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Biomedical subjects

P E Nolan

Publications and source records attributed to P E Nolan.

At least 19 recordsLinked to original sources
PubMed2001

Comparison of the CardioWest total artificial heart, the novacor left ventricular assist system and the thoratec ventricular assist system in bridge to transplantation.

BACKGROUND: Device selection has historically been supported by minimal comparative data. Since 1994, we have implanted 43 patients with the CardioWest Total Artificial Heart (CW), 23 with the Novacor Left Ventricular Assist System (N), and 26 with the Thoratec Ventricular Assist System (T). This experience provides a basis for our device selection criteria. METHODS: We reviewed retrospectively the results for survival, stroke, and infection in the CW, N, and T groups. Statistical methods included the Student's t-test, chi2 analysis, and Kaplan-Meier actuarial survival curves. RESULTS: The T group patients were younger and smaller sized than the CW or N group. The CW group had the highest mean central venous pressure (CVP) and lowest mean cardiac index. Survival to transplantation was 75% for CW, 57% for N, and 38% for T. Multiple organ failure postimplant caused most deaths in the CW and T groups. Right heart failure and stroke caused most N deaths. Linearized stroke rates (event/patient-month) were 0.03 for CW, 0.28 for N, and 0.08 for T. Serious infections were found in 20% of CW, 30% of N, and 8% of T patients, but linearized rates showed little difference and death from infection was rare. CONCLUSIONS: The N device should be used in "stable" patients with body surface area (BSA) greater than 1.7 m2 and with minimal right heart failure. Unstable patients with biventricular failure should receive a CW if the BSA is greater than 1.7 m2 or a T if they are smaller.

Adolescent↗
PubMed2001

Myroides odoratus cellulitis and bacteremia: case report and review.

A case of Myroides odoratus cellulitis with bacteremia in an apparently immunocompetent man is presented. Although common in soil and water, this agent is a rare clinical isolate and is often not considered pathogenic. The virulence of M. odoratus may be greater than is currently believed and it should be considered in bacteremias from cutaneous sources in immunocompetent patients.

Adult↗
PubMed2000

The CardioWest total artificial heart as a bridge to transplantation.

The CardioWest total artificial heart (TAH), formerly known as the Jarvik-7 and then the Symbion heart, is the only TAH in current clinical use. A new study, approved by the Food and Drug Administration (FDA), was initiated in 1993 with the goal of approving this pump for commercial release. Since then, 145 CardioWest TAHs have been implanted, including 37 pumps in 36 patients at our center. Our 36 patients were studied prospectively according to the investigational device exemption protocol approved by the FDA. Clinical and hemodynamic data obtained upon patients' entry into the study identified this group as mortally ill. After receiving a CardioWest TAH, 29 of the 36 patients (81%) survived to heart transplantation, and 26 (72% of the total group and 90% of the transplant recipients) have survived for up to 7 years (average, 24 months). Multicomponent anticoagulation, based on readily available tests, and the intrinsic properties of the TAH have resulted in a low linearized stroke rate of 0.48 event per patient-year. There have been no device-related mediastinal infections. In dying patients with nonexistent or severely compromised biventricular function, the CardioWest TAH has proved safe and effective, allowing a 72% survival rate for an average of 24 months.

Adult↗
PubMed2000

Antiarrhythmic agents: drug interactions of clinical significance.

