Medical History Ms. RW is a 58-yr. old woman with no prior history of heart dise
ID: 121868 • Letter: M
Question
Medical History
Ms. RW is a 58-yr. old woman with no prior history of heart disease. She has hypertension under good control with medications and was diagnosed with diabetes 15 yr. ago. Her last fasting blood glucose was 234 mg/dl, and her HbA1c was 8.7%. She is a former smoker (quit 10 years ago) and leads a rather sedentary lifestyle as a computer analyst for a large local firm. Over the past 3 months she has started to notice increased shortness of breath when climbing two flights of stairs at work; at the top of the stairs, she feels some moderate chest pressure that resolves in a couple of minutes after she sits down at her desk. Her primary care physician sends her for a routine exercise stress test. Exercise Test Results: She exercises on a standard Bruce protocol. At 4:30 min there is some horizontal ST depression, about 1 mm in inferior and lateral leads; by peak exercise (5:20) it is about 2 mm downsloping in the same leads, and she is developing chest pressure she described in her symptom history. ECG changes resolve by 10 min of recovery, and symptoms resolve in about 5 minutes of recovery. Resting ECG: Appears normal Heart rate: 65 bpm Blood pressure: 138/92 mmHg Heart and lung sounds: within normal limits Diagnosis: Severe two-vessel CAD. Stenting was performed to 95% occluded proximal left anterior descending coronary artery lesion. Ms. RW’s 75% occluded distal left circumflex lesion was not a candidate for revascularization at the time of the procedure. Medications: Metoprolol (beta-blocker) 50 mg twice daily; linsinopril (ACEi) 10 mg once daily, asprin, plavix (anti-platelet), and simvistatin.
1) As she hits a plateau in her ability to increase her intensity of aerobic exercise that is not due to further complications with her heart, what issues may be limiting her ability to increase her exercise intensity?
Explanation / Answer
Plateau is the VO2max which is the maximum rate of oxygen consumption attainable during maximal or exhaustive exercise. It is an indicator of cardio-respiratory endurance. Bruce protocol in fact tests the VO2max and as she described the events occured as she took that test at 4:30 min there was some horizontal ST depression, about 1 mm in inferior and lateral leads; by peak exercise (5:20) about 2 mm downsloping in the same leads, and she developed chest pressure. So it is VO2max.