ACUTE MYOCARDIAL INFARCTION

History of Present Illness

Mr. W.G. is a 53-year-old white man who began to experience chest discomfort while playing tennis with a friend. At first he attributed his discomfort to the heat and having had a large breakfast. Gradually, however, discomfort intensified to a crushing sensation in the sternal area and the pain seemed to spread upward into his neck and lower jaw. The nature of the pain did not seem to change with deep breathing. When Mr. G. complained of feeling nauseated and began rubbing his chest, his tennis partner was concerned that his friend was having a heart attack and called 911 on his cell phone. The patient was transported to the ED of the nearest hospital and arrived within 30 minutes of the onset of chest pain. En route to the hospital, the patient was placed on nasal cannulae and an IV D₅W was started. Mr. G. received aspirin (325 mg po) and 2 mg/IV morphine. He is allergic to meperidine (rash). His pain has eased slightly in the last 15 minutes but is still significant; was 9/10 in severity; now 7/10. In the ED, chest pain was not relieved by 3 SL NTG tablets. He denies chills.

ACUTE MYOCARDIAL INFARCTION

Past Medical History

• Ulcerative colitis X 22 years
• HTN X 12 years (poorly controlled due to poor patient compliance)
• Type 2 DM X 5 years
• S/P AMI 5 years ago that was treated with cardiac catheterization and PTCA;
chronic stable angina for the past 4 years
• BPH X 2 years
• Hypertriglyceridemia
• Adenomatous colonic polyps

ACUTE MYOCARDIAL INFARCTION

Family History

• Father died from myocardial infarction at age 55, had DM
• Mother died from breast cancer at age 79
• Patient has one sister, age 52, who is alive and well and one brother, age 44, with HTN
• Grandparents "may have had heart disease"

Social History

• 40 pack-year history of cigarette smoking
• Married and lives with wife of 29 years
• Has two grown children with no known medical problems
• Full-time postal worker for 20 years, before that a baker for 8 years
• Occasional alcohol use, average of 2 beers/week
• Has never used street drugs

ACUTE MYOCARDIAL INFARCTION

Review of Systems

• Positive for some chest pain with physical activity "on and off for a month or so," but the pain always subsided with rest

Allergies

• Meperidine (rash)
• Trimethoprim-sulfamethoxazole (bright red rash and fever)

ACUTE MYOCARDIAL INFARCTION

Medications

• Glyburide 10 mg po Q AM, 5 mg po QHD (stimulates insulin release)
• EC ASA 325 mg po QD (aspirin)
• Gemfibrozil 600 mg po BID (lipid reducing)
• Sulfasalazine 1.5 g po BID
• Terazosin 1 mg po QHS (every night at bedtime) (benign prostatic hyperplasia [BPH])
• Lisinopril 10 mg po BID (anti-hypertension in diabetes mellitus)
• NTG SL (sublingual) 0.4 mg q 5 min X 3, then call 911 (sublingual nitroglycerin)
• Isosobide mononitrate 30 mg po QD in the morning (extended release tablet)
• Metoprolol 25 mg QD (extended release tablet) (beta-blocker)

Physical Examination and Laboratory Tests

General Appearance

• The patient is an alert and oriented white male who appears to be his stated age. He is anxious and appears to be in severe acute distress.

Vital Signs

See Patient Case Table 1.1

Patient Case Table 1.1 Vital Signs
BP             160/98 right arm sitting	RR             18	HT              5'10½"
P               105 with occasional premature beat	T                 98.2°F	WT             184 lbs
		BMI             26.4 (overweight 25 – 29.9)

ACUTE MYOCARDIAL INFARCTION

Skin

• Cool, diaphoretic, and pale without cyanosis

Neck

• Supple without thyromegaly, adenopathy, bruits, or jugular venous distension

Head, Eyes, Ears, Nose, and Throat

• Pupils equal at 3 mm, round, responsive to light and accommodation
• Extra-ocular muscles intact
• Fundi benign
• Tympanic membranes intact
• Pharynx clear

