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• coronary heart disease :

  • leading cause of death in adults

  • rapidly increasing cause of death in developing countries

  EPIDEMIOLOGY

  — 580,300 Aus aged 18 + (2.8% of adult pop)

  — 2x as high among men (3.8%) as women (1.9% )

  — increased rapidly with age — 12 x as high in people aged 75 and over as in those aged 45 - 54

  — indigenous australian > non-indigienous australains.
• CHD Aetiology:

  Inadequate supply of blood to the myocardium due to obstruction of the epicardial coronary arteries

  due to atheroscelorosis

  results in myocardial hypoxia and accumulation of waste metabolites

  patients may have chronic (stable) or acute (unstable) disease

  — stable angina

  — silent ischemia (eg diabete mellitus ) , atypical chest pain

  — acute coronary syndrome

  • unstable angina , myocardial ischemia
• CHD aetiology

  
• Stable angina :

  Stable : predictable, transient chest discomfort or emotional stress

  pattern of symptoms related to degree of occlusion

  pressure , tightness, burning or heaviness in chest

  tachycardia , diaphoresis , nausea , dyspnoea , fatigue

  lasts < 5 - 10 min
• Acute coronary syndrome = unstable angina

  -development of myocardial ischemia

  -Myocardial infarction

  -non-ST elevation myocardial infarction (NSTEMI)

  -ST elevation myocardial infarction
• development of myocardial ischemia:

  • Causes can be divided into 3 phases

  • Atherosclerotic plaque disruption

  • Platelet aggregation

  • Secondary haemostasis
• myocardial ischemia : clinical manifestations

  • Sudden-onset angina at rest

  • Angina lasting > 20 minutes

  • Occurs at rest or minimal exertion

  • Severe and described as frank pain

  • Usually due to a trigger event
• coronary thrombosis :

  
• myocardial infarction:

  Ruptured plaque resulting in

  coronary thrombosis

  Reduced blood flow = death of

  myocardial cells

  Rest of the heart continues to

  function

  Compensatory mechanisms

  triggered to try to restore blood flow to the rest of heart and to body.

  If coronary artery 'services' a lot of myocardium, more tissue will be lost.
• myocardial infarction : clinical manifestations:

  -tachycardiac

  -nausea

  -crushing central chest pain radiating jaw or arm

  -syncope , fatigue or epigastric, back or right arm pain

  -sharp , burning sensation
• myocardial infarction: Demonstration of cell death , by measurement of cardiac markers

  presence of serum markers and intracellular proteins
• MI

  cardiac troponin I should not be found in the blood : signals myocardial cell damage
• MI

  morphological changes seen on an ECG

  • location of event

  • difference between angina and MI

  Angiograms to quantify the location and severity of the lesion
• Non - ST elevation myocardial infarction (NSTEMI)

  thrombus partly occludes an artery

  • part of heart muscle being supplied by affected artery dies.

  • no characteristic elevation in ST segment of ECG

  • cardiac enzymes e,g. CK-MB , troponin I , Troponin T determine if NSTEMI (unstable angina)
• ST elevation myocardial infarction :

  • thrombus completely blocks coronary artery

  • recognised by characteristic changes it produces on the ECG

  • prompt recognition to ensure reperfusion soon after presentation
• complications of MI:

  -decreased contractility = cardiogenic shock , congestive heart failure

  -ventricular thrombus = embolism

  -electrical instability =arrhythmia

  -tissue necrosis = ventricular rupture = cardiac temponade

  -pericardial inflammation = pericarditis = cardiac temponade
• extent of MI

  • location / extent of occlusion

  • amount of heart tissue supplied by vessel

  • duration of occlusion

  • metabolic needs of affected tissue

  • extent of collateral circulation

  • heart rate , blood pressure and cardiac rhythm
• cardiomyopathies : chronic ischaemic cardiomyopathy

  aetiology : diseases of myocardium associated with mechanical and /or electrical dysfunction

  not secondary to CAD , hypertension , congenital valvular or pericardial abnormalties

  lead to heart failure and progressive disability
• cardiomyopathy : dilated, hypertophic

  
• dilated cardiomyopathies :

