Rate-adaptive cardiac pacing: implications of environmental noise during craniotomy.
Explore the source record for details and available documents.
Aged↗
Biomedical subjects
D L Hayes
Publications and source records attributed to D L Hayes.
Permanent pacing in Ebstein's anomaly.
Patients with Ebstein's anomaly present unique challenges to permanent pacing due to anatomical variations and tricuspid valve replacement. We retrospectively reviewed our experience with permanent pacing in patients with Ebstein's anomaly between 1976 and 1993. We identified 401 patients with Ebstein's anomaly, of whom 15 (3.7%) required permanent pacing (1 of the 15 was implanted elsewhere). Of the 15, there were 8 females and 7 males (mean age 32 years [range 7-74]); the indications for pacing were AV block in 11 and sinus node dysfunction in 4. Eight patients were programmed with VVI and seven with DDD. All VVI patients were paced epicardially. Two patients with DDD pacemakers had transvenous atrial and ventricular leads, 4 DDD patients had transvenous atrial leads and epicardial ventricular leads, and 1 patient had both epicardial and transvenous systems. Associated surgical procedures included tricuspid valve replacement in 14 of 15, atrial septal defect repair in 10 of 15, atrioplasty in 7 of 15, prior tricuspid annuloplasty in 4 of 15, pulmonary vein dilation in 1 of 15, and conduction system ablation in 2 of 15. Patients had a mean follow-up of 35 months (range 1-168 months). Complications requiring operative intervention occurred in four patients. One patient had displacement of a transvenous ventricular lead. A second patient had an epicardial lead failure. A third patient had a nonfunctioning atrial lead that displaced across the tricuspid valve, causing severe tricuspid regurgitation. The fourth patient had multiple epicardial and endocardial leads exit block with secondary diaphragmatic stimulation. Permanent pacemakers were required in 3.7% of patients with Ebstein's anomaly, with the indication being intrinsic conduction disease in the majority of patients. Ninety-three percent of patients required tricuspid valve replacement, suggesting more severe manifestation of Ebstein's anomaly. Twenty-seven percent had complications requiring surgical intervention. Thus, permanent pacing in patients with Ebstein's anomaly can be challenging and should be approached by an experienced physician.
Adolescent↗
Newer clinical applications of pacing.
For many years, the indications for permanent cardiac pacing consisted primarily of AV block and sinus node dysfunction. In recent years, the indications for pacing have expanded considerably. This article details recent advances in the application of permanent pacing and the use of permanent pacing for patients with hypertrophic cardiomyopathy, dilated cardiomyopathy, prevention of atrial fibrillation, and pacing in the long QT syndrome. Pacing is now an accepted therapeutic modality in hypertrophic cardiomyopathy and has rapidly gained acceptance in the United States, although there are still many unknowns about selection of patients and long-term benefits. Even less is known about pacing for dilated cardiomyopathy. Certain patients do respond with definite subjective improvement and improved quality of life, although there are no data to date to suggest improved longevity. Pacing for long QT syndrome is now a well-accepted indication for this relatively small subset of patients. Pacing for the prevention of atrial fibrillation is still in the very early stages of development. Multiple methods have been tried with the current method of choice being dual site atrial pacing. However, it is too early to predict the long-term success of this modality.
Adult↗
Survival and functional independence after implantation of a permanent pacemaker in octogenarians and nonagenarians. A population-based study.
