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Management of Anginaand
Acute Myocardial Infarction
CLINICAL PRESENTATIONS
I. Stable angina pectoris Ischaemia due to fixed athromatous stenosis
II. Unstable angina Dynamic obstruction due to plaque
rupture and superimposed thrombosis
III. Acute Myocardial Infarction Myocardial necrosis due to acute occlusion of coronary artery
Acute Coronary Syndrome
Unstable Angina & AMI
Factors infulencing myocardial oxygen supply and demand
OXYGEN DEMAND
Cardiac work- Heart rate, blood pressure Myocardial contractility,
LV hypertrophy
OXYGEN SUPPLY
Coronary blood flow Duration of diastole
Coronary perfusion pressureCoronary vasomotor toneOxygenation- haemoglobin
oxygen saturation
Activities precipitating angina
Physical exertion
Cold exposure
heavy meals
Intense emotion
Lying flat
Vivid dreams
Risk stratification in stable angina
HIGH RISKPost infarction anginaPoor effort toleranceIschaemia at low work loadLt main or three vessel diseasePoor LV function
Low risk
Predictable exertional anginaGood effort toleranceIschaemia only at high workloadSingle or minor two vessel diseaseGood LV function
Management of Angina
Careful assessment of the likely extent and severity of arterial disease
Identification and control of significant risk factors
Use of measure to control symptoms
Identification of high risk patients and application of treatment to improve life expectancy
Advice to patient with stable angina
.Do not smoke
.Ideal body weightregular exercise.Avoid severe , unaccustomed exercise, vigorous exercise after heavy meal or in very cold weather.Sublingual nitrate before exertion that may induce angina
II. MEDICAL TREATMENT
A. Symptomatic ( prevent or relieve angina Nitrates- Sublingual / buccal GTN
Transdermal GTN Oral long acting ntrates
(isosorbide mono/dinitrates)
-Beta blockers- Atenolol 50-100 mg/d Metoprolol 25-50 mg/d
-Ca channel blocker( when beta blocker is contra-indicated or in case of coronary spasm)
Nifedipine 5- 20 mg 8 hourlyNicardipine 20-40 mg 8 hourlyAmlodipine 2.5-10 mg odDiltiazem 60-120 mg 8 hourlyVerapamil 40-80 mg 8 hourly
Potassium channel activator
Nicorandil sodium 10-30 mg 12 hourly
B. Prognostic treatment ( To improve long term prognosis and prevent coronary event )
-Asprin – 75-150 mg/d
-Other antiplatelet – Clopidogrel( if patient can not tolerate asprin) 75 mg daily
-Lipid lowering agents- Statins, Fibrates
III. SURGICAL ( INVASIVE ) TREATMENT
A. Percutaneous Coronary Intervention
-Balloon angioplasty-Implantation of coronary stent
B. Coronary Artery Bypass Graft ( CABG )
Antiplatelet ( Asprin and Clopidogrel ) and aggressive lipid lowering therapy shown to slow progression of disease in native coronary vessel and bypass graft
Comparism of PCI and CABGPCI CABG
Death 0.5% 1.5%MI 2% 10%Hospital stay 12-36 hour 5-8daysReturn to work 2-5 days 6-12weeksRecurrent angina 30% at 6 month 10% at 1 yearRecurrentrevascularisation 20% at 2 yr 2% at 2 yrNerological complication Rare common
Other complications Emergency CABG Diffuse myocardialVascular damage damage
InfectionWound pain
Management ofAcute Myocardial Infarction
DIAGNOSIS OF AMI
At least two of the followings
- History of ischaemic type of chest pain
- Evolving ECG changes
- Rise and fall of cardiac enzymes
ST Elevation Q wave
CARDIAC ENZYMES
Enzymes Peak Persist
Troponin I 2-4 hours 7 days
CKMB within 24 hours 48 hours
SGOT ( AST ) 48 hours 72 hours
LDH 72 hours 10 days
Treatment of Acute Myocardial Infarction
Acute condition
Keep in coronary care unit ( CCU ) provide facilities for defibrillation
High flow oxygen
IV access and ECG monitor for arrhythmias
Pain relief- IV morphine 10mg or diamorphine 5 mg
with metoclopramide or cyclizine
Asprin -300 mg chewed
REPERFUSION
IV thrombolysis with Streptokinase 1.5 million units over 1 hour (within 12 hour after onset of chest pain)
Other thrombolytic agents- r TPA
Urgent PTCA
As primary treatment
Failed thrombolysis
Contraindication to thrombolysis
Re infarction
Other treatments
-IV atenolol – improve survival prevent myocardial rupture
IV nitrate infusion- for persistent pain
Anticoagulants( SC heparin) in addition to oral asprin may prevent reinfarction after thrombolysis and prevent DVT and pulmonary embolism
SUBSEQUENT MANAGEMENT ( SECONDARY PREVENTION )
Oral beta blocker ( atenolol ) if LV function is good
ACEI if LV function is poor
Asprin 75-100 mg/d ay
Lipid lowering therapy
Modification of risk factor – Smoking, exercise, diet
PTAC or CABG
ACUTE COMPLICATIONS OF AMI
Cardiac arrest
Cardiac arrhythmias (especially ventricular arrhythmia )
Cardiac conduction disturbance ( heart block )
Cardiac failure- extensive myocardial infarction
Cardiogenic shock
Pericarditis
LATE COMPLICATIONS OF AMI
Recurrent angina or infarction
Thromboembolism
Mitral regurgitation – ruptured cordae tendinae/ papillary muscle dysfunction
Ventricular free wall rupture- haemopericardium
Ventricular aneurysm
Acute ventricular septal defect
Post-myocardial infarction syndrome (Dressler'ssyndrome ) Immunological reaction- fever,arthralgia,pericarditis, pericardial effusion
Recurrent arrhythmias
Shoulder hand syndrome
Psychological- depression
POOR PROGNOSTIC FACTORS
Old age
Large infarct
Poor LV function
Residual myocardial ischaemia
Ventricular arrhythmias