USMLE 2 Cardio Quick Notes

Mechanical complications of acute MI

RV FailureAcuteRCAhypotension,
clear lungs,
3 – 5
RCAacute, severe
edema; new

severe MR
with flail
IV septum
3 – 5
shock &
chest pain,
shunt VSD
Free wall
rupture of
5 days
2 wks
LADshock &
chest pain,
JVD, distant
▪ large pericardial effusion presenting as cardiac tamponade post-MI: LV free wall rupture
o dyspnea, hypotension, pulsus paradoxus, JVD
o electrical alternans
▪ hypotension or shock, JVD, clear lungs,
Kussmaul sign: RV infarct
o Kussmaul sign: ◇ JVD with inspiration
▪ EKG: inferior MI &/or ST elevation in V4R –V6R
▪ Rx: IV fluid bolus to improve RV preload
➢ nitro, diuretics, opioids may worsen hypotension
▪ Sarcoidosis: no definitive diagnostic test
▪ CXR: hilar adenopathy, reticulonodular infiltrates
▪ Bx: noncaseating granulomas; ◇serum ACE
▪ erythema nodosum, acute polyarthritis, cough,
anterior uveitis, dyspnea
▪ asymptomatics Rx: followed without treatment due to high rate of spontaneous remission
▪ symptomatic Rx: systemic glucocorticoid

Constrictive pericarditis

Etiologyidiopathic or viral, cardiac surgery,
radiation therapy (Hodgkin’s),
TB (developing countries)
Featuresfatigue, dyspnea on exertion,
right heart failure (peripheral edema,
ascites, JVD, Kussmaul sign )
hepatojugular reflux
pericardial knock (mid-diastolic sound)
pulsus paradoxus
complication: cardiac cirrhosis
DxEKG: a-fib, or low voltage QRS
pericardial calcifications & thickening
prominent x & y descents
RxNSAIDs, diuretics, pericardiectomy
▪ constrictive pericarditis is a complication of mediastinal irradiation (Hodgkin lymphoma),
TB, & cause of right heart failure (hepatomegaly, progressive peripheral edema, JVD, ascites)
▪ can present 10 – 20 yrs after irradiation or
anthracycline therapy
▪ scarring & inelastic pericardium results in diastolic dysfunction
➢ CXR: pericardial calcifications
▪ confirm Dx: echo show pericardial thickening, abnormal septal motion, bi-atrial enlargement
▪ Rx: diuretics for temporary relief;
pericardiectomy for refractory symptoms

Common complications after acute MI

▪ hours – 2 days ◇ reinfarction
▪ hours – 7 days ◇ ventricular septal rupture
▪ days – 2 wks ◇ LV free wall rupture
▪ hours – 1 month ◇ post-infarct angina
▪ 1– 3 days ◇ acute pericarditis
▪ 2 – 7 days ◇ papillary muscle rupture
▪ 5 days – 3 months ◇ LV aneurysm
▪ weeks – months ◇ Dressler’s pericarditis
▪ acute pericarditis occur 1 – 3 days post-MI
o pericardial friction rub with/without chest pain
o self-limited, resolves with supportive care
▪ posted-MI pericarditis occurring wks to months after an MI: Dressler syndrome
o immune-mediated pericarditis
o Rx: NSAIDs
▪ ventricular septum rupture: 3 to 5 days post-MI
▪ sudden onset hypotension, holosystolic murmur @ LLSB (VSD), CHF
▪ papillary muscle rupture: 3 to 5 days post-MI
▪ hypotension 2/2 severe acute mitral regurgitation, holosystolic murmur & pulmonary edema
▪ ventricular free wall rupture: mechanical complication 5 days – 2 weeks post- MI (anterior)
▪ hemopericardium & cardiac tamponade
▪ acute onset chest pain & profound shock, JVD, with rapid progression to PEA & death
➢ LV free wall rupture should be suspected in patients with PEA after a recent first MI & no signs of heart failure
▪ increased contractility & reflex tachycardia are secondary effects provoked by nitroglycerin due to changes in baroreceptor activity in response to decrease BP from venodilation
▪ cocaine use predisposes to aortic dissection with wide mediastinum & unilateral pleural effusion,
but not high amylase content

Clinical features of Marfan syndrome

 upper:lower body segment ratio
 arm:height ratio
pectus deformity, scoliosis/kyphosis
joint hypermobility
Ocularectopia lentis (lens subluxation)
Cardioaortic dilation, regurgitation,
dissection MVP
Pulmonaryspontaneous pneumothorax due to
apical blebs
▪ RV infarct: ◇ RA & RA pressures
▪ ◇ PCWP & cardiac index 2/2 reduced preload
▪ exertional dyspnea, syncope, angina: aortic stenosis
o systolic murmur, radiates to apex & carotids
o peripheral pulse: pulsus parvus et tardus (decreased amplitude & delayed upstroke)
▪ hypotension, tachycardia, distended neck veins, electrical alternans, pulsus paradoxus, (exaggerated decrease (> 10 mmHg) in systemic arterial BP with inspiration): cardiac tamponade
▪ pulmonary edema, a-fib, late diastolic murmur with opening snap: mitral stenosis
▪ sudden severe chest pain radiating to back, severe HTN, decrescendo diastolic murmur of aortic regurgitation: acute aortic dissection
o systolic BP > 20 mmHg difference between arms, & weak/absent peripheral pulses
o heard @ right sternal border
▪ CXR & EKG to exclude other Dx
▪ serum creatinine, contrast allergy?
▪ Dx: transesophageal echo (TEE) is preferred over chest CT with contrast in patients with kidney disease or contrast-induced nephropathy
▪ Rx: IV labetalol
o patients should not receive antiplatelets (ASA, clopidogrel) or anticoagulation without first
excluding aortic dissection
o nifedipine is a vasodilator that can induce reflex tachycardia & ◇ aortic shear stress
▪ complications: Horner’s, LE weakness/ischemia,
hemothorax, abdominal pain
▪ DDx: acute pericarditis, acute pancreatitis, PE, MI, angina, mediastinal tumor, pleuritis
▪ aortic dissection can extend to aortic valve, carotids, renal arteries, or pericardium, leading to aortic regurgitation, stroke, ARF, or tamponade
▪ aortic dissection is the most dangerous complication of Marfan
o aortic regurgitation is a complication
o autosomal dominant; fibrilin-1 mutation
▪ all Marfan patients with chest pain require evaluation for aortic dissection
▪ aortic regurgitation: early decrescendo diastolic
murmur along the LSB, 3rd/4th IC space, sitting upright, leaning forward, after full expiration
▪ aortic dissection risk factors
o HTN (most significant)
o Marfan
o Cocaine use