Biomedical subjects

L F Hamm

Publications and source records attributed to L F Hamm.

7 recordsLinked to original sources

PubMed1989

Safety and characteristics of exercise testing early after acute myocardial infarction.

Five hundred and seventy physicians, researchers and clinicians (42% response) responded to a mailed questionnaire about the safety and nature of exercise testing conducted less than or equal to 4 weeks after acute myocardial infarction (AMI). Of 570 institutions, 193 reported that they routinely performed testing early after AMI and data were provided on 151,949 tests. A majority (111 or 58%) used a low-level testing protocol, 50 (26%) used symptom-limited testing and 32 (16%) used both types. Testing was routinely conducted less than or equal to 14 days after AMI by 147 (76%) respondents, whereas 46 (24%) tested 15 to 28 days after AMI. Thirty-three (17%) respondents used a standardized research protocol and 160 (83%) did not. There were 41 (0.03%) fatal, 141 (0.09%) major nonfatal and 2,124 (1.4%) other cardiac complications reported during testing. No difference in incidence of major complications was observed at centers using a clinical versus research protocol. Compared with clinic-based testing, hospital-based testing had an increased risk for all major (2.1) and nonfatal major complications (2.1). Although a symptom-limited protocol increased the overall risk for major cardiac complications by 1.9 times compared with a low-level protocol, the incidence of fatal complications during symptom-limited testing (0.03%) was quite low and this greater risk is of dubious clinical importance.

Electrocardiography↗

PubMed1988

Prognostic endpoint yield of high-level versus low-level graded exercise testing.

The prognostic endpoint yield (PEY) of a low-level (less than or equal to 4.6 METS) vs a high-level graded exercise test administered soon after myocardial infarction was evaluated with 184 patients. Test endpoints considered prognostically significant for future cardiac events were (1) ST segment depression greater than or equal to 1mm, (2) angina pectoris, and (3) complex ventricular beats. Test endpoints were assigned to both low-level and high-level tests if they occurred less than or equal to 4.6 METS; test endpoints greater than 4.6 METS were assigned to the high-level test only. Allowing the 145 patients who were asymptomatic during the low-level test to continue into the high-level protocol revealed a 2.5 times greater occurrence of angina pectoris (38 vs 15), a 3.4 times greater occurrence of ST segment depression (27 vs 8), and twice the occurrences of ventricular beats (4 vs 2). This substantial increase in prognostic endpoint yield was demonstrated in the presence of a significantly longer exercise time with the high-level test (9.0 vs 5.1 min), with no significant difference between protocols for peak heart rate or systolic blood pressure. Therefore, a high-level graded exercise test appears to increase the yield of test endpoints with known prognostic importance.

Angina Pectoris↗

PubMed1987

Graded exercise testing early after myocardial revascularization surgery.

The response to early graded exercise testing (GXT) was studied in 227 patients at a mean of 15.3 days after myocardial revascularization surgery (MRS). GXT followed a modified Bruce protocol without multiples of resting energy expenditure (MET) restrictions and a target heart rate (HR) of 90% of age-predicted maximal HR. The decision as to precisely when to administer the GXT after surgery was made on an individual case basis by the cardiovascular surgeon and the attending cardiologist. For the data analysis, patients were grouped according to the number of days the GXT was administered after surgery: group 1, 7 to 14 days (n = 164); group 2, 15 to 28 days (n = 46); and group 3, greater than 28 days (n = 17). The use of beta blockers was also determined on an individual case basis by the attending cardiologist rather than on a random basis. Ninety-seven of the 227 patients were on beta blockers. Ventricular ectopic activity (VEA), ST-segment changes (STTC), peak HR, peak systolic blood pressure (SBP), peak rate-pressure product (RPP), and peak METs were assessed during exercise. No major complications occurred during testing. Approximately two thirds (67.4%) of the tests were terminated voluntarily by the patient, and 22.5% were stopped by the attending physician. Only 10.1% of the subjects reached the target HR. Chi-square analysis failed to reveal any association between time of testing after surgery and either STTC or VEA. Analysis of variance failed to reveal any effects of group or beta blocker on peak METs attained during GXT; however, patients not using beta blocker medication attained higher peak HR, SBP, and RPP.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗

PubMed1986

Short- and long-term prognostic value of graded exercise testing soon after myocardial infarction.

We attempted to determine whether graded exercise testing (GXT) soon after a myocardial infarction (MI) using an unlimited metabolic equivalent (MET) level and target heart rate (HR) of 90% of the age-predicted maximal HR is a safe procedure and yields prognostic results different from tests that use lower level end points. We administered GXT to a random sample of 85 patients at a mean of 14.8 days post-MI. End points that included ST-segment depression (STD), angina pectoris (AP), ventricular ectopic activity, and achieved MET level during testing were evaluated as predictors of cardiac events that include death, recurrent nonfatal MI, and coronary artery bypass graft surgery. We conducted short-term follow-up monitoring for one year after the initial MI and long-term follow-up monitoring for a mean of 864.7 days. No serious complications occurred during testing. Angina pectoris, STD accompanied by AP, and achieved MET level were predictive (p less than .05) of future fatal and nonfatal cardiac events during the first year of follow-up monitoring. Fifty-nine percent of the patients with AP suffered a subsequent cardiac event within one year, whereas only 17% of those without AP experienced another cardiac event. Sixty-seven percent of the patients with both STD and AP had a subsequent cardiac event within one year, but only 22% of those without AP and STD had a subsequent cardiac event. For the long-term follow-up monitoring, the presence of AP and a low achieved MET level during testing were associated with subsequent cardiac events.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Exercise testing early after myocardial infarction: historic perspective and current uses.

