Biomedical subjects

W J Rogers

Publications and source records attributed to W J Rogers.

At least 19 recordsLinked to original sources

PubMed1995

Better functional status in American than Canadian patients with heart disease: an effect of medical care?

OBJECTIVES: This study compared functional status in Americans and Canadians with and without prior symptoms of heart disease to separate the effects of medical care from nonmedical factors. BACKGROUND: Coronary angiography and revascularization are used more often in the United States than in Canada, yet rates of mortality and myocardial infarction are similar in the two countries. Recent data suggest that functional status after myocardial infarction is better among Americans than Canadians, but it is uncertain whether this difference is due to medical care or nonmedical factors. METHODS: Quality of life was measured in patients enrolled in seven American and one Canadian site in the Bypass Angioplasty Revascularization Investigation. Prior symptoms of heart disease were defined as angina, myocardial infarction or congestive heart failure before the episode of illness leading to randomization. Functional status was measured with the Duke Activity Status Index and overall emotional and social health using Medical Outcome Study measures on the basis of patient status before the index episode of acute ischemic heart disease. RESULTS: Quality of life was generally better in the 934 Americans than in the 278 Canadians, with overall health rated as excellent or very good in 30% of Americans versus 20% of Canadians (p = 0.0001), higher median Duke Activity Status Index scores (16 vs. 13.5, p = 0.03) but equivalent emotional health (76 vs. 76, p = 0.74) and social health scores (100 vs. 80, p = 0.07). Among the 350 patients without prior symptoms of heart disease, Americans and Canadians had similar overall health, Duke Activity Status Index and emotional and social health scores. However, of the 860 patients with previous symptoms of heart disease, Americans had higher overall health (p = 0.0001) and Duke Activity Status Index scores (p = 0.0008) but similar emotional and social health scores. The results were essentially unchanged after statistical adjustment for potential confounding factors. CONCLUSIONS: The functional status of patients without prior symptoms of heart disease is similar in Americans and Canadians. However, among patients with previous symptomatic heart disease, functional status is higher in Americans than in Canadians. This difference may be due to different patterns of medical management of heart disease in the two countries.

Aged↗

PubMed1995

Asymptomatic Cardiac Ischemia Pilot (ACIP) Study. Improvement of cardiac ischemia at 1 year after PTCA and CABG.

BACKGROUND: Cardiac ischemia on the ambulatory ECG (AECG) and/or on the exercise treadmill test (ETT) is associated with an increased risk of adverse outcome. Myocardial revascularization more often suppresses cardiac ischemia than does medical management alone. However, few studies have compared the effects of percutaneous transluminal coronary angioplasty (PTCA) with those of coronary artery bypass grafting (CABG) on cardiac ischemia and clinical outcome. METHODS AND RESULTS: A total of 558 patients were randomly assigned to one of three treatment strategies in the Asymptomatic Cardiac Ischemia Pilot (ACIP) study: angina-guided medical strategy (n = 184), ischemia-guided medical strategy (n = 182), or revascularization (n = 192). In patients assigned to revascularization, the choice of the procedure, PTCA or CABG, was made by the clinical unit staff and patient based on a coronary angiogram usually performed within 2 months of enrollment. CABG was selected in 78 patients and PTCA in 92 patients. At 12 weeks, ischemia on the AECG was suppressed in 70% of CABG patients versus 46% of PTCA patients (P = .002). Ischemia on the ETT was no longer present in 46% versus 23% of the patients, respectively (P = .005). Angina, within 4 weeks of the follow-up visit, was absent in 90% versus 68%, respectively (P = .001). These clinical variables remained improved in both groups at 1 year. Clinical events (myocardial infarction or repeat revascularization) occurred in 1 CABG patient versus 7 PTCA patients at 12 weeks, and in 1 versus 16 patients, respectively, at 12 months (P < .001). CONCLUSIONS: Ischemia on the AECG and ETT and angina were relieved in many patients after both procedures; however, CABG was superior to PTCA, and it was associated with a lower incidence of clinical events at 1 year. These results suggest that more complete revascularization relates to better clinical outcome. However, a large trial is needed to confirm these results.

