Cardio - Structural Heart Diseases Flashcards
What are structural heart diseases?
defects that affect the valves + chambers of the heart + aorta
What are the 2 main types of structural heart diseases?
→ congenital heart defects
→ ones formed later in life
What are some examples of congenital structural heart diseases?
→ atrial septal defect (ASD) → ventricular septal defect (VSD) → coarctation of aorta → patent foramen ovale (PFO) → Patent ductus arteriosus (PDA) → Tetralogy of Fallot (TOF)
What are some examples of structural heart diseases developed later in life?
→ valvular dysfunctions (Atrial stenosis /regurgitation)
→ muscular (cardiomyopathies)
What is ventricular septal defect (VSD)?
→ ventricular wall between two ventricles doesn’t develop properly
→ leads to hole in wall
What are pathophysiological consequences of VSD?
mix of oxygenated + deoxygenated blood in the ventricles
How does a child present with VSD?
→ poor weight gain
→ poor feeding
→ heart palpitations
How is VSD treated?
→ sometimes if hole small enough, it closes as the child develops
→ if not, open heart surgery needs to be done to put a patch on the hole
What is tetralogy of fallot (TOF)?
→ combination of 4 defects
→ ventricular septal defect
→ pulmonary stenosis (narrow pulmonary trunk)
→ widening of aortic valve (allows mixing of right ventricular + aortic blood)
→ right ventricle hypertrophy (thickening of right ventricular wall)
What is atrial septal defect (ASD)?
hole in the wall between the 2 atria
What is the coarctation of the aorta?
narrowing of the aorta
What are the consequences of coarctation of the aorta?
→ ventricle has to work harder to pump blood through the aorta
→ causes thickening of ventricular muscle
What is cardiomyopathy?
→ disease of the heart muscle that makes it harder for heart to pump blood to the rest of the body
→ can lead to heart failure
What are the 3 types of cardiomyopathy?
→ dilated
→ hypertrophic
→ restrictive
What is dilated cardiomyopathy?
characterised by left ventricular chamber enlargement + systolic dysfunction with normal left ventricular wall thickness
When does dilated cardiomyopathy most commonly occur?
third or fourth decade of life
What are the causes of dilated cardiomyopathy?
→ familial → idiopathic → heart valve disease → after child birth → thyroid disease → myocarditis → alcoholism → autoimmune disorders → ingestion of drugs → mitochondrial disorders
What is the hallmark gross finding of dilated cardiomyopathy?
left ventricular dilation, more than 4cm
What is familial DCM?
→ genetic predisposition to dilated cardiomyopathy
→ rare autosomal dominant inheritance pattern
→ first degree relative have a 50 % chance of getting DCM
What is the abnormal physiology of DCM?
→ Enlargement of the left ventricle
→ lower ejection fraction and increase in the ventricular wall stress and end systolic volumes
→ Early compensatory mechanisms include an increase in heart rate and tone of the peripheral vascular system.
→ neurohumoral activation of the renin-angiotensin aldosterone system and an increase in circulating levels of catecholamines.
→ levels of natriuretic peptides are also increased.
→ Eventually these compensatory mechanisms become overwhelmed + heart fails.
What is the common history + presentation of DCM?
→ dyspnoea → murmur → fatigue → angina → pulmonary congestion → low cardiac output → displaced apex beat (S3 or systolic)
What are the investigations that can be done for DCM?
→ genetic testing → viral serology → ECG → chest X-ray → cardiac catheterisation → cardiac MRI / CT scan → exercise stress test → echocardiography (ECG)
How is DCM managed ?
→ diet modification (fluid + sodium restrictions) → treatment of the underlying cause → treat the symptoms of heart failure → treat thrombo-embolic events → treat arrhythmias, etc.
What dietary modifications can be made for DCM?
fluid + sodium restrictions
How do you treat DCM if the underlying cause is sarcoidosis or myocarditis?
immunosuppressants
How do you treat DCM if the underlying cause is haemochromatosis?
phlebotomy
How do you treat the symptoms of heart failure for DCM?
→ ACE inhibitors
→ beta blockers
→ addition of angiotensin II receptor antagonists
When should the dose of ACEi be reduced in patients of DCM?
if patient develops:
→ a cough
→ hypotension
→ and/or renal dysfunction
What is given to surgical candidates of DCM when heart failure treatment is ineffective?
→ LVAD
→ orthotropic heart transplantation
What is given to non-surgical candidates of DCM when heart failure treatment is ineffective?
→ LVAD
→ optimise medical management
How are arrhythmias treated in patients with DCM?
