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Biomedical subjects

D M Steinhaus

Publications and source records attributed to D M Steinhaus.

11 recordsLinked to original sources
PubMed1998

Comparison of results in two implantable defibrillators. Jewel 7219D Investigators.

The Jewel 7219D was the first non-thoracotomy implantable cardioverter-defibrillator (ICD) with biphasic shock capability small enough to be placed in the prepectoral subcutaneous position. Size reduction of ICDs is desirable, but safety and efficacy of smaller devices must be demonstrated. Outcomes of patients treated with the Jewel 7219D defibrillator (n = 1,781) and with its precursor model PCD 7217B (n = 2,637) were compared. To use PCD patients (n = 2,637) as historical (n = 2,574) and concurrent controls (n = 63), statistical adjustments using the Cox proportional-hazards regression model were made. Jewel recipients (n = 1,781) treated in 106 US and 32 non-US centers exhibited similar characteristics including a mean age of 59 years, 78% men, ejection fraction of 34%, history of aborted sudden cardiac death in 41%, and coronary artery disease in 70%. Implantation was completed in 1,777 of 1,781 (99.9%) attempts and success with the first electrode configuration and polarity was 89.5%. Kaplan-Meier cumulative first-year survivals for cardiac and all-cause mortality were 98.5% and 93.3%. Complication-free first-year survival for Jewel implants in prepectoral subcutaneous (n = 582), subpectoral submuscular (n = 366), and abdominal (n = 449) positions did not differ (p > 0.05). First-year survival free of pocket-related complications exceeded 98% in all locations. Adjusted cardiac and all-cause first-year mortality, and efficacy in terminating spontaneous tachyarrhythmias did not differ between the 2 device groups. In conclusion, the safety and efficacy of Jewel model 7219D in the prepectoral subcutaneous position are at least equal to either those of Jewel models implanted in different positions or to those of the previously extensively characterized PCD 7217B.

Cardiac Surgical Procedures↗
PubMed1997

Atrial pacing leads following open heart surgery: active or passive fixation?

The right atrial appendage is often amputated at the time of cardiopulmonary bypass. Because of concerns regarding lead displacement, use of active fixation atrial leads has been recommended in patients who require permanent atrial or dual chamber pacing after open heart surgery. We evaluated the acute and chronic performance of active and passive fixation atrial leads implanted at our institution between 1985 and 1993 in patients with previous open heart surgery. Of 78 consecutive patients, 38 had an active fixation atrial lead, 28 had a passive fixation steroid-eluting lead, and 12 had a passive fixation lead without steroid-eluting properties. At implantation, sensed P wave amplitudes were similar in the three groups, but lead impedance and threshold were significantly higher for active fixation leads compared to all passive fixation leads. During follow-up, atrial pacing thresholds were significantly higher, and sensed P wave amplitudes significantly lower, in the patients with active fixation leads compared to those with passive fixation leads. Loss of sensing occurred in 6 of 38 (16%) patients with active fixation leads and 1 of 40 (2.5%) patients with a passive fixation lead (P = 0.027). Atrial lead displacement occurred in two patients with active fixation leads and one with a passive fixation lead. Comparison with a parallel group of patients without previous open heart surgery demonstrated that atrial lead performance was similar in the two groups. We conclude that, when permanent atrial or dual chamber pacing is necessary in patients with prior open heart surgery, it is appropriate to implant a passive fixation atrial lead except on the infrequent occasions when a stable atrial position cannot be obtained.

Aged↗
PubMed1996

Cost savings with nonthoracotomy implantable cardioverter-defibrillators.

We analyzed hospital and physician charges for 99 consecutive patients who underwent implantable cardioverter-defibrillator (ICD) implantation at our institution. Eighteen patients received an epicardial lead system and 81 were scheduled to receive a nonthoracotomy lead system, the generator being implanted either abdominally (n = 62) or pectorally (n = 19). The epicardial group had a significantly longer convalescent stay (11.6 +/- 2.5 days; mean +/- SEM) than the abdominal nonthoracotomy group, analyzed by intention to treat (4.6 +/- 0.5 days) or by treatment received (3.8 +/- 0.2 days; p <0.0001). Postoperative stay for the pectoral group was shorter still (2.9 +/- 0.4 days; p <0.033). Total charges for the epicardial group were $99,081 +/- $25,094, significantly higher than those for any of the nonthoracotomy groups (p <0.017). Total charges for the pectoral group were $44,128 +/- $2,465, significantly less than those for the abdominal nonthoracotomy group, analyzed by intention to treat ($59,961 +/- $1,369; p <0.05) or by treatment received ($56,679 +/- $635; p <0.05). Cost reductions in the nonthoracotomy groups were primarily due to decreased in-hospital convalescence period, lower surgeon and anesthesiologist fees, and lower procedure-day hospital charges in the pectoral group. The use of ICDs with nonthoracotomy leads can result in significantly shorter in-hospital convalescence and a reduction in total implant-related charges of 40% to 55%. The use of pectorally implanted ICDs results in further reduction in hospital stay and further cost reduction of 22% to 26%. The trend toward shorter convalescent stay without postimplant testing is likely to reduce further the overall costs of ICD implantation.