Angina Pectoris↗

PubMed1995

Factors influencing the time to administration of thrombolytic therapy with recombinant tissue plasminogen activator (data from the National Registry of Myocardial Infarction). Participants in the National Registry of Myocardial Infarction.

Very early administration of thrombolytic therapy for acute myocardial infarction (AMI) has significantly reduced mortality in eligible patients. The purpose of this study was to evaluate factors which influenced the time from symptom onset to hospital presentation and the time from hospital presentation to the onset of thrombolytic treatment in a large population of patients with AMI. This study included 212,990 patients from 904 hospitals that participated in the National Registry of Myocardial Infarction. The median time from symptom onset to hospital presentation for those treated was 1.5 hours versus 2.7 hours for those not receiving thrombolytic treatment. Older patients and women had increased delay times, as did those who arrived at the hospital during daytime hours. Of the 59,802 (28%) patients who received thrombolytic treatment, 23% were treated < 30 minutes from admission; 63%, < 60 minutes; and 83%, < 90 minutes. Time to treatment increased with age and was longer for women and for patients arriving between midnight and early morning. The most important factor associated with shorter time to treatment was the initiation of thrombolytic treatment in the emergency department rather than in the coronary care unit (47 vs 73 minutes, p < 0.0001). Hospital treatment times are much too long, given that quick identification and treatment of eligible patients are of primary importance in reducing mortality from AMI. To shorten these times, thrombolytic treatment should be initiated in the emergency department, and the effectiveness of hospital programs aimed at reducing time to treatment should be subject to continuing quality improvement surveillance.

Aged↗

PubMed1995

Early and 1-year clinical outcome of patients' evolving non-Q-wave versus Q-wave myocardial infarction after thrombolysis. Results from The TIMI II Study.

BACKGROUND: There are few data comparing clinical outcome and potential indications for routine post-myocardial infarction cardiac catheterization and revascularization of patients who sustain a non-Q-wave versus Q-wave infarct after thrombolytic therapy. METHODS AND RESULTS: A secondary analysis of 2634 patients enrolled in the TIMI II trial with a first myocardial infarction was performed to determine 6-week and 1-year cardiac event rates and identify clinical and angiographic differences between the 1867 patients (70.9%) who evolved a Q-wave infarct and the 767 patients (29.1%) who sustained a non-Q-wave infarct after treatment with intravenous thrombolytic therapy. Male sex (85.3% versus 75.6%; P < .001) and anterior wall infarcts (53.8% versus 43.7%; P < .001) were more frequent in the Q-wave versus the non-Q-wave group. During recombinant tissue-type plasminogen activator (rTPA) infusion, a greater percentage of non-Q-wave patients (37.3% versus 23.5%; P = .001) had normalization of initial ST-segment elevation. Infarct-related artery patency (TIMI flow grade 2 or 3) (P = .02), complete infarct-related artery reperfusion (TIMI 3 flow grade) (P < .001), and the percentage of patients with a predischarge resting left ventricular ejection fraction > 55% (P < .001) were greater in the non-Q-wave group. New congestive heart failure during hospitalization developed more frequently in Q-wave patients (18.9% versus 11.6%; P < .001). After 42 days, the occurrences of reinfarction (P = .76), death (P = .76), and combined death or reinfarction (P = .43) were similar in patients assigned to the invasive or conservative postlytic management strategy, regardless of infarct type. One-year mortality was 3.4% versus 4.4% for non-Q-wave versus Q-wave infarct type, respectively (P = .25). CONCLUSIONS: Angiographic and clinical differences were observed between patients who present with initial ST-segment elevation and evolve early non-Q-wave versus Q-wave myocardial infarcts after treatment with rTPA, heparin, and aspirin. Early mortality and adverse clinical cardiac events in these patients are not significantly different after a conservative compared with an invasive treatment strategy, regardless of whether the infarct type is non-Q wave or Q wave.

Angioplasty, Balloon, Coronary↗

PubMed1995

Bypass Angioplasty Revascularization Investigation (BARI): baseline clinical and angiographic data.

