Cardiac Failure Flashcards
(26 cards)
What aspects of a CV examination are especially important when assessing degree and cause of cardiac failure?
BP
Pulse (rate, rhythm; rapid AF may cause HF or be the result of HF)
JVP
Murmurs
Chest
Oedema
What findings might be expected on examination in a patient with cardiac failure?
Crackles (creps) on auscultation
Elevated JVP (indicates high RA and therefore RV EDP; often correlates with high LA and LV EDP)
Oedema (alongside an elevated JVP causes other than cardiac failure are unlikely)
What is cardiac failure termed when it is caused by the body’s increased needs?
High output heart failure
What is the Frank-Starling law?
Stretch of the myocardium increases contractility (therefore SV increases with EDV)
What are some of the possible mechanisms for pure RHF? Give examples of causes for each mechanism
Pulmonary HTN: cor pulmonale, PE
Structural disease: pulmonary or tricuspid valvular disease, R ventricular cardiomyopathy
Pericardial disease
List 7 causes of cardiac failure
IHD
Valvular heart disease
Hypertensive heart disease
Congenital heart disease
Cardiomyopathy
Cor pulmonale
Pericardial disease
What additional forms of treatment are available for cardiac failure? What is the goal of each?
Biventricular pacing (cardiac resynchronisation to improve function)
Implantable cardioverter defibrillator (to prevent SCD as a result of ventricular arrhythmias)
Cardiac assist devices and transplantation (uncommon)
List 4 broad causes of SOB
Cardiac
Respiratory
Anaemia
Poor fitness
What are 4 key parts to patient diagnosis in suspected HF?
Is it HF?
What is the underlying cause?
What is the precipitating cause of this episode?
What other problems are there?
Hows does RAAS help to maintain CO in cardiac failure?
Na+ and H2O retention
K+ loss
Vasoconstriction
What factors influence CO?
Preload
HR
Contractility
Afterload
What are the main drug classes used to treat cardiac failure? Give an example of each
Aldosterone antagonists (spironolactone), ACEI (“pril”), ARB (“sartan”)
Beta blockers (“olol”)
Calcium channel blockers
Diuretics (frusemide)
Give examples of possible complications of HF?
Cardiac ischaemia
Arrhythmias
Renal failure
Electrolyte imbalance
Liver failure
What are the 4 main principles of cardiac failure treatment and what is the aim of each?
Reduce preload: relieve congestion and oedema (BUT be careful not to reduce CO too much)
Block RAAS: long term fluid loss, vasodilation
Block SNS: block direct cardiac toxic effect
Treat underlying and precipitating causes
List 9 factors which may precipitate decompensated cardiac failure
A F****** BAD TIME:
New Arrhythmia (esp AF)
Fluid overload
Poor BP control
Anaemia
Change in Drugs
Thyrotoxicosis
Infection (esp pneumonia)
New MI or ischaemia
Pulmonary Embolus
What are the 2 possible mechanisms underlying cardiac failure and what measurement differentiates the 2?
Systolic dysfunction (reduced ejection fraction)
Diastolic dysfunction (stiff diastolic function, normal ejection fraction; less common)
Describe the progression from compensated to severe heart failure
In compensated cardiac failure, output may be maintained via fluid retention (however this may cause venous congestion)
In severe cardiac failure, CO is low and there is pulmonary and peripheral oedema
What venous pressure is required to cause pulmonary or systemic venous congestion?
>20-30 mmHg
What Ix are appropriate where cardiac failure is suspected? What are the expected findings?
CXR: ABCDE (alveolar oedema, Kerley B lines - intestitial oedema, cardiomegaly, dilated prominent upper lobe vessels, effusion - pleural)
Echocardiogram: chamber size (may be normal or increased), function (look for evidence of systolic or diastolic dysfunction), valves (look for valvular incompetence or stenosis), overall structure (look for evidence of hypertrophy)
What aspects of the patient’s Hx are important to elicit when looking for the underlying cause of cardiac failure? Think of the 7 main causes!
IHD: previous MI
Valvular heart disease: PHx rheumatic fever, known murmur
Hypertensive heart disease: PHx of HTN and degree of control
Congenital heart disease: PHx of congenital heart defect
Cardiomyopathy: alcohol, cytotoxic drugs
Cor pulmonale: PHx lung disease (including asthma, COPD, cystic fibrosis, pulmonary fibrosis)
Pericardial disease: signs of RHF (may precede signs of LHF)
Define cardiac failure
CO less than body needs (usually due to reduced CO but rarely due to increased body needs; “high output HF”)
What is the physiological response to reduced contractility in cardiac failure?
Reduced CO = reduced renal blood flow, causing activation of RAAS and leading to fluid retention
Reduced CO also stimulates the sympathetic NS, causing increased NA release and an initial increase in contractility
List 3 causes of diastolic dysfunction which may precipitate cardiac failure
Infarct-related scar
Chronic HTN
Ventricular hypertrophy
How is LHF due to systolic dysfunction classified in terms of its severity?
Mild: 40-50% EF
Moderate: 30-40% EF
Severe: less than 30%
