USMLE 2 Cardio Quick Notes
Mechanical complications of acute MI
| Time | Artery | Features | Echo | |
| RV Failure | Acute | RCA | hypotension, clear lungs, Kussmaul sign | hypokinetic RV |
| Papillary Muscle Rupture | Acute, 3 – 5 days | RCA | acute, severe pulmonary edema; new holosystolic murmur | severe MR with flail leaflet |
| IV septum rupture | Acute, 3 – 5 days | LAD apical RCA basal | shock & chest pain, holosystolic murmur, biventricular failure | left-to-right shunt VSD |
| Free wall rupture of ventricle | 5 days 2 wks | LAD | shock & chest pain, JVD, distant heart sounds, PEA | pericardial effusion with tamponade |
| ▪ 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
| Etiology | idiopathic or viral, cardiac surgery, radiation therapy (Hodgkin’s), TB (developing countries) |
| Features | fatigue, dyspnea on exertion, right heart failure (peripheral edema, ascites, JVD, Kussmaul sign ) hepatojugular reflux pericardial knock (mid-diastolic sound) pulsus paradoxus complication: cardiac cirrhosis |
| Dx | EKG: a-fib, or low voltage QRS pericardial calcifications & thickening prominent x & y descents |
| Rx | NSAIDs, 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
| Skeletal | arachnodactyly upper:lower body segment ratio arm:height ratio pectus deformity, scoliosis/kyphosis joint hypermobility |
| Ocular | ectopia lentis (lens subluxation) |
| Cardio | aortic dilation, regurgitation, dissection MVP |
| Pulmonary | spontaneous 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 |