BACKGROUND: The number of very elderly persons who are candidates for implantation of a permanent pacemaker is increasing, but the effect of cardiac pacing on long-term survival and functional variables has not been determined. OBJECTIVE: To determine long-term survival after implantation of a permanent pacemaker in octogenarians and nonagenarians and to assess functional independence after such implantation. DESIGN: Retrospective, population-based cohort study. SETTING: Epidemiologic setting from an unselected population. PATIENTS: 157 octogenarians and nonagenarians who initially received a pacemaker between 1962 and 1988 and were followed through 1992. MAIN OUTCOME MEASURES: Overall mortality rate, functional capabilities, and placement in a nursing home. RESULTS: Observed survival in patients with heart disease was significantly worse than that in age-and sex-matched controls (P < 0.001). Observed survival in community residents without heart disease was similar to that in controls (P > 0.2). Multivariable analysis identified congestive heart failure, chronic obstructive pulmonary disease, old age, syncope, cancer, and atrioventricular block as independent predictors of increased mortality. Symptoms decreased in 118 patients (75%) after pacemaker implantation. After implantation, 70 patients (45%) were permanently placed in nursing homes; this number is similar to the estimated probability of lifetime use of nursing homes from the National Mortality Followback Survey. Dementia developed or worsened in 51 patients (32%), and orthopedic disability occurred in 41 patients (26%). CONCLUSIONS: Normal relative survival in octogenarians and nonagenarians without heart disease is reassuring; the poor prognosis in patients with heart disease warrants careful evaluation of the methods and indications for cardiac pacing. Permanent pacing alleviates bradycardia-related symptoms. Placement in a nursing home and development or worsening of cardiac, neurologic, or orthopedic disabilities frequently occur after implantation of a permanent pacemaker in the very elderly.
Activities of Daily Living↗
Prospective evaluation of a chamomile mouthwash for prevention of 5-FU-induced oral mucositis.
BACKGROUND: Stomatitis has been found to be a major dose-limiting toxicity from bolus 5-fluorouracil-based (5-FU) chemotherapy regimens, despite the use of oral cryotherapy. Pursuant to preliminary data which suggested that a chamomile mouthwash might ameliorate this toxicity, a prospective trial was developed to test chamomile in this situation. METHODS: A Phase III, double-blind, placebo-controlled clinical trial was designed. Patients were entered into the study at the time of their first cycle of 5-FU-based chemotherapy. All patients received oral cryotherapy for 30 minutes with each dose of 5-FU. In addition, each patient was randomized to receive a chamomile or placebo mouthwash thrice daily for 14 days. Stomatitis scores were determined by health care providers and by patients themselves. RESULTS: There were 164 evaluable and well-stratified patients equally randomized to both treatment groups. There was no suggestion of any stomatitis difference between patients randomized to either protocol arm. There was also no suggestion of toxicity. Subset analysis did reveal unsuspected differential effects between males and females that could not be explained by reasons other than chance. CONCLUSION: The resultant data from this clinical trial did not support the prestudy hypothesis that chamomile could decrease 5-FU-induced stomatitis.
Antimetabolites, Antineoplastic↗
Effect of dual-chamber pacing on systolic and diastolic function in patients with hypertrophic cardiomyopathy. Acute Doppler echocardiographic and catheterization hemodynamic study.
OBJECTIVES: This study sought to evaluate prospectively the acute hemodynamic effect of dual-chamber pacing by using a combined hemodynamic approach of high fidelity pressure and Doppler velocity measurements. BACKGROUND: Dual-chamber pacing has been proposed recently as an alternative in the symptomatic treatment of patients with hypertrophic obstructive cardiomyopathy. Although early reports documented a decrease in left ventricular outflow tract gradient and symptomatic improvement, questions remain about the hemodynamic effects of dual-chamber pacing on systolic and diastolic function. METHODS: Twenty-nine patients with hypertrophic cardiomyopathy underwent a combined cardiac catheterization and Doppler echocardiographic study during normal sinus rhythm and P-synchronous pacing at various atrioventricular (AV) intervals. High fidelity pressure measurements of left ventricular inflow and left atrial pressures, ascending aortic pressure, thermodilution cardiac output and Doppler mitral flow velocity curves were obtained to evaluate both systolic and diastolic left ventricular function. RESULTS: During AV pacing at the shortest delay of 60 ms, there was a significant decrease in cardiac output (p < 0.05) and peak positive dP/dt (p < 0.05), an increase in mean left atrial pressure (p < 0.05) and a prolongation of tau, the time constant of relaxation (p < 0.05), compared with that during normal sinus rhythm. During pacing at the optimal AV delay (longest AV interval with pre-excitation), there was a similar trend, with deterioration in both systolic and diastolic function variables but of lesser magnitude than that during pacing at the shortest AV intervals. The deterioration in both systolic and diastolic function was present in 21 patients with and 8 without left ventricular outflow obstruction. There was a modest decrease in left ventricular outflow tract gradient from 73.3 +/- 45.0 (mean +/- SD) to 61.3 +/- 40.5 mm Hg (p = 0.03) during dual-chamber pacing at the optimal AV delay compared with that during normal sinus rhythm. CONCLUSIONS: The acute effect of pacing the right atrium and ventricle may be detrimental to both systolic and diastolic function of the left ventricle, particularly at the short AV intervals. Further studies of the long-term effects of dual-chamber pacing in carefully performed randomized studies are needed.
