Effect of Radiofrequency Catheter Ablation on Health-Related Quality of Life and Activities of Daily Living in Patients With Recurrent Arrhythmias
Background Although radiofrequency catheter ablation can be used to effectively treat a variety of arrhythmias, the effects of this procedure on health-related quality of life have not been systematically studied.
Methods and Results The SF-36 (a measure of general health status), the Symptom Checklist—Frequency and Severity Scale (an instrument specific for cardiac arrhythmias), and an Activities of Daily Living questionnaire were used to assess quality of life in 161 patients before radiofrequency catheter ablation. These same instruments were used to measure quality of life 1 and 6 months after ablation with complete data in 159 of the original 161 patients. Before ablation, SF-36 scores of the study population were low compared with the US normative data base reflecting significant impairment in physical functioning and well-being. The lowest scores were reported by patients with atrial fibrillation and atrial flutter. Catheter ablation was associated with significant improvement in quality of life that was sustained over the 6 months after ablation. Improvements were measured in both the generic SF-36 health status questionnaire and the disease-specific Symptom Checklist—Frequency and Severity Scale. Catheter ablation was followed by improved performance of activities of daily living and a marked decrease in the number of visits to physicians and emergency rooms in the 6 months after ablation compared with the 6 months before ablation.
Conclusions Radiofrequency catheter ablation improves the health-related quality of life for patients with a variety of cardiac arrhythmias.
Radiofrequency catheter ablation is highly effective for the treatment of many forms of supraventricular and ventricular tachycardia.1 2 3 4 5 6 Because most tachycardias that are amenable to radiofrequency ablation are not life threatening, the goal of treating these arrhythmias is usually to improve the patient's quality of life. The assumption inherent to the proliferation of catheter ablation procedures is that this therapy achieves several fundamental objectives of medical care, namely, relieving distress, restoring function, and preventing disability.7 However, the validity of this assumption has not been rigorously tested. Prior reports that have evaluated the effects of catheter ablation on the quality of life in patients with arrhythmias have included limited numbers of patients8 or a narrow spectrum of arrhythmia mechanisms.9 Thus, a prospective study of the impact of catheter ablation on the quality of life of patients with tachyarrhythmias is necessary to accurately assess the outcome of this procedure.
Definition of Quality of Life
Quality of life encompasses the total well-being of the person, including physical and psychosocial aspects.10 Assessments of quality of life rely on evaluation of functional capacity, symptomatology, and the patient's perception of well-being. Functional capacity includes the ability to perform activities of daily life or self-care as well as social, emotional, and intellectual functions. Functional capacity is importantly related to the maintenance of economic status.11 Included in the physical and mental health dimensions of quality of life12 are the presence or absence of symptoms and their frequency, intensity, and associated degree of distress.13 Perhaps most importantly, quality of life is dependent on the individual's evaluation of his or her life.14 15 16 Thus, accurate quantification of quality of life must be patient based and include both generic and disease-specific measures.17 18 This study was designed to prospectively quantify the effects of catheter ablation on the health-related quality of life of patients with recurrent supraventricular and ventricular arrhythmias.
Patient Population and Study Design
The potential study population included all patients 18 years of age or older who were referred to the University of Alabama at Birmingham between January 17, 1994, and July 1, 1994, for radiofrequency catheter ablation of symptomatic ventricular or supraventricular arrhythmias. Patients who agreed to participate were asked to complete a self-administered questionnaire before and at 1 month (range, 4 to 8 weeks) and 6 months (range, 24 to 70 weeks) after radiofrequency catheter ablation. Accompanying each questionnaire was a letter explaining the purpose of the study and the procedures to be used for completion of the questions. Assurance of patient confidentiality was maintained by substituting an alphanumeric code for the patient name. At the designated intervals after catheter ablation, questionnaires were mailed to patients with a self-addressed, stamped envelope provided. If the questionnaire had not been returned within 2 weeks, the patient was contacted by telephone. Vigorous efforts were made to measure quality of life in all patients 6 months or longer after ablation.
