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Biomedical subjects

R G Hauser

Publications and source records attributed to R G Hauser.

16 recordsLinked to original sources
PubMed1988

The automatic implantable cardioverter-defibrillator. Clinical experience, complications, and follow-up in 25 patients.

Twenty-five patients with recurrent ventricular tachyarrhythmias underwent implantation of an automatic implantable cardioverter-defibrillator. The mean length of follow-up was 11.9 +/- 10.8 months. Before the implantation, the patients had survived one or more cardiac arrests (mean, 1.7; range, 1 to 4) and episodes of syncope (mean, 2.2; range, 2 to 3) and had received 6.0 +/- 1.0 antiarrhythmic drug trials. The in-hospital complications included death (two patients), reoperation (one patient), intraoperative myocardial infarction (one patient), sensing-failure (one patient), infection (five patients), and pocket seroma (two patients). The posthospital complications included device failure (four patients), device deactivation (one patient), and inappropriate discharge (two patients). The device discharged appropriately in seven patients due to sustained ventricular tachycardia. During electrophysiologic measurements, the energy requirement for successful cardioversion-defibrillation was related to the type of ventricular arrhythmia induced (monomorphic or pleomorphic ventricular tachycardia or fibrillation). Ventricular tachycardia acceleration occurred in ten patients (40%). No significant changes were found in the size of the electrograms or in the cardioversion threshold during early and late follow-up measurements. Life table analysis showed a 12-month survival rate of 86% and an arrhythmic death survival rate of 100%. We confirm the improved rate of survival in this high-risk group of patients, despite significant complications.

Adult↗
PubMed1988

Carotid sinus hypersensitivity in patients with unexplained syncope: clinical, electrophysiologic, and long-term follow-up observations.

To assess the incidence and clinical characteristics of carotid sinus hypersensitivity and the relationship to electrophysiologic findings, 76 patients with unexplained syncope underwent carotid sinus massage during electrophysiologic studies for syncope evaluation. Twenty-one patients (28%) were found to have carotid sinus hypersensitivity. Of these 21 patients, 11 (52%) had coronary artery disease, two (10%) had hypertensive heart disease, and eight (38%) had no organic heart disease. During electrophysiologic studies, abnormal sinus node function was found in three patients (14%), abnormal atrioventricular (AV) node function was noted in four (19%), and combined abnormal sinus node and AV node functions were seen in three (14%). Eleven patients (53%) had a normal electrophysiologic study. During carotid sinus massage, sinus arrest alone was observed in 12 patients (57%), and combined sinus arrest and AV nodal block was seen in nine (43%). Thirteen patients were treated with a permanent pacemaker, in whom either carotid sinus massage reproduced the symptom or concomitant sinus node or AV node abnormality, or organic heart disease was present. With a mean follow-up of 42 +/- 19 months, none of these 13 patients had recurrent syncope. However, one of eight patients (13%) who did not receive a pacemaker had recurrence of syncope. Subsequently, this patient has done well after implantation of a pacemaker. These observations suggest that there is a significant incidence of carotid sinus hypersensitivity in patients with unexplained syncope. Permanent pacing appears to be beneficial in selected patients based on clinical and electrophysiologic findings.

Arrhythmia, Sinus↗
PubMed1988

Electrocardiographic manifestations of the rapid recharge function of pulse generators after sensing.

In this report, we present our observations in three patients with Medtronic Spectrax VVI pulse generators that exhibited unusually clear electrocardio-Spectrax VVI pulse generators that exhibited unusually clear electrocardiographic artifacts, due to the rapid recharge function upon sensing. Although many contemporary pulse generators contain rapid recharge circuits operative after the delivery of a pacemaker stimulus, only certain Medtronic Spectrax pulse generators also possess a rapid recharge capability after sensing. Rapid recharge upon sensing may produce electrocardiographic deflections that should not be misinterpreted as pacemaker malfunction.

Electrocardiography↗
PubMed1987

Performance of implantable cardiac rhythm management devices.