The management of cardiac arrhythmias has grown more complex in recent years. Despite the recent focus on nonpharmacological therapy, most clinical arrhythmias are treated with existing antiarrhythmics. Because of the narrow therapeutic index of antiarrhythmic agents, potential drug interactions with other medications are of major clinical importance. As most antiarrhythmics are metabolised via the cytochrome P450 enzyme system, pharmacokinetic interactions constitute the majority of clinically significant interactions seen with these agents. Antiarrhythmics may be substrates, inducers or inhibitors of cytochrome P450 enzymes, and many of these metabolic interactions have been characterised. However, many potential interactions have not, and knowledge of how antiarrhythmic agents are metabolised by the cytochrome P450 enzyme system may allow clinicians to predict potential interactions. Drug interactions with Vaughn-Williams Class II (beta-blockers) and Class IV (calcium antagonists) agents have previously been reviewed and are not discussed here. Class I agents, which primarily block fast sodium channels and slow conduction velocity, include quinidine, procainamide, disopyramide, lidocaine (lignocaine), mexiletine, flecainide and propafenone. All of these agents except procainamide are metabolised via the cytochrome P450 system and are involved in a number of drug-drug interactions, including over 20 different interactions with quinidine. Quinidine has been observed to inhibit the metabolism of digoxin, tricyclic antidepressants and codeine. Furthermore, cimetidine, azole antifungals and calcium antagonists can significantly inhibit the metabolism of quinidine. Procainamide is excreted via active tubular secretion, which may be inhibited by cimetidine and trimethoprim. Other Class I agents may affect the disposition of warfarin, theophylline and tricyclic antidepressants. Many of these interactions can significantly affect efficacy and/or toxicity. Of the Class III antiarrhythmics, amiodarone is involved in a significant number of interactions since it is a potent inhibitor of several cytochrome P450 enzymes. It can significantly impair the metabolism of digoxin, theophylline and warfarin. Dosages of digoxin and warfarin should empirically be decreased by one-half when amiodarone therapy is added. In addition to pharmacokinetic interactions, many reports describe the use of antiarrhythmic drug combinations for the treatment of arrhythmias. By combining antiarrhythmic drugs and utilising additive electrophysiological/pharmacodynamic effects, antiarrhythmic efficacy may be improved and toxicity reduced. As medication regimens grow more complex with the aging population, knowledge of existing and potential drug-drug interactions becomes vital for clinicians to optimise drug therapy for every patient.

Animals↗
PubMed1999

Arizona experience with CardioWest Total Artificial Heart bridge to transplantation.

BACKGROUND: We hypothesized that bridge to transplantation with the CardioWest Total Artificial Heart would succeed in a large percentage of patients. Further, we hypothesized that this success rate would not be significantly decreased by infection or thromboembolism. METHODS: From 1993 to March 1999, 24 patients received implants with the intention of bridge to transplantation. Data were collected prospectively. Heparin, coumadin, aspirin, ticlopidine, dipyridamole, and pentoxifylline were used for anticoagulation. RESULTS: Four patients died while on device support. Nineteen of 23 patients (83%) were transplanted. All 19 survived long term. One patient remains on CardioWest Total Artificial Heart support 6 weeks after implant. There was one stroke on the day of transplantation. There was a second stroke on the day of implantation. Neither stroke caused significant residual deficits. Both were in close relationship to an operative procedure. There were no serious device-related infections. CONCLUSIONS: The CardioWest Total Artificial Heart salvaged 20 of 24 critically ill patients. Neither infections nor neurologic problems were significant. We believe it is the device of choice for decompensating patients with biventricular failure who have adequate body and heart size.

Adult↗
PubMed1999

Procainamide-induced psychosis: a case report and review of the literature.

OBJECTIVE: To describe a case of procainamide-induced psychosis in an adult treated for atrial fibrillation. CASE SUMMARY: A 45-year-old Native American woman developed acute psychosis within 72 hours of initiating procainamide for atrial fibrillation. Symptoms abated within 24 hours of discontinuing procainamide. Serum procainamide/N-acetylprocainamide concentrations were therapeutic throughout treatment. Sotalol was started without recurrence of symptoms. DISCUSSION: Psychosis is a rare complication of treatment with procainamide, but the exact mechanism for this adverse event is not fully understood. Seven cases implicating procainamide as the cause of acute psychosis are reported in the literature. Cases of psychosis involving other antiarrhythmic agents have also been reported. CONCLUSIONS: Healthcare personnel should be aware of this adverse event related to procainamide and other antiarrhythmic agents.

Adult↗
PubMed1995

Treatment of resistant atrial fibrillation. A meta-analysis comparing amiodarone and flecainide.

