Heart failure (HF)

• Background  

  

  Definition and epidemiology

  • Heart fails to provide adequate blood flow to meet body's needs.
  • Chronic disease with intermittent decompensations (acute HF), and eventually terminal.
  • The term 'congestive heart failure' is ill-defined, but typically refers to HF with fluid overload, especially pulmonary oedema.
  • Prevalence: 1/70.

  Left ventricular failure (LVF)

  Heart failure with reduced ejection fraction (HFrEF)

  Overview:

  • Left ventricular ejection fraction (EF) <40%. A normal EF is ≥50%, with 40-49% a 'mid-range' grey area.
  • Also known as systolic heart failure or left ventricular systolic dysfunction (LVSD).

  Causes:

  • IHD/MI: commonest cause.
  • HTN
  • Diabetes, usually via IHD.
  • Dilated cardiomyopathy.
  • Valve disease.
  • Arrhythmias
  • Drugs or alcohol.

  Heart failure with preserved ejection fraction (HFpEF)

  Overview:

  • LV relaxation failure → inadequate filling → ↓stroke volume despite normal EF (≥50%).
  • Also known as diastolic heart failure.

  Causes:

  • HTN: commonest cause.
  • Diabetes
  • Constrictive pericarditis.
  • Cardiac tamponade.
  • Restrictive cardiomyopathy

  Right-ventricular failure (RVF)

  Right ventricular systolic dysfunction, due to:

  • Cor pulmonale: primary lung disease (e.g. COPD) → vasoconstriction in poorly ventilated lung tissue to correct ↓V/Q → pulmonary HTN → RVF.
  • LVF → pulmonary HTN → RVF.
  • Pulmonary valve stenosis (uncommon).

  High output heart failure

  Normal heart but increased needs. Due to:

  • Anaemia
  • Pregnancy
  • Hyperthyroidism

• Signs and symptoms

  LVF

  Respiratory symptoms:

  • SOB
  • Orthopnea. Ask how many pillows they sleep with.
  • Paroxysmal nocturnal dyspnoea (PND) and nocturnal cough.
  • Pink frothy sputum.
  • Wheeze

  Other symptoms:

  • Palpitations
  • Poor exercise tolerance.
  • Fatigue
  • ↓Weight (cachexia) or ↑weight (fluid retention).

  Signs:

  • Crackles
  • S3 heart sound ('gallop rhythm'). S4 is commoner in diastolic HF.
  • Murmurs
  • Cachexia
  • Cold peripheries.
  • Displaced apex.
  • Pulsus Alternans: Arterial Amplitude strong then weak.

  RVF

  Symptoms:

  • Liver congestion leads to nausea, anorexia, early satiety, and right upper quadrant pain.
  • Epistaxis
  • Nocturia: on lying flat, fluid backs up from legs to kidneys.

  Signs:

  • ↑JVP
  • Peripheral oedema
  • Ascites
  • Hepatomegaly
  • Right ventricular heave due to pulmonary HTN.

  NYHA functional classes

  1. No symptoms.
  2. Slight limitation, mild symptoms.
  3. Marked limitation, symptoms with minor activity.
  4. Severe limitation, symptoms at rest.

• Investigations

  Basic investigations

  Bloods:

  • FBC: anaemia may mimic or exacerbate symptoms.
  • U+E and LFTs: liver and kidney function can be affected in HF, and are a differential for fluid retention.
  • TFT: thyrotoxicosis can cause high output failure, while hypothyroidism may cause symptoms of fatigue and oedema.
  • Investigate cardiac RFs: cholesterol, blood glucose.

  CXR:

  • May show cardiomegaly and pulmonary oedema.

  ECG:

  • Abnormal in 80%.
  • Usually non-specific changes: previous MI or AF (common), or axis deviation (less common). Only 20% have the specific features listed in the following points.
  • LVF: Voltage criteria are met if the combined height of {S in V1} + {R in V5 or V6} is at least 35 mm (7 large squares). LV strain pattern is ST depression and T inversion in V5-6; less commonly, there is the mirror image ST elevation in V1-3.
  • RVF: Tall R in V1 (>7 small squares or R>S in V1), and large S waves in V4-6. RV strain pattern is ST depression or T inversion in V1-3.

