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Atrial fibrillation (AF) is a common arrhythmia associated with substantial morbidity, mortality, and health care cost. Although AF is responsible for a variety of symptoms, at least one third of patients report no overt symptoms and are unaware of their arrhythmic condition.1 This silent AF is diagnosed incidentally during routine physical or electrocardiographic examination. In some cases, asymptomatic AF is revealed only after complications such as stroke or congestive heart failure have occurred. Implantable pacemakers or defibrillators equipped with long term Holter memory function have shown that a very large proportion of patients (> 50%) have unsuspected episodes of silent AF.2
Silent AF is likely to be associated with morbidity and mortality rates similar to those in symptomatic AF, but its effect on quality of life (QoL) has not yet been established. We studied 154 patients with paroxysmal (60.5%) or persistent (39.5%) AF. Symptoms relevant for AF were selected from Bubien and Kay's symptom checklist, including palpitations, dyspnoea, dizziness, exercise intolerance, chest discomfort, and syncope. Thirty eight patients with the lowest quartile symptom scores (⩽ 25.4) were considered asymptomatic or very mildly symptomatic (group 1); 118 patients in the other three quartiles (> 25.4) were considered symptomatic (group 2). Palpitations (68%), dyspnoea (60%), and fatigue (62%) were the most common symptoms reported by these patients. A control group consisted of 49 subjects (mean (SD) age 54 (14) years, 45% men) referred for routine health examination, without documented cardiovascular or any serious systemic disease. Symptom burden, as assessed by the symptom frequency and severity checklist, did not differ between normal subjects and group 1 patients, confirming that the latter were truly asymptomatic. Group 1 and group 2 patients did not differ with respect to age (58.6 (12.3) years v 57.6 (11.1) years), left ventricular ejection fraction (62.4 (14.1)% v 60.8 (16.1)%), left atrial dimension (4.3 (0.6) cmv 4.2 (0.6) cm), or New York Heart Association (NYHA) functional class I (91.7%v 87.9%). There was a significantly greater proportion of women among symptomatic compared to “asymptomatic” patients (32.5% v 13.2%, p = 0.022).
QoL was assessed by a generic health scale, the 36 item short form health survey (SF-36) with standardised scores ranging from 0–100 to measure eight health dimensions. Total functional capacity was measured by a modified Goldman specific activity scale, and the illness intrusiveness ratings scale was used to assess the lifestyle disruption attributable to illness. In addition, global life satisfaction was evaluated using a one item visual analogue scale ranging from 1 (worst possible life) to 10 (best possible life).
Patients with AF had substantially impaired QoL compared with healthy subjects (p < 0.003, table 1). Although the conventional “objective” measures of illness severity were similar in group 1 and group 2 patients, the latter reported significantly lower scores on all SF-36 scales (p < 0.005). Group 2 patients had a significantly increased illness intrusiveness compared with group 1 patients (39 (15)v 25 (10), p < 0.001). Total functional capacity and global life satisfaction were significantly lower in symptomatic patients compared to “asymptomatic” patients (p < 0.005).
NYHA class and symptom frequency and severity were related to SF-36 scores but accounted for only 7% of total variability of the latter (P Dorian, unpublished data).
Although most SF-36 scale scores did not differ much between normal subjects and “asymptomatic” AF patients, and total functional capacity was similar in both groups, the perception of general health was significantly poorer in the latter (p < 0.003). Global life satisfaction was significantly decreased in “asymptomatic” patients compared with normal subjects (p < 0.003).
This study suggests that the subjective effects of AF on isolated physical aspects or on social and emotional spheres may be subtle in patients with little or no symptoms, but the arrhythmia may significantly decrease the overall perception of well being in this population. Our data are consistent with the results of other studies evaluating QoL in patients with AF. In the Canadian trial of atrial fibrillation, 289 patients with paroxysmal or persistent AF reported better QoL and had significantly higher scores in physical functioning, vitality, mental health, and role emotional when they perceived themselves to be in sinus rhythm.3 Complete atrioventricular node ablation in patients with refractory AF resulted in a remarkable improvement in general QoL. An improvement in QoL and a reduction of symptoms after ablation was significantly greater than after atrioventricular node modification, probably because of better control of the rate and regularity of the ventricular response.4 Although a noticeable increase in QoL has been seen in ablation studies, these usually addressed highly symptomatic patients with poorly controlled AF; only in a small series of patients with permanent AF and a normal ventricular rate response, a similar significant improvement in symptom scores and in the perception of general health have also been achieved after atrioventricular node ablation.5
Even less is known about QoL in patients whose rhythm and/or rate are believed to be well controlled by antiarrhythmic drugs or in those who can be potential candidates for treatment with implantable atrial defibrillators. Although pharmacological treatment may prevent the arrhythmia recurrence, it often renders symptomatic AF to asymptomatic, and the assessment of QoL in these patients may have an impact on the risk-benefit ratio of antiarrhythmic drugs. A serious consideration should be given to QoL in atrial defibrillator recipients as this device may decrease a total symptom burden of AF but usually it does not affect the recurrence of arrhythmia, in particular, short, non-treated episodes which may be well tolerated or may be unrecognised by a patient as AF.6
The issue of long life anticoagulation also remains open in patients with AF in whom frequent, long lasting, highly symptomatic episodes have been suppressed by either kind of treatment but the arrhythmia has not been completely abandoned. This study indicates that several aspects of QoL may be reduced in patients with AF, even in the absence of symptoms of the arrhythmia. QoL should be assessed and treatment for the improvement of QoL should be considered in patients with “asymptomatic” AF.