For each of the clinical scenarios A–E, select the most appropriate option from the cardiovascular parameters listed below.
| |
Heart rate (per min) |
Stroke volume (ml) |
Pulse pressure (mmHg) |
| 1 |
60 |
80 |
40 |
| 2 |
120 |
35 |
20 |
| 3 |
180 |
110 |
110 |
| 4 |
40 |
140 |
50 |
| 5 |
100 |
70 |
70 |
| 6 |
240 |
15 |
15 |
- A 30-year-old man has been admitted to hospital for minor elective surgery. He is a long-distance runner of national standard. His cardiac shadow is enlarged on chest Xray and there is concern about his very slow pulse.
- A 50-year-old woman has been admitted to hospital for thyroid surgery and is found to have signs of severe uncontrolled hyperthyroidism. Her peripheries are warm and moist and her pulse is rapid and bounding.
- A 40-year-old woman trains regularly for physical fitness but has been concerned recently about chest discomfort, fearing coronary artery disease. She undertakes cardiological assessment during progressive exercise on a treadmill and the results correspon
- A 40-year-old woman reports recent episodes of threatened loss of consciousness during exercise and such an episode occurs during treadmill testing in hospital.
- A 70-year-old man has been admitted to hospital after he collapsed at home and found he could not sit up without feeling he was about to faint. He suffers from epigastric pain treated by a proton pump inhibitor and has recently noticed his bowel motions a
Medicine
A. Option 4 These results are typical of a high level athlete – a normal resting cardiac output of 5.6 litres per minute with a very slow pulse rate compensating for a huge resting stroke volume. Such people have relatively large powerful hearts which contrast dramatically with the large weak hearts of patients with cardiac failure, some of whom may suffer from a pathologically slow heart rate which exacerbates their condition.
B. Option 5 Hyperthyroidism leads to a hyperdynamic circulation at rest – rapid strong pulse associated with a high pulse pressure and an increased cardiac output (7 litres per minute in her case). This is required for the increased metabolic rate due to the overactive thyroid. The increased metabolic rate also generates excess heat, hence the sweating.
C. Option 3 This woman is typical of patients with chest pain not due to coronary artery disease. In association with regular training she is very fit and can exercise to the maximal level used in the treadmill cardiac stress test. At this stage she shows typical findings of a cardiac output of about 20 litres per minute and arterial blood pressure 180/70 (high systolic due to powerful ejection by the left ventricle and rapidly falling pressure due to very low peripheral resistance). She has achieved the maximal predicted heart rate (220 minus age in years).
D. Option 6 Syncope or pre-syncope during exercise can be due to an abnormal ineffective rapid cardiac rhythm (tachycardia). As with the previous case the maximal expected rate is 180 and a rate of 240 does not allow adequate filling for a useful stroke volume. Such a low cardiac output (3.6 litres per minute) would lead to loss of consciousness during mild to moderate exercise.
E. Option 2 This patient gives a history suggesting peptic ulcer treated by a drug which raises gastric pH to relieve the pain. The history is strongly suggestive of chronic loss of blood in the faeces (melaena). With an arterial blood pressure of 80/60 he cannot sustain adequate cerebral blood flow in the upright posture. This is because of the reduced venous return experienced by everyone in the upright position. Raising the foot of the bed maximizes venous return. He is suffering from peripheral circulatory failure due to severe blood loss and blood transfusion is urgently indicated.
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