Heart failure

• Cardiac output is defined as:

  CO (mL/min) = heart rate (bpm) x stroke volume (mL/beat)
• Left sided heart failure is the most common type of heart failure. Causes include coronary artery disease, myocardial infarction and hypertension
• Left sided HF leads to back flow into the pulmonary veins, leading to pulmonary oedema
• Symptoms of left sided HF:

  • dysponea
  • reduced exercise tolerance
  • orthopnoea
  • paroxysmal nocturnal dyspnoea
  • nocturnal cough (with or without pink frothy sputum)
  • wheeze (cardiac asthma)
• Right heart failure is generally as a result of left sided heart failure due to raised intrathoracic pressure
• In right heart failure blood backs up into the vena cava, leading to peripheral/systemic oedema
• Cor pulmonale is right ventricle dysfunction/failure due to a primary disorder of the respiratory system. The respiratory disorder leads to pulmonary hypertension and therefore increased preload
• Signs of right HF:

  • peripheral oedema
  • ascites
  • facial engorgement
  • pulsation in neck + face (tricuspid regurgitation)
• systolic heart failure = reduced left ventricle ejection fraction. Less blood is being pumped out of the heart during systole leading to increased blood remaining in the heart. This leads to ventricular stretch, dilation and remodelling.
• Diastolic heart failure = preserved left ventricle ejection fraction. Ventricular relaxation and filling is impaired.
• Less than 50% function means reduced LVEF
• Ejection fraction = (stroke volume / end diastolic volume) x 100
• Signs of HF on examination:

  • pallor - pale due to poor perfusion
  • Oedema - peripheral / ascites
  • bilateral basal crackles
  • 3rd heart sounds
  • murmurs
  • increased capillary refill time
• New York heart association classification is a way of rating a patients dyspnoea from I - IV. IV means the patient is symptomatic at rest.
• The RAAS is activated in HF due to reduced cardiac output and renal hypoperfusion. Angiotensin II and aldosterone lead to the retention of sodium and water. This increases the preload.
• The sympathetic nervous system is activated by heart failure. It is activated by Baroreceptors and the RAAS. This increases heart rate and therefore afterload.
• Natriuretic peptides are released from the heart in response to abnormal stretch and volume overload. BNP (brain natriuretic peptide) is released from the ventricles which leads to vasodilation.
• Causes of heart failure include:

  • ischaemic heart disease
  • hypertension
  • valvular disease (commonly AS)
  • arrhythmias (commonly AF)
  • dilated cardiomyopathy
• For suspected heart failure, measure NT-proBNP

  • > 2000 ng/L needs an urgent referral for specialist assessment and TTE within 2 weeks
  • 400-2000 ng/L needs a specialist assessment and TTE within 6 weeks
  • <400 ng/L is unlikely to be heart failure
• TTE is a transthoracic echocardiogram. It can assess for valve disease plus the systolic and diastolic function of the ventricles.
• Gold standard imaging for heart failure is a cardiac MRI but TTE is first line
• An ECG should be performed for suspected heart failure:

  • Raised resting heart rate
  • Left axis deviation
  • Left ventricle hypertrophy
  • ST and T wave abnormalities
  • LBBB
  • Atrial fibrillation as a potential cause
• CXR findings suggestive of heart failure:

  • Cardiomegaly - increased cardiothoracic ratio
  • Bat wings - alveolar oedema
  • Prominent upper lobe vessels
  • Kerley B lines - interstitial oedema
  • Blunting of costophrenic angles - pleural effusion
• Management of reduced LVEF:

  1. ACEi + Beta blocker (can use ARB if not tolerating ACEi)
  2. Mineralocorticoid receptor agonist + ACEi / ARB + Beta blocker
  3. Specialist- digoxin, ivabradine, valsartan
• When commencing a patient on an ACEi / ARB make sure to check U&Es before and 1-2 weeks after. Also check after every dose increase.

  These medications are also used in hypertension so monitor patients blood pressure.
• Spironolactone is a MRA that can cause hyperkalaemia so make sure to monitor potassium levels
• For all types of heart failure, diuretics are used for relief from fluid congestion. Patients with reserved LVEF tend to be on low dose furosemide.
• Calcium channel blockers should be avoided in heart failure patients with reduced LVEF
• All heart failure patients should receive pneumococcal and influenza vaccinations. They should also have an echocardiogram every 6-12 months.
• Acute heart failure is often caused by decompensated chronic heart failure
• Causes of acute heart failure:

  • Overload with aggressive IVI
  • MI
  • Arrhythmias
  • Sepsis
  • Hypertensive emergency
• Symptoms of acute heart failure:

  • Chest pain - if ACS underlying cause
  • Acute dyspnoea
  • Confusion
  • Cough +/- frothy pink sputum
  • Fever - in sepsis
  • Palpitations - in arrhythmias
• Signs of acute heart failure on examination:

  • Tachypnoea
  • Hypoxia
  • Tachycardia
  • 3rd heart sound
  • Bilateral basal crackles- pulmonary oedema
  • Hypotension - cardiogenic shock
  • Raised JVP
  • Peripheral oedema
• BNP should tested in suspected acute heart failure. It is sensitive but not specific. When negative it can rule out heart failure as the cause of the patients symptoms.
• An ABG in acute heart failure will show type 1 respiratory failure- low oxygen without a raise in CO2
• Acute heart failure treatment = SODIUM

  S - Sit up

  O - oxygen

  D - diuretics

  I - IV fluids stopped

  U - underlying cause

  M - monitor fluid balance
• In severe cases of acute heart failure the following may be needed:

  • IV opiates - vasodilators (in severe hypertension or ACS)
  • IV nitrates - vasodilators (in severe hypertension or ACS)
  • Inotropes to increase cardiac output
  • Vasopressors such as noradrenaline to increase blood pressure
  • NIV or invasive ventilation
• The most common cause of right heart failure is left heart failure