Subject(s)
Endocardial Cushion Defects/surgery , Heart Ventricles/abnormalities , Aortic Valve/abnormalities , Blood Pressure , Cardiac Output , Cardiac Volume , Feasibility Studies , Heart Ventricles/surgery , Humans , Mitral Valve/abnormalities , Treatment Outcome , Ventricular Dysfunction, Right/surgery , Ventricular Function, LeftABSTRACT
The warm-up phenomenon, described in patients with coronary artery disease, refers to the improved performance following a first exercise test. The aim of this study was to investigate the causes of the warm-up phenomenon. Fifteen patients with coronary artery disease and positive exercise test were enrolled. Patients were off treatment throughout the study. They underwent two consecutive treadmill exercise tests according to the Bruce protocol, with a recovery period of 10 min to re-establish baseline conditions. A third exercise test was then performed 2 h later. Before the onset of ischaemia, the rate-pressure product for a similar degree of workload was similar during the first and second exercise test, while it was lower during the third test (P < 0.05). Time to 1.5 mm ST-segment depression during the second and third exercise test was greater than during the first test (454 +/- 133 and 410 +/- 161 vs 354 +/- 127 s, P < 0.01, respectively). Similarly, the time to anginal pain onset was increased during the second and third exercise tests, compared to the first test (356 +/- 208 and 310 +/- 203 vs 257 +/- 204 s, P < 0.01, respectively). In contrast, rate-pressure product at 1.5 mm ST-segment depression during the second test was higher than that during the first test (232 +/- 47 vs 210 +/- 39 beats.min-1.mmHg.10(2), P < 0.01), while in the third test it was similar to that during the first (209 +/- 43 beats.min-1.mmHg.10(2), P = ns). The warm-up phenomenon observed a few minutes after exercise is characterized by an increase of both time to ischaemia and ischaemic threshold; this adaptation to ischaemia may be due to an improvement of myocardial perfusion or to preconditioning. Conversely, the warm-up phenomenon observed a few hours after repeated exercise is characterized by an increase of time to ischaemia but not of ischaemic threshold and is caused by a slower increase of cardiac workload. Thus, the mechanisms of the warm-up phenomenon may be different, time dependent and related to previous training.
Subject(s)
Angina Pectoris/physiopathology , Coronary Circulation , Exercise Test , Adaptation, Physiological/physiology , Aged , Analysis of Variance , Female , Hemodynamics/physiology , Humans , Male , Middle AgedABSTRACT
Percutaneous cardiopulmonary bypass has been introduced to support circulation in critical patients. In our preliminary experience we resuscitated two patients who sustained a prolonged cardiac arrest (52 min. and 31 min.) after coronary angiography and elective cardiac surgery, respectively. Cannulation was achieved percutaneously within 10 min. in both cases. Pump flow ranged from 2 to 31/m. Total support lasted from 52 min. to 180 min.. Both patients were successfully weaned. Patient 1 was declared brain dead and expired 17 days later. Patient 2 was discharged from the hospital and is doing well. Cannulation was attempted in a third patient after 30 min. of cardiac arrest. Despite surgical cut down of the femoral vessels, it was impossible to advance the arterial cannula because of bilateral occlusive disease. We conclude that PCPS is a powerful technique in selected patients to recover a stable cardiac function after prolonged cardiac arrest.