BACKGROUND: Chronic atrial fibrillation (AF) is a common arrhythmia with significant morbidity and mortality. Maintenance of normal sinus rhythm (NSR) can be achieved with antiarrhythmic drug therapy. The antiarrhythmic effects of amiodarone hydrochloride and flecainide acetate in patients with resistant chronic AF have been investigated separately in several small studies. This investigation compared amiodarone to flecainide in maintaining NSR in patients with resistant chronic AF. METHODS: Studies using amiodarone or flecainide in the treatment of patients with chronic AF refractory to class I antiarrhythmic drugs or sotalol hydrochloride were identified. The results of six trials of amiodarone (200 to 400 mg/d, 315 patients) and two trials of flecainide (200 to 300 mg/d, 163 patients) were aggregated using meta-analytic techniques. The percentages of patients taking amiodarone or flecainide and remaining in NSR at 3 and 12 months were compared relative to results for quinidine, which were acquired from a meta-analysis of quinidine used as first-line therapy for AF. RESULTS: After 3 and 12 months of treatment with amiodarone, 217 (72.6%) of 299 patients and 64 (59.8%) of 107 patients, respectively, remained in NSR. These percentages were significantly greater (P < .0001) than those for quinidine (70% and 50%, respectively). For flecainide, the percentage of patients remaining in NSR was significantly lower (P < .0001) than for quinidine: 79 (48.5%) and 56 (34%) of 163 patients, respectively. The aggregated percentages of patients requiring withdrawal of amiodarone and flecainide were similar: 9.5% and 8.6%, respectively. Mortality and proarrhythmia could not be assessed. CONCLUSION: This analysis suggests that low-dose amiodarone is more efficacious and equally well tolerated when compared with flecainide in the management of chronic, drug-resistant AF.

Adolescent↗
PubMed1995

Selective stability-indicating high-performance liquid chromatographic assay for recombinant human regular insulin.

This report presents a selective HPLC assay capable of separating recombinant human regular insulin from insulin decomposition and transformation products. The assay utilizes an isocratic delivery of mobile phase, a C18 peptide column, UV detection and is performed at ambient temperature. The standard curve ranges from 0.2 to 2.5 U/ml. The inter-day and intra-day variabilities are less than 7 and 5%, respectively, at the concentrations studied. The accuracy and precision are within 5% over the range of the standard curve.

Chromatography, High Pressure Liquid↗
PubMed1993

Empiric long-term amiodarone prophylaxis following myocardial infarction. A meta-analysis.

BACKGROUND: The prophylactic administration of amiodarone following acute myocardial infarction has been investigated in several small trials. This study combined the results of these small trials in a meta-analysis to determine the effects of prophylactic low-dose amiodarone on mortality following acute myocardial infarction. METHODS: Four prospective, randomized, placebo-controlled trials, which investigated the prophylactic administration of low-dose amiodarone (200 to 400 mg/d) to patients after acute myocardial infarction, were selected from the current literature according to strict inclusion criteria. A total of 1140 patients, 566 in the amiodarone-treated group and 574 in the placebo-treated group, were included in the analysis. Sudden cardiac death, cardiac mortality, and total mortality were the end points of interest. In addition, the effect of impaired left ventricular function (ejection fraction, < 45%) on total mortality was assessed. Data were aggregated by using the Mantel-Haenszel method to obtain final summary statistics for these end points. RESULTS: Patients treated with low-dose amiodarone exhibited a lower incidence of sudden cardia death (3.1%) and total mortality (6.1%) when compared with patients treated with placebo (6.9% and 11.2%, respectively; both P < .01; and 95% confidence interval [CI], 0.011 to 0.065 and 0.013 to 0.082, respectively). There was no significant difference between the amiodarone- and placebo-treated groups with respect to cardiac mortality (2.6% vs 3.7%, respectively; P = .26; and 95% CI, -0.012 to 0.032). For patients with a left ventricular ejection fraction of less than 45%, total mortality was 5.5% in the amiodarone-treated group and 9.4% in the placebo-treated group (P = .30; CI, -0.023 to 0.101). CONCLUSIONS: Although further data from ongoing large, randomized trials are needed, this meta-analysis suggests that the prophylactic administration of low-dose amiodarone to patients following acute myocardial infarction reduces the incidence of both sudden cardiac death and total mortality. The benefits of low-dose amiodarone may be limited to patients with preserved left ventricular function.