The study protocol was approved by the Institutional Review Board for Research Involving Human Subjects at the University of Alabama at Birmingham. Participation was limited to patients from the United States who demonstrated the ability to read and write. Patients who failed to give informed consent, those with dementia, or those with a life expectancy of <6 months due to a concomitant illness were excluded from participation. Follow-up electrophysiological studies were not routinely performed.
Quality of Life Instruments
The Medical Outcomes Study Short-Form Health Survey (SF-36) and the Symptom Checklist: Frequency and Severity Scale (version 3) were the principal instruments selected to measure quality of life. Questions regarding the patient's perception of the influence of his or her arrhythmia on overall health and questions specific to life style were also used to measure the effect of arrhythmias on activities of daily living.
The SF-36 is a standardized, generic health survey instrument that measures an individual's physical functioning, bodily pain, and perception of ability to perform physical, emotional, and social role functions, as well as sense of vitality and of mental and general health. Because the range of possible scores varies for each subscale, scores were normalized to a scale ranging from 0 to 100, with lower scores representing a lower quality of life. The eight subscales of the SF-36 assess health status and well-being regardless of age, disease, or treatment group. Sex biases and value statements were systematically eliminated during development of this instrument. Missing data were handled as suggested by the developers of the SF-36. For example, if an individual answered that strenuous activities requiring a high level of physical functioning posed no difficulty, it was assumed (in accordance with the SF-36 methodology) that less vigorous activities also posed no difficulty.19 20 21
Symptom Checklist—Frequency and Severity Scale
The Symptom Checklist—Frequency and Severity Scale was developed as disease-specific instrument intended to measure the patient's perception of the frequency and severity of arrhythmia-related symptoms. Previous versions of this instrument have been demonstrated to discern sequential changes in the symptomatology of patients with atrial fibrillation who are undergoing atrioventricular node ablation, those implanted with rate-adaptive pacemakers for sinus node dysfunction or complete heart block, and those with supraventricular tachycardias who are undergoing radiofrequency catheter ablation.8 22 23 24 The instrument has been demonstrated to be valid for use in patients with chronic or paroxysmal atrial fibrillation. Scoring of version 3 of the Symptom Checklist—Frequency and Severity Scale was revised so that lower scores represented less symptomatic impairment, with possible scores ranging from 0 to 64 for symptom frequency and from 0 to 48 for symptom severity.
Perceived Impact of the Arrhythmia on Activities of Daily Living
A four-item scale, identical in construction to the Physical Role Function subscale of the SF-36, was administered to determine the patient's perception of the effects of arrhythmias on daily life. These questions were designed to measure the impact of arrhythmias on daily activities such as the amount of time and effort required for work and other activities. The Perceived Impact of Arrhythmia on Activities of Daily Living was scored identically to the Physical Role Function subscale of the SF-36, with a normalized range from 0 to 100 and higher scores representing less impairment.
Performance of Activities of Daily Living
Patients were asked to complete nine questions specific to the effects of arrhythmias on performance of activities of daily living. These questions were used to assess the effects of arrhythmias on ability to perform routine physical, social, and family activities; to travel and vacation; and to drive an automobile (as well as assessing the degree of worry or concern about driving). The number and type of physician office visits and emergency room admissions were also measured for the 6 months before and after catheter ablation.
The SF-36 and the Symptom Checklist—Frequency and Severity Scales were analyzed with the use of two-way, repeated-measures ANOVA to discern quality of life over time. The study was powered to detect a minimum of a 10-point difference in all eight subscales of the SF-36 and at least a 5-point difference in the subscales of physical functioning, mental health, and vitality, with a power of 80% and an intertemporal correlation between scores of.60.19 Changes in the SF-36 subscales and the Performance of Activities of Daily Living scale from baseline to 6-month follow-up were correlated with the baseline scores of arrhythmia-related symptom frequency and severity with the use of Pearson's correlation coefficient.
