Diagnosing Heart Failure: Why Natriuretic Peptides Come Before the Echo

This is congestive cardiac failure — combined right and left heart failure — and the patient should ideally be hospitalised for close monitoring of renal function and electrolytes. For NYHA class 3 or 4 patients like this, we now routinely add acetazolamide alongside loop diuretics, which improves diuresis and speeds resolution of congestion as long as renal function isn't severely impaired. If blood pressure is low, low-dose renal-dose dopamine in addition to diuretics can help significantly, particularly with right heart failure and valvular dysfunction. Given the liver cirrhosis, use a higher dose of spironolactone, since it also acts on hepatic ascites, and monitor hepatorenal function closely.

The mechanism is glycosuria, which is a nidus for genitourinary infections — balanitis in men and UTIs in women, at an incidence of around 5 to 6%. Counsel every patient on personal and perineal hygiene when starting the drug. If a genitourinary infection develops, get a urine culture, and if confirmed, hold the SGLT2 inhibitor until it resolves, then restart with reinforced hygiene counselling.

There is no substantial long-term beneficial role — it is like flogging a dead horse, a transient cardiac output boost without sustained benefit. It's useful only as a short-term emergency bridge for a profoundly hypotensive patient. We now more routinely use noradrenaline rather than dobutamine in acute low-output heart failure.

The Sgarbossa criteria identify acute myocardial infarction in the presence of a left bundle branch block, where it is otherwise difficult to tell whether ECG changes represent an acute MI or simply the LBBB pattern — specifically, 4mm or more of ST elevation discordant to the QRS is considered an acute MI regardless of the LBBB. This is used specifically in the context of chest pain with LBBB, not in the context of established heart failure management.

A failing heart relies on two compensatory mechanisms: increased heart rate and elevated blood pressure. A beta blocker reduces both, so cardiac output falls initially and the patient feels rough — but only for the first one to two weeks. After that, sustained reduction in neurohormonal activation reverses adverse cardiac remodelling and the patient improves steadily. Always counsel patients about this dip in advance and reassure them it will get better; a heart failure nurse is an excellent resource for this kind of communication.

BNP and NT-proBNP are released specifically when the heart is under stretch or stress and aren't meaningfully elevated in any other condition, which makes them uniquely reliable for diagnosing or excluding heart failure in a breathless patient.

Clinical assessment and a 12-lead ECG, followed immediately by a natriuretic peptide level.

When both the natriuretic peptide and the ECG are normal. In that case, heart failure is very unlikely and other diagnoses should be pursued instead.

HFrEF is below 40%, HFmrEF is 41 to 49%, and HFpEF, previously called diastolic dysfunction, is above 50%.

Either is acceptable. Routine use carries a Class 1A recommendation in the 2021 ESC guidelines, and the choice comes down to whichever assay is locally available.