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Biomedical subjects

R Quigg

Publications and source records attributed to R Quigg.

7 recordsLinked to original sources
PubMed2001

Relation of thallium uptake to morphologic features of chronic ischemic heart disease: evidence for myocardial remodeling in noninfarcted myocardium.

OBJECTIVES: The aim of this study was to investigate the disparity between the extent of myocardial injury as assessed by thallium and the severity of left ventricular (LV) dysfunction in chronic ischemic heart disease. BACKGROUND: Although it is believed that thallium differentiates between viable and nonviable myocardium, in some patients with chronic ischemic heart disease, viable regions by thallium may fail to improve function after revascularization. METHODS: Thirteen transplant candidates with chronic ischemic heart disease (LV ejection fraction = 14 +/- 6% at rest) were studied prospectively with stress-redistribution-reinjection thallium single-photon emission computed tomography. We examined pretransplantation quantitative thallium uptake and post-transplantation extent and the histological distribution of collagen replacement in infarcted and noninfarcted myocardium and in 13 age-matched control hearts. RESULTS: The volume fraction of collagen varied inversely with wall thickness (r = -0.70, p < 0.001) and was higher in irreversible (30.9 +/- 15.8%) compared with reversible (20.2 +/- 12.6%, p < 0.001) or normal thallium segments (15.0 +/- 8.7%, p < 0.001). The irreversible thallium segments had lower wall thickness and more severe coronary artery narrowing (9.7 +/- 2.8 mm and 95 +/- 8%) compared with reversible (11.7 +/- 2.7 mm and 87 +/- 13%, p < 0.001) and normal thallium segments (12.8 +/- 2.6 mm and 80 +/- 14%, p < 0.001). Mean volume fraction of collagen was significantly lower in noninfarcted than it was in infarcted segments (13 +/- 6% vs. 36 +/- 13%, p < 0.001) but exceeded that in the control hearts (4 +/- 2%, p < 0.001). Noninfarcted segments had predominantly interstitial fibrosis with either microscopic or patchy areas of replacement fibrosis. CONCLUSIONS: In chronic ischemic heart disease with severe LV dysfunction, patterns of normal, reversible and irreversible thallium uptake correlated with the magnitude of collagen replacement, segmental wall thickness and severity of coronary artery narrowing. The finding of scattered areas of replacement fibrosis in noninfarcted myocardium may explain the observed disparity between LV contractile dysfunction and the extent of myocardial injury assessed by thallium.

Adult↗
PubMed2000

Rationale and design of the OPTIME CHF trial: outcomes of a prospective trial of intravenous milrinone for exacerbations of chronic heart failure.

BACKGROUND: The optimal management of an acute exacerbation of chronic heart failure (CHF) is uncertain. There is little randomized evidence available to support the various treatment strategies for patients hospitalized with an exacerbation of CHF. Inotropic agents may produce beneficial hemodynamic effects, and although they are currently used in these patients, their effect on clinical response and impact on clinical outcome is unclear. We present a unique and simple study designed to determine whether a treatment strategy for CHF exacerbations that includes an intravenous agent with inotropic properties can reduce hospital length of stay and lead to improved patient outcome. METHODS: The OPTIME CHF (Outcomes of a Prospective Trial of Intravenous Milrinone for Exacerbations of Chronic Heart Failure) trial is an ongoing multicenter, randomized, placebo-controlled trial of a treatment strategy for patients with acute exacerbations of CHF. The design of this study provides a novel approach to the evaluation of treatment strategies in the care of this population. The OPTIME CHF design uses early initiation of intravenous milrinone as both an adjunct to the best the medical therapy and to facilitate optimal dosing of standard oral therapy for heart failure. Patients with known systolic heart failure requiring hospital admission for a CHF exacerbation are randomly assigned within 48 hours of admission to receive a 48-hour infusion of either intravenous milrinone or placebo. The primary end point of this design is a reduction in the total hospital days for cardiovascular events within 60 days after therapy. Enrollment of 1000 patients began July 7, 1997, at 80 US centers and is projected to conclude in late 1999.

Adolescent↗
PubMed2000

Defibrillators in nonischemic cardiomyopathy treatment evaluation.

The Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation (DEFINITE) is a multicenter randomized trial. Patients will have nonischemic cardiomyopathy (LVEF < or = 35%), a history of symptomatic heart failure and spontaneous arrhythmia (> 10 PVCs/hour or nonsustained ventricular tachycardia defined as 3-15 beats at a rate of > 120 beats/min) on Holter monitor or telemetry within the past 6 months. Patients will be randomized to an implantable cardioverter defibrillator (ICD) versus no ICD. All patients will receive standard oral medical therapy for heart failure including angiotensin converting enzyme inhibitors and beta-blockers (if tolerated). Patients will be followed for 2-3 years. The primary endpoint will be total mortality. Quality-of-life and pharmacoeconomics analyses will also be performed. A registry will track patients who meet basic inclusion criteria but are not randomized. We estimate an annual total mortality of 15% at 2 years in the treatment arm that does not receive an ICD. The ICD is expected to reduce mortality by 50%. Approximately 204 patients will be required in each treatment group. Twenty-five centers will be included in a trial designed to last an estimated 4 years.