This report presents baseline clinical and angiographic data from the Bypass Angioplasty Revascularization Investigation (BARI), a multicenter international trial assessing the relative efficacy of percutaneous transluminal coronary angioplasty (PTCA) versus coronary artery bypass graft surgery (CABG) in selected patients with multivessel coronary artery disease. PTCA is commonly performed in patients with multivessel coronary artery disease, yet its long-term efficacy in comparison to CABG is unknown. From August 1988 through August 1991, 1,829 qualifying patients with multivessel disease suitable for either procedure were randomized to PTCA or CABG; sample size estimates were based on anticipated 5-year mortality. Two registry populations were also defined for follow-up: (1) 2,013 patients eligible for randomization but not randomized; and (2) 422 patients considered by angiography as unsuitable for randomization. Patients randomized in BARI were at relatively high risk for subsequent cardiac events: 39% were > or = 65 years old, 55% had prior myocardial infarction, 69% presented with unstable angina or non-Q wave myocardial infarction, and 43% had 3-vessel coronary artery disease. Patients randomized to PTCA and CABG were equally matched in all the important baseline variables. The randomized and the eligible but not randomized groups were similar in most respects. However, the nonrandomized group had a higher proportion with college education; fewer with a history of myocardial infarction, heart failure, diabetes, and smoking; and a somewhat better average ejection fraction. At the 3-month follow-up, PTCA had been performed more commonly in the nonrandomized eligible patients, especially those with 2-vessel disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗

PubMed1995

Asymptomatic Cardiac Ischemia Pilot (ACIP) study: effects of coronary angioplasty and coronary artery bypass graft surgery on recurrent angina and ischemia. The ACIP investigators.

OBJECTIVES: The Asymptomatic Cardiac Ischemia Pilot (ACIP) study showed that revascularization is more effective than medical therapy in suppressing cardiac ischemia at 12 weeks. This report compares the relative efficacy of coronary angioplasty or coronary artery bypass graft surgery in suppressing ambulatory electrocardiographic (ECG) and treadmill exercise cardiac ischemia between 2 and 3 months after revascularization in the ACIP study. BACKGROUND: Previous studies have shown that coronary angioplasty and bypass surgery relieve angina early after the procedure in a high proportion of selected patients. However, alleviation of ischemia on the ambulatory ECG and treadmill exercise test have not been adequately studied prospectively after revascularization. METHODS: In patients randomly assigned to revascularization in the ACIP study, the choice of coronary angioplasty or bypass surgery was made by the clinical unit staff and the patient. RESULTS: Patients assigned to bypass surgery (n = 78) had more severe coronary disease (p = 0.001) and more ischemic episodes (p = 0.01) at baseline than those assigned to angioplasty (n = 92). Ambulatory ECG ischemia was no longer present 8 weeks after revascularization (12 weeks after enrollment) in 70% of the bypass surgery group versus 46% of the angioplasty group (p = 0.002). ST segment depression on the exercise ECG was no longer present in 46% of the bypass surgery group versus 23% of the angioplasty group (p = 0.005). Total exercise time in minutes on the treadmill exercise test increased by 2.4 min after bypass surgery and by 1.4 min after angioplasty (p = 0.02). Only 10% of the bypass surgery group versus 32% of the angioplasty group still reported angina in the 4 weeks before the 12-week visit (p = 0.001). CONCLUSIONS: Angina and ambulatory ECG ischemia are relieved in a high proportion of patients early after revascularization. However, ischemia can still be induced on the treadmill exercise test, albeit at higher levels of exercise, in many patients. Bypass surgery was superior to coronary angioplasty in suppressing cardiac ischemia despite the finding that patients who underwent bypass surgery had more severe coronary artery disease.

Angina Pectoris↗

PubMed1995

Asymptomatic Cardiac Ischemia Pilot (ACIP) study: impact of anti-ischemia therapy on 12-week rest electrocardiogram and exercise test outcomes. The ACIP Investigators.