Our data represent use, follow-up, and management decisions from seven independently functioning centers and most importantly, actuarial survival of ICRMDs that have been implanted for sufficient time period to allow assessment of time versus failure. General patterns of possible target durations for adequate performance for present or future generations of similar clinical devices may be suggested by the data that we have presented. However, it would be inappropriate to conclude from these data that any presently implanted ICRMD would have a particular functional reliability. These data, furthermore, only summarized device hardware performance and cannot and must not be used to determine either short-term or long-term individual patient status, management, or outcome.

Actuarial Analysis↗
PubMed1986

Temporary pacing. Indications, modes, and techniques.

This article reviews the indications for temporary pacing, describes and illustrates the techniques, discusses the fundamentals of electrical stimulation, and explores special applications, including overdrive and dual-chamber DDD pacing.

Bradycardia↗
PubMed1986

Twelve years of clinical experience with lithium pulse generators.

The clinical performance of 9,651 lithium pulse generators, which were implanted at our registry hospitals since 1973, was assessed by analysis of actuarial survival data and information obtained at the time of pacemaker failure. Cumulative survival estimates for all units were: 5 years, 94 percent, 7 years, 81 percent, 10 years, 62 percent. Discriminant actuarial analysis revealed no differences between lithium iodine and lithium cupric sulfide longevity. Battery depletion was found in 49.1 percent of 277 units subjected to detailed explant analysis, while 31 percent and 8.7 percent had component and hermetic seal defects, respectively. Of the pulse generators with battery depletion, all but two units exhibited normal end-of-battery life behavior. We conclude that the lithium iodine and lithium cupric sulfide batteries are safe, long-term energy sources; however, the impact of reduced battery size and dual chamber pacing on these performance parameters is unknown.

Electronics, Medical↗
PubMed1985

Programmability: a clinical approach.

Programmability is a vital characteristic of any implantable pacing system. It allows the physician to alter or adjust pulse-generator behavior at any time during or after pacemaker insertion. This capability has been shown to reduce the need for reoperation to correct sensing and pacing malfunctions. Moreover, programmability can be utilized to prolong battery life, evaluate lead-electrode performance, and individualize the pacemaker prescription.

Atrioventricular Node↗
PubMed1985

The cost of tachyarrhythmia management.

Health economy measures in the United States demand that physicians develop more cost effective approaches to the management of patients who have tachyarrhythmias. Accordingly, the hospital records of 47 patients admitted for electrophysiologic evaluations were reviewed. The average length hospital stay for patients who had ventricular tachycardia was 32 days (range: 7-75) and the average cost of hospitalization was $41,988 (range: $6,299-131,259) per patient. Hospitalization costs were significantly less for 14 patients who had supraventricular tachycardia and for 10 patients who were evaluated for syncope of uncertain etiology. The cost of hospitalization correlated significantly with the length of hospital stay (r = 0.98). Therefore, new approaches to managing critical arrhythmias are needed; these include outpatient surveillance and intervention systems, use of potentially curative therapies; e.g. resection or ablation application of electrical devices capable of detecting and terminating lethal arrhythmias.

Aged↗
PubMed1979

Occlusive disease confined to the right coronary artery: clinical features, surgical treatment and long-term follow-up in 124 patients.

The clinical presentation and surgical results in 124 consecutive patients who underwent aorta to right coronary arterial bypass surgery from January 1970 through June 1977 were reviewed. Preoperatively, 75 percent of the patients were in New York Heart Association functional class III or IV, 9 percent presented with unstable angina and 5 percent had life-threatening ventricular arrhythmias. All patients had high grade occlusive disease confined to the right coronary artery; 34 percent of the patients had associated nonsignificant disease (less than 50 percent intraluminal narrowing) of the left anterior descending or circumflex artery. Left ventricular function was normal in 63 percent and minimally impaired in 37 percent. The operative mortality rate was 1.6 percent. The course of the 122 survivors was followed up for 3.7 years. There were four late deaths, and the 5 year mortality rate was 4.0 percent. Eight patients were reoperated on because of recurrence of symptoms and occlusion of the graft or progression of occlusive disease of the other major coronary arteries, or both. Of the remaining 110 patients, 98 are either in functional class I or II, 60 are taking no cardiovascular medications, 52 are working full time without angina nad 73 are asymptomatic. In summary, bypass surgery for isolated right coronary artery disease has a low mortality rate and results in excellent long-term symptomatic improvement.

Adult↗