To Study The Prevalence And Clinical Profile Of Chronic Atrial Fibrillation In Hospitalized Patients

Introduction :

Atrial fibrillation is the most common clinically significant cardiac arrhythmia1. Cardiac co-morbidities that are associated with AF include hypertension, coronary artery disease (CAD), valvular heart disease (VHD), congestive heart failure (CHF), cardiomyopathy, pericarditis, congenital heart disease (CHD) and cardiac surgery^2–9. Noncardiac co morbidities that are associated with AF include acute pulmonary embolism, chronic obstructive pulmonary disease (COPD), obstructive sleep apnea, hyperthyroidism and obesity^10–14.

Atrial fibrillation (AF) is a major risk factor for ischemic stroke, congestive heart failure and mortality.¹2³ The prevalence of AF is influenced by age, gender,^4,5,6 cardiovascular disease (CVD) such as valvular heart disease, and CV risk factors such as hypertension, diabetes,7 obesity,8 and insulin resistance.9 It was calculated that currently more than 3 million inhabitants of the USA suffer from atrial fibrillation and that this will increase to more than 7 million by 2050.15 Comparable figures for India are not available.

Knowing the prevalence of atrial fibrillation and documentation of medical management are important in the provision of primary care. This study sought to determine the prevalence of chronic atrial fibrillation in a tertiary care center and to identify the clinical profile of chronic AF in hospitalized patients.

Methods and Material :

All patients admitted to Mamata General Hospital in medicine/cardiology wards with atrial fibrillation during

the period January 2012 to December 2012 were the potential subjects. The principal inclusion criteria were a clinical diagnosis of chronic atrial fibrillation (persistent and permanent). The principal exclusion criteria were new onset AF and acute AF. The baseline data on cardiovascular diseases, respiratory diseases and other pertinent aspects of the medical history obtained by means of questionnaire.

Diagnosis of AF: AF was diagnosed based on the routine 12-lead electrocardiogram (ECG) records during the hospitalization.

Patients with documented AF were classified into two subgroups based on their first ECG recorded on arrival in either Emergency Department or Coronary Care Unit. An ongoing AF group included patients who had either chronic AF or developed AF before admission and a new-onset AF group consisted of patients who developed AF during hospitalization.

The presence of atrial fibrillation was based on documentation in the continuous patient profile, the clinic notes, consultant letters, emergency department or hospital discharge summaries, electrocardiograms, Holter monitor reports, echocardiograms, or stress test reports.

Chronic Atrial Fibrillation is defined as longer than 7 days for this study.

• Persistent AF - Episodes of AF persisting more than 7 days and require either pharmacologic or electrical intervention to terminate

• Permanent AF - Continuous AF, that has failed cardioversion, or where cardioversion has never been attempted

Results :

A total of 87 potential patients who were hospitalized in the medicine department/cardiology department of Mamata General Hospital were screened for the study. Of these, 49 were found to be eligible. The main reason for exclusion was new onset of AF and AF which lasted for less than 7 days.

Discussion :

In the present study, AF was seen more common in the 2050 age group. This is in contrast to that reported by other authors. According to Lip Gy, Golding DJ majority of people fibrillated after the age of 50 years.¹⁶ Epidemiological studies have shown that AF is fairly uncommon in people aged under 50 years but is found in 0.5% of people of aged 50-59, increasing to 8.8% at age 80-89.¹⁷ PT Onundarson et al showed that the prevalence of chronic AF is low in randomly selected population 32-64 years of age.¹⁸ These differences are because of the etiological cause of chronic AF. Nowadays ischemic heart disease is the most prevalent cardiac disease related with the development of AF in the western countries. In the present study the rheumatic heart disease is still the common etiology.

In the present study the sex ratio of female to male is 1.22:1, AF with valvular disease being more frequent among women than men. According to Lok NS, Lan CP, the ratio is 1.8:1. In these studies the female predominance is there.¹⁹

In the present study dyspnea (83.67%), palpitations (53.06%) and chest pain (30.61%) are the most common presentations. In Lok NS, Lau CP study dyspnea and palpitation were the most common symptoms.¹⁹ Gregory YH Lip described dyspnea (52%), chest pain (34%) and palpitation (24%) as the presenting symptoms in emergency admissions in AF. We also noticed that the symptoms are of longer duration in rheumatic etiology and are of shorter duration in other causes.

In our study congestive heart failure was the most common associated condition, nearly in 50% cases. CHF was a powerful independent predictor of the occurrence of AF in the Framingham study, in both symptomatic and asymptomatic LV dysfunction. AF is diagnosed in 10% to 35% of patients with CHF during the course of the disease and is related to the clinical severity of its symptoms.²⁰

In the present study stroke is seen in 13.33% of cases only. In a study from Trieste, Italy, 34% of patients with chronic AF had a significantly higher rate of thrombo-embolism, suggesting that in addition to age, chronicity may be a risk factor for stroke in the lone AF population.²¹

Conclusion:

In summary it was concluded that, the prevalence of chronic AF is still more common below the age of 50 years in this part of our country despite of increase in prevalence of IHD and increase in life expectancy of average Indian citizen and this is mostly due to high prevalence of rheumatic heart disease in India. CHF is the most common associated condition with chronic AF.