You have recently begun your daytime shift at the emergency department in Canadian Janus General Hospital. You are seeing a patient when you receive a call on your companion phone from an ECG technician to urgently read an ECG on a gentleman with chest pain at triage. Before you even get to triage, the tech meets you along the way and she hands you this ECG:
More specifically, the patient is in normal sinus rhythm at a rate of 60 bpm, with a normal axis and normal PR and QT intervals. The QRS complexes are narrow. You appreciate the obvious impressive down sloping ST segment depressions in multiple leads, including II, III, aVF and V3-V6. Furthermore, you suspect a hint of ST elevation in V1 and possibly aVR. The T wave in V1 is upright (often inverted in V1), which in this setting is also highly associated with ischemia. Findings of ST segment down sloping and ST depression >2mm (substantial) and >2 leads (widespread) are associated with poor prognosis and extensive coronary disease.
You quickly go see the patient, and find a man in his 50’s, who is laying supine and appears unwell. He is talking to his wife and he is still connected to the ECG machine. Suddenly, the patient loses consciousness and you look at the ECG reading while checking his pulse and you see this (as the tech, by your side, hits the print button):
More specifically, the ECG shows ventricular fibrillation.
You immediately start chest compressions and call for a code blue. The stretcher is quickly mobilized from the triage area and you climb on, continuing compressions as your nurses wheel you both to a resuscitation room. The patient stiffens up beneath your hands and turns bluer and bluer. Once you arrive in the room, defibrillation pads are placed on the patient’s chest and someone else takes over compressions. In the meantime, you charge the biphasic defibrillator to 120 joules in case the patient is still in VF. Compressions are paused momentarily while you perform a rhythm & pulse check.
Pulse – none
Rhythm on the monitor – ventricular fibrillation
You immediately shock the patient and quickly resume CPR. Before 30 seconds pass, the patient begins to stir and move his limbs. Compressions stop and the patient has a pulse back. He is alert, coherent and able to tell you the following:
Name, date, place
PHx – smoking, HTN
Meds – ramipril
His chest pain started last night and abated, but recurred since early in the morning. He describes it as retrosternal pressure radiating to his shoulders bilaterally, worse on exertion. He was in a town nearby (2 hours away!) and decided to drive to your hospital. He still has chest pain now and looks unwell. You repeat the ECG. Your newest post-arrest ECG shows the following:
Interpretation: STILL SCARY
More specifically, you have an ST-elevation MI, with anterior leads V2-V3 showing significant ST segment elevation, as well as leads I and aVL. There is still ST depression in the inferior leads and V4-V6. The findings of ST elevation in precordial leads as well as I and aVL (high lateral leads) is highly associated (87%) with proximal LAD occlusion.
You give the patient ASA immediately and the cath lab at a nearby facility is contacted. He receives 60 mg of prasugrel and a 60 unit/kg IV blus of heparin and is sent to the receiving hospital with advanced paramedics and a fellow physician. Fortunately, the patient has no more episodes of malignant arrhythmias and he arrives to the cath lab in good condition. His procedure reveals a 99% occlusion of the proximal LAD, which is stented open. His troponin peaks at 54 (normal <0.12). Three days later, his ECG is as follows:
Interpretation: NSR around 55 bpm. The now evolved MI demonstrates poor R-wave progression and T-wave inversion in the precordial and lateral leads. ST depressions (and elevations) have disappeared.
Fortunately this gentleman had an excellent outcome. Had he presented to hospital 5 minutes later there would have been an out-of-hospital arrest, which would have let to delayed CPR and defibrillation.
Channer K and Morris F. ABC of clinical electrocardiography: Myocardial ischaemia. BMJ. Apr 27, 2002; 324(7344): 1023–1026.
Life in the Fast Lane – T waves on ECG:
Life in the Fast Lane – Lateral STEMI on ECG:
For more on ECG’s, please check out my two favourite ECG websites:
Amal Mattu’s EKG of the week video series: http://ekgumem.tumblr.com/
Dr Stephen Smith’s ECG blog: http://hqmeded-ecg.blogspot.ca/