Blood Flow Velocity↗
Wireless phones and pacemaker interaction.
Explore the source record for details and available documents.
Humans↗
State of the science: pacemaker and defibrillator interference from wireless communication devices.
The use of wireless communication devices has increased rapidly, with current industry estimates of 50,000,000 subscribers of cellular telephone services, a number that is expected to double by the year 2000. Because wireless communication devices emit RF signals, they have the potential to interfere with implantable devices. The mechanism of interference and the magnitude of interference must be considered in terms of the type of wireless communication device being used and the characteristics of the individual implantable device that is exposed to the RF emission of the cellular phone. This article reviews the potential effects of wireless communication devices on implantable devices and makes initial recommendations for patients with implantable devices.
Defibrillators, Implantable↗
Short- and long-term results with an active-fixation, bipolar, polyurethane-insulated atrial pacing lead.
Since 1989, 136 Medtronic 4058 and 4058M bipolar atrial screw-in leads have been implanted at the Mayo Clinic. Early lead related complications included dislodgment in 4 (2.9%). Over a median follow-up time of 14.4 months (1 day to 3.3 years), there were 11 lead related complications (undersensing, failure to capture, diaphragmatic pacing, and gross lead dislodgment). Chronic complications resulted in reoperations in four patients (2.9%). Of 77 patients in whom pacing thresholds were measured between 2 and 4 months after implantation, 9 (11.7%) and 2 (2.6%) had high pacing thresholds and very high thresholds, respectively. The Kaplan-Meier estimate of the probability of 1-year complication-free lead survival was 93.5%. There were no lead material failures. We conclude that the 4058/4058M lead implanted in the atrial position has favorable acute and chronic performance data, with a tendency toward high pacing thresholds at 3 months. The cause of this phenomenon and its course over time should be further evaluated.
Actuarial Analysis↗
Serial fluoroscopic evaluation of a pacing lead.
A recall of the Telectronics Accufix 330-801 atrial lead was issued in November 1994, because of fracture of the "J"-shaped retention wire. To assess the integrity of the retention wire, we have performed fluoroscopic screening on 209 patients with the Accufix 330-801 atrial lead in place. Cine films of all 135 patients originally classified as normal were reevaluated after the original screening. Eighty patients have undergone two serial fluoroscopic evaluations separated by 158 +/- 5.4 days. Nine retention wires originally classified as normal were reclassified as fracture without protrusion, and two were reclassified as fracture with protrusion when the original films were reevaluated. Eight of the 11 leads reclassified were screened during our first 2 days of fluoroscopic evaluation of this lead. Of the 80 patients who underwent a second fluoroscopic screening, 70 were initially classified as normal (9 of which were reclassified as described above), 1 fractured, and 9 indeterminate. There were no new fractures detected in this group, and the fractured retention wires did not appear to change during this observation period. We conclude that there is a definite learning curve associated with fluoroscopic evaluation of this lead, and continue to recommend that screening be performed by cardiologists experienced in fluoroscopic screening. Fractured retention wires remained stable in appearance during this observation time. No new retention wire fractures were detected; however, longer follow-up will be required before the incidence of retention wire fracture can be determined.
Cineangiography↗
Extraction of permanent pacing leads: there are still controversies.
Explore the source record for details and available documents.
Equipment Failure↗
Dual-chamber pacing for cardiomyopathies: a 1996 clinical perspective.
Implantation of a permanent pacemaker is an accepted mode of therapy for symptomatic bradyarrhythmias. Application of pacemaker technology for the treatment of cardiomyopathies has generated considerable interest and enthusiastic support in recent years. In both hypertrophic cardiomyopathy and dilated cardiomyopathy, dual-chamber pacing has been shown to decrease symptoms and improve hemodynamics; however, not all patients will benefit from dual-chamber pacing. Technical considerations must be acknowledged in order to obtain optimal benefit with dual-chamber pacing. In addition, other more accepted therapies are available for patients with symptomatic cardiomyopathies. The purposes of this article are to review critically the current literature on the use of dual-chamber pacemakers in patients with either hypertrophic or dilated cardiomyopathy and to provide a clinical perspective based on current knowledge.