A total of 229 patients underwent successful catheter ablation of supraventricular or ventricular arrhythmias during the study period. Only 7 patients declined to participate. After excluding 15 patients <18 years old and 19 who met other exclusion criteria (illiteracy, dementia, or life expectancy of <6 months), the study population comprised 188 patients. Questionnaires were returned by 161 (85.6%) of eligible patients before catheter ablation. Of these 161 patients completing the baseline evaluation, 38 provided incomplete questionnaires 1 month after catheter ablation. Data were complete for late follow-up (>6 months after ablation) in 159 of the 161 patients enrolled. Late follow-up was not available because of stroke in 1 patient and death due to congestive heart failure in another patient. Both of these patients had congestive heart failure and had undergone catheter ablation of the atrioventricular node because of poorly controlled atrial fibrillation.
The mean age of the study group was 49±15.8 years, with a range of 18 to 82 years. There were 70 men and 89 women. The indications for catheter ablation were supraventricular arrhythmias related to the Wolff-Parkinson-White syndrome in 46 patients, atrioventricular nodal reentrant tachycardia in 59 patients, atrial fibrillation treated by atrioventricular node ablation and permanent pacemaker implantation in 22 patients, atrial flutter or atrial tachycardia in 22 patients, and idiopathic ventricular tachycardia arising from the right ventricular outflow tract (n=8) or left ventricle (n=2) in 10 patients (Table 1⇓). Patients with ventricular tachycardia were usually younger (mean age, 36.1±13.0 years) and had a shorter duration of arrhythmias (1.6 years) than patients with Wolff-Parkinson-White syndrome, atrioventricular nodal reentrant tachycardia, atrial fibrillation, or atrial flutter. In addition, these patients had received fewer antiarrhythmic drugs than the other groups. Catheter ablation was successful in eliminating the arrhythmia in all patients. However, a repeat catheter ablation session was required for 3 patients who experienced recurrence of arrhythmias after an initially successful ablation.
Comparison of Study Group With Other Cardiac Disease Populations: Baseline
The scores of the eight subscales of the SF-36 before catheter ablation are shown in Table 2⇓ for the study group and for control groups reported for the general US population, as well as for populations with hypertension, congestive heart failure, and recent myocardial infarction. The baseline SF-36 scores for the study group were lower than for the US population, especially for the Vitality, Emotional, and Social Role subcategories. The SF-36 scores before ablation were similar to those reported for patients with congestive heart failure but lower than for patients with hypertension or recent myocardial infarction. After catheter ablation, scores for the study population improved to approximate those of the US population.
Effect of Catheter Ablation on Health-Related Quality of Life
With the exception of the General Health score, all subscales of the SF-36 were significantly improved 1 month after catheter ablation compared with baseline. The improvements were maintained 6 months after ablation, with no significant change between 1 and 6 months after ablation. Similar improvements in arrhythmia-related symptoms were measured with the Symptom Checklist—Frequency and Severity Scale (Table 2⇑) at 1 and 6 months after catheter ablation compared with baseline. As might be expected in a population with generally paroxysmal arrhythmias, the General Health subscale was not measurably improved by the use of catheter ablation. In contrast, the patient's perception of the impact of arrhythmias on his or her health improved after ablation. These results were maintained between 1 and 6 months after ablation. Although 90.2% of the patients indicated that their heart rhythm problems influenced their health perception at baseline, this frequency declined to 59.4% at 1 month and 57.5% at 6 months.
Activities of Daily Living
Catheter ablation was followed by marked improvement in how patients perceived their ability to perform activities of daily living (Table 3⇓). The percentage of patients who expressed concern about the sudden onset of a tachyarrhythmia declined from 92.96% at baseline to 69.1% at 1 month and further decreased to 48.57% at 6 months. Limitations due to physical difficulty or fears concerning driving an automobile also decreased significantly 1 and 6 months after ablation. Similarly, patients reported that interference with social activities had declined by 1 and 6 months after catheter ablation. Self-imposed restrictions on physical or social activities and travel or vacation plans because of arrhythmias were also markedly reduced. A precipitous decline was observed in the proportion of patients requiring emergency room or nonscheduled office visits to physicians within the 6 months before compared with the 6 months after catheter ablation (85.92% versus 13.1%).
