Catheter ablation of permanent atrial fibrillation: medium term results.

OBJECTIVE: To investigate the feasibility of catheter ablation as a treatment for symptomatic patients with longstanding permanent atrial fibrillation (AF). METHODS: Radiofrequency ablation was applied to encircle all pulmonary veins (PVs) and create lines from the left inferior PV to the mitral valve, along the roof of the left atrium between the PVs, and along the tricuspid valve-inferior vena cava isthmus. A seven day Holter was recorded at discharge and at follow up to assess arrhythmia burden. If patients developed a symptomatic, sustained atrial arrhythmia a repeat ablation procedure was advised. RESULTS: 42 patients underwent the procedure that took a mean of five hours with 50 minutes of fluoroscopy. After a median follow up of 8.4 months, 31 of 41 surviving patients (76%) were in sinus rhythm. Of these, 29 patients were no longer taking any antiarrhythmic drugs but 22 (52%) required more than one procedure. During follow up 49% experienced a sustained atrial tachycardia. Twenty six repeat procedures were performed. Maintenance of sinus rhythm after the first, second, or third procedure was 36% (15 of 42), 58% (11 of 19), and 71% (5 of 7), respectively. From a total of 68 procedures there were two serious complications (2.9%): a stroke from which a full recovery was made, and a PV stenosis. CONCLUSION: Catheter ablation can be used to cure longstanding permanent AF; however, there is a significant complication rate. Whether this is offset by a mortality benefit associated with sinus rhythm is unknown. Many patients will need more than one procedure to achieve success.

Ventricular arrhythmia, Cheyne-Stokes respiration, and death: observations from patients with defibrillators.

OBJECTIVE: To determine whether ventricular arrhythmia related to nocturnal hypoxaemia during Cheyne-Stokes respiration (CSR) explains the observation that CSR is an independent marker of death in heart failure. DESIGN: Prospective, observational study. PATIENTS: 101 patients at high risk of clinical serious ventricular arrhythmia fitted with an implantable cardioverter-defibrillator (ICD). MEASUREMENTS: Patients were studied at baseline for CSR during sleep. Arrhythmia requiring device discharge was used as a surrogate marker for possible sudden cardiac death. RESULTS: 101 patients (42 with CSR) were followed up for a total of 620 months. Twenty six patients experienced 432 ICD discharge episodes. Twenty four (6%), 210 (49%), 125 (29%), and 73 (17%) episodes occurred across the time quartiles 0000-0559, 0600-1159, 1200-1759, and 1800-2359, respectively. Kaplan-Meier analysis showed a relative risk of 1 (95% confidence interval 0.5 to 2.2, p = 1) for device discharge in the CSR group. The average (SED) numbers of nocturnal ICD discharges per patient per month of follow up were 0.01 (0.01) and 0.04 (0.02) for patients with and without CSR, respectively (p = 0.6). CONCLUSION: These findings refute the proposition that CSR is related to heart failure death through nocturnal serious ventricular arrhythmia.

Contemporary management of chronic stable angina.

Chronic stable angina is a common condition with a prognosis that is less benign than is generally appreciated. The optimal treatment strategy of this disorder is unclear, and few anti-ischaemic agents have been rigorously tested in prospectively randomised mortality studies. The evidence base for the anti-ischaemic therapy of chronic angina draws upon data 'borrowed' from studies in acute coronary syndromes, and from studies in chronic angina using surrogate endpoints such as ambulatory silent ischaemia. Such evidence leads us to believe that anti-ischaemic therapy with beta-blockers offers a mortality benefit in chronic angina. In contrast, the mortality benefit of lipid lowering therapy and antiplatelet agents is well proven. Angioplasty offers no mortality benefit in the treatment of chronic angina, although it is more effective than medical therapy alone for the relief of symptoms. In a few patients with high order proximal coronary disease, coronary bypass surgery offers a distinct mortality advantage compared with medical treatment alone. Most patients, however, do not warrant such an approach, and only require surgery for when they remain symptomatic despite adequate medical therapy. Alternative strategies such as cardiac transplantation, transmyocardial laser revascularisation and spinal cord stimulation are now accepted in a subgroup of patients for the treatment of chronic angina refractory to standard therapy.

Cognitive impairment in heart failure with Cheyne-Stokes respiration.

OBJECTIVES: To document the degree of cognitive impairment in stable heart failure, and to determine its relation to the presence of Cheyne-Stokes respiration during sleep. SUBJECTS: 104 heart failure patients and 21 healthy normal volunteers. METHODS: Overnight oximetry was used (previously validated as a screening tool for Cheyne-Stokes respiration in heart failure). Cognitive function was assessed using a battery of neuropsychological tests. Left ventricular function was assessed by echocardiography. RESULTS: Heart failure patients performed worse than the healthy volunteers in tests that measured vigilance. Reaction times were 48% slower (0.89 (0.03) s v 0.60 (0.05) s p < 0.005) and they hit twice as many obstacles on the Steer Clear simulator (75 (6.4) v 33 (4.6); p < 0.005). Cognitive impairment within the heart failure group was unrelated to either the presence of Cheyne-Stokes respiration, the degree of left ventricular dysfunction, or indices of nocturnal oxygenation. CONCLUSIONS: Vigilance was impaired in heart failure but this did not appear to be related to the presence of Cheyne-Stokes respiration during sleep. Impaired vigilance as measured on the Steer Clear test has been associated with an increased risk of motor vehicle accidents. The issue of fitness to drive in heart failure requires further attention.

