Heart Failure

Background to Congestive Heart Failure Normal cardiac output needed to adequately perfuse peripheral organs – Provide O 2, nutrients, etc – Remove CO 2, metabolic wastes, etc – Maintain fluid flow from capillaries into interstitial and back into venous system  if flow reduced or pressure increased in venous system  build up of interstitial fluid = edema Because CO is a function of – Heart Rate – determined by pacemaker cells in the sinoatrial node – Stroke volume – determined by fill rate and contractile force – Atrial/ventricular/valvular coordination Any negative change on above can lead to inadequate perfusion and development of the syndrome of heart failure

Heart rate – Function of sympathetic, vagal nervous activity Neuro-hormonal substances – 1° angiotensin II – 2º vasopression (anti-diuretic hormone = ADH) Stroke volume – Function of – Venous tone function of sympathetic activity (α 1, α 2 receptors) – Vascular volume depends on » Intake of fluids (thirst) » Output of fluids (urine, sweat, etc) » Distribution of fluids (Starling’s law) Myocardial contractility (MC proportional to sympathetic tone [β 1 receptors])

Characteristics of some adrenoceptors (sympathetic nerves) α1α1α1α1 α2α2α2α2 β1β1β1β1 β2β2β2β2 Smooth muscle Arteries/ Arteries/ veins veinsconstrictconstrict/dilatedilate Skeletal Skeletal muscle muscledilate Heart Rate Rate(increase) Force of Force ofcontractionincrease Tissues and effects receptors

Risk factors Hypertension Coronary artery disease Male gender Diabetes mellitus Valvular heart disease Myocardial infarction Atrial fibrillation

Causes of heart failure Diastolic Ischaemic Heart Disease Hypertension Idiopathic dilated cardiomyopathy Heart valve disease Systolic Ischaemic Heart Disease Hypertension Idiopathic dilated cardiomyopathy Chronic alcohol Viral infections Heart valve disease Obesity

Systolic versus diastolic heart failure Systolic – 3rd heart sound – Cardiomyopathy – Shift of left apex – Mitral regurgitation – Male – Heart disease – smoker Diastolic – High BP – Aortic ejection murmur – 4th heart sound – Female – hypertension

Symptoms and signs Breathlessness – Exercise – Changing posture Paroxysmal nocturnal dyspnoea Ankle oedema Cough or wheeze Reduced exercise Fatigue Low blood pressure Tachycardia  Jugular venous pressure (JVP)  Serum creatinine  Serum urea Low serum sodium

Remove/treat precipitating factors Arrhythmias Anaemia Hyper/hypothyroidism Infection Salt and fluid intake Drugs Alcohol

Medications exacerbating HF NSAIDs – includes COX-2 inhibitors Negative ionotropes – verapamil and diltiazem – Anti-arrhythmic medication (except amiodarone & digoxin) – too high dose or rapid escalation of beta blockers Complementary medicines

Pharmacotherapy in Systolic Heart failure Drug treatment of heart failure associated with a reduced left ventricular ejection fraction (left ventricular systolic dysfunction) Diuretic (loop)( Patients with fluid overload) ACEI – angiotensin-II receptor antagonist may be a useful alternative for patients who, because of side effects such as cough, cannot tolerate ACE inhibitors – Patients who cannot tolerate an ACE inhibitor or an angiotensin-II receptor antagonist, or in whom they are contra-indicated, may be given isosorbide dinitrate with hydralazine Beta blocker (add when stable) – bisoprolol and carvedilol Digoxin (earlier if AF) Spironolactone – If spironolactone cannot be used, eplerenone may be considered for the management of heart failure after an acute myocardial infarction with evidence of left ventricular systolic dysfunction Increasing severity

Diastolic Heart Failure - A lack of evidence Beta blockers – Slow heart -allow filling – Decrease myocardial O 2 demand ACEI/ ARBs – Some evidence of benefit Allow filling to occur – reverse left ventricular hypertrophy Diuretics – Only if oedema present Aldosterone antagonists Statins-secondary prevention

Considerations and Adverse effects Diuretics – Dehydration, electrolyte imbalance ACEI/ ARBs – First dose BP, cough, RF, potassium Beta Blockers – Worsening symptoms heart failure, classic side effects Digoxin – toxicity Spironolactone – Gynaecomastia, potassium disturbances