|Home | About | Journals | Submit | Contact Us | Français|
Acute total occlusion of the left main stem (LMS) is a rare cause of myocardial infarction but carries a high risk of morbidity and mortality including presentation as sudden death. We describe the case of a 68-year-old woman who presented acutely with chest pain and ST segment elevation in lead aVR on her ECG suggestive of possible LMS occlusion. Emergency coronary angiography confirmed acute total LMS occlusion as well as an anomalous dominant right coronary artery. The patient underwent emergency percutaneous coronary intervention of the LMS with a good angiographic result and resolution of her symptoms. The patient was treated for acute left ventricular failure but made a gradual recovery and was discharged home 7 days after admission.
Acute total occlusion of the left main stem (LMS) is known to be a catastrophic event which usually manifests as sudden cardiac death and/or acute myocardial infarction. It is therefore important to be aware of this possibility when assessing any patient with chest pain and the classical ECG changes of ST elevation in lead aVR and ST depression elsewhere, as these patients benefit from urgent coronary angiography and revascularisation. We therefore feel it is important for readers to be reminded of this important ECG finding.
A 68-year-old woman was admitted to her local emergency department with central chest pain radiating to both shoulders. The initial 12-lead ECG showed ST segment depression in the lateral leads and she was commenced on standard therapy for an acute coronary syndrome. She continued to have chest pain and serials ECGs progressed to show ST segment elevation in lead aVR with global depression in all other leads (figure 1). She then sustained a ventricular fibrillation (VF) arrest from which she was successfully resuscitated with a single DC shock following which she was urgently transferred to our centre for emergency coronary angiography.
On arrival at our centre she was haemodynamically stable but still had ongoing chest pain with persistent ECG changes. She therefore underwent urgent coronary angiography which showed acute total occlusion of the distal LMS with no anterograde flow (figure 2). The right coronary artery (RCA) was seen to have an anomalous origin from the left coronary sinus (figure 3) and appeared a dominant vessel and unobstructed thus explaining why the patient was haemodynamically stable.
Given the patient's ongoing symptoms we proceeded to emergency percutaneous coronary intervention to the distal LMS occlusion. This was successfully performed with two drug eluting stents deployed from the distal LMS into the left anterior descending artery (LAD) and also the circumflex artery with adjuvant pharmacological therapy with abciximab. Follow-up angiography a week later showed a good result with a patent left coronary system (figure 4).
The patient was pain-free post procedure but required treatment for acute left ventricular failure but did not require invasive ventilation. A transthoracic echocardiogram showed significant regional wall motion abnormalities in the LAD territory and overall moderately impaired left ventricular systolic function.
She was commenced on secondary prevention medications as well as therapy for her heart failure and made a gradual recovery. She was discharged home 7 days after her admission and will be followed up in the cardiology and heart failure clinics and will be considered for a primary prevention implantable defibrillator in the future.
Acute total occlusion of the LMS usually manifests as sudden cardiac death and/or haemodynamically compromised acute myocardial infarction. The rare patients who survive to be admitted to hospital and undergo coronary angiography are likely to have an unobstructed dominant RCA, as demonstrated in our case.
Since the introduction of percutaneous coronary intervention, acute total LMS occlusion can now be treated quickly and safely and is a life-saving intervention particularly when delay to coronary bypass surgery is not possible due to haemodynamic compromise.1 2
The ECG in this case (figure 1) is classical of LMS occlusion and we had anticipated the angiographic finding based on the ECG alone. This ECG pattern can be very useful in detecting patients who may have such high risk coronary anatomy. The combination of ST segment elevation in lead aVR and widespread depression in the other leads during chest pain is highly suggestive of significant disease involving the LMS or severe three vessel coronary artery disease.3 4 Patients presenting to the emergency department with chest pain and this ECG pattern should prompt urgent discussion with the local interventional cardiology service as these patients benefit from urgent coronary angiography and revascularisation.
Competing interests None.
Patient consent Obtained.