Video Didactic Preparation Augments Problem-Based Learning for First Year Medical Students.

Problem-based learning (PBL) utilizes a self-directed strategy. This process relies on group participation to succeed. Students without a background in biology or medicine can feel overwhelmed by the complexity of the subject matter and unable to participate in the group learning process.

Lung function and pulmonary regurgitation limit exercise capacity in postoperative tetralogy of Fallot.

Fifty-five patients with repair of tetralogy of Fallot were evaluated with treadmill exercise, pulmonary function testing and rest two-dimensional and Doppler echocardiography to determine the relation among cardiopulmonary function, exercise capacity and ventricular arrhythmias. The mean age at repair was 8.1 +/- 2.

Long-term results of total repair of tetralogy of Fallot in childhood.

Between 1958 and 1977, 170 children aged 10 years or less underwent total repair of tetralogy of Fallot at The Johns Hopkins Hospital. Follow-up data were obtained on 128 (90%) of the 143 who survived the operation at 10 to 28 years postoperatively (mean follow-up, 18 years). All patients completed an extensive questionnaire, and 59 returned for a thorough evaluation consisting of a history and physical examination, electrocardiogram, 24-hour Holter monitoring, exercise stress testing, pulmonary function testing, and two-dimensional and Doppler echocardiography.

The effective treatment of postpericardiotomy syndrome after cardiac operations. A randomized placebo-controlled trial.

Although the postpericardiotomy syndrome is a common complication of cardiac operations, the most effective drug regimen for the treatment of this condition has not been established. The present study was designed to evaluate the effectiveness of nonsteroidal antiinflammatory drugs (NSAIDs) in the treatment of postpericardiotomy syndrome, in a double-blind, placebo-controlled randomized trial with a 10-day course of ibuprofen or indomethacin. Of 1019 adult patients undergoing cardiac operations during a 14-month period, a diagnosis of postpericardiotomy syndrome was made in 187, and 149 were enrolled in the study.

The epidemiology of the postpericardiotomy syndrome: a common complication of cardiac surgery.

PPS is a major cause of morbidity after cardiac surgery and may cause bypass graft closure and fatal cardiac tamponade. Little is known about its incidence and cause. To better define this syndrome characterized by postoperative fever, pericardial friction rub, and pericardial pain, we used two out of three of the preceding criteria to diagnose PPS.

Long-term valvular function after total repair of tetralogy of Fallot. Relation to ventricular arrhythmias.

Patients with total repair of tetralogy of Fallot may have residual valvular dysfunction, the long-term effect of which is poorly defined. We prospectively studied 59 patients for 18 +/- 5 (mean +/- SD) years postoperatively by Doppler echocardiography and by 24-hour electrocardiographic monitoring. Right ventricular outflow gradients were estimated from the peak continuous-wave Doppler pulmonary artery velocity.

The long-term success of skeletal muscle in aortic repair.

To determine the efficacy of skeletal muscle for aortic repair, 23 swine underwent repair of descending thoracic aortic defects. In one group, a vascularized muscle flap was used to patch a 2- to 3-cm aortic defect. In two other groups, a short segment of aorta was removed and a 2-cm tube graft of freshly harvested but devascularized skeletal muscle or Vicryl mesh was used to repair the aorta.

The rapid evolution of a myocardial infarction in an end-artery coronary preparation.

The potential for salvaging infarcting myocardium depends on the time course of the infarction process. To determine the rate of infarct evolution in an end-artery coronary preparation similar to the coronary arterial system of the human heart, each of 84 swine underwent a reversible occlusion of the left anterior descending coronary artery for varying lengths of time, after which flow was reestablished into the occluded region for either 2 or 48 hr. Infarct size was assessed by nitro blue tetrazolium (NBT) staining and confirmed by histologic examination in the 48 hr animals.

The effects of age on outcome after coronary bypass surgery.

To study the effects of increasing age on outcome after coronary artery bypass grafting (CABG), 684 patients who underwent CABG from 1980 to 1985 were entered into a noncurrent prospective study. Patients were matched by date of operation and placed into three groups according to age: (1) 70 and older, (2) 55 to 69, or (3) less than 55. In addition to intraoperative and postoperative data collected on all patients, follow-up was obtained on 97% of the patients at a mean of 30 +/- 16 months.