Cardiac Pacing, Artificial↗
Extraction of the Telectronics Accufix 330-801 atrial lead: the Mayo Clinic experience.
OBJECTIVE: To document a cumulative experience with removal of the Telectronics 330-801 Accufix atrial lead after it was withdrawn from the market. DESIGN: We reviewed our results with 96 attempted lead extraction procedures through Dec. 1, 1995. MATERIAL AND METHODS: All patients underwent preoperative assessment, including fluoroscopic screening of the lead. Patients had blood typing and screening done before the extraction procedure, and extractions were performed with cardiac surgical intervention available. Pacing dependence was assessed to determine the need for temporary pacing. RESULTS: The mean patient age was 65.7 +/- 1.6 years and the mean duration of lead implantation was 31.0 +/- 1.4 months. Of the 96 lead extractions attempted, 94 were successful. Of the 96 cases, the retention wires were normal in 29, fractured without protrusion in 34, and fractured with protrusion in 33. Fifty-three leads were removed with use of simple traction only, and seven leads were removed by using a locking stylet and telescoping sheaths. The Cook workstation was used in the removal of 32 leads through the femoral vein; in 1 of these 32 patients, the retention wire was removed before lead extraction. The retention wire was removed but the lead was left intact in one patient. One lead was removed during an opertive maze procedure. Associated complications were minimal. CONCLUSION: Although lead extraction is a potentially fatal procedure, the Telectronics 330-801 Accufix atrial lead can be extracted safely with minimal morbidity when performed by experienced personnel.
Aged↗
Expanding indications for permanent pacemakers.
PURPOSE: To review the current clinical experience with new and expanding indications for permanent cardiac pacing. DATA SOURCES: A MEDLINE search was done of the English-language literature published from 1980 through 1994 about indications for permanent pacing. Five major areas were identified and searched: cardiomyopathies, atrial fibrillation, the long QT syndrome, cardiac transplantation, and vasovagal syncope. A manual search was then done for other contributions, including abstracts. STUDY SELECTION: Because published reports in these areas are scarce, all of the peer-reviewed articles and most of the relevant abstracts found were reviewed. DATA EXTRACTION: Data were manually extracted from the various sources, and the reports were classified and summarized according to specific indications. RESULTS: Pacing is becoming an important option in the treatment of patients with symptomatic drug-resistant hypertrophic obstructive cardiomyopathy. Symptomatic and hemodynamic benefits have been shown in patients with pacing over various periods of follow-up. In patients with the long QT syndrome in whom medical therapy had failed, pacing at relatively fast rates markedly reduced symptoms and almost completely abolished fainting spells. Preliminary results suggest that pacing may be beneficial in dilated cardiomyopathy and in preventing episodes of paroxysmal atrial fibrillation. Further studies are needed to clarify the mechanisms of and to improve selection criteria for pacing in these conditions. Our ability to select cardiac transplant recipients for permanent pacing and our ability to optimize the timing of pacing in these patients have recently improved considerably. The role of pacing therapy in patients with neurally mediated (vasovagal) syncope remains incompletely understood. Better classification of these patients, made according to the sequence of hemodynamic events leading to syncope, is likely to clarify the potential benefit of pacing in these patients and improve the selection of patients for pacing. CONCLUSION: Few peer-reviewed clinical trials have been done, and further studies are needed to confirm the promising effects of pacing in patients with these newly recognized and expanding indications for pacing.
Atrial Fibrillation↗
Mechanism of hemodynamic improvement by dual-chamber pacing for severe left ventricular dysfunction: an acute Doppler and catheterization hemodynamic study.