Cardiomyopathy, Dilated↗
PubMed1998

Impaired exercise capacity late after cardiac transplantation: influence of chronotropic incompetence, hypertension, and calcium channel blockers.

BACKGROUND AND METHODS: Patients undergoing orthotopic cardiac transplantation manifest reduced exercise capacity during the first postoperative year, which is related primarily to chronotropic incompetence of the denervated heart. To determine whether exercise capacity improves during the long term after transplantation, we prospectively studied 45 patients from 1 month to 6 years after cardiac transplantation by use of maximal treadmill exercise testing for measurement of exercise duration, peak heart rate, and peak VO2. All had normal left ventricular ejection fractions. Patients were categorized according to length of time since transplant and compared to 14 untrained normal subjects. RESULTS: Peak exercise heart rate and exercise duration were progressively higher as time after transplantation increased. However, patients who had undergone transplantation more than 2 years earlier continued to manifest a significant reduction in peak exercise heart rate (157+/-3 beats/min vs 178+/-14 beats/min) and reduced exercise duration (8.6+/-0.5 minutes vs 13.2+/-2.0 minutes) compared with controls. In contrast, peak VO2 was similar at all times after transplant and remained markedly reduced in patients who underwent transplantation more than 2 years earlier as compared with controls (22.1+/-0.7 mL/kg/min vs 42.1+/-9.1 mL/kg/min). The potential effects of 14 clinical variables on exercise performance were evaluated by regression modeling. Patients with poorly controlled hypertension had a shorter median exercise duration (7.4 minutes vs 9.7 minutes) and a lower median peak VO2 (20.3 mL/kg/min vs 23.2 mL/kg/min) compared with patients with normal or well-controlled blood pressure. Patients treated with calcium channel blockers for hypertension had greater chronotropic incompetence during exercise (peak heart rate 139 beats/min vs 158 beats/min). There was no relation between exercise capacity and recipient age, donor age, recipient sex, donor ischemic time, pretransplant diagnosis, length of peritransplant hospitalization, percentage of ideal body weight, left ventricular ejection fraction, frequency or severity of allograft rejection, or long-term use of oral prednisone therapy. CONCLUSIONS: Exercise capacity, as measured by treadmill exercise time and peak heart rate, improves in the first 2 years after transplantation, but does not reach normal values in patients up to 6 years after transplant. Peak VO2 remains significantly reduced at all times after transplantation despite the presence of normal resting left ventricular systolic function.

Adult↗
PubMed1996

Effectiveness and safety of diltiazem or lisinopril in treatment of hypertension after heart transplantation. Results of a prospective, randomized multicenter trail.

OBJECTIVES: The purpose of this study was to determine the effectiveness and safety of diltiazem or lisinopril for treatment of hypertension after heart transplantation. BACKGROUND: Systemic hypertension is common after heart transplantation, and to date there are no randomized, prospective multicenter treatment trials. METHODS: Members of the Cardiac Transplant Research Database Group developed and implemented a prospective, randomized multicenter trial of the effectiveness and safety of diltiazem or lisinopril in the treatment of hypertension in cyclosporine-treated patients after heart transplantation. RESULTS: One hundred sixteen patients with hypertension (blood pressure > or = 140/90 mm Hg) after heart transplantation were randomized for > or = 3 months of treatment. Of 55 diltiazem-treated patients, 21 (38%) were responders (diastolic blood pressure < 90 mm Hg), 23 (42%) were nonresponders (diastolic blood pressure > or = 90 mm Hg), and 11 (20%) were withdrawn from the study. Of 61 lisinopril-treated patients, 28 (46%) were responders, 22 (36%) were nonresponders, and 11 (18%) were withdrawn. There was no difference in baseline characteristics or percent responders between the two groups. Systolic pressure decreased from 157 +/- 2.3 to 130 +/- 2.0 mm Hg (mean +/- 1 SEM) in the diltiazem-treated responders and from 153 +/- 2.1 to 127 +/- 2.7 mm Hg in the lisinopril-treated responders (p < 0.0001). Diastolic pressure decreased from 100 +/- 0.9 to 85 +/- 1.6 mm Hg in the diltiazem-treated responders and from 100 +/- 1.0 to 84 +/- 2.0 mm Hg in the lisinopril-treated responders (p < 0.0001). There were a total of 35 reported adverse events, 22 of which led to withdrawal of the patient from the study. All drug-related side effects were considered minor and resolved with discontinuation of the drug. CONCLUSIONS: These results indicate that both diltiazem and lisinopril are safe for treatment of hypertension after heart transplantation, although titrated monotherapy with either drug controlled the condition in < 50% of patients.

Aged↗
PubMed1992

Melbourne AIDS vigil.

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Acquired Immunodeficiency Syndrome↗