Rosemary S. Bubien

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.

Effect of catheter ablation of the atrioventricular junction on quality of life and exercise tolerance in paroxysmal atrial fibrillation.

The effect of catheter ablation of the atrioventricular junction (AV) and implantation of a rate-adaptive pacemaker on quality of life and exercise capacity was evaluated prospectively in 12 consecutive patients with paroxysmal atrial fibrillation (AF). All patients had been demonstrated to have paroxysmal AF that was refractory to medical therapy over a long period of time (mean 9 +/- 7 years). Patients performed a symptom-limited treadmill exercise test on the day before catheter ablation and 6 weeks after hospital discharge. Quality of life was measured using the physical dimension of the McMaster Health Index Questionnaire and the Psychological General Well-Being Index before and 6 weeks after ablation. There were no serious complications related to catheter ablation or permanent pacemaker implantation. All patients remain in complete AV block with a completely paced rhythm at a mean follow-up of 8 +/- 2 months. The McMaster Health Index scores increased from a mean of 0.69 +/- 0.20 before to 0.92 +/- 0.14 after ablation (p = 0.002). The mean Psychological General Well-Being score improved from 59.8 +/- 14.8 at baseline to 84.9 +/- 13.6 6 weeks after discharge (p = 0.001). Treadmill exercise duration increased from 6.4 +/- 4.6 to 9.9 +/- 2.6 minutes (p = 0.03) and correlated strongly with changes in functional capacity measured with the McMaster Health Index (r = 0.70, p = 0.03). These results suggest that catheter ablation of the AV junction and implantation of a rate-adaptive pace-maker significantly improve the quality of life and exercise capacity of patients with paroxysmal AF refractory to medical therapy.

Development and Validation of the Atrial Fibrillation Effect on QualiTy-of-Life (AFEQT) Questionnaire in Patients With Atrial Fibrillation

Background—Atrial fibrillation (AF) has a deleterious impact on health-related quality-of-life (HRQoL), but measuring this outcome is difficult. A comprehensive, validated, disease-specific questionnaire to measure the spectrum of QoL domains affected by AF and its treatment is not available. We developed and validated a 20-item questionnaire, Atrial Fibrillation Effect on QualiTy-of-life (AFEQT), in a 6-center, prospective, observational study. Methods and Results—Factor analyses established 4 conceptual domains (Symptoms, Daily Activities, Treatment Concern, and Treatment Satisfaction) from which individual domain and global scores were calculated. Participants from 6 centers completed the AFEQT at baseline, at month 1, and at month 3. Psychometric analyses included internal consistency and known-group validity. Test-retest reliability was assessed by comparing 1-month changes in scores among those with no change in therapy. Effect size was used to assess responsiveness after intervention. Among 219 patients age 62±11.9 years, 94% completed the AFEQT at baseline and 3 months; 66% had paroxysmal, 24% persistent, 5% longstanding persistent, and 5% permanent AF. Internal consistency was >0.88 for all scales. Lower AFEQT scores were observed with increased AF severity, categorized as asymptomatic, mild, moderate and severe, respectively: 71.2±20.6, 71.3±19.2, 57.9±19.0, and 42.0±21.2. Intraclass correlations for Overall, Symptoms, Daily Activities, Treatment Concern, and Satisfaction scores were 0.8, 0.5, 0.8, 0.7, and 0.7, respectively. Changes in 3-month scores were larger after ablation than with pharmacological adjustments, and both were greater than those observed in stable patients. Conclusions—This initial validation of AFEQT supports its use as an outcome in studies and a means to clinically follow patients with AF.