OBJECTIVES: This report from the Asymptomatic Cardiac Ischemia Pilot (ACIP) study examines differences in the magnitude of reduction of myocardial ischemia as determined by exercise treadmill testing in patients randomized to three different treatment strategies: angina-guided medical therapy, ischemia-guided medical therapy and coronary revascularization. BACKGROUND: No prospective randomized clinical trials in patients with exercise electrocardiographic (ECG) abnormalities and asymptomatic cardiac ischemia on ambulatory ECG monitoring have compared the impact of different treatment strategies, including coronary revascularization, in terms of reducing myocardial ischemia. METHODS: The ACIP exercise protocol was used. Exercise variables measured included final exercise stage; presence of exercise-induced angina or ischemia; time to angina; time to 1-mm ST segment depression; number of exercise ECG leads with abnormalities; maximal depth of ST segment depression in any lead; sum of ST segment depression; ST/HR index; and rate-pressure product at time to angina, at time to 1-mm ST segment depression and at peak exertion. RESULTS: Peak exercise time was increased by 0.5, 0.7 and 1.6 min in patients assigned to the angina-guided, ischemia-guided and coronary revascularization strategies, respectively, from the qualifying visit to the 12-week visit (p < 0.001). At the qualifying visit, the sum of exercise-induced ST segment depression was 9.4 +/- 5.0 (mean +/- SD), 9.6 +/- 4.7 and 9.9 +/- 5.5 mm (p = NS) in the three treatment strategies, respectively. At the 12-week visit, the sum of exercise-induced ST segment depression was 7.4 +/- 5.7, 6.8 +/- 5.3 and 5.6 +/- 5.6 mm (p = 0.02) in the three treatment strategies, respectively. Each treatment strategy resulted in a significant reduction in all exercise-induced variables of myocardial ischemia measured at 12 weeks. CONCLUSIONS: Coronary revascularization significantly reduced the extent and frequency of exercise-induced myocardial ischemia compared with either medical strategy. The prognostic impact of these observations should be evaluated in a large-scale multicenter clinical trial.

Analysis of Variance↗

PubMed1995

Asymptomatic Cardiac Ischemia Pilot (ACIP) study: outcome at 1 year for patients with asymptomatic cardiac ischemia randomized to medical therapy or revascularization. The ACIP Investigators.

OBJECTIVES: This report discusses the outcome at 1 year in patients in the Asymptomatic Cardiac Ischemia Pilot (ACIP) study. BACKGROUND: Comparative efficacy of medical therapy versus revascularization in treatment of asymptomatic ischemia is unknown. The ACIP study assessed the ability of three treatment strategies to suppress ambulatory electrocardiographic (ECG) ischemia to determine whether a large-scale trial studying the impact of these strategies on clinical outcomes was feasible. METHODS: Five hundred fifty-eight patients with coronary anatomy amenable to revascularization, at least one episode of asymptomatic ischemia on the 48-h ambulatory ECG and ischemia on treadmill exercise testing were randomized to one of three treatment strategies: 1) medication to suppress angina (angina-guided strategy, n = 183); 2) medication to suppress both angina and ambulatory ECG ischemia (ischemia-guided strategy, n = 183); or 3) revascularization strategy (angioplasty or bypass surgery, n = 192). Medication was titrated atenolol-nifedipine or diltiazem-isosorbide dinitrate. RESULTS: The revascularization group received less medication and had less ischemia on serial ambulatory ECG recordings and exercise testing than those assigned to the medical strategies. The ischemia-guided group received more medication but had suppression of ischemia similar to the angina-guided group. At 1 year, the mortality rate was 4.4% in the angina-guided group (8 of 183), 1.6% in the ischemia-guided group (3 of 183) and 0% in the revascularization group (overall, p = 0.004; angina-guided vs. revascularization, p = 0.003; other pairwise comparisons, p = NS). Frequency of myocardial infarction, unstable angina, stroke and congestive heart failure was not significantly different among the three strategies. The revascularization group had significantly fewer hospital admissions and nonprotocol revascularizations at 1 year. The incidence of death, myocardial infarction, nonprotocol revascularization or hospital admissions at 1 year was 32% with the angina-guided medical strategy, 31% with the ischemia-guided medical strategy and 18% with the revascularization strategy (p = 0.003). CONCLUSIONS: After 1 year, revascularization was superior to both angina-guided and ischemia-guided medical strategies in suppressing asymptomatic ischemia and was associated with better outcome. These findings require confirmation by a larger scale trial.