Effect of Arrhythmia Mechanism on Patient's Response to Catheter Ablation
The type of clinical arrhythmia had a major impact on the baseline quality of life measurements (Table 4⇓) and performance of activities of daily living (Table 5⇓). Although initial physical function scores on the SF-36 were higher for patients with ventricular tachycardia than for other groups, these patients nevertheless reported impaired Physical Role Function. This suggests that although these individuals were capable of more vigorous physical activity than were other subgroups, their arrhythmias had interfered with physical performance. Furthermore, although impaired Physical Functioning was not detected with the SF-36 in these younger individuals with ventricular tachycardia, their sense of well-being was nevertheless reduced. The Mental Health and Vitality subscales of the SF-36 as well as Emotional Role Function were depressed before catheter ablation. Accordingly, the health-related quality of life of patients with the Wolff-Parkinson-White syndrome or ventricular tachycardia had higher scores on the quality of life instruments and demonstrated less change after catheter ablation. In general, these patients did not have coexisting medical conditions such as arthritis or congestive heart failure that would have affected their score.
The persistently low quality of life exhibited by patients with atrial fibrillation who had undergone atrioventricular nodal ablation was examined with Sche´ffe post-hoc analysis to determine whether significant differences in quality of life existed between subgroups at baseline and whether the underlying arrhythmia influenced their response to catheter ablation. The Symptom Checklist—Frequency and Severity Scale scores, the Perceived Impact of the Arrhythmia on ADL scores, and the SF-36 subscales of Physical Role Function, Social Role Function, Vitality, and Physical Function were significantly worse (P<.05) for patients with atrial fibrillation than for other arrhythmia subgroups. Although patients with atrial flutter also differed significantly in most of these categories at baseline, these differences in large part resolved after ablation.
Correlation Between SF-36 and Activities of Daily Living Instruments
Because patients with episodic arrhythmias might be expected to report good general health during arrhythmia-free intervals but experience significant symptoms during arrhythmias, the correlation between the more general SF-36 subscales and the more specific questions that assess the effect of arrhythmias on activities of daily living was examined. Changes in scores before and after catheter ablation regarding interference of arrhythmias with social activities in the Performance of Activities of Daily Living instrument correlated well with changes in Social Role Function as measured with the SF-36 subscale (r=.68 and P<.01 at 1 month; r=.71 and P<.01 at 6 months). Similarly, changes in items regarding limitations of physical activities in the Performance of Activities of Daily Living instrument correlated with changes in Physical Role Function measured with the SF-36 subscale (r=.64 and P<.01 at 1 month; r=.48 and P<.01 at 6 months).
Because the Symptom Checklist—Frequency and Severity Scale is specific for symptoms related to arrhythmias, the scores of this instrument were anticipated to improve after successful catheter ablation. Indeed, the Symptom Checklist—Frequency and Severity Scale demonstrated significant reductions in the frequency and severity of arrhythmia-related symptoms after catheter ablation. The changes in the scores from this instrument correlated well with the physical and social subscales of the SF-36 (r=−.44 to −.65, P<.0005), suggesting that elimination of cardiac arrhythmias was a major explanation for the improvement in overall quality of life reported by the study population.
Effect of Baseline Arrhythmia Frequency and Severity on Response to Catheter Ablation
The influences of the frequency and severity of arrhythmia-related symptoms before catheter ablation on the response to catheter ablation are shown in Table 6⇓. Note that the Physical and Social Role subscales of the SF-36 demonstrated the most significant improvement after catheter ablation when the baseline symptom frequency and severity scores were high. As might be expected, changes in the Bodily Pain, Mental Health, and General Health subscales of the SF-36 demonstrated no correlation with the baseline frequency and severity of arrhythmia-related symptoms.