Intracoronary ethanol ablation for the treatment of recurrent sustained ventricular tachycardia

The selective infusion of ethanol into the coronary circulation supplying the site of origin of incessant ventricular tachycardia has been demonstrated to abolish this arrhythmia in selected patients. The present study was designed to evaluate the efficacy and safety of the intracoronary ethanol ablation technique in patients with paroxysmal ventricular tachycardia related to prior myocardial infarction. Twenty-three patients with sustained monomorphic ventricular tachycardia that was refractory to conventional antiarrhythmic drug therapy were prospectively studied. After induction of ventricular tachycardia by programmed electrical stimulation, the response of the arrhythmia to the infusion of radiographic contrast medium or saline solution into the ostia of the native coronary arteries and coronary artery bypass grafts was assessed. If ventricular tachycardia was reliably interrupted by injections into the proximal coronary artery or bypass graft, the vessel was cannulated with a steerable guide wire and 2.7F infusion catheter to determine the smallest arterial branch that would result in termination of the arrhythmia with selective injections. If reliable interruption of ventricular tachycardia was observed with saline or contrast injections, ethanol (2 ml) was then delivered through the infusion catheter. Ventricular tachycardia could be terminated by injections of saline solution or contrast medium in 11 of 21 patients in whom the protocol could be completed. Ethanol was infused in 10 of these patients. Ventricular tachycardia was inducible in only 1 of 10 patients immediately after ethanol infusion. At a follow-up electrophysiologic study performed 5 to 7 days after ablation, ventricular tachycardia became inducible in two other patients, in one of whom the arrhythmia substrate was successfully ablated after three sessions. The mean left ventricular ejection fraction was 0.33 +/- 0.1 before and 0.35 +/- 0.11 after ablation. Complications of the procedure included complete atrioventricular block in four patients and pericarditis in one patient. Thus, intracoronary ethanol ablation is associated with a moderate degree of efficacy but the potential for important complications. Despite these limitations, this technique may provide effective long-term control of ventricular tachycardia for some patients.

North American Society of Pacing and Electrophysiology. Standards of professional practice for the allied professional in pacing and electrophysiology.

The North American Society of Pacing and Electrophysiology (NASPE) was established in recognition of the unique challenges that the management of patients with cardiac rhythm disorders present. As with other subspecialty fields within cardiology, the genesis of this specialty evolved from technological innovations and ensuing biomedical applications, which fueled the development of electrophysiological related interventions. The provision of services accompanying these technology-based interventions created an opportunity for health care professionals to specialize in the field of cardiac rhythm management. Known as Allied Professionals (APs), this diverse group of nurses, physician assistants, technologists, technicians, and engineers is dedicated to promoting excellence in the care of patients with cardiac rhythm disorders. The provision of safe, optimal care is contingent on the coordinated efforts of multiple disciplines, the acquisition of a defined specialized knowledge base, and the application of knowledge and skills in rendering patient care and technical support services. The Standards of Professional Practice for the Allied Professional in Pacing and Electrophysiology have been developed to articulate the scientific foundation, clinical skills, and technical knowledge requisite to provide and facilitate the provision of safe quality patient care. The Standards of Professional Practice address the scope of activities of the AP employed in the field of cardiac rhythm management. The first section, Core Knowledge and Skills, addresses essential areas of practice germane to the specialty to provide professional care and technical support services. Subsequent sections address knowledge requirements for specific technology-based interventions and therapies to patients undergoing invasive and noninvasive diagnostic, therapeutic,

Rate-modulated cardiac pacing based on transthoracic impedance measurements of minute ventilation: Correlation with exercise gas exchange

The relation of pacing rate to physiologic variables of metabolic demand was examined in 10 consecutive patients with a minute ventilation-sensing, rate-modulating ventricular pacemaker implanted for complete heart block. All patients had paroxysmal (seven patients) or chronic (three patients) atrial fibrillation and were referred for catheter ablation of the atrioventricular junction. Treadmill exercise testing with measurement of expired gas exchange and respiratory flow was performed before ablation and 4 weeks after pacemaker implantation, with the pacemaker programmed to both the fixed-rate VVI and rate-modulating minute ventilation VVIR pacing modes in random sequence. The relation of pacing rate to oxygen consumption (VO2), expired carbon dioxide concentration (VCO2), respiratory quotient, tidal volume, respiratory rate and minute ventilation was determined during exercise in the rate-modulating minute ventilation pacing mode. Pacing rate was highly correlated with minute ventilation (r = 0.89), respiratory quotient (r = 0.89), VCO2 (r = 0.87), tidal volume (r = 0.87), VO2 (r = 0.84) and respiratory rate (r = 0.84). The mean exercise duration increased from 8.3 +/- 2.8 min in the fixed rate pacing mode to 10.2 +/- 3.4 min in the rate-modulating, minute ventilation mode (p = 0.0001). The maximal VO2 increased from 13.4 +/- 3.4 to 16.3 +/- 4.1 cc/kg per min (p = 0.0004). The maximal heart rate achieved in the minute ventilation pacing mode was 136 +/- 9.7 beats/min, similar to that observed in the patients intrinsic cardiac rhythm before ablation (134.9 +/- 30.1 beats/min, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