ACUTE MYOCARDIAL INFARCTION

Chest and Lungs

• No tenderness with palpation of chest wall
• No dullness with percussion
• Slight bibasilar inspiratory crackles with auscultation
• No wheezes or friction rubs

Cardiac

• Tachycardia with occasional premature beat
• Normal S1 and S2
• No S3, soft S4
• No murmurs or rubs

Abdomen

• Soft and non-tender
• Negative for bruits and organomegaly
• Bowel sounds heard throughout

ACUTE MYOCARDIAL INFARCTION

Musculoskeletal/Extremities

• Normal range of motion throughout
• Muscle strength on right 5/5 UE/LE; on left 4/5 UE, 5/5 LE
• Pulses 2+
• Distinct bruit over left femoral artery
• No pedal edema

Neurological

• Cranial nerves II-XII intact
• Cognition, sensation, gait, and deep tendon reflexes within normal limits
• Negative for Babinski sign

Laboratory Blood Test Results (3½ hours post-AMI)

See Patient Case Table 1.2

Patient Case Table 1.2 Laboratory Blood Test Results
N                              133 meq/L	Mg                           1.9 mg/dL	CK-MB                         6.3 IU/L
K                               4.3 meq/L	PO4                         2.3 mg/dL	Troponin I                    0.3 ng/mL
Cl                             101 meq/L	Chol                         213 mg/dL	Hb                               13.9 g/dL
HCO3                       22 meq/L	Trig                         174 mg/dL	Hct                              43%
BUN                         14 mg/dL	LDL                         143 mg/dL	WBC                           4,900/mm3
Cr                             0.9 mg/dL	HDL                         34 mg/dL	Plt                                267,000/mm3
Glu, fasting               264 mg/dL	CPK                         99 IU/L	HbA1c                          8.7%

Note: Normal values, please refer to Laboratory Values posted on Canvas

ACUTE MYOCARDIAL INFARCTION

Arterial Blood Gases

• pH 7.42
• PaO₂ 90 mmHg
• PaCO₂ 34 mmHg
• SaO₂ 96.5%

Electrocardiogram

• 4 mm ST segment elevation in leads V2-V6

Chest X-Ray

• Bilateral mild pulmonary edema (< 10% of lung fields) without pleural disease or widening of the mediastinum

ACUTE MYOCARDIAL INFARCTION

Clinical Course

Patient history showed no contraindications to thrombolysis. The patient received IV reteplase, IV heparin, metoprolol, and lisinopril. Approximately 90 minutes after initiation of reteplase therapy, the patient's chest pain and ST segment elevations had resolved and both heart rate and blood pressure had normalized. The patient was stable until two days after admission when he began to experience chest pain again. Emergency angiography revealed a 95% obstruction in the left anterior descending coronary artery. No additional myocardium was at risk – consistent with single-vessel coronary artery disease and completed AMI. Percutaneous transluminal coronary angioplasty of the vessel was successfully performed, followed by placement of a coronary artery stent. After the stent was placed, the patient received abciximab infusion (platelet aggregation inhibitor). Ejection fraction by echo cardiogram three days post-AMI was 50% and the patient's temperature was 99.5°F. The remainder of the patient's hospital stay was unremarkable. He was gradually ambulated, physical activity was slowly increased, and he was discharged eight days post-AMI.

ACUTE MYOCARDIAL INFARCTION

Medical Abbreviations

AMI	Acute myocardium infarction
BPH	Benign prostatic hyperplasia
CK-MB	Creatine kinase-MB
CPK	Creatine phosphokinase
DM	Diabetes mellitus
EC ASA	Enteric coated aspirin
HTN	Hypertension
LE	Lower extremity
PTCA	Percutaneous transluminal coronary angioplasty
S/P	Status post
E	Upper extremity

ACUTE MYOCARDIAL INFARCTION

Clinical Values for Case Study Problem-Solving

Click at the link below to learn more:
Clinical Values for Case Study Problem-Solving

Abbreviations

Click at the link below to learn more:
Abbreviations