Aged↗

PubMed1995

Recurrence of angina after coronary artery bypass surgery: predictors and prognosis (CASS Registry). Coronary Artery Surgery Study.

OBJECTIVES: This study sought to define the predictors and prognosis of postoperative angina in patients undergoing coronary artery bypass surgery. BACKGROUND: Angina recurs in the first postoperative year in 20% to 30% of patients after coronary artery bypass surgery. The Coronary Artery Surgery Study Registry provides an opportunity to study the predictors and prognosis of postoperative angina in a large sample. METHODS: All patients with isolated coronary artery bypass surgery in the registry were identified, and anginal status was determined on a yearly basis. The influence of angina on mortality, recurrent myocardial infarction and need for reoperation was determined. RESULTS: Angina recurred in the first year in 24% of patients and by the sixth year in 40%. The significant predictors in a multivariate analysis were minimal coronary artery disease, preoperative angina, use of vein grafts only, previous myocardial infarction, incomplete revascularization, female gender, smoking and younger age. In subsequent years important predictors were angina in the first postoperative year, female gender, younger age and incomplete revascularization. The presence of angina in the first postoperative year was associated with more frequent myocardial infarction (p = 0.04) and greater need for reoperation (p = 0.003) but did not affect survival during the 6-year follow-up period. CONCLUSIONS: These findings show that the predictors of postoperative angina are features that are or could be predicted before bypass surgery. Thus, patients with these features before bypass surgery could be advised that they would be more likely to experience postoperative angina than those without these features. Postoperative angina is associated with an increased risk of late myocardial infarction and reoperation.

Angina Pectoris↗

PubMed1995

Contemporary management of acute myocardial infarction.

Acute myocardial infarction, the leading cause of death in western society, has been the focus of more randomized clinical trial effort over the past decade than any other area of medicine. As a result of this worldwide effort, involving hundreds of thousands of patients with myocardial infarction, data have accumulated showing substantially lower mortality of acute myocardial infarction with simple interventions such as i.v. thrombolytic therapy, aspirin, beta-blockers, and angiotensin-converting enzyme inhibitors. Emergency coronary angioplasty appears to be a suitable alternative to i.v. thrombolytic therapy in skilled centers. Several previously recommended therapies (routine i.v. lidocaine, calcium channel blockers, magnesium, nitrates) have not been proved to be life-saving. Whether routine coronary arteriography should be employed after myocardial infarction remains controversial, but it is generally accepted that patients with evidence of residual ischemia after infarction, either spontaneous or provoked by stress testing, should undergo prophylactic coronary revascularization.

Algorithms↗

PubMed1995

A noninvasive comparative study of myocardial strains in ischemic canine hearts using tagged MRI in 3-D.

Regional reduction in myocardial function has long been utilized for noninvasive detection and localization of ischemic regions in the left ventricle. In this study, we compared the ability of 13 different myocardial strain indexes to discriminate between ischemic and nonischemic tissue. Using magnetic resonance imaging with tagging and three-dimensional reconstruction, we noninvasively tracked the deformation of 24 myocardial cuboids in each of nine canine hearts with acute ischemia induced by coronary artery ligation. Monastral blue staining was used for postmortem assessment of ischemia. The ability of each index to discriminate between normal and ischemic zones was evaluated using the "t" statistic. The best discrimination was obtained by the endocardial area strain [t = 7.5 +/- 3.0 (SD)], a local measure of systolic shrinkage on the endocardial surface, and by the magnitude of the endocardial principal strain (t = 7.0 +/- 1.9). Transmural wall thickening (t = 6.1 +/- 2.3) was the third best functional index. The same three indexes correlated most closely with perfusion, as assessed by monastral blue staining. These findings imply that these are the preferable functional indexes for mapping of ischemic myocardial regions.

Animals↗

PubMed1994

Comparison of primary angioplasty versus thrombolytic therapy for acute myocardial infarction. Alabama Registry of Myocardial Ischemia Investigators.