NASPE Expert Consensus Document: Use of IV (Conscious) Sedation/Analgesia by Nonanesthesia Personnel in Patients Undergoing Arrhythmia Specific Diagnostic, Therapeutic, and Surgical Procedures

Use of IV (Conscious) Sedation/Analgesia by Nonanesthesia Personnel in Patients Undergoing Arrhythmia Specific Diagnostic, Therapeutic, and Surgical Procedures. This article is intended to inform practitioners, payers, and other interested parties of the opinion of the North American Society of Pacing and Electrophysiology (NASPE) concerning evolving areas of clinical practice or technologies or both, that are widely available or are new to the practice community. Expert, consensus documents are so designated because the evidence base and experience with the technology or clinical practice are not yet sufficiently well developed, or rigorously controlled trials are not yet available that would support a more definitive statement. This article has been endorsed by the American College of Cardiology, October 1997.

A prospective evaluation of intracoronary ethanol ablation of the atrioventricular conduction system.

The clinical efficacy and complications associated with ablation of the atrioventricular (AV) conduction system by the selective infusion of ethanol into the AV node artery were prospectively assessed in 12 consecutive patients with medically refractory atrial arrhythmias. Six of the patients had previously failed to have permanent complete AV block created with direct current or radiofrequency catheter ablation. The AV node artery was cannulated with a 0.016 in. (0.041 cm) guide wire in all 12 patients. It was also possible to advance a 2.7F infusion catheter into the AV node artery in all patients. Transient AV block was induced by selective injections into the AV node artery of iced saline solution (8 patients) and of radiographic contrast agent (ioxaglate) (10 patients). The infusion of 2 ml of ethanol (96%) induced immediate complete AV block in all 10 patients who demonstrated AV block with ioxaglate. The escape rhythm exhibited a narrow QRS complex preceded by a His bundle deflection in nine patients and left bundle branch block in one patient. The immediate mean rate of the escape rhythm was 45.3 +/- 13.4 beats/min. In two patients who demonstrated reflux of contrast agent into the distal right coronary artery with selective injections into the AV node artery, transient ST segment elevation developed in the inferior electrocardiographic leads with the infusion of ethanol. There was no change in the left ventricular ejection fraction from the baseline value (0.53 +/- 0.12) to that measured after ablation (0.55 +/- 0.11) and no patient developed wall motion abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship Between Heart Rate and Oxygen Kinetics During Constant Workload Exercise

Background: Oxygen uptake during constant workload exercise increases exponentially from its resting value before reaching a steady state. The difference between the actual rate of oxygen consumption at the onset of exercise and the steady state is an oxygen deficit. Similarly, the normal sinus node increases its rate at the onset of exercise before achieving a steady state, thereby producing a heart rate deficit. The purpose of this study was to test the hypothesis that elimination of the heart rate deficit by an instantaneous increase in heart rate at the onset of constant workload exercise to the steady‐state level would reduce the oxygen deficit and improve the perceived difficulty of exertion as compared with the chronotropic response of the normal sinus node. Methods and Results: Ten subjects with normal sinus node function who had DDD pacemakers implanted for A V block completed a symptom‐limited maximal treadmill exercise test using the Chronotropic Assessment Exercise Protocol (CAEP) to assess sinus node function, maximal heart rate, and VO2 max. The subjects then performed constant workload exercise tests (6‐min duration) at a workload equal to approximately 50% of metabolic reserve with the pacemaker randomly programmed to each of three patterns of chronotropic response: (1) DDD (lower rate 60 beats/ min); (2) Fast (lower rate abruptly programmed to the expected value at 50% metabolic reserve); and (3) Overpaced (lower rate at least 80% of the age predicted maximum). The oxygen deficit was lower with the fast chronotropic response (434 ± 238 ml O2) than with either the DDD (512 ± 233; P = 0.02), or overpaced chronotropic patterns (488 ± 238; P = 0.02 vs fast). The rate constant for change in VO2 was highest with the fast chronotropic pattern (2.85 ± 1.38) compared with either the DDD (2.25 ± 0.64; P = 0.01) or overpaced (2.38 ± 0.43; P = 0.02) patterns. The Borg perceived exertion rating was lowest with the fast chronotropic response (P = 0.02 vs DDD and P = 0.02 vs overpaced). Conclusions: The results of this study suggest that oxygen kinetics and exertional symptoms are improved by an abrupt increase in pacing rate at the onset of exercise to a value that is appropriate for metabolic demand as compared with the DDD pacing mode in patients with normal sinus node function. In contrast, an overly aggressive chronotropic response was not associated with improved oxygen kinetics or exertional symptoms.

