Permanent pacemakers and the elderly: concerns, costs and benefits.
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Aged↗
Biomedical subjects
R S Bexton
Publications and source records attributed to R S Bexton.
Antibiotic prophylaxis in permanent pacemaker implantation.
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Antibiotic Prophylaxis↗
Impact of the recommendations of the British Pacing and Electrophysiology Group on pacemaker prescription and on the immediate costs of pacing in the Northern Region.
BACKGROUND: The report from the Working Party of the British Pacing and Electrophysiology Group recommends the use of more sophisticated pacemakers in most patients. These proposals were initially circulated in September 1990 and are likely to have major cost implications. Their impact on pacing practice and the immediate costs of pacemaker hardware in the Northern Region were retrospectively audited. METHODS: The pacing records of 550 patients undergoing a first pacemaker insertion at the Freeman Hospital between March 1990 and August 1991 were reviewed. The patient's age, indication for pacing, pacing mode, and the cost of generator and lead(s) were recorded. The cost was compared with the costs of pacing with the optimal and alternative modes recommended by the Working Party. The costs were calculated from the actual mean cost of the recommended unit over the 18 month period of study multiplied by the number of patients who would have received that unit. RESULTS: 96% of patients were paced for sinus node dysfunction, atrioventricular block, or atrioventricular block and atrial fibrillation. The mean (SD) ages of patients in each diagnostic group were: sinus node dysfunction 69.4 (14), sinus node disease and atrioventricular block 67.2 (17.6), atrioventricular block 73.9 (12.5), atrial fibrillation and atrioventricular block 74.0 (13.9), and carotid sinus hypersensitivity 74.6 (11.6) years. Over the 18 month audit period there was an increase in physiological pacing. AAI pacing in patients with sinus node dysfunction increased by 100% and DDD pacing in atrioventricular block increased by atrioventricular block increased by 56%. Over the whole 18 month period the adoption of the British Pacing and Electrophysiology Groups optimal recommendations would have increased expenditure on pacemaker hardware in the Northern Region by 94% and the use of the alternative mode would have increased it by 61%. For the last six months alone the excess would be 78% and 48%. CONCLUSIONS: The adoption of the recommendations of the British Pacing and Electrophysiology group in the Northern Region would greatly increase the cost of pacing hardware. The greater part of this increase would be attributable to the routine use of dual chamber pacing in patients with atrioventricular block and the increased use of rate responsive units. The benefits of sophisticated pacing in a predominantly elderly population need to outweigh the disadvantages of the increased cost and complexity of follow up.
Aged↗
Optimal pacing modes after cardiac transplantation: is synchronisation of recipient and donor atria beneficial?
OBJECTIVE: To investigate the response of the transplanted heart to different pacing modes and to synchronisation of the recipient and donor atria in terms of cardiac output at rest. DESIGN: Doppler derived cardiac output measurements at three pacing rates (90/min, 110/min and 130/min) in five pacing modes: right ventricular pacing, donor atrial pacing, recipient-donor synchronous pacing, donor atrial-ventricular sequential pacing, and synchronous recipient-donor atrial-ventricular sequential pacing. PATIENTS: 11 healthy cardiac transplant recipients with three pairs of epicardial leads inserted at transplantation. RESULTS: Donor atrial pacing (+11% overall) and donor atrial-ventricular sequential pacing (+8% overall) were significantly better than right ventricular pacing (p < 0.001) at all pacing rates. Synchronised pacing of recipient and donor atrial segments did not confer additional benefit in either atrial or atrial-ventricular sequential modes of pacing in terms of cardiac output at rest at these fixed rates. CONCLUSIONS: Atrial pacing or atrial-ventricular sequential pacing appear to be appropriate modes in cardiac transplant recipients. Synchronisation of recipient and donor atrial segments in this study produced no additional benefit. Chronotropic competence in these patients may, however, result in improved exercise capacity and deserves further investigation.
Adolescent↗
Long-term pacing in heart transplant recipients is usually unnecessary.
