Cardiac Flashcards
The most likely complication of left circumflex occlusion is: (March 2015)
a. Apical thrombus
b. Mitral valve rupture
c. Ventricular tachycardia
d. SA or AV node dysfunction
e. Atrial fibrillation (?possible recall)
Complications of myocardial infarction:
Arrhythmias:
- Any cardiac arrhythmia can occur with an infarct
- Any infarct can lead to an abnormal conduction interface (ie re-entry rhythms such as ventricular tachycardia or atrial flutter)
- Any infarct can lead to impaired ventricular filling, acute atrial enlargement and subsequently atrial fibrillation
Hypotension:
- Can be caused by: Hypovolaemia, Excessive vasodilation from nitrate therapy, Decreased left ventricular filling secondary to right ventricular infarction, Marked reduction in cardiac output due to extensive infarction or a mechanical complication
Mechanical complications:
Acute mitral regurgitation:
- Rupture of a left ventricular papillary muscle causing a flail leaflet (most commonly posterior)
- Most commonly with inferior MI
- RCA>LCx supply the postero-medial head which is more prone to rupture
Ventricular septal rupture:
- Several days after rupture
- Softening of the necrotic portion of the septum
- Inferoposterior and anterior myocardial infarction
Left ventricular free wall rupture:
- Several days after rupture
- Softening of the necrotic portion of the wall
Other complications:
o Left ventricular aneurysm:
- LAD occlusion causing antero-apical infarction
- Dilation occurs following weakening of the wall
- Akinetic dilated wall prone to apical thrombus formation and resultant embolic events
o Right ventricular infarction: Almost exclusively in right coronary artery occlusion
o Pericarditis:
- Several days after infarction, due to inflammatory exudate in the pericardium
o Cardiogenic shock:
- Marked reduction in cardiac output leading to hypotension, decreased organ perfusion
- Elevated left ventricular filling pressures => CCF
- Caused by massive infarction or mechanical complications
ANSWER: Ventricular tachycardia from a re-entry circuit
Which of the following is a complication of right coronary artery occlusion? (March 2014)
a. AV conduction block
b. Aneurysm
c. Mural thrombus
ANSWER: AV conduction block, aneurysm and mural thrombus formation is seen with LAD MI
Which is least likely to be caused by myocardial infarction? (March 2016, March 2017)
a. Aortic regurgitation
b. Mitral regurgitation
c. Pericardial tamponade
ANSWER: Aortic regurgitation
Which is the least likely complication of myocardial infarction? (March 2017)
a. Haemopericardium
b. Fibrinous pericarditis
c. Mural thrombus
d. Arrythmia
ANSWER: All are complications of MI
Which is false? (March 2015, August 2016)
a. Dressler syndrome occurs in the initial days following AMI
b. Haemopericardium
c. Mitral regurgitation
d. Aortic regurgitation
e. More likely to be transmural than subendocardial
Dressler syndrome:
o Delayed immune mediated or secondary pericarditis which develops weeks to months following myocardial infarction
o Markedly decreased incidence following the widespread use of reperfusion therapy
o Most commonly seen following transmural infarction
Consequences and complications of myocardial infarction (Robbins):
o Contractile dysfunction - 10-15% of patients, 70% mortality in cardiogenic shock
o Right heart failure - Right ventricular infarcts
o Arrhythmias - Myocardial irritability and/or conduction disturbances
Associated arrhythmias: • Sinus bradycardia • Atrial fibrillation • Heart block • Tachycardia • Ventricular premature contractions • Ventricular tachycardia • Ventricular fibrillation
