L9: Congestive Heart Failure: evidence-based treatment Flashcards
MYOCARDIAL INFARCTION is death of part of myocardium AKA HEART ATTACK.
Caused by total occlusion of a coronary artery. However, if narrowing of coronary artery not complete -> patients may develop ANGINA (chest pain on exhersion); can progress & may develop pain at rest called UNSTABLE ANGINA.
MI -> cardiac arrest -> death
ALL OF THE ABOVE IS RELATED TO A DISEASE PROCESS CALLED ATHEROSCLEROSIS
What is atherosclerosis??
The process of progressive thickening and hardening of the walls of medium and large-sized arteries as a result of cholesterol deposition mainly in the presence of high BP/hypertension.
Cardiovascular disease risk factors:
Non-Modifiable Risk Factors:
- Age
- Male sex
- Family History
- Low Birth weight
- Premature Birth
Modifiable Risk Factors:
- Hypertension
- Smoking
- Diabetes mellitus
- Hypercholesterolemia
- Obesity
- Physical inactivity
Which types of risk factors can we treat for cardiovascular diseases?
Modifiable risk factors
How can MI occur due to an atheroma?
Plaque rupture -> atheroma in contact with blood -> initiates thrombosis -> expands and may block entire lumen = acute myocardial infarction = necrosis = heart failure
Cardiovascular Continuum Concept
The diagram shows how heart failure progresses and can cause death
Definition of heart failure + what is forward + backward symptoms
- A complex of symptoms: shortness of breath, fatigue, and congestion
- Due to an impairment of the heart’s ability to (contract) empty* or (relax) fill* properly,
- Leading to inadequate perfusion of tissues during exertion (causes forwards symptoms), and retention of fluid (causes backward symptoms)
Types of heart failure
- Systolic Heart Failure = Unable to contract
- Diastolic Heart failure = heart muscle unable to relax
Forward + Backward Symptoms
Heart = pump
Inedeuqate supply = tiredness + fatigue; blood stagnation + congestion = oedema
Forward:
- Tiredness,
- shortness of breath,
- coughing
Backward:
- Odema in legs + ankles
- Ascites
- Pleural effusion
- Pulmonary odema
Heart failure Prevalance
- Affects 1-2% of population
- 10% among persons ≥ 70 years
- Prognosis 25-40% mortality ~ 5 years (similar to cancer)
- Prognosis worse if:
1. severe symptoms
2. high dose of diuretics
3. low BP
4. low sodium
Why is low BP = worse prognosis?
Drugs needed to prevent heart failure further reduce BP
Causes of Heart Failure?
- Decreased Contractility, due to:
- Coronary heart dis.
- Cardiomyopathies (Primary disease of myocardium - independent of coronary arteries): Viral myocarditis (Covid can increase these); Infiltrations (e.g. lymphoma)
- Drugs (that make myocardium weaker): ß-adrenergic blockers, Verapamil (CCB), Doxorubicin (cancer drug)
- Arrhythmias (atrial fibrillation) - Increased Afterload (myocardium normal but in front of LV, obstruction/increased resistance):
- Hypertension
- Valvular disease (e.g. aortic stenosis- narrowing of aorta)
- HOCM (hypertrophic obstructive cardiomyopathy) - myocardium v. thick between ventricles = block outflow of LV. - Increased Output (heart is normal but body needs more cardiac output due to):
- Anaemia
- Hyperthyroidism
- AV shunts (blood goes from artery to vein)
What is acute decompensation of heart failure?
Means the patient had been treated, symptoms resolved but there’s a reappearance of symptoms
Can be due to one or more of these events:
- Discontinuation of treatment
- ACS (new event e.g. another MI or developed arrhythmia)
- Arrhythmias (AF)
- Infection in urine or chest
- Anaemia
- Pulmonary Embolism
The stages/classification of Heart Failure: New York Heart Association (NYHA) Classification
Class I:
- No limitation of physical activity
- Ordinary physical activity does not cause SOB (dyspnoea) or fatigue
Class II:
- Slight limitation of physical activity (running after bus)
- Ordinary physical activity result in dyspnoea or fatigue
Class III:
- Marked limitation of physical activity (walk to toilet)
- Less than ordinary physical activity result in dyspnoea or fatigue
Class IV:
- Inability to carry out any physical activity without discomfort
- Symptoms are present at rest
Diagnosis of Heart Failure
- NT-proBNP (ANP derivative) – measured in urine; if <400 ng/L = HF unlikely
- If NT-proBNP high -> ECHO cardiogram (ultrasound of heart - tells us what type of HF (diasytolic or systolic): can diagnose with:
1. HFrEF (heart failure with reduced ejection fraction)
2. or HFpEF (heart failure with preserved ejection fraction) - Cardiac MRI (CMR)
- Other tests: ECG, CXR, U&Es, ABGs, D-dimer
- Look for cause(s) of decompensation: Troponin for ACS, ECG for Arrhythmias, etc..
What is ejection fraction?
= % of how much blood left ventricle pumps out with each contraction. (by seeing on echocardiogram the reduction in size of LV)
EF of 60% = 60% of total amount of blood in left ventricle is pushed out with each heartbeat – 50% is normal
EF also called Fractional shortening
Types of HF + when do we diagnose people with them?
- HFpEF (Heart failure with preserved ejection fraction >50%)
- Aka Diastolic HF
- HFpEF patients are older, female, hypertension, obesity, anemia, and AF
- Failure of filling of blood - HFrEF (Heart failure with reduced ejection fraction ≤40%)
- Failure of ejection of blood
- Systolic HF - HFmrEF (mid-range ejection fraction)
- in between normal of 50 and abnormal of 40 (41-49%), now name changed to mildly reduced ejection fraction (no treatment options yet)
What are the aims of HF treatment?
- Removal of the underlying or precipitating causes
- Improving survival & reducing mortality
- Relief of symptoms (& Improvement in quality of life)
- Prevention of re-admissions to hospital, recurrent ischaemic events, and further deterioration in left ventricular function
How do we remove precipitating causes?
- Treatment of hypertension
- Correction of valvular lesions
- Treat anaemia, thyrotoxicosis, fluid overload, increased dietary salt intake
- Improve compliance with treatment
- Drugs that worsen HF: beta-blockers, salt-retaining drugs (NSAIDs, steroids)
How do we treat HF with drugs?
Standard Drug Therapy:
- First-Line Drugs:
- ACE inhibitors
- ARNI (angiotensin receptor blockers/neprilysin inhibitor) e.g. Sacubitril-Valsartan
- Beta Blockers - Second-line
- Angiotensin receptor antagonists (ARBs)
- Aldosterone antagonists
- Hydralazine/nitrate - Third-line
- Diuretics
- Digoxin
- SGLT2 inhibitors
RAAS System
Angiotensinogen (made in liver)