OBJECTIVES: This study was undertaken to determine the mechanism by which improvement in hemodynamic variables may occur with dual-chamber pacing in patients with severe left ventricular dysfunction. BACKGROUND: Dual-chamber pacing has recently been proposed as a therapeutic alternative for the relief of symptoms in patients with dilated cardiomyopathy. METHODS: Fifteen patients with severe left ventricular systolic dysfunction were studied acutely during atrioventricular (AV) sequential pacing at various AV intervals (60, 100, 120, 140, 180 and 240 ms) with use of combined Doppler velocity curves and pressures obtained by high fidelity manometer-tipped catheters and thermodilution cardiac output. RESULTS: Neither cardiac output nor mean left atrial pressure was significantly different when hemodynamic variables in the baseline state were compared with those during AV sequential pacing at the various AV intervals in all patients. The patients were classified into two groups. In group I (eight patients with PR intervals > 200 ms on the rest 12-lead electrocardiogram), cardiac output was significantly increased when AV sequential pacing at the optimal AV interval to output was compared with that at the baseline state (3.0 +/- 1.0 vs. 3.9 +/- 0.43 liters/min, p = 0.005) because timing of mechanical atrial and ventricular synchrony was optimized. In addition, left ventricular end-diastolic pressure and duration of diastolic filling were increased, and diastolic mitral regurgitation was abolished. In group II (seven patients who had normal AV conduction at rest), cardiac output during AV pacing decreased from the baseline value without change in the diastolic filling period. CONCLUSIONS: Dual-chamber pacing may improve acute hemodynamic variables in selected patients with dilated cardiomyopathy, mainly by optimization of the timing of mechanical atrial and ventricular synchrony. Reestablishment of the optimal diastolic filling period and abolition of diastolic mitral regurgitation may also contribute to hemodynamic improvement.
Aged↗
Guidelines for training in adult cardiovascular medicine. Core Cardiology Training Symposium (COCATS). Task Force 6: training in specialized electrophysiology, cardiac pacing and arrhythmia management.
Explore the source record for details and available documents.
Adult↗
Atrial "J" pacing lead retention wire fracture: radiographic assessment, incidence of fracture, and clinical management.
UNLABELLED: In November 1994, Telectronics Pacing Systems issued a voluntary recall of their Accufix 330-801 and 329-701 "J"-shaped atrial pacemaker leads. To assess the integrity of the lead, 156 consecutive patients with the Accufix 330-801 atrial lead implanted underwent fluoroscopic screening. Leads were visualized in at least two orthogonal views. When identified, fractured retention wires were classified into one of four groups, depending on the degree of wire extrusion outside of the lead insulation. RESULTS: Of the 156 patients, 35 patients (22.4%) had a definite retention wire fracture, and an additional 13 patients (8.3%) had indeterminate leads. Neither the age of the patients, the time since lead implant, nor the site of fracture correlated with the incidence of wire fracture. When analyzed to include indeterminate leads that were re-evaluated and found to be fractured, as well as two leads that were identified as being radiographically normal but found to be fractured after extraction, the incidence of retention wire fracture is 25.6% (40 of 156 leads evaluated). CONCLUSIONS: The incidence of retention wire fracture in the Accufix 330-801 lead is significantly higher than originally reported. Patients should be notified of the potential dangers associated with this lead. Cardiac digital fluoroscopy is an effective method of screening for wire fracture. Leads with fractured retention wires should be extracted and those with normal fluoroscopic appearance should undergo regular fluoroscopic screening.
Aged↗
Multicenter experience with a bipolar tined polyurethane ventricular lead.
A multicenter study was undertaken to determine the failure rate of a specific bipolar tined polyurethane ventricular pacing lead, the Medtronic 4004/4004M pacing lead. Seven centers in the United States and Canada implanted 586 Medtronic 4004/4004M pacing leads. The study was designed to determine the probability and clinical manifestations of lead failure. Only failures compatible with an insulation problem were included. The Kaplan-Meier estimate of the percentage of 4004/4004M lead failures within 4 years after implantation was 14.1% (95% confidence interval: 8.5%-19.3%). Failures were manifested as sensing abnormalities, failure to capture, early battery depletion, and significant decrease in measured impedance compared with previous impedance measurements. The observed rate of failure is unacceptable, and strong consideration should be given to replacing the 4004/4004M pacing lead in pacemaker dependent patients and closely monitoring nondependent patients.
Adolescent↗