Tuesday ConferenceTuesday Conference

Myocardial InfarctionDiagnosis and management

ObjectivesObjectives• Define the major types of myocardial

infarction (MI). • Describe the mechanisms leading to

ischemia or necrosis of myocardial cells.• List the major risk factors for acute MI

(AMI).• Identify the common and uncommon signs

and symptoms in AMIs.

ObjectivesObjectives• Outline the initial diagnostic tests and

therapies, and understand their importance. • Discuss reperfusion techniques and their

complexities and benefits. • Describe the long-term benefits of various

medications. • List other advantageous secondary

prevention therapies and their limitations.

Case 1Case 1

• A 48-year-old white man is brought to your office by his wife, complaining of heartburn that has been bothering him off and on for the last several days. As they were driving in, his pain became much worse than any he’d had before.

Case 1Case 1• He said the pain was squeezing his chest so

badly that he couldn’t breathe and felt like he would throw up.

• He has not been a patient of yours, so you have no past history. He does admit to being under a lot of stress and smokes several packs of cigarettes per day.

Case 1Case 1

• His initial evaluation including vital signs is as follows: blood pressure 160/100, pulse 88, weight and height not done. He is mildly obese and looks very uncomfortable. He is not taking any medicines and has no other complaints.

MCQ 1MCQ 1• What is the next most important evaluation to

determine the cause of this man’s symptoms?

• Full history and physical examination• Blood tests for CK-MB fraction and troponin I• Echocardiogram• Electrocardiogram (ECG)• Complete blood cell count and chemistry and lipid

profiles

MCQ 2MCQ 2• If the ECG shows ST elevation in leads V1-V3 and the patient’s chest

pressure continues, all but one of the following is important in his immediate care:

• Sublingual nitroglycerin (NTG), 0.4 mg every 5 minutes x 3, if he has not used an erectile dysfunction medication in the last 24 hours

• Non-enteric coated aspirin 162 mg, chewed if he is not allergic to aspirin

• Arrange for the patient’s wife to drive him to the ER immediately

• Short acting beta-blocker if no contraindications

• Supplemental oxygen

MCQ 3MCQ 3• If the patient continues to have pain along with the ECG

changes already noted, which of the following would exclude him from consideration for reperfusion therapy?

• More than 60 minutes from the onset of his pain to ER arrival

• Evidence of dissecting aortic aneurysm

• No cardiologist available

• No catheterization facility with qualified personnel within 30 miles

• A dose of unfractionated heparin on arrival in the ER

MCQ 3MCQ 3• Which of the following statements is incorrect concerning fibrinolytic

therapy?

• The plasminogen activators as a class show restoration of coronary blood flow in 50% to 80% of MI patients compared to over 90% in PCI procedures

• Streptokinase has potential for an allergic response and is less expensive than other fibrinolytics

• Both unfractionated heparin and LMWH are often used with fibrinolytics

• Compared to thrombolytics, PCI has a better long term survival rates

CASE 1 (Part 2)CASE 1 (Part 2)• Our 48-year-old gentleman has now been

hospitalized for 3 days, has undergone coronary artery stenting, and is anxious to get home and back to work. He had minimal myocardial damage due to early intervention.

• His tests came back showing the following: cholesterol = 200, high-density lipoprotein cholesterol = 30, low-density lipoprotein (LDL) cholesterol = 150, glucose = 120.

MCQ 4MCQ 4• According to recent Guidelines which LDL level requires

statins for patients presenting with a Myocardial infarction?

• LDL 130• LDL 100• LDL 70• Every patient with Myocardial infarction should be treated

with a statin regardless of LDL level

Case 1 (Part 2)Case 1 (Part 2)

• The rest of his chemistry profile and CBC were normal. The ECG showed normalization of the ST segments with no obvious Q-wave abnormalities. His chest x-ray was within normal limits. His blood pressure is now 120/76, with pulse rate of 64. His weight is 200 lbs, height 5 ft 7 in.

Case 1 (Part 2)Case 1 (Part 2)• His medications include metoprolol, enalapril,

atorvastatin, nitroglycerin dermal patch, and enteric-coated aspirin. He has received educational materials on smoking cessation, low-cholesterol and low-fat diets, weight loss and diabetes prevention, and activity recommendations, and is scheduled for follow-up evaluations.

MCQ 5MCQ 5• All the medications he is on are recommended during

the first hours of an acute MI. Which one is not recommended for indefinite use?

• Atorvastatin• NTG• Metoprolol• Aspirin• Enalapril

MCQ 6MCQ 6• Major risk factors, any one of which will double the risk

of atherosclerotic coronary artery disease, include tobacco use, high cholesterol, diabetes mellitus, and all but one of following?

• Family history of coronary disease• Diastolic hypertension• Systolic hypertension• Male gender• High LDL cholesterol

Key pointsKey points • Quickly reopening the occluded coronary artery is the most important key to preventing myocardial damage.

• This can be accomplished either by IV infusions with fibrinolytics or PCI.

• IV fibrinolysis or PCI should be given to every patient with at least 0.1mV ST elevation in 2 contiguous leads or a new bundle branch block on ECG within the 30- or 90-minute time frame, unless there are contraindications.

• Although treatment is most effective within this window, treatment may still beneficial up to 12 hours after pain onset.

Key points• It is now the expected standard of care that every

patient with signs or symptoms of suspected AMI should get at least 160 mg of chewable aspirin, sublingual NTG, and oxygen immediately.

• With ECG or lab evidence of acute myocardial ischemia, additional immediate treatment with beta-blockers, unfractionated heparin along with PCI or Fibrinolytics ( if STEMI), and/or glucoprotein IIb/IIIa antagonists is beneficial.

Key points• The indefinite use of beta-blockers, aspirin,

angiotensin-converting enzyme inhibitors, and statins is considered standard therapy in most post-MI patients. Nitrates are not recommended for long-term indefinite therapy.

• Both systolic and diastolic hypertension double the risk of coronary atherosclerosis and should be treated along with the other modifiable risk factors of hypercholesterolemia, diabetes mellitus, and tobacco use.

Key points• Transmural and non-transmural MIs are anatomical

definitions and cannot be predicted by Q waves or ST-segment changes.

• Cardiac stress testing, cardiac rehabilitation with exercise and dietary recommendations, implantable cardiac defibrillators in those with ejection fraction less than 30%, aggressive and long-term lipid management, and stents at the time of percutaneous angiography have all been shown to improve the individual’s long-term outcome following an MI.

Thank You