EKG

Fibrinolytic Therapy for STEMI

Case

You are on a swing shift at a remote, island-based community hospital when a 58 year-old male presents with sudden onset chest pain. The pain started at rest, radiates to his jaw, and is associated with diaphoresis and nausea. He has a history of coronary artery disease (CAD), and during his last cardiac catheterization in 2008, a stent was placed in his proximal left anterior descending coronary artery. His past medical history is also significant for diabetes, chronic obstructive pulmonary disease, hyperlipidemia, and hypertension.  He is an active smoker.

On exam, he is not only diaphoretic and clenching his chest, but also describes the pain as “an elephant sitting on my chest.” Initial vital signs are P 110, BP 175/100, RR 20, PO2 98% on RA, T 98.9 F. You give him aspirin 324 mg and nitroglycerin sublingual 0.4 mg, and his chest pain improves from a 10/10 to 8/10. His initial electrocardiogram (EKG) is below.

Figure 1: The patient’s presenting EKG.

Figure 1: The patient’s presenting EKG.

DIAGNOSIS

ST elevation myocardial infarction (STEMI)

Management Options

You call the critical care transport ambulance, as well as the nearest cardiac catheterization team to alert them of your patient.   Unfortunately, it is a stormy evening in the middle of winter and all bridges off the island are closed; helicopters are grounded due to the storm.  There are no transfer options available to your patient at this time. What else can you do?

Indications for Fibrinolytic Therapy

According to the American Heart Association, there are several considerations when it comes to fibrinolytic therapy in myocardial infarction:

Class I recommendations:

  1. STEMI

  2. Symptom onset in the last 12 hours

  3. Percutaneous Cardiac Intervention (PCI) cannot be performed within 120 minutes of arrival to the Emergency Department

  4. Absence of any contraindications (see below)

Class II recommendations:

  1. Evidence of ongoing ischemia 12-24 hours after symptom onset

  2. Large area of myocardium affected

  3. Hemodynamic instability

Absolute contraindications:

  1. Any prior intracranial hemorrhage

  2. Known structural cerebral vascular lesion

  3. Ischemic stroke <3 months

  4. Suspected aortic dissection

  5. Known intracranial malignancy

  6. Active bleeding or bleeding diathesis

  7. Significant closed head trauma <3 months

  8. Intracranial/intraspinal surgery <2 months

  9. Severe uncontrolled HTN (>175/110)

  10. Oral anticoagulants

Relative contraindications:

  1. Significant HTN on arrival (pressure > 180 mmHg)

  2. Ischemic stroke >3 months

  3. Dementia

  4. Other intracranial pathology

  5. Traumatic CPR >10 min

  6. Major surgery <3 weeks

  7. Internal bleeding <3 weeks

  8. Non-compressible vascular punctures

  9. Pregnancy

  10. Active peptic ulcer disease

PCI versus Systemic Fibrinolytic Therapy

If you are able to transfer the patient to a hospital with PCI capability within 1 hour of presentation or they have contraindications to fibrinolytic therapy, it is recommended that you transfer the patient as soon as possible. Otherwise, the goal is fibrinolytic infusion within 30 minutes of arrival to the ER. In either case, concurrently initiate maximal medical management including full-dose aspirin, Plavix or Brilinta, and anticoagulation (unfractionated heparin or lovenox). Tenecteplase is generally the preferred fibrin-specific agent, given its ease of use and lower rates of non-cerebral bleeding compared to other agents.

Reassess After Fibrinolysis

If your patient has resolution of chest pain and >70% reduction of ST elevation, or ST elevation resolves within 60-90 minutes, you have likely restored flow. If you see <50% decrease in STE and no reperfusion arrhythmias (see below) at 2 hours after fibrinolytic dosing, you have partially improved flow but not completely restored it.

Criteria for Transfer after fibrinolytic therapy

  1. Immediate transfer: acute heart failure or cardiogenic shock

  2. Urgent transfer: failed reperfusion or reocclusion

  3. 3-24 hours: hemodynamically stable, successful reperfusion

Reperfusion Arrhythmias 

You plan for ICU admission because you are unable to transfer the patient to a PCI center when the nurse hands you the following EKG:

Figure 2: Accelerated idioventricular rhythm.

Figure 2: Accelerated idioventricular rhythm.

This is an example of accelerated idioventricular rhythm. This is a normal sign of reperfusion after STEMI and does not require treatment.   In fact, such a rhythm is generally viewed as a positive response to fibrinolytic therapy as indicates reperfusion. 

Criteria:

  1. Regular rhythm

  2. Rate 50-110bpm (slower is ventricular escape, faster is VT)

  3. Three or more ventricular complexes

  4. Fusion (F) and capture (C) beats (see below)

Figure 3: Fusion and capture beats after successful reperfusion.

Figure 3: Fusion and capture beats after successful reperfusion.

General goals of care after fibrinolytic therapy should be to transfer for diagnostic angiography and percutaneous coronary evaluation which is promptly accomplished for your patient the following day after the storm resolves.


Faculty reviewer: Dr. Kristina McAteer


References

  1. O'Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: executive summary: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation 2013; 127:529.

  2. O'Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation 2013; 127:e362.

  3. White HD. Thrombolytic therapy in the elderly. Lancet 2000; 356:2028.

  4. Armstrong PW, Gershlick AH, Goldstein P, et al. Fibrinolysis or primary PCI in ST-segment elevation myocardial infarction. N Engl J Med 2013; 368:1379.

  5. Effectiveness of intravenous thrombolytic treatment in acute myocardial infarction. Gruppo Italiano per lo Studio della Streptochinasi nell'Infarto Miocardico (GISSI). Lancet 1986; 1:397.

  6. Randomised trial of intravenous streptokinase, oral aspirin, both, or neither among 17,187 cases of suspected acute myocardial infarction: ISIS-2. ISIS-2 (Second International Study of Infarct Survival) Collaborative Group. Lancet 1988; 2:349.
    Indications for fibrinolytic therapy in suspected acute myocardial infarction: collaborative overview of early mortality and major morbidity results from all randomised trials of more than 1000 patients. Fibrinolytic Therapy Trialists' (FTT) Collaborative Group. Lancet 1994; 343:311.

  7. Labinaz M, Sketch MH Jr, Ellis SG, et al. Outcome of acute ST-segment elevation myocardial infarction in patients with prior coronary artery bypass surgery receiving thrombolytic therapy. Am Heart J 2001; 141:469.

  8. Peterson LR, Chandra NC, French WJ, et al. Reperfusion therapy in patients with acute myocardial infarction and prior coronary artery bypass graft surgery (National Registry of Myocardial Infarction-2). Am J Cardiol 1999; 84:1287.

  9. Karnash SL, Granger CB, White HD, et al. Treating menstruating women with thrombolytic therapy: insights from the global utilization of streptokinase and tissue plasminogen activator for occluded coronary arteries (GUSTO-I) trial. J Am Coll Cardiol 1995; 26:1651.

  10. Woodfield SL, Lundergan CF, Reiner JS, et al. Angiographic findings and outcome in diabetic patients treated with thrombolytic therapy for acute myocardial infarction: the GUSTO-I experience. J Am Coll Cardiol 1996; 28:1661.

  11. Mak KH, Moliterno DJ, Granger CB, et al. Influence of diabetes mellitus on clinical outcome in the thrombolytic era of acute myocardial infarction. GUSTO-I Investigators. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries. J Am Coll Cardiol 1997; 30:171.