The indications for and timing of permanent pacing were reviewed in all 17 of 154 adult heart transplant recipients at this center who have had permanent pacemakers implanted. Resting 12-lead ECGs recorded during routine follow-up were examined. A prospective study of pacing requirement was then undertaken. Holter monitoring was performed before and after reprogramming the pacemakers to VVI mode at 50 beats/min. Exercise responses in various pacing modes were then assessed in seven patients with rate responsive pacemakers using a standard Bruce protocol treadmill test. The indication for pacing was sinus node dysfunction in 59% (10/17) and atrioventricular (AV) block in 41% (7/17). The majority of pacemakers were implanted between seven and 21 days after transplantation. There was a progressive reduction in the frequency of pacing on 12-lead ECGs with time after transplantation. There was a progressive reduction in the frequency of pacing on 12-lead ECGs with time after transplantation. Eight of 14 patients with empirically selected programming paced during Holter monitoring. After reprogramming to 50 beats/min VVI mode only three of 14 patients, all with sinus node dysfunction, paced. Rate responsive pacing made no difference to exercise time. The requirement for long-term pacing in cardiac transplant recipients is small (3/154) and is limited to patients with sinus node dysfunction. Rate responsive pacing did not increase exercise tolerance.
Adult↗
Effect of single lung transplantation on pulmonary hypertension in patients with end stage fibrosing lung disease.
OBJECTIVE: To investigate the effect of successful single lung transplantation on pulmonary haemodynamic variables and right ventricular function. DESIGN: Pulmonary haemodynamic variables and right ventricular function were measured at right heart catheterisation after single lung transplantation. The results were compared with the preoperative pulmonary haemodynamic variables measured at the time of assessment for transplantation. SETTING: A tertiary referral centre. PATIENTS: Five survivors of single lung transplantation performed for end stage lung disease. INTERVENTIONS: Cardiac catheterisation in all five patients at a mean of 18 months postoperatively. Preoperative catheter data were available for comparison in four. Right heart pressures and cardiac output were measured and right ventricular angiography was performed. Perfusion scans performed for clinical reasons were used to assess the percentage of cardiac output passing through each lung. MAIN OUTCOME MEASURES: Right heart pressures, cardiac output, right ventricular function, percentage perfusion to lungs. RESULTS: After operation mean peak right ventricular pressure fell from 53 mm Hg to 33 mm Hg, mean pulmonary artery pressure from 33 mm Hg to 18 mm Hg, total pulmonary resistance from 11.2 U x m2 to 5.8 U x m2, and pulmonary arteriolar resistance from 8.9 U x m2 to 3.6 U x m2. Pulmonary artery wedge pressure and cardiac index were unchanged. Right ventricular function improved in all patients. The transplanted lung received most of the cardiac output. CONCLUSION: In patients with moderate pulmonary hypertension and right ventricular dysfunction secondary to end stage fibrosing lung disease single lung transplantation was followed by an improvement in pulmonary haemodynamic variables and right ventricular function.
Blood Pressure↗
Disseminated zygomycosis and systemic lupus erythematosus.
A young woman with long-standing systemic lupus erythematosus and rheumatic fever presented with deteriorating renal function. She had severe gastritis treated with cimetidine and received methylprednisolone when her blood cultures were repeatedly negative. She developed spontaneous bruising and bleeding from venepuncture sites, leading to clotting studies and a diagnosis of thrombotic thrombocytopenic purpura. At post-mortem, extensive evidence of disseminated zygomycosis was found. The likely portal of entry was the gastric route.
Adult↗
Atrial antitachycardia pacing in patients with supraventricular tachycardia: clinical experience with the Intertach pacemaker.
During a 3-year period, 22 patients with recurrent supraventricular tachycardia have been treated with antitachycardia pacemakers (Intermedics Intertach, 262-12, n = 17, and Intertach II, 262-16, n = 5). Eighty-two percent were female, the mean age was 44 +/- 14 years; 86% had atrioventricular node reentrant tachycardia. Symptoms had occurred over 11.8 +/- 7.1 years, with 3.6 hospital admissions per patient, despite 4.7 +/- 2.1 antiarrhythmic drugs. Following pacemaker implantation, during a follow-up of 14.8 +/- 11.5 months, only two patients have been readmitted to a hospital because of supraventricular tachycardia (mean 0.1 per patient). One patient is taking an antiarrhythmic agent, and four are taking beta adrenergic blocking agents. Thus, 23% are taking cardioactive drugs (it was anticipated that two patients would continue on drugs after pacemaker implantation). There have been no serious complications. Atrial antitachycardia is thus an effective therapy in carefully selected patients with recurrent supraventricular tachycardia, reducing hospital admissions for supraventricular tachycardia and reducing the need for antiarrhythmic drugs.
Adrenergic beta-Antagonists↗
The value of the electrocardiogram in the diagnosis of acute rejection after orthotopic heart transplantation.
