Download Cardiovascular 20 – Ischaemic Heart Diease and Chest Pain

Cardio 20 – Ischaemic Heart Disease and Chest Pain
Anil Chopra
1 & 4. State the main cardiac factors which give rise to chest pain and define
myocardial ischaemia and its pathophysiology.
Angina Pectoris: chest pain due to myocardial ischaemia. Coronary artery has
limited flow due to atherosclerosis. Oxygen demand of the myocardium is not met.
Coronary Stenosis:
70% loss of luminal area  exercised induced angina
90% loss of luminal area  rest angina
Angina can also be due to:
 Coronary artery spasm
All REDUCE
 Microvascular ischaemia
SUPPLY of
 Coronary arterio-venous fistula.
blood to the heart
 Anaemia
 Uncontrolled tachycardia (fast heart beat)
All INCREASE
 Left ventricular hypertrophy
DEMAND of O2
 Hypertension
demand in the
 Increased catecholamine levels (stress)
myocardium
Types of Angina
Stable Angina – occurs over several weeks but on exertion.
Unstable Angina – angina even at rest but gets worse on exertion
Variant Angina – pain is spontaneous, shows ST elevation on ECG.
Syndrome X – myocardial ischaemia without evident coronary atherosclerosis or
large vessel disease.
2. State the main clinical investigations that help diagnose angina.
Investigations
HISTORY:
 Should be simple, un-technical and open
 Site, radiation, character, onset (i.e. sudden or gradual) severity, positional,
alleviating factors.
 Risk factors: smoking, diabetes, hypertension, cholesterol, family history.
 Past medical history, previous treatment, drug history, allergies, social history.
Differential diagnoses for Chest Pain
Angina
Pericarditis
Musculoskeletal problem
Gastro-oesophageal
Pulmonary
Differential Diagnosis for Severe Chest pain at Rest
Myocardial infarction
Aortic dissection
Pericarditis
Pulmonary Embolus
EXAMINATION:
 Pulse rhythm
 Blood pressure
BLOOD TEST:
 Lipids (triglyceride, LDL and HDL count)
 Blood glucose
 Thyroid function tests
 Full blood count (FBC)
CORONARY ANGIOGRAPHY:
 Tube inserted in artery in the leg and directed toward coronary artery, dye is
injected and arteries taken.
RESTIING 12 LEAD ECG:
 May be normal if no pain at rest.
 May be evidence of previous myocardial infarctions in q-waves.
 May show LV hypertrophy.
 Check rhythm & conduction abnormalities.
 ST elevation in myocardial infarction.
EXERCISE/STRESS TEST
 Use treadmill/bicycle to cause exertion
 Look at ECG changes
 Can also use vasodilators and inotropic drugs.
3. State some of the drug treatments for angina.
TREAT THE UNDERLYING PROBLEM
(Symptom alleviation)
β-blockers:
o 1st line of therapy
o lower heart rate, reduce myocardial wall tension, and reduce cardiomonocyte
ATP requirement.
 Don’t use if bradycardia, AV block, sick sinus syndrome, left ventricular failure,
asthma, depression, vascular diseases are present.
 Side-effects include fatigue, lethargy, insomnia, erectile dysfunction.
 E.g.s  atenolol, metoprolol, bisprolol
Calcium Antagonists:
o Decrease heart rate
o Increase coronary flow.
o Decrease coronary spasm
o Negative inotropic reactions
 Don’t use if decompensated heart failure, bradycardia, AV block, sick sinus
syndrome are present.
 Side-effects include hypotension, peripheral oedema, constipation, headache and
dizziness.
 E.g.s  Vermapil, Diltiazem, nifedpine, amlodipine
Nitrates:
o Reduce preload by reducing venous dilation
o Dilates coronary arteries.
o Glyceryl trinitrate is used for prophylaxis during exercise.
o Are converted to NO and cause vasodilation.
 Don’t use if aortic sinus, or hypertrophic cardiomyopathy are present.
 Side-effects include headache, hypotension, presyncope and syncope
Nicorandil:
o Activates K+ channels with nitrate and causes veno & ateriodilation
o Only used when previous drugs are not safe.
 Don’t use in situations of low cardiac output.
 Side-effects include headaches and flushing.
If Channel Blockers:
o Reduces heart rate by reducing sinus rhythm
o Improves exercise capability.
o Used only if β-blockers are unable to be used.
 Side-effects include visual disturbances.
Angioplasty:
o Balloon attached to catheter placed in coronary artery and then blown up, or
stent used.
o Increases coronary blood supply.
o Used for symptom control although ineffective in stable angina.
Coronary Bypass:
o Other artery used to bypass coronary artery. Lasts long.
 There are other risks in open heart surgery & rehabilitation.