o Myocardial rupture (2-4 days post MI)
- Rupture of the ventricular free wall (most common)
- Rupture of the ventricular septum (less common) - Acute VSD and left to right shunting of blood
- Papillary muscle rupture (least common) - Acute onset severe mitral regurgitation
Rupture occurs at the stage when the myocardial wall is at its weakest, with coagulative necrosis, infiltration of neutrophils and lysis of collagen
o Ventricular aneurysm
- Bounded by myocardium which has been scarred
- Late complication of large transmural infarcts
- Complications of ventricular aneurysm:
• Mural thrombus
• Arrhythmias
• Heart failure
• Rupture does not usually occur as the aneurysm is tough and fibrous
o Pericarditis - Fibrinous or fibrinohaemorrhagic pericarditis in the second or third day following a transmural infarction
o Infarct expansion:
- Disproportionate stretching, thinning and dilation of the infarct region (especially with anteroseptal infarcts)
- Occurs as a result of weakening of necrotic muscle
- Often associated with mural infarcts
o Mural thrombus:
- Caused by the combination of abnormal contractility (causing stasis) and endocardial damage (causing a thrombogenic surface)
- can be complicated by thromboembolism
o Papillary muscle dysfunction:
- Most post-infarct mitral valve regurgitation results from ischaemic dysfunction of papillary muscle (and the myocardium), ventricular dilatation or papillary muscle scarring/fibrosis leading to shortening
- Papillary muscle rupture is less common
o Progressive late heart failure (chronic ischaemic heart disease)
ANSWER: Dressler syndrome occurs weeks to months following MI, also aortic valve regurgitation is not listed as a complication of myocardial infarction
What is implicated in coronary artery disease? (August 2014)
a. Lupus anticoagulant
Risk factors for coronary artery disease:
o Modifiable:
- Hypercholesterolaemia, LVH, Obesity, HTN, DM, Smoking, Alcohol
o Non-modifiable:
- FHx, Age, Male gender
Lupus anticoagulant is not associated with coronary artery disease in isolation, but patients with lupus have an increased risk of CAD
- Patients have an increased incidence of right heart failure secondary to recurrent pulmonary emboli (lupus anticoagulant)
ANSWER: Lupus anticoagulant is not strongly implicated in the development of coronary artery disease
Which of the following will not cause systemic hypertension? (March 2014)
a. Recurrent pulmonary embolism
b. Coarctation of the aorta
ANSWER: Recurrent pulmonary embolism – this will cause pulmonary hypertension
Diastolic dysfunction is most likely caused by: (August 2014)
a. Hypertension
b. Constrictive pericarditis
c. Diabetes
Diastolic dysfunction is caused by stiffening of the left ventricle
Causes: Hypertension Aortic stenosis Diabetes mellitus Advancing age
ANSWER: Hypertension
A patient has a cardiac MRI. What is most associated with a bicuspid aortic valve? (August 2016, March 2017)
a. Left ventricular hypertrophy
b. No flow void in the ascending aorta
Bicuspid aortic valve
o Two functional valves of unequal size
- Can be congenital (with several genes implicated such as NOTCH1) or acquired (usually secondary to rheumatic heart disease)
Complications:
- Calcific stenosis - - Dilation of the proximal ascending aorta
Associations:
- Turner syndrome (10-12%) - Co-arctation of the aorta (70%) - Left sided heart lesions e.g. hypoplastic left heart - Other congenital cardiac lesions including ASD and VSD, patent ductus arteriosus - ADPKD - Intracranial aneurysms
ANSWER: Left ventricular hypertrophy (as a complication of aortic stenosis). A flow void or jet can be seen in the aorta from the stenosed valve.
