Heart Failure (CVS) Flashcards
(C)
Define heart failure
Heart failure may be defined as a clinical syndrome where the heart is unable to generate sufficient CO to meet the metabolic needs of the body.
aka congestive heart failure (CHF).
Can’t pump enough blood baso.
What is the functional classification of HF?
Systolic HF = Heart failure with reduced ejection fraction
Diastolic HF = Heart failure with preserved ejection fracture
These two specifically always refer to left sided HF
Describe HFrEF and causes
This is systolic left HF. This occurs when there is impaired vent contraction in systole resulting in reduced ejection fraction as the vents can relax and fill but cannot eject enough (rEF is <40%)
Causes: IHD, dilated cardiomyopathy, myocarditis, arrhythmias
Describe HFpEF and causes
This is diastolic left HF (pEF >50%) The LV has preserved systolic function however the LV is unable to relax and fill properly due to stiffness resulting in inadequate filling in diastole.
Causes: left ventricular hypertrophy (e.g. due to chronic hypertension), hypertrophic cardiomyopathy, cardiac tamponade, constrictive pericarditis
Difference between left sided HF and right sided HF
LHF = left side is affected first/primary. Blood builds up in the left heart as it is not ejected out (both in rEF and pEF) and backs up into the lungs -> pulmonary oedema.
Describe right sided HF and brief aetiology
RHF = Often secondary to LHF (commonest cause).
The incr pulm pressure causes incr resistance against the right heart contraction. The right heart then compensates with vent hypertrophy.
However, isolated RHF can also occur and is often secondary to lung diseases such as pulmonary hypertension and pulmonary emboli - in these cases the HF is referred to as cor pulmonale
Describe the NYHA classification
This classifies HF based on severity of symptoms
Class 1 (no limitation): ordinary physical activity does not cause undue fatigue, dyspnea or palpitations
Class II (mild limit): ‘’ causes fatigue, dyspnea, palps, or angina
Class III (moderate limit): comfortable at rest, less than ordinary activity causes above symptoms
Class IV (severe limit): symptoms at rest, any phys acticity incr discomfort
Difference between low output HF and high output, which is more common
Low-output is much more common than high-output.
Low-output occurs when CO = reduced due to a primary problem with the heart and the heart is unable to meet the body’s needs.
High-output = normal CO, but there is an increase in peripheral metabolic demands that the heart is unable to meet.
What are the risk factors for HF?
Advancing age (>65 years old)
Hypertension
Diabetes
Causes/Main risk factors of the causes
Describe starling’s law pathophysiology of HF
The pathogenesis of heart failure is complex and follows from mechanisms that result in a failure of cardiac output.
One mechanism is the altered starling’s law. Due to poor contraction, ESV increases. Usually, this incr stretch so incr SV. However, this doesn’t happen in HF as much and the curve flattens out and drops. This is due to the relationship between cardiomyocyte stretch and contractility being altered.
Describe compensatory mechanisms in the pathophysiology of HF
In HF, neurohormonal compensatory mechanisms develop which are initially helpful but eventually become detrimental and contribute to the development of symptoms.
The drop in CO is what leads to compensatory mechanisms - incr in SNS activity, RAAS, vasopressin activity.
Average of HF diagnosis in UK?
75
Commonest causes of HF in europe and north america?
CAD, hypertension and valvular disease.
Significant cause of HF in south america?
Chagas disease, but rare in europe and north america
What are the symptoms of Left HF?
LHF causes pulm congestion/oedema (bc blood/pressure backs up) and systemic hypoperfusion.
Fatigue!
Shortness of breath on exertion (
Orthopnea
Paroxysmal nocturnal dyspnea
Nocturnal cough (+/- pink frothy sputum)
You might get RHF symptoms if its progressed to that
What clinical signs of left HF may be found in exam?
Tachypnea
Bibasal fine crackles on auscultation of the lungs
Cyanosis
Prolonged capillary refill time
Hypotension