Aged↗
PubMed1993

Effectiveness and costs of digoxin treatment for atrial fibrillation and flutter.

Clinical outcomes and costs associated with the use of digoxin in atrial fibrillation and flutter were evaluated in a prospective, observational study at 18 academic medical centers in the United States. Data were collected on 115 patients (aged > 18 years) with atrial fibrillation or flutter who were treated with digoxin for rapid ventricular rate (> or = 120 beats/min). The median time to ventricular rate control (i.e., resting ventricular rate < 100 beats/min, decrease in ventricular rate of > 20%, or sinus rhythm) was 11.6 hours from the first dose of digoxin for all evaluable patients (n = 105) and 9.5 hours for those only receiving digoxin (n = 64). Before ventricular rate control, the mean +/- SD dose of digoxin administered was 0.80 +/- 0.74 mg, and a mean of 1.4 +/- 1.8 serum digoxin concentrations were ordered per patient. Concomitant beta-blocker or calcium antagonist therapy was instituted in 47 patients (41%); in 19 of these, combination therapy was initiated within 2 hours. Adenosine was administered to 13 patients (11%). Patients spent a median of 4 days (range 1 to 25) in the hospital; 28% spent time in a coronary/intensive care unit and 79% in a telemetry bed. Loss of control (i.e., resting ventricular rate returned to > 120 beats/min) occurred at least once in 50% of patients and was associated with a longer hospital stay (p < 0.05). Based on 1991 data, the estimated mean hospital bed cost for patients with atrial fibrillation or flutter was $3,169 +/- $3,174.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

High-performance liquid chromatographic method for the quantitation of quinidine and selected quinidine metabolites.

A specific and sensitive assay for the separation and quantitation of quinidine, 3-hydroxyquinidine, quinidine-N-oxide, O-desmethylquinidine and dihydroquinidine is presented. The assay is shown to be sensitive to concentrations of 0.1 microgram/ml for all the above compounds when using a serum sample of 0.1 ml. The standard curve demonstrates linearity at concentrations from 0.1 to 5 micrograms/ml. The extraction procedure consists of adjusting the serum to an alkaline pH and extracting once with a mixture of methanol-dichloromethane (15:85). The organic extract is dried and the residue is solubilized in mobile phase. The chromatographic conditions are an isocratic delivery of the mobile phase 0.01 M K2HPO4-acetonitrile (96:4) through a C18 column at ambient temperature. Detection of the compounds of interest is by ultraviolet absorption at a wavelength of 210 nm. For each compound the inter-assay variation is less than 10% and the intra-assay variation is less than 15%. No interfering compounds were detected when a commercially prepared serum spiked with 28 commonly used therapeutic compounds was assayed by this method. The analytical method presented here for the isolation and quantitation of quinidine, several active metabolites, and dihydroquinidine has adequate sensitivity and specificity for monitoring the concentration of quinidine and quinidine metabolites in patient samples.

Chromatography, High Pressure Liquid↗
PubMed1991

Studies in phlebitis: detection and quantitation using a thermographic camera.

A new method for the detection of acute phlebitis in superficial veins is investigated. A thermographic camera is utilized for the quantitation of temperature changes in a rabbit ear model. A control group receiving no injection is compared against each of five treatment groups receiving these commercially available parenterals: amiodarone hydrochloride, phenytoin sodium, mechlorethamine hydrochloride, cephalothin sodium, and diazepam. The vehicles of the above-mentioned drugs as well as several commonly used organic cosolvents are also investigated. Local tissue responses to the parenteral challenges are measured and a good correlation between the visual and the thermographic data was seen.

Animals↗