The value of a change in summated electrocardiographic voltage as a predictor of cardiac rejection is uncertain in patients treated with low-dose triple immunotherapy (cyclosporin, azathioprine, and corticosteroids) following orthotopic cardiac transplantation. Ten recipients were studied daily and the summated QRS voltages from 600 electrocardiograms were calculated. A single observer graded 147 endomyocardial biopsies. During the study period there were 18 episodes of acute rejection with myocyte necrosis. Only three episodes of rejection were heralded by a significant change in QRS voltage, yielding a positive predictive value of 13% for the technique. Three episodes of severe bacterial infection were preceded by significant decreases in QRS voltage. In one patient with a global pericardial effusion, QRS voltage was related to the depth of effusion measured by echocardiography. These data show that QRS voltage is of extremely limited value in the prediction of cardiac rejection in patients treated with low-dose triple immunotherapy.
Adult↗
Isometric exercise in the denervated heart: a Doppler echocardiographic study.
The haemodynamic responses to isometric exercise of eight recipients of orthotopic heart transplants and eight healthy controls were studied. Each performed sustained exercise at 30% of maximal voluntary contraction for three minutes on a handgrip dynamometer. Cardiac output was measured by combined Doppler and cross sectional echocardiography before exercise and every 30 seconds during and after exercise. In the controls cardiac output and blood pressure increased significantly owing to an increase in heart rate with no change in stroke volume. In the transplant group cardiac output, heart rate, and stroke volume remained unchanged throughout exercise. In contrast with its response to dynamic exercise the denervated human heart is unable to increase cardiac output during isometric exercise. The pressor response that occurs is mediated via an increase in peripheral vascular resistance.
Adult↗
Intravenous flecainide acetate for the clinical management of paroxysmal tachycardias.
Intravenous flecainide acetate (2 mg/kg) was administered to 40 patients undergoing routine electrophysiological evaluation for the investigation of recurrent paroxysmal tachycardias. Ten patients had recurrent atrial flutter, 11 patients had recurrent atrial fibrillation, one of whom also had paroxysmal left atrial tachycardia, and 19 patients had recurrent ventricular tachyarrhythmias (17 with recurrent ventricular tachycardia and 2 with recurrent fascicular tachycardia). Flecainide was administered during tachycardia (over 5 to 10 minutes) to all patients with atrial flutter, to 10 patients with atrial fibrillation, and to 17 patients with ventricular tachyarrhythmias. In the remaining 3 patients with ill-sustained arrhythmias flecainide was administered during sinus rhythm and reinitiation of tachycardia was then attempted. Flecainide restored sinus rhythm in only 2 patients with atrial flutter (20%), in 9 patients with atrial fibrillation (90%), in 12 patients with ventricular tachycardia (80%), and in one of the 2 patients with fasicular tachycardia. Flecainide also successfully terminated the left atrial tachycardia. Two patients experienced proarrhythmic side effects during flecainide administration, one of whom required intervention by cardioversion. Minor dose effects included oral paresthesia, transient drowsiness or dizziness, and occasional visual blurring. Flecainide acetate is an effective antiarrhythmic agent for the acute termination of recent onset paroxysmal atrial and ventricular tachyarrhythmias.
Adolescent↗
Flecainide--an intravenous infusion regimen.
An intravenous infusion regimen for flecainide was studied in 12 patients. Therapeutic drug levels were rapidly established and maintained throughout the 48-h infusion period. Two patients were withdrawn because of possible drug related problems, but in general the regimen seemed both effective and well tolerated.
Aged↗
Unusual sinus node response curves in two cardiac transplant recipients.
We describe unusual responses of the sinus node to programmed atrial stimulation in two asymptomatic cardiac transplant recipients. In one patient the sinoatrial conduction time, calculated using the revised method of Strauss, is extremely short (5 ms), and in the other it is extremely long (460 ms). The various mechanisms that might be involved in these atypical responses to atrial extrastimulation are discussed. These include sinus node suppression, shift of pacemaker, direct stimulation of the sinus node and shortening of the sinus node action potential duration.
Action Potentials↗
Diurnal variation of the QT interval--influence of the autonomic nervous system.
