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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3063_Библиотеки_им_академика_М_И_Перельмана
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Cardiology
Case 1
Chief Complaint
“I have severe pain in my chest.”
History and Physical Examination
A 68-year-old man comes to the emergency department with 30 min of severe, dull,
substernal chest pain. There is no radiation of the pain. He is somewhat short of breath but
is not diaphoretic or nauseated. The pain occurred while he was helping his son move
furniture into his new apartment. He is a nonsmoker whose father died at 67 of “heart
trouble.”
Vital signs are T 37.4 C (99.3 F), BP 130/80 mm Hg, and respirations 22/min. Head, eyes,
ears, neck, and throat examination is normal. The chest is clear bilaterally, and the pain is
not reproduced by palpation. Cardiovascular exam shows tachycardia with no murmurs or
gallops. The liver is not enlarged, and the extremities are not edematous.
CCS NOTE
111
Exertional chest pain is very specific for ischemia.
Differential Diagnosis
CCS NOTE
How much physical examination should you choose for the CCS? Think about which
parts of the physical exam might be abnormal and choose those. Do not worry if they
are all normal. All that matters is that they might have been abnormal.
Initial Management
Setting: emergency department
Diagnostic/Therapeutic Plan
Unstable angina
1.
Acute myocardial infarction (MI)
2.
Dissecting aortic aneurysm
3.
Pericarditis
4.
Esophageal spasm
5.
Pulmonary embolism
6.
Musculoskeletal pain
7.
Pancreatitis
8.
Pneumothorax
9.
GERD
10.
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Test Results
CCS NOTE
When the story is consistent with ischemic pain, order aspirin, morphine, and
nitroglycerin at the same time that you order the EKG.
Assessment
Determining the etiology of chest pain depends on the following:
Aspirin oral; nitroglycerin sublingual or paste to chest wall; morphine
Electrocardiogram
CK-MB and troponin
Chest x-ray
Pulse oximetry
Electrocardiogram: sinus tachycardia with 2 mm of ST elevation in leads V2–V4
CK-MB and troponin: normal
Chest x-ray: normal
Pulse oximetry: 98% saturation on room air
Quality of the pain
Where it radiates
Risk factors present
Whether pain develops during exertion
113
Pain that is pleuritic (i.e., changes with respiration) occurs with pulmonary emboli,
pneumothorax, pneumonia, and pericarditis. Aortic aneurysmal pain typically radiates to the
back and is described as “tearing” quality. Acute myocardial infarction is often preceded by
escalating episodes of exertional chest pain, often accompanied by nausea, vomiting, and
diaphoresis, and may radiate to the jaw, arms, or back.
Until the electrocardiogram or cardiac enzymes are performed, however, it is impossible to
distinguish between unstable angina and infarction. Infarction may occur with only a single
millimeter of ST elevation. Infarctions mostly give ST segment elevation. Ischemia mostly
gives ST segment depression. It is possible to have an MI with ST segment depression. A
benign physical examination does not include or exclude an infarction. The initially normal
CK-MB is expected because CK-MB does not elevate until 4–6 hrs after the start of the
infarction and does not peak until 12–18 hrs later.
Troponin is another cardiac enzyme with a very high specificity for the heart. It can be used as
an alternative to CK-MB levels and may begin to elevate earlier than CK-MB levels. The only
cardiac enzyme that elevates in the first 3 hrs is myoglobin.
Virtually any elevation in troponin level is an indication of myocardial damage. Myoglobin is
another cardiac enzyme that is very sensitive for myocardial damage and can elevate even
within 4 hrs of damage. Unfortunately, it is very nonspecific. Troponin elevation lasts for 1–2
wks, whereas CK-MB elevation lasts for just 2–3 days.
Further Management Plan
Clopidogrel oral (or prasugrel or ticagrelor)
Metoprolol IV, statin such as atorvastatin oral, ACE inhibitor (e.g., lisinopril) oral
Angioplasty or thrombolytics
Cardiology consultation
Repeat CK-MB and troponin in 4 hrs
Repeat EKG after 15 minutes
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Discussion
This patient is having an acute myocardial infarction. There are primary objectives in the
management are to decrease oxygen demand and reestablish perfusion.
CCS NOTE
All consultations will ask for a 10-word explanation clarifying the need for the
consultation. Explain why you called.
The usual medications such as nitrates and morphine are given for any patient with anginal
pain. If the patient had a normal electrocardiogram or ST depression indicative of unstable
angina, and had no contraindication to anticoagulation, he would be given heparin alone.
This patient should receive tPA, streptokinase, or other thrombolytics (i.e., alteplase, APSAC,
reteplase, tenecteplase). They have similar efficacy and produce a 25% reduction in mortality
when used within 6 hrs. There is little benefit in using thrombolytics >12 hrs after the start of
an infarction. Indications for thrombolytics are chest pain starting within the last 12 hrs, >1 mm
ST elevation, and a new left bundle branch block.
