial fibrillations:

• Electrocardiogram (ECG) is considered the primary tool in diagnosing atrial fibrillations. 
• Holter monitor monitors a 24 hour period of cardiac electrical activity to detect intermittent AF cases.
• Event recorder will record cardiac activities in a period of weeks to months. It comes with an access button that the patient could easily press during an event or period of chest discomfort or irregularity for real time recording of the dysrhythmia. 
• Echocardiography elucidates the heart structures and clot formations during atrial fibrillation events [9].
• Blood tests will determine the presence of electrolyte imbalance and hormonal hyperactivity like hyperthyroidism that can cause clinical dysrhythmias like AF.
• Chest radiography will demonstrate other anatomic pathology of the heart, pericardium, and the lungs that may induce atrial fibrillation.

The general treatment goals involved in the control of atrial fibrillation include the resetting of the heart rate and rhythm, and the active prevention of blood clot formation. Conservative approaches to atrial fibrillation using medications to control rhythm is primarily sought before invasive procedures are implored. Some patients presenting with an organic disease like hyperthyroidism that induces atrial fibrillation may be treated accordingly to relieve the heart of these unnecessary stresses.

To reset the heart to normal rhythm, physicians often resort to cardioversion of the heart which may done by either electrical means (Electrical cardioversion), and by medical cardioversion. When the abnormal rhythm is normalized after electrical cardioversion, patients are often given antiarrhythmic drugs like flecainide, propafenone, dofetilide, and amiodarone to prevent the recurrence of the atrial dysrhythmia. Medications to control resting heart rate may be given like digoxin, beta blockers, and calcium channel blockers although proper precautions must be made to prevent hypotension [10].

In cases, where medical cardioversion fails to achieve its goals, surgical approaches like cardiac catheter ablation, atrio-ventricular node (AV node) ablation, and surgical maze procedures may be the only options left. Patients with atrial fibrillation are at high risk for the development of thrombi and embolus from blood clots; thus, anticoagulation therapy like warfarin, dabigatran, rivaroxaban, and apixaban may be given as a preventive measure.

Atrial fibrillation is closely associated with thromboembolic events that is why patients with AF have up to 1.9 fold risk of death compared to those who don’t suffer from it [6]. Mild asymptomatic AF has a good long term prognosis. The administration of maintenance medications like rate control and anticoagulants does not increase the survival rating of AF patients that are asymptomatic [7].

The risk of a thromboembolic stroke among AF patients beyond 75 years of age is staggering; thus, anticoagulant therapy is perpetually given unless other contraindications are identified. Meta-analysis data revealed that patients who were brought to the emergency room with myocardial infarction presenting with AF have a 40% increase in mortality rate [8].

Atrial fibrillation may be induced by any of these conditions:

• Coronary artery disease (CAD)
• History of heart surgery
• Viral endocarditis
• Sick sinus syndrome
• Sleep apnea
• Pneumonia and other lung diseases
• Stimulants like coffee, tobacco, alcohol and medications
• Hyperthyroidism
• Electrolyte imbalance
• Heart valve abnormalities
• Congenital heart disease
• Neurologic disorders
• Carditis and pericarditis
• Genetic factors

In the United States alone, more than 2.2 million Americans are suffering from atrial fibrillation. This cardiac dysfunction is primarily age related, because a fourth of the patients beyond 40 years old are at risk of developing atrial fibrillation in their remaining lifetime [2].

The increasing prevalence of atrial fibrillation among the elderly population is expected to double by 2050 in the US. Atrial fibrillation is relatively rare in infants and childhood, except for those who have undergone prior cardiac surgery [3]. Atrial fibrillation is more common among males than in females, and it is commonly seen in the white race than the black. Patients reaching the seventh decade the prevalence doubles per 10 year increment [4].

Arial fibrillation is strongly associated with cardiovascular diseases like coronary artery diseases (CAD), congestive heart failure (CHF) and diabetes mellitus [5]. Although the exact mechanism is inconclusively elaborated, theories abound that excessive catecholamine, hemodynamic stress and cardiac inflammation causes the AF phenomenon. There are theories of the occurrence of an automatic focus of electrical conduction from sources other than the AV node like some focal regions in the pulmonary vein can cause the unsynchronized impulses that gives rise to AF.