To determine the relative merits of primary percutaneous transluminal coronary angioplasty (PTCA) and intravenous thrombolytic therapy for acute myocardial infarction, 12 tertiary care hospitals entered patients who had > or = 30 minutes of chest pain and were admitted to a cardiac intensive care unit within 12 hours of symptom onset into a prospective registry. Of 1,170 such patients, 118 (10%) underwent primary PTCA and 230 (19%) received intravenous thrombolytic therapy within 6 hours of registry hospital admission (144 at the registry hospital and 86 prior to arrival at the registry hospital). Baseline demographic characteristics of PTCA and thrombolytic subgroups were remarkably similar. The interval from initial evaluation at the registry hospital to treatment was shorter with intravenous thrombolytic therapy than with primary PTCA (64 vs 104 minutes, p < 0.001), as was the interval from pain onset to treatment (184 vs 252 minutes, p < 0.001). Among the 230 thrombolytic patients, coronary arteriography and PTCA were performed within the first 24 hours in 44% and 18%, respectively, and during the entire hospitalization in 90% and 49%, respectively. During hospitalization, blood was transfused in 16% of the 230 thrombolytic patients versus 5.9% of the 118 PTCA patients (p < 0.001). Otherwise, adverse events during the initial hospitalization were similar in PTCA and thrombolytic groups. Survival at 1-year follow-up was 88% in the PTCA group and 91% in the thrombolytic group (p = NS), and survival free of reinfarction was 85% and 88%, respectively (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Effect on outcome of the presence or absence of chest pain at initiation of recombinant tissue plasminogen activator therapy in acute myocardial infarction. The Thrombolysis in Myocardial Infarction Investigators.

To ascertain whether the outcome of patients with suspected myocardial infarction differs when chest pain is still present at initiation of thrombolytic therapy, participants in the Thrombolysis in Myocardial Infarction Phase II study, all of whom presented within 4 hours of symptoms onset, were retrospectively divided into 2 groups: (1) those with chest pain present at onset of intravenous thrombolysis, n = 3,000; and (2) those who were free of chest pain on beginning intravenous thrombolytic therapy, n = 337. Patients free of chest pain were older (58 vs 57 years, p = 0.01), more often women (23 vs 17%, p = 0.01), had fewer electrocardiographic leads with ST elevation (3.8 vs 4.1, p < 0.001), and the presenting event was confirmed less often as myocardial infarction than as chest pain without infarction (88 vs 96%, p < 0.001). There were no significant differences between the 2 groups for in-hospital death, reinfarction, recurrent ischemic events, stroke, overall hemorrhagic complications, coronary angioplasty or bypass surgery. At 6-weeks follow-up, more pain-free patients had resting ejection fraction > 0.55 (35 vs 31%, p = 0.001) and fewer developed congestive heart failure (12 vs 20%). At 1-year follow-up, fewer pain-free patients developed congestive heart failure (15 vs 21%, p = 0.009), but no differences existed between the 2 groups in frequency of death, reinfarction, coronary angioplasty, bypass surgery or anginal class. Thus, there are several observations in patients who were free of chest pain at onset of lytic therapy. (1) The majority developed enzymatic or electrocardiographic evidence of acute myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1994

Dose-response study of intravenous torsemide in congestive heart failure.

In a double-blind dose-response study, 49 patients with New York Heart Association functional class III or IV heart failure were randomized to receive a single intravenous dose of 5, 10, or 20 mg torsemide or 40 mg furosemide. Torsemide produced dose-related decreases in body weight and increases in sodium and chloride excretion and urine volume. With the 20 mg dose of torsemide and the 40 mg dose of furosemide, body weight decreased significantly relative to baseline, and total and fractional 24-hour urinary excretion of sodium, chloride, and potassium and urine volume increased significantly. The 10 mg torsemide dose also produced a significant increase in urine volume. The results indicate that intravenous torsemide is effective for the acute treatment of sodium and fluid retention resulting from moderate to severe congestive heart failure.

Adult↗

PubMed1994

Patient perception of a long-term clinical trial: experience using a close-out questionnaire in the Studies of Left Ventricular Dysfunction (SOLVD) Trial. SOLVD Close-out Working Group.