CLINICAL PEARL
Reperfusion treatment: for symptoms <12 hrs
Direct percutaneous coronary intervention (PCI):
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Absolute contraindications to thrombolytics include severe GI bleed, intracranial hemorrhage,
recent surgery, aortic dissection, and any other active internal bleed. Relative contraindications
include BP >180/110 mm Hg, active ulcers, recent head trauma, and pregnancy.
Do not use streptokinase in those who have had streptokinase before. Thrombolytics, aspirin,
and nitrates all directly contribute to increasing blood flow. Beta-blockers decrease heart rate
and myocardial contractility and therefore decrease myocardial work and oxygen consumption.
In the absence of a specific contraindication, conduction defects, hypotension, or markedly
decreased ejection fraction, a beta-blocker can be added to acute treatment.
MI without ST segment elevation is treated with most of the same things, only glycoprotein
IIb/IIIa inhibitors are used instead of thrombolytics.
Further Management Plan/Results
Elevated at 12 and 18 hrs after presentation
with 5.8% MB fraction and elevated troponin
level
CCS NOTE
The order in which you write out the tests and treatment does not matter. As long as you
write them all at the same time, they are all considered to be done simultaneously.
Glycoprotein IIb/IIIa (abciximab)
Coronary stenting
Repeat CK-MB or troponin
1.
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Discussion
The most common complication of an acute MI in the first 3 days is arrhythmia. This is why
patients are placed in a monitored setting in the critical care unit. Other complications of MI
are the following:
CCS NOTE
The CCS does not require you to know doses. You are unable to actually order a
specific dose.
Follow-up Management and Prevention
Valvular dysfunction
Cardiogenic shock
Aneurysm formation
Mural thrombus
Myocardial rupture
Conduction defects such as atrioventricular (AV) dissociation (complete heart block) and
left bundle branch block and pericarditis (also known as Dressler syndrome)
Admit to critical care unit.
Primary angioplasty has superior efficacy compared with thrombolytics. It should be
performed within 90 min of coming to the door. Primary angioplasty is also preferred if
there are any contraindications to thrombolytics or if the pain >2 hrs.
Beta-blockers (metoprolol ) and statins reduce mortality.
Thrombolytic therapy (tPA or streptokinase) should be followed by heparin use within 12
hrs of chest pain.
117
In long-term management, ACE inhibitors also decrease mortality by improving myocardial
remodeling. This is particularly true in the presence of left ventricular dysfunction, as
evidenced by signs of decreased cardiac output or decreased ejection fraction on
echocardiogram.
CCS NOTE
For the exam you can order the generic or brand name of medications, e.g., metoprolol
or Toprol. However, learn the generic names in general, as they are more reliably
useful for questions.
Emergency coronary bypass is performed after thrombolytics and angioplasty when there is
still evidence of ongoing ischemia.
ACE inhibitors when ejection fraction is low (<40%) or in any large anterior infarction.
ACE inhibitors can be started in any MI, but should be stopped at 6 wks if there is normal
left ventricular function.
Clopidogrel, prasugrel, or ticagrelor is continued for several months if there is a stent.
Intra-aortic balloon pump (IABP) if your case describes valve rupture.
A decreased ejection fraction or large anterior infarction is an indication to start ACE
inhibitors. Primary angioplasty is superior in efficacy to thrombolytics.
The use of angioplasty in acute MI is always indicated if there is a reason not to use
thrombolytics, such as a predisposition to bleeding.
Angioplasty also has greater efficacy when there is evidence of cardiogenic shock or if the
patient has had thrombolytics and is still getting worse.
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Calcium-channel blockers can be used if there is a major contraindication to the use of beta-
blockers. Calcium blockers do not lower mortality.
Final Diagnosis
Acute myocardial infarction
119
Case 2
Chief Complaint
Rapid drop in blood pressure
History and Physical Examination
A 68-year-old man was recently admitted through the emergency department to your ICU
for chest pain and electrocardiogram abnormalities consistent with an acute inferior wall
myocardial infarction. The chest pain resolved, and he has been stable. You are called by
the nurse to see the patient because of a sudden drop of blood pressure from 130/90 mm
Hg to 70/50. The patient denies chest pain, though he is somewhat confused.
Vital signs are T 37.0 C (98.6 F), BP 70/50 mm Hg, and pulse 40/min. Physical
examination shows visible “cannon” a-waves. Chest is clear bilaterally, and
cardiovascular examination shows a 2/6 systolic murmur. His abdomen is benign. The
patient is confused as to time and place, but the neurologic examination is otherwise
nonfocal.
Differential Diagnosis
Hypovolemia
1.
Cardiogenic shock from extension of the MI
2.
Valvular or chordae tendineae rupture
3.
Papillary muscle rupture
4.
Jarisch-Bezold reflex
5.
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