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Picture Quiz
Case history
A man aged 75 years had a myocardial infarction six months ago. He was admitted to hospital on this occasion complaining of breathlessness and a painful left leg and foot. His leg was not swollen but looked pale. His electrocardiogram was similar to the one performed when he attended his outpatient follow up appointment six weeks after his myocardial infarction.
Questions
- What does his chest x ray film show?
- What does the electrocardiogram show, and what is the cause of this?
- What is the most likely cause of the patient's painful leg?
- What other complications may he suffer?
Answers
- Cardiomegaly and pulmonary oedema. A cardiac monitoring lead is also seen with attachments. There is evidence of fluid in the right horizontal fissure and Kerley B lines at the bases. These are short horizontal white lines, which are the result of interalveolar oedema seen in the early stages of left ventricular failure. There is cardiomegaly if the cardiothoracic ratio is >0.5. It is not always possible to distinguish on a chest x ray film which chamber of the heart is enlarged. If the heart is boot shaped (not in this case), however, it is an indication of left ventricular enlargement, and enlargement of the left atrium gives a straight left heart border, and indeed the left heart border may be convex instead of concave. A large left atrium will also produce a double shadow on the right heart border as the right atrial border which lies behind the heart can also be seen as well as the right ventricular border. The left hilum is also elevated in left atrial enlargement as the left atrium pushes the hilum upwards.
- There is marked ST elevation in the anteroseptal leads (V1-V5). This has clearly persisted since the patient's anterior myocardial infarction six months previously and is most likely because of a left ventricular aneurysm. Left ventricular aneurysms cause persistent ST elevation on the electrocardiogram. If the changes were new then, the patient could have had a further myocardial infarction even though he does not complain of chest pain (silent infarction).
- His painful left leg is the result of a femoral arterial embolus from a thrombus in the left ventricular aneurysm. This causes a painful, pulseless, pale, and perishing cold leg as in this case. The leg does not swell. Conversely, a deep vein thrombosis produces a swollen, painful, and warm leg. An embolus in the femoral artery must be removed immediately, otherwise the leg will become gangrenous and amputation may be required. An embolectomy should be performed, and the patient needs to start taking anticoagulant drugs with heparin initially and then warfarin.
- Complications of left ventricular aneurysm are as follows.
- Left ventricular failure.
- Left ventricular arrhythmias--for example, ventricular tachycardia.
- Peripheral arterial emboli:
Cerebral embolus produces stroke
Femoral embolus, as in this case
Mesenteric embolus produces colicky abdominal pain and bloody diarrhoea owing to gangrenous bowel, which has to be resected immediately.
- Cardiac tamponade because of rupture of the aneurysm.
Discussion
A left ventricular aneurysm is more likely to occur after an anterior, rather than an inferior, myocardial infarction. A left ventricular thrombus forms in more than 50% of cases, and the patient needs lifelong anticoagulation treatment. The diagnosis is made when the aneurysm is clearly visible on two-dimensional, transthoracic echocardiography. However, intracardiac thrombi may not be seen clearly on transthoracic echocardiography, and transoesophageal echocardiography may be necessary, which is more specific for thrombi. The clinical implications of a left ventricular aneurysm have been listed above. Patients are usually managed with medication: anticoagulating drugs, antiarrhythmic drugs for ventricular arrhythmias, diuretics and angiotensin converting enzyme inhibitors for heart failure. In some patients who continue to deteriorate clinically despite medication an aneurysectomy may be necessary to improve cardiac function, but this is not without risk
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