To assess the influence of diurnal changes in the autonomic nervous system on the QT interval, 24 hour dynamic electrocardiographic monitoring was performed in six pacemaker dependent patients with normally innervated hearts, in six cardiac transplant patients with anatomically denervated hearts (but which respond to circulating catecholamines), and in nine diabetic patients with confirmed autonomic neuropathy. QT and RR intervals from hourly intervals were measured and Bazett's formula was used to correct QT intervals during sinus rhythm. All QT intervals were normalised by dividing by the mean QT for the 24 hours in each patient and were expressed as a percentage. There was pronounced diurnal variation of normalised QT in the patients with normally innervated hearts. QT intervals were longer during sleep than during waking hours (06.00 vs 18.00 h, 102.5% vs 97.8%). Diurnal variation was blunted in the transplant patients (101.3% vs 98.1%) and absent in the diabetic patients (100.0% vs 100.3%). In the normally innervated patients changes were most pronounced at the time of waking (06.00 vs 09.00 h, 102.5% vs 95.4%). There was no change in normalised QT in the transplant and diabetic patients at this time. There was no significant difference between normalised QT for the three groups during sleep, but this variable was shorter in innervated patients during waking hours (for example at 10.00 h, innervated 96.5%, transplant 100.7%, diabetic 100.7%). Diurnal changes of the QT interval may be pronounced in the innervated heart and are dependent on both variations in autonomic tone and concentrations of circulating catecholamines. These changes in repolarisation may be related to the reported diurnal pattern of ventricular arrhythmias.
Adult↗
Diathermy-induced loss of DDD pacemaker identity.
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Adolescent↗
Clinical usefulness of flecainide acetate in the treatment of paroxysmal supraventricular arrhythmias.
Flecainide acetate depresses both the upstroke of the intracellular action potential and the rate of diastolic depolarisation in isolated tissue preparations of atrial myocardium. It produces no consistent effect on action potential duration. Predictably, in the human heart, studied by clinical cardiac electrophysiological techniques, conduction velocity through atrial myocardium, the atrioventricular (AV) node and anomalous tissue is depressed following flecainide administration. Refractoriness of normal atrial or AV nodal myocardium is not prolonged but the recovery time of anomalous or abnormal tissue is lengthened by the drug. In response to the intravenous injection of flecainide, atrial fibrillation (90%), atrial tachycardia (100%), intra-AV nodal tachycardia (89%) and atrioventricular re-entrant tachycardia (80%) are generally terminated, and although atrial flutter is slowed, only a small proportion (20%) is terminated. There is little experience of the long term treatment of supraventricular tachycardia with oral flecainide. However, preliminary results suggest that flecainide is equally effective in the treatment of both supraventricular and ventricular arrhythmias. Thus, flecainide acetate is a 'broad spectrum' antiarrhythmic agent.
Animals↗
The proarrhythmic effects of flecainide.
Flecainide acetate, a new potent class I antiarrhythmic agent, was administered to 152 patients (orally to 46, intravenously to 106) over a period of 22 months. Seven patients developed proarrhythmic effects. The only conduction abnormalities induced were PR interval prolongation and QRS complex widening, and no patient developed significant sinus bradyarrhythmias; patients with known serious abnormalities of impulse generation or conduction were excluded from this study. Five patients, of whom only 3 had pre-existing ventricular arrhythmias, developed ventricular tachycardia or ventricular fibrillation. QT and QTc interval prolongation was observed, but was due to QRS complex widening rather than an increase in the JT interval. A patient with Wolff-Parkinson-White syndrome had an inducible orthodromic atrioventricular tachycardia before flecainide administration, but only an antidromic tachycardia was induced after taking the drug. In 1 patient, flecainide administration resulted in an increase of atrial flutter cycle length, which resulted in the development of 1:1 atrioventricular conduction rate, and, overall, a faster ventricular rate. Two patients who developed ventricular arrhythmias were taking other antiarrhythmic agents, and in this series proarrhythmic effects occurred with both normal and high flecainide concentrations. Other published series are also summarised.
Adult↗
Catheter ablation of atrioventricular conduction.
35 patients with refractory supraventricular arrhythmias were treated in three centres by high-energy shocks delivered to the atrioventricular conduction system from a conventional transvenous pacing catheter. After a mean interval of ten months, 26 patients (74%) had persistent complete heart block, 2 (6%) had intermittent complete heart block, and 3(9%) had first-degree heart block. 3 patients continued to have conducted atrial fibrillation, but with slower ventricular rates than previously, and 1 had normalisation of dual atrio-His conduction. In 1 patient a septal accessory pathway was ablated. 30 patients (86%) are completely symptom-free without additional therapy. There were no important long-term complications. Transvenous ablation of atrioventricular conduction is a safe and effective technique for treating a wide range of refractory atrial and junctional arrhythmias.
Adolescent↗