Which is true? (March 2015)
a. Libman-Sacks vegetations occur on the pulmonary valve
b. Ankylosing spondylitis causes mitral valve incompetence
c. Spherocytic anaemia is a complication of valve replacement
Libman-Sacks endocarditis:
o Sterile vegetations on the mitral and aortic valves
o One of the cardiac complications of SLE
Ankylosing spondylitis:
o Causes aortic regurgitation
o Progressive fibrosis to the aortic leaflets and root
Valve replacements result in schistocytes, from mechanical trauma to the red blood cells
ANSWER: All false
What differentiates acute from subacute endocarditis? (September 2013)
a. Larger vegetations
b. No perforation of valve leaflets on echo
c. No metastatic infection
Acute endocarditis
- High virulent organisms (e.g. staph aureus)
- Typically seeds a previously normal valve
- Necrotizing, ulcerating and invasive infections
- Clinical: rapid onset fever and constitutional symptoms
- Right heart valves more commonly affected than left valves in IV drug users
- Bulky vegetations with underlying valve destruction
- Invasion into adjacent myocardium or aorta can occur
- Distal embolization with septic infarcts and mycotic aneurysms
Subacute endocarditis:
o Moderate to low virulence organisms
- Streptococcus viridans most common (50-60%)
- Enterococci
- HACEK group of oral comsensals:
(Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella)
o Seeding of a previously abnormal or damaged valve
o Less valvular destruction
o Nonspecific clinical course, lower mortality rate than acute infective endocarditis
o Smaller vegetations - Less likely to cause distal embolic phenomena due to their small size
ANSWER: Acute endocarditis has larger vegetations than those associated with subacute endocarditis
Which is the most correct? (March 2016)
a. Subacute bacterial endocarditis causes valvular destruction
b. Subacute bacterial endocarditis is complicated by aneurysms and emboli
ANSWER: Subacute bacterial endocarditis is complicated by aneurysms and emboli (bland infarcts)
Regarding infective endocarditis, which is false? (September 2013)
a. Fungal infection is rare
b. Aortic valve infection can spread to the pericardium through the valve ring
c. Aortic valve infection can lead to regurgitation
Fungal infection accounts for 2% of infective endocarditis
o Candida and aspergillous most common
o Usually prosthetic valves and immunocompromised patients
Aortic valve infection typically spreads to the myocardium and the aorta
o ?can infection spread through the fibrous valve leaflet
ANSWER: ?aortic valve infection can spread to the pericardium through the valve ring seems the least plausible answer
Regarding infective endocarditis, which is false? (March 2017)
a. Acute infective endocarditis involves previously damaged/abnormal valves
b. Subacute infective endocarditis usually involves previously damaged/abnormal valves
c. Can cause valve leaflet perforation
d. Can be complicated by perivalvular abscess
e. Strep viridans is a cause of subacute bacterial endocarditis
ANSWER: Acute endocarditis typically involves previously normal valves, as the pathogens are more virulent
Which two processes are associated? (March 2016)
a. Mitral valve prolapse is caused by calcification
b. Mitral valve annular calcification is associated with mitral regurgitation
c. Aortic annular calcification is associated with aortic stenosis
d. Before 70 years, bicuspid aortic valve and aortic valve calcification are not associated with aortic stenosis
Bicuspid aortic valve:
- Two functional leaflets which are often unequal in size
- Congenital bicuspid aortic valve is considered one of the most common causes of congenital aortic stenosis
o Associations:
- Dilatation of the ascending aorta
- Turner syndrome (10-20% of Turner women)
- Coarctation of the aorta (70%)
- Left sided lesions e.g. hypoplastic left heart
- Other congenital lesions e.g. atrial and ventricular septal defects, patent ductus arteriosus
- ADPKD
- Intracranial aneurysm
o Prognosis:
- Young adults may develop aortic regurgitation
- Majority go on to develop progressive aortic valve stenosis (99%)
- Symptomatic adults will require valvuloplasty earlier than aortic stenosis patients without a bicuspid valve
o Complications:
- Aortic stenosis:
- Aortic insufficiency:
- Ascending aortic aneurysm
- Aortic dissection:
- Endocarditis: due to turbulent flow
Causes of aortic stenosis:
o Supravalvular:
- Congenital – isolated or associated with William syndrome
- Acquired – post-surgical or sequelae or aortitis
o Valvular:
- Congenital – bicuspid aortic valve, unicuspid, quadricuspid or abnormal tricuspid (varying sizes)
- Acquired – rheumatic heart disease, senile calcific stenosis/degenerative aortic stenosis
o Subvalvular:
- Congenital – subaortic membrane, idiopathic hypertrophic subaortic stenosis associated with hypertrophic cardiomyopathy
ANSWER: Mitral valve annular calcification is associated with mitral regurgitation.
