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Cardiology Core Curriculum - part 2

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Tham khảo tài liệu 'cardiology core curriculum - part 2', y tế - sức khoẻ, y học thường thức phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Cardiology Core Curriculum Cardiac stress tests are designed to quantitate the cardiovascular responses to controlled incremental increases in metabolic demands using conventional protocols. Stress tests fall into two categories physical exercise and pharmacologic. Irrespective of the type of stress test protocol used the measurements routinely obtained include heart rate and blood pressure electrocardiograms at each incremental increase in workload and a continuous account of symptoms. Stress testing is frequently performed in combination with imaging techniques or various nuclear cardiac imaging techniques which allow additional measurements to be made during stress testing including ventricular contractile performance i.e. ejection fraction regional left ventricular wall motion and myocardial perfusion and metabolism . Exercise stress tests Exercise stress tests are conducted either on a treadmill or a bicycle ergometer. Exercise is begun at a low workload that the patient can easily sustain. The workload is then increased in increments at regular intervals predefined by the exercise protocol until the patient achieves the maximum exercise workload of the protocol achieves 85 of their predicted heart rate for age and sex achieves his or her anaerobic threshold develops typical symptoms with electrocardiographic evidence of ischemia becomes hypotensive or develops ventricular dysrhythmias. All of these are reasons to terminate any and every stress test whether exercise or pharmacologic. Pharmacologic stress tests Pharmacologic stress tests are used in patients who cannot engage in physical exercise for various reasons. They are conducted by administering a drug that either increases myocardial workload dobutamine or vasodilates the coronary microvasculature dipyridamole or adenosine . Abnormal findings Abnormal findings during stress that reflect impaired performance of the coronary circulation and the myocardium are as follows. 52 Cardiac non-invasive imaging .