Effect of oxygen on sleep quality, cognitive function and sympathetic activity in patients with chronic heart failure and Cheyne-Stokes respiration.

BACKGROUND: Cheyne-Stokes respiration disrupts sleep, leading to daytime somnolence and cognitive impairment. It is also an independent marker of increased mortality in heart failure. This study evaluated the effectiveness of oxygen therapy for Cheyne-Stokes respiration in heart failure. METHODS: Eleven patients with stable heart failure and Cheyne-Stokes breathing were studies. Oxygen and air were administered for 4 weeks in a double-blind, cross-over study. Sleep and disordered breathing was assessed by polysomnography. Symptoms were assessed using the Epworth Sleepiness Scale, visual analogue and quality of lift scores. Cognitive function was assessed by neuropsychometric testing. Overnight urinary catecholamine excretion was used as a measure of sympathetic nerve activity. RESULTS: Ninety-seven percent of apnoeas were central in origin. Oxygen therapy reduced the central apnoea rate (18.4 +/- 4.1 vs 3.8 +/- 2.1 per hour; p = 0.05) and periodic breathing time (33.6 +/- 7.4 vs 10.7 +/- 3.9% of actual sleep time; p = 0.003). Oxygen did not improve sleep quality, patient symptoms or cognitive failure. Oxygen reduced urinary noradrenaline excretion (8.3 +/- 1.5 vs 4.1 +/- 0.6 nmol.mmol-1 urinary creatinine; p = 0.03). CONCLUSION: Oxygen stabilized sleep disordered breathing and reduced sympathetic activity in patients with heart failure and Cheyne-Stokes respiration. We were unable to demonstrate an effect on either patient symptoms or cognitive function.

Nocturnal desaturation in patients with stable heart failure.

OBJECTIVE: To determine the prevalence of sleep disordered breathing within a United Kingdom heart failure population. SUBJECTS: 104 patients and 21 matched normal volunteers. METHODS: Overnight home pulse oximetry with simultaneous ECG recording in the patient group; daytime sleepiness was assessed using the Epworth sleepiness scale (ESS); 41 patients underwent polysomnography to assess the validity of oximetry as a screening test for Cheyne-Stokes respiration. RESULTS: Home oximetry was a good screening test for Cheyne-Stokes respiration (specificity 81%, sensitivity 87%). Patients with poorer New York Heart Association (NYHA) classes had higher sleepiness scores (p < 0.005). Twenty three patients had "abnormal" patterns of nocturnal desaturation suggestive of Cheyne-Stokes respiration. The mean (SEM) frequency of dips in Sao2 exceeding 4% was 10.3 (0.9) per hour in the patients and 4.8 (0.6) in normal controls (p < 0.005). Ejection fraction correlated negatively with dip frequency (r = -0.5, p < 0.005). The patient subgroup with > or = 15 dips/hour had a higher mean (SEM) NYHA class (3.0 (0.2) v 2.3 (0.1), p < 0.05), and experienced more ventricular ectopy (220 (76) v 78 (21) beats/hour, p < 0.05). There was no excess of serious arrhythmia. CONCLUSIONS: Nocturnal desaturation is common in patients with treated heart failure. Low ejection fraction was related to dip frequency. Lack of correlation between dips and ESS suggests that arousal from sleep is more important than hypoxia in the aetiology of daytime sleepiness in heart failure. Overnight oximetry is a useful screening test for Cheyne-Stokes respiration in patients with known heart failure.

"Value" of improved treadmill exercise capacity: lessons from a study of rate responsive pacing.

OBJECTIVES: To compare the value of a series of cardiovascular measurements in patients with symptomatic disease receiving an effective treatment (rate responsive pacing). PATIENTS: 12 pacemaker dependent patients with VVIR units. INTERVENTIONS: Single blind crossover between VVI and VVIR. OUTCOME MEASURES: Exercise capacity was assessed by treadmill tests (modified Bruce protocol and a fixed workload protocol) with respiratory gas analysis. Self paced corridor walk tests were also undertaken. Quality of life (QOL) was assessed by questionnaire. Daily activity was measured in the patients' homes using shoe and belt pedometers. RESULTS: Treadmill tests and QOL questionnaires correctly identified the clinical benefit associated with VVIR. The modified Bruce protocol was superior to the fixed workload protocol as it was better tailored to the fairly well preserved exercise capacity of the patients. Symptom scores, but not walking times, were improved with VVIR during corridor walk tests. VVIR did not improve daily activity measured using either the belt or shoe pedometers. CONCLUSIONS: VVIR pacing improved some but not all measures of exercise capacity. This finding illustrates the difficulty of selecting an instrument to measure symptomatic improvement in clinical research; and raises the question, what is the best way of measuring exercise capacity?