The results of the present study demonstrate that patients with arrhythmias who are treated with catheter ablation perceive a significant negative impact of their condition on the quality of their lives. Although many of these arrhythmias are paroxysmal in nature, the study population reported significant impairment in scores for both general and arrhythmia-specific measures of health-related quality of life.
Others have reported that two thirds of patients with supraventricular arrhythmias experienced moderate disruption in their lives.25 In the present study, radiofrequency catheter ablation was followed by improvement in a wide range of physical, emotional, and social functions. This procedure was also associated with a decrease in the frequency and severity of symptoms related to cardiac arrhythmias and a reduction in self-imposed restrictions related to activities of daily living. The amount of improvement in quality of life after ablation correlates with the frequency and severity of arrhythmia-related symptoms. Successful catheter ablation significantly reduced emergency room and unscheduled physician visits.
There are several limitations to this study that must be recognized. First, all patients had been referred for (and consented to) definitive treatment of symptomatic arrhythmias. Since all patients had been willing to undergo an invasive procedure with the potential for important morbidity, this study group was both highly motivated and highly selected. The low quality of life scores measured at the baseline evaluation before catheter ablation reflect significant symptomatic impairment of the study population. Second, in most cases patients were poorly controlled with standard drug treatment or had experienced intolerable side effects. The potential negative impact of antiarrhythmic drug therapy on quality of life may have significantly contributed to the low baseline scores, further motivating patients to seek nonpharmacological therapy. The marked improvement in measurements of quality of life may have been related to withdrawal of medications as well as to elimination of cardiac arrhythmias. Third, anxiety regarding the sudden and unpredictable onset of severe symptoms that is characteristic of many paroxysmal arrhythmias is likely to have been the major reason for self-imposed limitations in activities of daily living, affecting the emotional and social roles of the study population. Similar changes in quality of life may not occur in less symptomatic populations. Indeed, the baseline frequency and severity of arrhythmia-related symptoms were correlated with the improvement in measures of quality of life that were measured from before to after ablation. Finally, a control group of patients with similar arrhythmias treated without catheter ablation was not studied. However, it would be difficult to withhold catheter ablation from a very symptomatic group of patients receiving medical therapy to compare the impact on quality of life of this procedure with other forms of therapy. Nevertheless, since the quality of life measurements were obtained before and after catheter ablation, each patient served as his or her own control.
There are other limitations that are inherent to measurements of quality of life. Although the items in each of the quality of life instruments were specifically constructed to minimize response bias, and although response bias is decreased with the use of anonymous mail surveys, self-reporting methods may be confounded by underreporting of undesirable characteristics and overreporting of socially desirable behaviors. Participants may describe themselves in favorable terms or as possessing socially desirable characteristics. In addition, participants who undergo an invasive procedure may report improvements in quality of life simply as a result of being part of a treatment group. Stewart et al26 noted that the impact of coexisting chronic conditions such as arthritis or back problems may account for a 9-point difference in physical functioning in the SF-36, and a ≤13-point difference can be attributed to the presence of diabetes or congestive heart failure. Examination of the atrial fibrillation and flutter groups indicated that these older individuals had some degree of congestive heart failure and often had important problems with mobility attributed to arthritis. Thus, the variance noted between arrhythmia categories may have been attributed to a number of variables, including coexisting medical problems.
Patients with symptomatic arrhythmias who are treated with radiofrequency catheter ablation report significant reductions in arrhythmia-related symptoms and improvement in physical, emotional, and social indexes of their health-related quality of life after the procedure. Self-imposed restrictions on physical and social roles are markedly reduced after catheter ablation. These improvements in a wide range of quality of life measures occur within the first month after catheter ablation and are maintained through 6 months after the procedure. In addition, the specific Symptom Checklist—Frequency and Severity Scale proved a valid adjunct to the generic SF-36 in this patient population. The Symptom Checklist—Frequency and Severity Scale may be especially useful when more generic quality of life measures demonstrate less impairment, allowing more specific limitations to be more readily detected.
- Received January 25, 1996.
- Revision received March 1, 1996.
- Accepted March 13, 1996.
- Copyright © 1996 by American Heart Association
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