Heart Failure Flashcards
What genetic abnormalities are implicated in HCM?
In 60-70%
Mutations in sarcomeric contractile protein genes
Most commonly b-myosin heavy chain + cardiac myosin binding protein C gene
What is the most specific imaging modality to diagnose HCM?
CMRI
What treatments have been shown to have mortality benefit in heart failure and what are the approx benefits (RR)?
ACE-I = 15% B-blocker = 33% Spironolactone = 25% CRT = 29% ICD = 26%
Every article quotes different values, this is from a meta analysis
What 3 types of immunosuppressive drugs are used post cardiac transplant?
Calcineurin inhibitor (Cyclosporin, Tacrolimus)
Inhibitor of T-cell proliferation (Mycophenolate, azathioprine)
Steroids
What is the mean survival post cardiac transplant?
Mean 14 years
> 1/3 survive greater then 20 years
What are indications for heart transplant?
Severe symptomatic heart failure (Class IV) despite maximal medical therapy
Cardiogenic shock
Requiring mechanical cardiac support
Frequent repeated discharges from ICD
Intractable angina despite optimal medical/surg and intervention
What are the 2 classifications of heart failure?
HF with reduced election fraction (HFrEF)
HF with preserved ejection fraction (HFpEF)
What are the NYHA classes of heart failure?
Class 1-no limitation
Class 2 - limited slightly on physical exertion
Class 3 - markedly limited in physical exertion
Class 4 - symptoms at rest
What is the main late complication of cardiac transplant, not related to immunosuppression?
Cardiac allograft vasculopathy
- transplant coronary artery disease
- usually diffuse, distal, concentric, non calcified and hard to treat
What other things are important to consider in heart failure aside from medications + devices?
Vaccinations
Cardiac rehab and MDT
Advanced care planning
What drugs are used in heart failure that provide symptomatic benefit only?
Diuretics
Digoxin (note withdrawal of digoxin CHF can worsen symptoms, only really indicated starting digoxin in those with CHF and AF)
What is the requirements to qualify for CRT?
Sinus rhythm, LBBB
QRS >120ms (definite for > 150)
LVEF less then or equal to 35%
Ongoing symptoms (NYHA II, III + IV) despite optimal medical therapy
What two drugs slow the remodelling process?
B-blockers - reduce sympathetic input + neurohormonal activation
ACE-I -block RAA system
What are two new drugs in heart failure (not available in NZ)?
Ivabradine - direct sinus node inhibitor, doesn’t cause hypotension. When used in patients with SR and HR > 70bpm, reduced mortality by 5%
Angiotensin-Neprilysin inhibition - neprilysin breaks down naturetic peptides (anp/bnp) which work to reduce blood volume by decreasing SVR and increasing naturesis, by blocking their degradation the affect is enhanced
What are the major risk factors for sudden cardiac death in HCM?
Aborted cardiac death Spontaneous sustained VT FH of premature sudden death Unexplained syncope LV thickness > 30mm Abnormal exercise blood pressure response Non-sustained VT on holter
Above help risk stratify regarding who requires ICD
What drugs should be avoided in patients with HCM?
Avoid drugs that decrease pre-load because they decrease LV size and worsen LV function
E.g nitrates, diuretics + ACE-I
Also digoxin should not be used for rate control in AF as the ionotropic affects can exacerbate HF
What is AVRC and what mutations is it often due to?
Myocardium of free wall is replaced by fibrofatty tissue
Mutations in cell adhesion genes in 40-60% of cases
What is the murmur due to in HCM and what exacerbates it?
Outflow tract turbulence and mitral regurgitation
Valsalva and standing after squatting makes it more prominent
Squatting and hand grip makes it quieter
What causes LVOT obstruction in HCM?
Thickened septum and systolic anterior motion of the mitral valve (SAM)
When does dilated cardiomyopathy occur with pregnancy?
3rd trimester and up to 6 months postpartum
What is the toxin responsible for alcoholic cardiomyopathy?
Acetylaldehyde - toxic metabolite of alcohol
What is giant cell myocarditis?
A granulomatous disease associated with other autoimmune diseases. Causes progressive heart failure by development of diffuse granulomatous lesions and inflammatory infiltrate
What percentage of dilated cardiomyopathies have an genetic component?
20-30%
Principles of family screening in HCM?
If index patient has a proven mutation - genetically test 1st degree relatives for mutation
If no mutation test 1st degree relatives annually from age 12-18 (hypertrophy typically develops on adolescence) and every 5 years from 18 onwards.
Screen with ECG, ECHO and clinical examination
