The Canadian CV Society Function Score for Atrial Fibrillation
The Canadian CV Society Function Score for Atrial Fibrillation
Abstract & Commentary
By John P. DiMarco, MD, PhD
Source: Dorian P, et al. Validation of a new simple scale to measure symptoms in atrial fibrillation: The Canadian Cardiovascular Society Severity in Atrial Fibrillation Scale. Circulation Arrhythmia Electrophysiol. 2009;2:218-224.
In this paper, Dorian et al attempt to validate a relatively simple symptom scoring system for use in patients with atrial fibrillation (AF). The proposed Canadian Cardiovascular Society Severity in Atrial Fibrillation (CCS-SAF) scale is based upon symptoms attributable to AF, the association between symptoms and documentation of AF or AF therapies, and the functional consequences of these symptoms on the patient's daily life. The SAF class is then rated on a scale from 0 for asymptomatic patients to 4 for patients who have a severe impact of symptoms on their quality of life and activities of daily living. The goal of the scale is to mimic the 0 to 4 scales successfully used in patients with heart failure and angina.
In this study, the CCS-SAF score was determined in 484 Canadian patients with a history of atrial fibrillation recruited from five centers. The CCS-SAF score was then compared to data obtained using other standard quality-of-life instruments, including the SF-36 and the Disease Specific Atrial Fibrillation Severity Scale (AFSS) score within the same time period. Patients in the study group were 62 ± 12 years of age, 67% were male, 62% had paroxysmal AF, and the median duration of AF was 48 months. Almost half the patients had lone atrial fibrillation. Thirty percent of patients had hypertension, 7% coronary artery disease, 9% valvular disease, and 5% nonischemic cardiomyopathy. A rate control strategy was being used in 48%, a rhythm control strategy in 42%, no drug therapy in 6%, and both rate control and rhythm control in 4%. There was a significant positive linear relationship between the five class SAF score and the AFSS symptom and severity subscales. For example, the AFSS global well-being score decreased from 8 among patients in SAF class 1 to 4.8 among SAF patients in class 4. Similar correlations were noted in AFSS severity and symptoms subscales. Of note, there was no relationship between SAF score and subjectively reported AF frequency or duration on the AFSS score. SAF class also correlated well with the SF-36 subscales for physical functioning, bodily pain, general health, vitality, social functioning and mental health, and the two SF-36 summary scales for physical and mental health. In this population, SAF class was not related to age, but was higher among women than among men. Patients in higher SAF classes had a greater proportion of electrical cardioversions, more emergency room visits, and more specialist appointments and hospitalizations during a one-year period of observation.
Dorian et al conclude that the relatively simple SAF classification system can provide a clinically useful method for classifying patients with atrial fibrillation. This scoring system may be of value both to individual physicians in their practices and for studies evaluating the efficacy of therapy in patients with atrial fibrillation.
Commentary
The new SAF score proposed in this paper is similar to scoring systems used in both congestive heart failure and angina. The relatively simple 0 to 4 point scoring system allows patients to be quickly categorized at each visit, and changes in SAF score over time can be used to assess the effectiveness of therapy.
Quality of life and symptom scoring of atrial fibrillation is notoriously difficult. Patients with atrial fibrillation often are elderly and have numerous comorbidities that often affect quality of life, independent of AF status. Traditional methods for assessing quality of life in AF patients use complex questionnaires and cannot usually be integrated into everyday practice. The relatively simple scoring system here is likely to prove useful, as physicians follow individual patients over time, making it a possible tool that could be used in evaluating therapies in atrial fibrillation. However, this study included a relatively high proportion of patients with idiopathic atrial fibrillation and paroxysmal atrial fibrillation. Further studies in larger groups of patients with structural heart disease, and either persistent or permanent atrial fibrillation, are needed before the SAF score can become a standard tool for evaluating therapy.
In this paper, Dorian et al attempt to validate a relatively simple symptom scoring system for use in patients with atrial fibrillation (AF). The proposed Canadian Cardiovascular Society Severity in Atrial Fibrillation (CCS-SAF) scale is based upon symptoms attributable to AF, the association between symptoms and documentation of AF or AF therapies, and the functional consequences of these symptoms on the patient's daily life.Subscribe Now for Access
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