A close-out questionnaire was distributed to the participants in a long-term heart failure trial, Studies of Left Ventricular Dysfunction (SOLVD). The respondents' primary motivation for enrollment, positive and negative experiences, and reported changes in habitual behavior was analyzed. Seventy-four percent (N = 3522) of the eligible patients responded to the survey. The most commonly cited reason for enrollment was recommendation by the primary physician. A wish "to contribute to medical science" and "to help others" was also a frequent incentive. A majority of the respondents were satisfied with participation and would be willing to participate in a future clinical trial. Most negative experiences included transportation to and from the clinic and frequent staff changes. A significant number of the patients reported changes in their smoking habits, alcohol intake, and diet despite the absence of behavioral interventions in the study protocol. There were minor differences between attitudes and perceptions of the male and female participants. No differences were found between patients who had previously participated in a clinical trial and those who had not.

Attitude↗

PubMed1994

Effects of treatment strategies to suppress ischemia in patients with coronary artery disease: 12-week results of the Asymptomatic Cardiac Ischemia Pilot (ACIP) study.

OBJECTIVES: The Asymptomatic Cardiac Ischemia Pilot (ACIP) study was initiated to determine the feasibility of a large trial in evaluating the effects of treatment of ischemia on outcome (mortality and myocardial infarction). The study was designed to examine the effects of medical treatment to control angina compared with treatment strategies guided by ambulatory electrocardiographic (ECG) ischemia or coronary anatomy. BACKGROUND: Treatments to suppress ischemia (asymptomatic and symptomatic) have not been evaluated in a large prospective, randomized trial. Before undertaking such a trial, issues about recruitment and treatment strategies must be addressed. METHODS: The 618 enrolled patients had coronary artery disease suitable for revascularization, ischemia on stress test and asymptomatic ischemia on ambulatory ECG. Patients were assigned randomly to one of three treatment strategies: 1) angina-guided medical strategy with titration of anti-ischemic medication to relieve angina (angina-guided strategy); 2) angina-guided plus ambulatory ECG ischemia-guided medical strategy with titration of anti-ischemic medication to eliminate both angina and ambulatory ECG ischemia (ischemia-guided strategy); and 3) revascularization by angioplasty or bypass surgery (revascularization strategy). RESULTS: Ambulatory ECG ischemia was no longer present at the week 12 visit in 39% of patients assigned to the angina-guided strategy, 41% of patients assigned to the ischemia-guided strategy and 55% of patients assigned to the revascularization strategy. All strategies reduced the median number of episodes and total duration of ST segment depression during follow-up ambulatory ECG monitoring. Revascularization was the most effective strategy. Treadmill test results were concordant with those of ambulatory ECG monitoring. For most patients in the two medical strategies, angina was controlled with low to moderate doses of anti-ischemic medication, and the majority of patients (65%) in the revascularization strategy did not require medication for angina. CONCLUSIONS: This pilot study demonstrated that cardiac ischemia can be suppressed in 40% to 55% of patients with either low or moderate doses of medication or revascularization and that a large trial is feasible.

Aged↗

PubMed1994

Rotational deformation of the canine left ventricle measured by magnetic resonance tagging: effects of catecholamines, ischaemia, and pacing.