→ amiodarone
→ dofetilide
→ ICD or CRT
How are thromboembolic events in patients with DCM treated?
anticoagulants e.g. warfarin after assessing previous TE, severe systolic dysfunction or ventricular dilation
What is hypertrophic cardiomyopathy?
→ defined by increase in LV wall thickness
→ not solely explained by abnormal loading conditions
How is HCM contracted?
→ genetic cardiovascular disease
→ familial HCM = autosomal dominant Mendelian-inherited disease in approx 50 % of cases
What is HCM the leading cause of?
sudden cardiac death (in preadolescent + adolescent children)
What are the symptoms of HCM?
→ most patients are asymptomatic
→ first clinical manifestation can range from atrial fibrillation, tachycardia or sudden cardiac death
What is the hallmark of HCM?
myocardial hypertrophy that is inappropriate, often asymmetrical, occurs in absence of obvious hypertrophy stimulus
Where does HCM frequently present in the left ventricle?
→ can be anywhere
→ frequently involves inter ventricular septum
What does hypertrophy of the inter ventricular septum result in?
obstruction of flow through the LF outflow tract
What is the abnormal physiology of HCM?
→ abnormal diastolic function = impaired ventricular filling + increased filling pressure despite small or normal ventricular cavity
→ abnormal calcium kinetics
→ sub-endocardial ischemia
→ related to profound hypertrophy + myopathic process
What are some of the signs and symptoms of symptomatic HCM?
→ double carotid artery impulse → S3 gallop → syncope → presyncope → ejection systolic murmur → congestive heart failure → dizziness → palpitations → angina → sudden cardiac death
What are the investigations that can be done to confirm HCM?
→ haemoglobin level → brain natriuretic peptide (BNP) → troponin T levels → ECG → CXR → cardiac MRI
Why does Hb level need to be checked in HCM?
anaemia exacerbates chest pain + dyspnea
Why do BNP and troponin T levels need to be check in HCM?
high levels of both are associated with higher risk of CVD events, heart failure + death
How are the symptoms of HCM managed? What are the medications and order of prescription?
→ beta blockers → verapamil → disopyramide → mechanical therapy → PM with short AV delay → septal myectomy or ablation
When is verapamil given to a patient with HCM instead of or after beta blockers?
→ after side effects from beta blockers
→ instead of beta blockers if there is non-cardiac contraindication to beta blockers
When is disopyramide given to a patient with HCM?
if there is:
→ LVOT gradient
→ and persistent symptoms
→ and absence of contraindication to disopyramide
When is mechanical therapy given to a patient with HCM?
when the patient presents with refractory symptoms
When is a PM with an AV delay prescribed to a patient with HCM?
when patient has a existing PM or contraindication to more invasive management
When is septal myectomy or ablation appropriate for a patient with HCM?
when refractory symptoms present to a PM with AV delay AND there’s no contraindication to more invasive management
What is restrictive cardiomyopathy?
→ increased stiffness of the myocardium
→ diastolic dysfunction with restrictive ventricular physiology
→ atrial enlargement due to impaired ventricular filling during diastole
→ systole function, volume + wall thickness of ventricles is usually normal
Why is RCM a less well-defined cardiomyopathy?
diagnosis is based on establishing the presence of a restrictive ventricular filling pattern
What percent of diagnosed cardiomyopathies does RCM account for?
5%
What is the aetiology of RCM?
→ idiopathic
→ familial (related to troponin I or design mutations to do with skeletal myopathy)
→ various systemic disorders
What systemic disorders can cause RCM?
→ haemochromatosis → amyloidosis → sarcoidosis → Fabry's disease → carcinoid syndrome → scleroderma → anthracycline toxicity → previous radiation
What is the pathophysiology of restrictive cardiomyopathy?
→ Infiltrative CMs are characterized by deposition of abnormal substances (ie, amyloid proteins, non-caseating granulomas, iron) within the heart tissue.
→ Infiltration causes the ventricular walls to stiffen, leading to diastolic dysfunction
→ Restrictive physiology predominates in the early stages, causing conduction abnormalities and diastolic heart failure
→ Adverse remodelling may lead to systolic dysfunction and ventricular arrhythmias in advanced cases.
What abnormal physiology does RCM present with?
→ Increased stiffness of the myocardium causes ventricular pressures to rise precipitously with small increases in volume
→ accentuated filling occurs in early diastole + terminates abruptly at the end of the rapid filling phase
→ reduced compliance due to increased diastolic stiffness = LV doesn’t fill adequately in normal filling pressures
→ reduced LV filling = reduced cardiac output
What are the common signs and presentations of RCM?