  Diagnosis

  Diagnostic pathway:

  • Screen with BNP or NT-proBNP, and proceed to transthoracic echo if elevated. Consider going straight to echo if there is a prior history of MI.
  • If diagnosis not clear after echo, consider further tests: cardiac MRI, transoesophageal echocardiography.
  • HFrEF diagnosis: {signs and symptoms of HF} plus {echo or MRI evidence of EF <40%}.
  • HFpEF diagnosis: {signs and symptoms of HF} plus {EF ≥50%} plus {↑BNP/NT-proBNP} plus {structural or functional heart disease such as left ventricular hypertrophy or left atrial enlargement}.
  • HFmrEF (HF with mid-range EF): as for HFpEF but EF 40-49%.

  B-type natriuretic peptide (BNP):

  • Pro-BNP is synthesised in the ventricular wall when it is stressed. Then circulates as BNP and N-terminal Pro-BNP – either of which can be used to help diagnose HF – and serves to lower peripheral resistance.
  • Levels can be increased by: IHD, AF, PE, kidney failure, cirrhosis, and sepsis. Levels also naturally rise with age, so a high reading under 60 is more concerning than in someone very elderly.
  • Levels can be lowered by cardiac meds (ACEi, ARBs, β-blockers, spironolactone) and obesity.
  • ↑↑BNP is a poor prognostic factor, although ongoing BNP monitoring to guide treatment does not appear to be useful.

• Management

  Overview

  • Can be mostly managed in primary care, but specialist referral is needed for initial diagnosis, NYHA class 4 HF, treatment-resistant HF, or HF associated with pregnancy or valve disease.
  • Specialist nurses should be involved if available.
  • Follow-up at least every 6 months, including U+E and weighing.

  Lifestyle and preventative measures

  • Refer all stable patients to cardiac rehab.
  • Stop smoking.
  • Flu and pneumococcal vaccination.
  • Monitor weight and fluid balance, advising moderate fluid restriction. Get help if rapid gain e.g. 2 kg in 3 days. Evidence for salt restriction is limited, and some studies say it may be harmful.
  • Treat co-morbidities such as IHD, AF, and dyslipidaemia.

  HFrEF

  Pharmacalogical

  Most patients are on four agents, all of which except diuretics have a mortality benefit:

  • ACEi – any one (though enalapril has most evidence) – should be offered to all, and titrated to evidence-based dose. ARB if intolerant.
  • β-blockers – bisoprolol, metoprolol, or carvedilol – should also be offered to all, and titrated to evidence-based dose.
  • Diuretics – loop (furosemide, bumetanide) or thiazides – if there is fluid overload (pulmonary or peripheral oedema), which is usually the case.
  • Mineralocorticoid receptor antagonists (MRA) – spironolactone or eplerenone – should be added if patient remains symptomatic. Given to block effects of aldosterone on heart as opposed to diuretic effect.

  Further options if symptoms persist:

  • Digoxin, especially if there is AF. Reduces admissions but not mortality.
  • Sacubitril-valsartan (Entrestro) combines a neprilysin inhibitor – which prevents breakdown of vasodilators – and ARB (hence replaces existing ACEi or ARB). Consider if EF ≤35%. Reduces admissions and mortality.
  • Ivabradine inhibits the sinus node If ('funny') channel – the mixed Na+ and K+ channel whose opening initiates depolarization – slowing the heart. Consider if EF ≤35% and sinus rhythm with HR ≥75.
  • Hydralazine plus nitrate, especially if African or Caribbean ethnicity.

  Interventional and surgical

  • Cardiac resynchronisation therapy (CRT) (aka biventricular pacing) if {NYHA 2-4 with EF ≤35%} and {QRS ≥150 ms or LBBB}.
  • Implantable cardioverter defibrillator (ICD) if there is a history of VF or VT, or a high risk of it. Can be combined with CRT in CRT-D.
  • LV assist devices (LVAD) as a bridge towards transplant.
  • Transplant if end-stage and no other options.