OBJECTIVE: The aim was to investigate the generation of rotation of the left ventricular apex with respect to the base by magnetic resonance tagging, a non-invasive method of labelling the myocardium, in a canine model. METHODS: 18 dogs were imaged at baseline and during: (1) inotropic stimulation with dobutamine; (2) chronotropic stimulation with atrial pacing; (3) anterior wall ischaemia; (4) posterior wall ischaemia; and (5) varying left ventricular activation site; six dogs underwent each intervention. Apical rotation of the apex (torsion) was quantified. The epicardium and the endocardium were considered separately, as were the anterior and posterior walls. RESULTS: Mean torsion of the epicardium [anterior 3.1(SEM 1.2) degrees, posterior 9.9(1.0) degrees] was less than that of the endocardium [anterior 8.1(2.6) degrees, posterior 14.9(2.0) degrees, p < 0.05 for both]. Anterior torsion was less than posterior torsion for both the epicardium, p < 0.05, and the endocardium, p < 0.05. Dobutamine increased torsion of both the epicardium [anterior 13.3(2.2) degrees, posterior 12.6(1.7) degrees, p < 0.05 for both] and the endocardium [anterior 24.6(2.3) degrees, posterior 16.5(2.1) degrees, p < 0.05 for both]. Atrial pacing at 160% baseline rate increased torsion of both the anterior wall [epicardium 6.6(1.0) degrees, endocardium 11.3(1.2) degrees, p < 0.05] and the posterior wall [epicardium 13.0(1.3) degrees, endocardium 19.4(1.9) degrees, p < 0.05]. Anterior wall ischaemia reduced torsion of the anterior wall only [epicardium -2.0(1.0) degrees, endocardium 6.7(2.3) degrees, both p < 0.05]. Posterior wall ischaemia reduced torsion of the posterior wall of the epicardium only [7.1(1.2) degrees, p < 0.05] but also reduced torsion of the anterior wall [epicardium 0.7(1.0) degrees, endocardium 2.4(1.6) degrees, p < 0.05 for both]. Altering the pattern of left ventricular activation by atrioventricular pacing reduced torsion of the posterior wall of the epicardium [6.6(1.2) degrees, p < 0.05] and of the anterior [3.6(1.9) degrees, p < 0.05] and posterior [7.1(1.6) degrees, p < 0.05] walls of the endocardium. CONCLUSIONS: Rotational deformation of the left ventricle is dependent on the pattern of left ventricular activation and the contractile state. That a decrease in the contractile state in one area (by ischaemia) can cause a decrease in rotation in another suggests that this rotation depends on the complex fiber arrangement of the whole ventricle.

Animals↗

PubMed1994

Relation of regional cross-fiber shortening to wall thickening in the intact heart. Three-dimensional strain analysis by NMR tagging.

BACKGROUND: The mechanism by which small amounts of myofiber shortening lead to extensive wall thickening is unknown. When isolated fibers shorten, they thicken in the two orthogonal directions. In situ fibers, however, vary in their orientation through the wall, and each is tethered to near or distant neighbors, which allows shortening to occur both in the direction of the fibers and also perpendicular to them. This "cross-fiber" shortening may enable the wall to shorten in two directions and thereby thicken extensively in the third. METHODS AND RESULTS: Nuclear magnetic resonance tagging is a noninvasive method of labeling and tracking myocardium of the entire heart in three dimensions that does not interfere with myocardial motion. To investigate the presence and importance of cross-fiber shortening in the intact left ventricle, 10 closed-chest dogs were studied by nuclear magnetic resonance tagging. Five short-axis and four long-axis images were acquired to reconstruct 32 cubes of myocardium in each dog at end diastole and end systole. Pathological dissection was performed to determine the fiber direction at the epicardium, midwall, and endocardium of each cube. Strain was computed from the three-dimensional cube coordinates in the fiber and cross-fiber directions for epicardial and endocardial surfaces, and thickening of the full wall and its epicardial and endocardial halves was determined. Shear deformations were also calculated. Fiber strain at the epicardium and endocardium was -6.4 +/- 0.7% and -8.5 +/- 0.6% (mean +/- SEM), respectively (difference, P > .05). Cross-fiber strain at epicardium and endocardium was -0.6 +/- 0.5% and -25 +/- 0.6%, respectively (difference, P < .05). Thickening of the full wall reached 32.5 +/- 1.0%, composed of epicardial thickening of 25.5 +/- 0.6% and endocardial thickening of 43.3 +/- 1.0% (difference, P < .05). Fiber/cross-fiber shear strain was small (< 3%). Significant regional differences were present in all strains. A significant correlation was found between the extents of regional thickening and cross-fiber shortening. CONCLUSIONS: Cross-fiber shortening at the endocardium, therefore, far exceeds cross-fiber shortening at the epicardium and fiber shortening at both epicardium and endocardium. Since no active shortening can occur locally in the cross-fiber direction, the extensive endocardial cross-fiber shortening must result from interaction with differently aligned fibers at a distance. The correlation between regional thickening and cross-fiber shortening supports the hypothesis that this interaction is the mechanism for amplifying small amounts of fiber shortening to cause extensive endocardial thickening.

Animals↗