The active prevention of heart diseases through a heart friendly diet, exercise, and lifestyle may prevent occurrence of an acquired atrial fibrillation. A healthy lifestyle connotes the willful avoidance of stimulants like caffeine, alcohol and tobacco. Regular exercises and physical activity to maintain ideal body weight is also paramount in the prevention of heart diseases. Patients must understand that severe anger and stress can directly cause heart rhythm dysfunction on a long term basis.

Atrial fibrillation (AF) is clinically defined as a fast and irregular heart rate that reduces blood flow all over the body. Although atrial fibrillation is not considered life-threatening, persistent symptoms may require immediate treatment to prevent serious complications.

The desynchronized atrial contraction in atrial fibrillation may lead to thrombi or emboli formation that can functionally obstruct blood flow in multiple distant organs and cause ischemia. Atrial fibrillation is often times approached by interventions and medications to normalize the cardiac electrical activities. Atrial fibrillation is classified into three patterns: Paroxysmal AF, persistent AF, and permanent AF [1].

Definition

Atrial fibrillation is clinically defined as a fast and irregular heart rate that reduces blood flow all over the body.

Cause

Atrial fibrillation may be triggered by an ongoing heart disease, metabolic disease, neurologic disorders, and the intake of stimulants.

Symptoms

Patients may be asymptomatic, or may complain of palpitation, dizziness and weakness.

Diagnosis

Electrocardiography, echocardiography, Holter monitoring, blood tests and a chest X-ray may be used to diagnose the condition.

Treatment and follow-up

Medical and electrical cardioversion, and cardiac surgery ablation are the most common treatment options.

1. Fuster V, Rydén LE, Asinger RW, et al. ACC/AHA/ESC Guidelines for the Management of Patients With Atrial Fibrillation: Executive Summary A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences (Committee to Develop Guidelines for the Management of Patients With Atrial Fibrillation) Developed in Collaboration With the North American Society of Pacing and Electrophysiology. Circulation. Oct 23 2001; 104(17):2118-50.
2. Lloyd-Jones DM, Wang TJ, Leip EP, Larson MG, Levy D, Vasan RS, et al. Lifetime risk for development of atrial fibrillation: the Framingham Heart Study. Circulation. Aug 31 2004; 110(9):1042-6.
3. Abdel Latif A, Messinger-Rapport BJ. Should nursing home residents with atrial fibrillation be ant coagulated? Cleve Clin J Med. Jan 2004; 71(1):40-4.
4. Rathore SS, Berger AK, Weinfurt KP, Schulman KA, Oetgen WJ, Gersh BJ, et al. Acute myocardial infarction complicated by atrial fibrillation in the elderly: prevalence and outcomes. Circulation. Mar 7 2000; 101(9):969-74.
5. Kannel WB, Wolf PA, Benjamin EJ, Levy D. Prevalence, incidence, prognosis, and predisposing conditions for atrial fibrillation: population-based estimates. Am J Cardiol. Oct 16 1998; 82(8A):2N-9N.
6. Wolf PA, Abbott RD, Kannel WB. Atrial fibrillation as an independent risk factor for stroke: the Framingham Study. Stroke. Aug 1991; 22(8):983-8.
7. Wyse DG, Waldo AL, DiMarco JP, Domanski MJ, Rosenberg Y, Schron EB, et al. A comparison of rate control and rhythm control in patients with atrial fibrillation. N Engl J Med. Dec 5 2002; 347(23):1825-33.
8. Jabre P, Roger VL, Murad MH, et al. Mortality associated with atrial fibrillation in patients with myocardial infarction: a systematic review and meta-analysis. Circulation. Apr 19 2011; 123(15):1587-93.
9. Klein AL, Grimm RA, Murray RD, Apperson-Hansen C, Asinger RW, Black IW, et al. Use of transesophageal echocardiography to guide cardioversion in patients with atrial fibrillation. N Engl J Med. May 10 2001; 344(19):1411-20.
10. Hagens VE, Ranchor AV, Van Sonderen E, Bosker HA, Kamp O, Tijssen JG, et al. Effect of rate or rhythm control on quality of life in persistent atrial fibrillation. Results from the Rate Control Versus Electrical Cardioversion (RACE) Study. J Am Coll Cardiol. Jan 21 2004; 43(2):241-7.

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