  Drug contraindications in HF

  • NSAIDs, especially diclofenac. Low-dose aspirin is OK.
  • Steroids
  • Most CCBs, especially rate-limiting.
  • Pioglitazone
  • TCAs
  • β-agonists.

  RVF and HFpEF

  • There is little evidence-based treatment for RVF or HFpEF, except for symptomatic relief with diuretics, management of co-morbidities, and lifestyle changes.
  • Long term O2 therapy is beneficial in cor pulmonale.

• Prognosis

  Death:

  • Usually due to arrhythmia or pump failure.
  • 30% in 1 year, 50% in 5 years.

• Acute pulmonary oedema

  Causes

  Cardiogenic pulmonary oedema

  Aka acute heart failure.

  Increased hydrostatic pulmonary capillary pressure due to LV dysfunction or volume overload, caused by:

  • Decompensated HF or cardiomyopathy.
  • Hypertension
  • MI: flash pulmonary oedema (acute), ventricular septal rupture (days later).
  • Valve disease: AR, AS, MR, infective endocarditis.
  • Arrhythmias
  • Kidney failure.
  • Others: myocarditis, aortic dissection, hypothyroidism, high-output failure (anaemia, hyperthyroidism).

  Non-cardiogenic pulmonary oedema

  Altered capillary membrane permeability, due to:

  • Acute respiratory distress syndrome (ARDS), secondary to pneumonia, sepsis, aspiration, or severe trauma.
  • Rarely: neurogenic (seizures, trauma, SAH), PE.
  • It is almost never due to reduced oncotic pressure.

  Signs and symptoms

  • Respiratory: SOB, orthopnea, cough ± pink frothy sputum, sat up and leaning forward.
  • Sweaty, pale, anxious, nauseated.
  • Fluid overload: bilateral fine crackles, peripheral oedema.
  • CV signs: cool peripheries, ↓BP, ↑HR, ↑JVP, S3 heart sound, murmur, cardiac wheeze.

  Investigations

  Treatment should start first if acutely unwell.

  Bedside:

  • ABG: may show ↓O2.
  • ECG: arrhythmias, ischaemic changes.
  • POCUS: bilateral B-lines, pleural effusions.

  Bloods:

  • Basics: FBC (↓Hb as cause), U+E (investigate renal cause and as giving furosemide), LFT (RVF).
  • Extras: troponin (MI), TFT (high or low as cause), BNP (only if diagnosis unclear).

  CXR:

  • Alveolar oedema: bilateral patchy shadowing which may be in bat's wings distribution. More diffuse patchiness in ARDS.
  • Other signs of heart failure e.g. cardiomegaly, Kerley B lines. See CXR findings in heart failure.

  Echo:

  • Heart failure, valve disease.

  Management

  Initial:

  • Supplementary O2 to treat hypoxia. Noninvasive ventilation (CPAP or BiPAP) if persistent hypoxia, acidosis, or respiratory distress despite this.
  • Furosemide IV to reduce fluid overload. If already on PO long-term, double the dose by using the 'same' dose for IV (as IV is double the potency of PO). Monitor fluid balance, and consider fluid restriction and placing urinary catheter.
  • Nitrate IV infusion if BP >140 to reduce cardiac preload. Can be given as SL spray initially.

  If poor response:

  • Critical care options: intubation if refractory to NIV, dobutamine and/or noradrenaline if cardiogenic shock.
  • Further diuretic options: thiazide, spironolactone, metolazone.
  • Salbutamol if there is cardiac wheeze.

  Continued management:

  • Fluid balance: fluid restriction, daily weights. If there is fluid overload, aim for ~1 kg loss per day.
  • Switch to furosemide PO.
  • DVT prophylaxis.
  • Start on HFrEF medication before leaving hospital if this is a first presentation.