Breathlessness with constant lethargy and leg swelling

What is Heart Failure?

Heart Failure is a clinical diagnosis characterised by
typical symptoms of shortness of breath, lethargy, orthopnoea, PND, leg swelling, etc, and is due to
an underlying ventricular dysfunction, which can be left, right, or both.
supported by ECG changes and typical CXR pictures.
Can be divided into acute vs chronic based on presentation.
Can be classified into HF with reduced EF(<40) vs HF with preserved EF(>50).

Aetiologies: CHAMPI

Coronart artery diseases
Hypertension
Arrhythmias, Anaemia
Mechanical (valves problems, cardiomyopathies & congenital heart diseases)
Pericarditis/cardiac tamponade/pulmonary embolism
Infection: rheumatic fever/infective endocarditis/myocarditis/viral carditis

Precipitating factors:
same as above! when you have chronic stable heart failure,
any event from above will cause an acute decompensation,
also include: non compliance to fluid restriction/medications & stress(infection)

let's first get some facts right, look at the following formula:

ejection fraction(EF) = stroke volume / end diastolic volume

In left ventricular diastolic heart failure (impairment of ventricular filling),
the myocardial contractility can be preserved, resulting in
heart failure with preserved ejection fraction(HFrEF).

Some might get confused, since the ejection fraction is preserved,
why is it a heart failure?

Well bear in mind, when you have poor filling resulting in a
LOW End Diastolic Volume, despite with 'normal' stroke volume(relative to the EDV!)
due to normal contractility and thus normal ejection fraction,
the actual 'stroke volume' that you get is actually LOW, thus heart failure! 

*based on CPG: often patients with left ventricular dysfunction with have features
of diastolic dysfunction as well.

*sympathetic nervous system, renin-angiotensin-aldosterone-system.

* BNP or N-terminal pro BNP

*ACE inhibitors and Spironolactones can cause hyperkalaemia

*Other diuretics will cause hypokalaemia, so often potassium supplements are given.

Bonus
Possible Implantable devices in Cardiology
1) pacemaker
2) implantable cardioverter defribillator (ICD) (decrease risks of VT/VF)
3) Cardiac Resynchronisation Therapy with a biventricular pacemaker(severe HF)