Anesthesiology↗
PubMed1996

Initial experience with an implantable hemodynamic monitor.

BACKGROUND: Measurement of intracardiac hemodynamic parameters has been limited to brief periods in the acute care setting. We developed and evaluated an implantable hemodynamic monitor that is capable of measuring chronic right ventricular oxygen saturation and pulmonary artery pressure. METHODS AND RESULTS: The device consists of an electronic controller placed subcutaneously and two transvenous leads placed in the right ventricle (reflectance oximeter) and pulmonary artery (variable capacitance pressure sensor). Implantation was performed in 10 patients with severe left ventricular dysfunction. Average implant pulmonary artery pressures were systolic, 52 +/- 16 mm Hg; diastolic, 29 +/- 11 mm Hg; and mean, 40 +/- 12 mm Hg. The mean right ventricular oxygen saturation at implant was 51%. Provocative maneuvers, including postural changes, sublingual nitroglycerin, and bicycle exercise, demonstrated expected changes in measured oxygen saturation and pulmonary artery pressures over time. At follow-up of 0.5 to 15.5 months, there were no significant differences between pulmonary artery pressures or oxygen saturation values transmitted from the device and simultaneous measurement with balloon flotation catheters. Four of the pulmonary artery leads dislodged and three demonstrated sensor drift, whereas two of the oxygen saturation sensors failed. Four patients died and four received transplants. Pathological study did not demonstrate injury to the right ventricular outflow tract or pulmonic valve. CONCLUSIONS: Chronic measurement of hemodynamic parameters in the outpatient setting with implantable sensor technology appears to be feasible. The devices are well tolerated without significant untoward effects, and the sensors generally function well over time, providing reliable information. Clinical usefulness remains to be established.

Adult↗
PubMed1988

Cutaneous mucormycosis in a heart transplant patient.

We present the first case of cutaneous mucormycosis reported in a patient who had undergone a heart transplant operation. This appeared to be a localized infection without a predisposing local factor such as a surgical adhesive and without evidence of dissemination. Prompt treatment with intravenous amphotericin B resulted in an apparent cure.

Adult↗
PubMed1986

Cardiac conduction abnormalities complicating native valve active infective endocarditis.

Two hundred eleven episodes of native valve active infective endocarditis treated at the Massachusetts General Hospital between 1975 and 1983 were reviewed. The aortic (36%) and mitral (33%) valves were most frequently involved, but in 21% of the cases the site of infection could not be localized. Streptococcal (50%) and staphylococcal (35%) species were the most frequently isolated pathogens. New or changing ("unstable") conduction abnormalities developed in 9% of the patients, while an additional 7% had conduction abnormalities of "indeterminate" age. Unstable conduction block was more likely to develop in patients with aortic valve infective endocarditis than in those with mitral infection. Surgery was performed in 23% of the patients. Unstable conduction abnormalities were significantly associated with valve replacement, but in a multivariate analysis, this effect could be explained by the site of valvular infection. The mortality rate was 20%. Patients with unstable conduction abnormalities had a significantly higher mortality rate, even after other significant predictors of death (age, type of causative organism) were taken into account. Patients whose conduction changes persisted had a worse prognosis than those with transient conduction abnormalities. Although more hemodynamically compromised, patients with unstable conduction block who underwent valve replacement did at least as well as those given medical therapy alone. Patients with native valve active infective endocarditis in whom persistent, unstable conduction abnormalities develop without other identifiable cause, especially in the presence of aortic valve infection, should be considered for valve replacement.

Adolescent↗
PubMed1984

Creatine kinase levels after jogging in patients with cardiac disease.

Acute muscle injury is a well-documented complication of strenuous exercise, but milder forms of exertion have not been studied in detail. This report describes a patient undergoing cardiac rehabilitation in whom atypical chest pain developed and who was treated for a myocardial infarction only because of an elevated creatine kinase level. Serum creatine kinase levels were determined before and after exercise in 27 patients undergoing cardiac rehabilitation. In 21 patients who jogged less than three miles, creatine kinase levels were not appreciably changed. In six patients who jogged more than three miles, the mean creatine kinase level rose from 41 to 54 mU/ml, an increase of 31 percent. In four of these six patients, creatine kinase levels rose to abnormal levels, but MB creatine kinase levels remained normal, with no clinical evidence of myocardial ischemia. Serum creatine kinase levels should be interpreted with caution in the setting of even modest exercise.

Adult↗
PubMed1984

Pacemaker-mediated tachycardias: an unresolved problem.

The advent of dual chamber pacing systems that restore atrioventricular synchrony and allow rate variability in response to physiologic stress has provided a major advance in pacing therapy. Undesirable pacemaker-mediated tachycardias may arise when the atrial sensing amplifier of a VDD or DDD device detects a retrogradely conducted P-wave, ectopic atrial tachycardia, myopectoral contractions, or environmental electromagnetic interference. The rate of the resultant tachycardia is determined by the programmed upper tracking rate of the pacemaker. Although seldom life-threatening, troublesome myocardial ischemia may ensue in patients with coronary artery disease. In most instances, the incidence and rate of pacemaker-mediated tachycardias may be minimized by judicious programming.

Cardiac Pacing, Artificial↗