Exercise testing performed earlier than six weeks post-MI is accepted as "standard" medical practice. Although both heart rate-limited and symptom-limited exercise protocols are used with nearly equal frequency, the latter appears more valuable because the prognostic yield is greater without sacrificing patient safety. Treadmill or cycle ergometers are the preferred modes of testing because of higher exercise work loads imposed and increased sensitivity and specificity of results. The physiologic exercise responses to graded work loads among these acute MI survivors include a mean maximal heart rate range of 118 to 136 beats/min, a peak systolic blood pressure between 137 and 170 mmHg, a mean peak double product from 16,000 to 22,400, and a mean maximal work load between 4.8 and 7.0 METS. Exercise findings which are most clinically useful are greater than 1 mm ST segment depression from rest level, presence of angina pectoris during exercise, decrease in systolic blood pressure with increasing work, presence of complex or frequent VEBs, and exercise tolerance less than 4 METS. These exercise findings identify, in recent post-MI survivors, groups of patients that have significantly different estimated future cardiac morbidity and mortality rates. The most consistent indices of multi-vessel coronary heart disease are ST segment depression, angina pectoris, and poor exercise tolerance. The most important role of stress testing in this period post-MI is identification of individuals who urgently need evaluation for coronary bypass surgery. In addition to risk stratification, exercise testing provides valuable information regarding exercise prescription for cardiac rehabilitation, direct psychologic benefit for resuming an active lifestyle, and motivation for exercise participation. Although safety of the early post-MI stress test has not been systematically studied, reports from individual studies indicated low morbidity and mortality. Attesting to this is the frequency with which it is performed as a routine office procedure. Finally, there has been a growing use of this procedure not only among cardiologists but also among internists and family practice physicians.

Angina Pectoris↗

PubMedDate not supplied

The Toronto Cardiac Rehabilitation and Secondary Prevention Program: 1968 into the new millennium.

Given our approach to the cardiac rehabilitation process, which is reflected in the program structure and services and our high patient volume, this program model is effective for us. The model permits us to treat relatively large number of patients with relatively small numbers of staff. On average, a patient attends 32 supervised exercise sessions at the Centre over the course of 12 months. This is actually fewer supervised sessions than the popular model of 3 times per week for 12 weeks. However, the 12-month program provides an additional 9 months to work with patients on heart-healthy lifestyle modifications. At the same time, we realize our model is not the model of choice for all people in all settings for a variety of reasons. We trust that some elements of our program may be of interest and beneficial to some readers. Undoubtedly, the program will continue to evolve and develop into the future. Currently, we are conducting a cardiac rehabilitation outcomes study in an effort to determine the appropriate duration of cardiac rehabilitation to achieve optimal physiological, psychological, and cost benefits for patients. This study involves more than 700 patients and the results are intended to help us further refine the program structure and selected program elements. As the new millennium approaches, healthcare system reforms and continuing changes in the delivery of medical care to cardiac patients present opportunities, challenges, and some uncertainties for cardiac rehabilitation. To continue our services to patients and the medical community, cardiac rehabilitation programs will need to identify and develop even more innovative and effective concepts in response to ever-changing local, regional, and national issues.

Coronary Disease↗

PubMedDate not supplied

Risk profile and health awareness in male offspring of parents with premature coronary heart disease.

BACKGROUND: The offspring of parents who suffer from premature coronary heart disease have a significantly higher risk of early cardiac death than controls. A genetic predisposition is compounded by a commonality of environmental risk factors within families. Increasing awareness, early detection and modification of risk factors are essential components of an effective public health strategy to protect this highly vulnerable population. METHODS: The sons (n = 571) of parents with premature coronary heart disease attended the Toronto Rehabilitation Centre for a risk factor evaluation that included an interview with questionnaire, measurement of body dimensions and blood lipids, and cardiopulmonary exercise testing. A follow-up questionnaire was sent out 2 years after the evaluation. RESULTS: Despite concern about family history, 23% of subjects were smokers and 75% were inactive. Objective data confirmed a substantial prevalence of cardiac risk factors: less than optimal cardiovascular fitness (48%), overweight (34%), total cholesterol > or = 200 mg/dL (46%), high-density lipoprotein cholesterol < or = 35 mg/dL (26%), low-density lipoprotein cholesterol > or = 160 mg/dL (16%), triglycerides > or = 200 mg/dL (27%), and lipoprotein (a) > 30 mg/dL (24%). Although almost all had a family physician whom they had seen an average of 1.8 times in the past year, and 4.7 times in the previous 3 years, screening and risk factor intervention strategies were disappointing. Two-year follow-up data showed a heightened health awareness, with a greater proportion of subjects exercising and attempting to maintain an appropriate body mass. CONCLUSIONS: The male offspring of parents who have suffered a premature coronary event exhibit a substantial prevalence of modifiable risk factors. The family physician can play an essential role in promoting a healthy lifestyle through risk reduction counselling and screening.

Adult↗