→ more comfy in sitting position because fo fluid in abdomen or lungs
→ frequent ascites + pitting edema of the lower extremities
→ liver enlarged + full of fluid = very painful
→ weight loss + cardiac cachexia common
→ Increased jugular venous pressure
→ pulse volume is decreased, consistent with decreased stroke volume and cardiac output
What findings are consistent with amyloidosis causing RCM?
→ Easy bruising
→ periorbital purpura
→ macroglossia
→ other systemic findings e.g. carpal tunnel syndrome
What investigations can be carried out for RCM?
→ CBC (complete blood count) → serology → amyloidosis check → CXR → ECG → catheterisation → MRI / biopsy
How is RCM managed?
→ heart failure medication → anti arrhythmic therapy → immunosuppression - steroids → pacemaker → cardiac transplantation
What heart failure medication is used to treat RCM?
should be initiated in patients with reduced LV: → ACE inhibitors → angiotensin receptor II blockers → diuretics → aldosterone inhibitors
What is the equation for cardiac output?
cardiac output = heart rate x stroke volume
How do you calculate stroke volume?
stroke volume = end diastolic volume - end systolic volume
How do you calculate ejection fraction?
ejection fraction = (stroke volume / end diastolic volume) / 100
How can mean arterial pressure (MAP) be calculated using systolic + diastolic pressure?
MAP = DP + 1/3(SP-DP)
What is infective endocarditis?
infection of the endocardium or vascular endothelium of the heart
→ result of bacteria entering the blood stream and forming a “vegetation” in the endocardium
→ vegetation = bacterial infection surrounded by layer o platelets + fibrin
What part of the heart does infective endocarditis normally affect?
heart valves
What are the main bacterial causes? What is the most common?
→ STREPTOCOCCI (20 - 40%)
→ strep viridans
→ staph aureus
→ gram negative bacteria
What are the signs + symptoms of infective endocarditis?
→ fever → malaise → sweats → unexplained weight loss → cardiac decompensation → anaemia → raised markers of infection
What abnormal physiology can be observed in the heart in infective endocarditis?
→ vegetation
→ abscess
→ valve perforation and/or new dehiscence of prosthetic valve
→ regurgitation of the affected valve
What investigations can be performed for infective endocarditis?
→ ECG → CXR → blood tests → blood cultures → transoesophageal echocardiogram
Why is a transoesophageal echo better than a trans thoracic?
higher sensitivity in the first one
What is Duke’s major criteria for infective endocarditis?
→ persistently positive blood culture for typical organisms
→ ECHO : vegetation, dehiscence of prosthetic valve, abscess
→ new valvular regurgitation murmur
→ coxiella brunetti infection
What is Duke’s minor criteria for infective endocarditis?
→ predisposing heart condition or IV drug use
→ fever greater than 38 degrees celsius
→ vascular emboli to organs ro brain
→ immunological signs e.g. glomerulonephritis, Osler snores, Roth spots
→ positive blood cultures that don’t meet the major criteria
What part of Duke’s criteria needs to be met to diagnose definite endocarditis?
→ 2 major clinical criteria OR
→ 1 major and 3 minor clinical criteria OR
→ 5 minor clinical criteria OR
→ positive gram stain or culture from surgery or autopsy
What part of Duke’s criteria needs to be met to diagnose possible endocarditis?
→ 1 major and more than 1 minor clinical criteria OR
→ 3 minor criteria
What part of Duke’s criteria needs to be met to reject endocarditis?
→ resolution after less than 4 days of antibiotic treatment
→ no evidence of infection after surgery
→ definite or possible criteria not met
How is infective endocarditis treated?
→ first-line medical management = IV antibiotic course
→ surgical management to repair or replace a damaged heart valve or drain away any abscesses
What are the signs of cardiac decompensation?
→ shortness of breath → frequent coughing → swelling of legs + abdomen → fatigue → raised JVP (jugular venous pressure) → lung crackles → oedema
What valves does infective endocarditis affect the most? The least?
→ aortic
→ then mitral
→ then right-sided valves
Why are valves most commonly affected by infective endocarditis?
→ easier for vegetation to occur on valves that are already damaged
→ damage occurs most to the valves of the heart that experience turbulent blood flow
What communities have increased risk of infective endocarditis?
→ IV drug users
→ those who undergo dental surgeries
→ immuno-suppressed
→ congenital heart defects that lead to damaged endocardium
What genes have been associated with inheritance of DCM?
mutations in genes encoding cardiac cytoskeletal proteins: → Titin → Lamin → Phospholamban → Cardiac myosin binding protein C → myosin heavy chain