The Effect of Maximum Heart Rate On Oxygen Kinetics and Exercise Performance at Low and High Workloads

The normal heart rate is lineurly related to oxygen consumption during exercise. The maximum heart rate of the normal sinus node is approximated by the formula: HRmax= (220‐age) with a variance of approximately 15%. However, the nominal upper rate of most permanent pacemakers is 120 beats/min, a value that remains unchanged for many patients. As this nominal setting falls well below the maximum predicted heart rate for most patients, it is possible that the chronotropic response of rate adaptive pacemakers during moderate und maximal exercise workloads may be less than optimal. The purpose of this study was to determine the effect of the upper programmed rate on oxygen kinetics during submaximal exercise workloads and maximum exercise performance during symptom‐limited treadmill exercise. Exercise performance with an upper rate programmed to 220‐age was compared with an upper rate of 120 beats/min. Eleven patients (5 men and 6 women, mean age 54 ± 10 years) with complete heart block following catheter ablation of the atrioventricular junction for refractory atrial fibrillation who were implanted with permanent, rate‐modulating VVIR pacemakers comprised the study population. The rate adaptive sensors were based on activity in 8 patients, minute ventilation in 2 patients, and mixed venous oxygen saturation in 1 patient. After performing a symptom‐limited treadmill exercise test to determine maximum exercise capacity and to optimize programming of the rate adaptive sensor, each subject performed two treadmill exercise tests in random sequence with a rest period of at least 1 hour between tests. During one of the tests the upper rate was programmed to a value calculated by the formula: HRmax= (220‐age). During the other exercise test the upper rate was programmed to 120 beats/min. Patients were blinded as to their programmed values and to the hypothesis of the study. A novel treadmill exercise protocol was used that consisted of a 6 minute, constant‐workload phase at approximately 50% of maximum workload followed immedictely by incremental, symptom‐limited exercise using a modified Chronotropic Assessment Exercise Protocol (CAEP) with 1 minute stages until peak exertion. Breath‐by‐breath analysis of expired gases was performed with subjective scoring of exertional difficulty at the end of the constant workload phase and during each stage of incremental exercise using the Borg Perceived Exertion Scale. Exercise duration was significantly longer (6.37 ± 47 vs 611 ±48 seconds. P < 0.005) with the higher programmed upper rate. Oxygen kinetics were also significantly improved with an age predicted upper rate with a lower O2 deficit (258 ± 88 vs 395 ± 155 ml, P = 0.002) and higher VO2 rate constant (3.6 ± 1.0 vs 2.4 ± 0.7. P < 0.001.). The V02maxduring peak exertion was higher with an age predicted upper rate than with an upper rate of 120 beats/min (1807 ± 751 vs 1716 ± 702 mL/min, P = 0.01). The mean Borg score was lower during the last common treadmill stage during maximum exercise with an age predicted upper rate than with an upper rate of 120 beats/min (15.7 ± 2.0 vs 16.5 ± 1.9. P = 0.04). The mean Borg score during submaximal. constant workload exercise was also lower with a higher upper rate (9.0 ±2.5 vs 9.6 ± 2.2, P = 0.10). Programming the upper rate of rate adaptive pacemakers based on the age of the patient improves exercise performance and exertional symptoms during both low and high exercise workloads as compared with a standard nominal value of 120 beats/min.