Free radical scavengers improve functional recovery of stunned myocardium in a model of surgical coronary revascularization.

This study examined whether treatment with the oxygen free radical scavengers, superoxide dismutase and catalase, could improve functional recovery in hearts subjected to regional ischemia and global cardioplegic arrest. Regional left ventricular (LV) function was assessed in open chest pigs with sonomicrometry and micromanometry to calculate an index of regional work from the LV pressure-segment length relationship. After measuring baseline preischemic function, the left anterior descending artery was occluded, creating a region-at-risk in 20% of the LV mass.

Retrograde coronary sinus perfusion prevents infarct extension during intraoperative global ischemic arrest.

To determine whether continuous infusion of cardioplegia retrograde through the coronary sinus could improve the salvage of infarcting myocardium, 54 pigs were utilized in a region at risk model. All hearts underwent 30 minutes of reversible coronary artery occlusion, and were divided into six groups. Group 1 served as controls and underwent two hours of coronary reflow without global ischemic arrest.

Anatomic and anesthetic considerations in experimental cardiopulmonary surgery in swine.

We have used immature commercial swine (13-25 kg) successfully in a variety of experimental cardiopulmonary surgical procedures in our laboratories since 1981. Multiple drug anesthetic protocols using barbiturates, narcotics, paralytic and antiarrhythmic agents have been employed in over 400 procedures per year. Complications, including fatal cardiac arrhythmias, have been greatly reduced by anesthetic protocols and surgical procedures developed through experience.

Major stroke after coronary artery bypass surgery: changing magnitude of the problem.

Between January 1974 and December 1984, 3816 patients underwent isolated CABG at this hospital. During this 11-year interval, the number of patients having operation annually as well as the mean age at operation of the patients have increased significantly. The increase in the mean age from 51.

Stroke following coronary artery bypass grafting: a ten-year study.

To identify possible risk factors for the occurrence of stroke during coronary artery bypass grafting (CABG), the cases of 3,279 consecutive patients having isolated CABG from 1974 to 1983 were reviewed. During this period, the risk of death fell from 3.9% to 2.

Reperfusion before global ischemic arrest improves the salvage of infarcting myocardium.

To study the effect of hypothermic global ischemic arrest on an evolving myocardial infarction and of perfusion of the ischemic zone or region at risk before global ischemia, 62 farm pigs underwent 15, 30, or 60 minutes of reversible coronary occlusion. Twenty-eight of these animals served as controls: reflow to the region at risk was established by removal of the coronary occluder without the addition of global ischemia. Another 26 animals had similar periods of coronary occlusion and then were placed on cardiopulmonary bypass; they underwent aortic cross-clamping and cardioplegia-induced global hypothermic arrest for 45 minutes.

The use of muscle flaps in the repair of aortic defects.

The successful repair of an infected arterial anastomosis is often hampered by the need to leave prosthetic material at the site of infection. To determine whether an aortic defect could be repaired by direct closure with a muscle flap, thereby eliminating the need for prosthetic material, we subjected 33 young pigs weighing 17 to 19 kg to a left lateral thoracotomy under sterile conditions. An aortic defect 2 cm in diameter was created in the descending thoracic aorta just distal to the origin of the left subclavian artery.

Coronary artery bypass grafting in women. A ten-year perspective.

Between January 1974 and December 1983, 3279 patients have undergone isolated coronary artery bypass (CAB) grafting at the Johns Hopkins Hospital. There were 639 women in this group. Women represented 18 to 22% of the patients having isolated CAB grafting throughout the 10-year period, except in 1976 when only 13% of the CAB patients were women.

A method to study in vitro proliferation of lymphocytes from individual mice on repeated occasions.

A micro-method was developed that allowed the proliferation of blood lymphocytes from individual mice incubated with phytohemagglutinin to be measured on repeated occasions. Lymphocytes were isolated from 0.4 ml of heparinized blood by centrifugation through a Ficoll-Hypaque solution.