  Leading indication for heart transplant

  • Ventricular enlargement with a reduction in ventricular wall thickness

  • Decreased contractile function - impaired systolic function
• dilated cardiomyopathies: aetiology

  Genetics, inflammation, toxic,

  viral, alcohol and metabolic

  factors
• dilated cardiomyopathies: clinical manifestation

  • Fatigue, lightheadedness,

  • Exertional dyspnoe

  • Pulmonary congestion

  • Venous congestion

  • Peripheral oedema
• hypertrophic cardiomyopathies: pathogenesis

  • Diastolic dysfunction

  • Mitral regurgitation

  • Systolic dysfunction (LV ejection

  fraction <50%)
• hypertrophic cardiomyopathies: aetiology

  Genetically determined heart muscle disease

  • L ventricular hypertrophy + disproportionate thickening of ventricular septum

  • Common cause of sudden

  cardiac death in young athletes
• hypertrophic cardiomyopathies :clinical manifestation

  Dyspnoea owing to elevated diastolic LV pressure

  • Angina

  • Syncope

  • Arrhythmias –

  ventricular fibrillation
• pericardium:

  double-layered fibro-elastic sac of visceral and parietal

  layers separated by a (potential) space, the pericardial cavity

  In healthy individuals, pericardial cavity contains 15 to 50 mL

  of an ultrafiltrate of plasma
• pericardium functions :

  Isolates the heart from other thoracic structures

  • Maintains its position in the thorax

  • Prevents it from overfilling

  • Contributes to coupling the distensibility between the two

  ventricles during diastole
• pericarditis:

  acute inflammation of pericardium

  common disorder , viral SLE, RA , Postcardiac surgery , trauma , drug toxicity , inflammatory processes

  
  

  clinical manifestation:

  chest pain , fever , dyspnoea
• pericardial effusion

  accumulation of fluid in pericardial cavity

  
  

  aetiology:

  large fluid volume accumulates in pericardial sac

  -acute pericarditis

  -neoplasm

  -cardiac surgery , trauma , cardiac rupture due to MI

  -dissecting aortic aneurysm
• pericardial effusion: clinical manifestations

  asymptomatic

  dull constant ache in left side of chest

  dysphagia , dysponea , hoarseness , hiccups

  severe = cardiac tamponade signs and symptoms
• cardiac tamponade:

  compression of heart due to accumulation of fluid, pus , or blood in pericardial sac
• constrictive pericarditis :

  
  

  fibrous, calcified scar tissue develops between visceral and parietal layers

  associated with acute pericarditis

  long -standing inflammation : cardiac surgery , infection

  
  

  clinical manifestations include:

  ascites , oedema , dysponea , fatigue , exercise intolerance , muscle wasting , WL , hypotension , arrhythmias
• causes if heart failure :

  -Coronary heart disease

  -high blood pressure

  -faulty heart valves

  -cardiomyopathy
• function of heart:

  moves deoxygenated blood from venous system through right heart into pulmonary circulation

  • moves oxygenated blood from pulmonary circulation through left heart into arterial system

  • right and left heart maintain an equal output to function properly
• heart failure : clinical diagnosis

  Symptoms caused by impaired ability of one or both ventricles to pump at a normal pressure

  structual or functional cardiac disorder
• heart failure: characterised by

  Specific symptom’s e.g. dyspnoea and fatigue

  signs e.g. fluid retention
• epidemiology of heart failure :

  102,000 people with HF , 2018, 2/3 over 65
• vicious cycle of heart failure

  
• heart failure with reduced ejection fraction (HFrEF)

  left ventricular EF <40

  common cause : CHD , previous MI , hypertension

  less common : idiopathic dilated cardiomyopathy , valvular disease

  leads to : poor cardiac output , activated neurohormonal responses that long term can be either maladaptive or ineffectual
• Heart failure with preserved ejection fraction (HFpEF)

  Left ventricular EF > 50%

  Pathophysiology :

  highly heterogenous disease

  Echocardiography — important diagnostic for structural and functional changes

  myocardial stiffening, reduced left ventricular compliance and impaired relaxation plus impaired oxygen uptake and remodelling of skeletal muscle