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Chapter 1: Chest Pain & Acute Coronary Syndromes
Chapter 2: Valvular Heart Disease
Chapter 3: Heart Failure
Chapter 4: Cardiac Arrhythmias
Chapter 5: Atrial Fibrillation
Chapter 6: Cardiovascular Prevention
Chapter 7: Coagulation
Chapter 8: Lipids & Cardiovascular Disease
Chapter 9: Diet – Eat healthy for a better heart
Cardiovascular disease remains a major health problem in South Africa. There are many excellent cardiology textbooks currently available. However, these are large, extremely comprehensive and not ideal to look up something quickly. Medical students, general practioners, medical officers and registrars need a resource that is readily available. EasiRead series fits into this niche. In Heart Disease I have arranged the chapters in a manner that covers the day to day cardiac problems encountered in daily practice. I have attempted to keep the text concise, easily readable yet accurate and current.
Professor Pravin Manga MBBCh, FCP (SA), PhD, FRCP Professor and Academic Head Division of Cardiology University of Witwatersrand and Charlotte Maxeke Johannesburg Academic Hospital additional authors: Professor D Raal Doctors AG Beeton, RE Hodgson and PF Wessels
Chapter 1 CHEST PAIN AND ACUTE CORONARY SYNDROMES
In South Africa over eight hundred thousand people experience acute mycocardial infarction (AMI) of which two hundred thousand die and half do so before reaching the hospital. Before the era of the coronary care unit mortality reached 30%. With the introduction of coronary care units the mortality dropped to 15% and in the modern era of revascularisation, mortality has dropped to 5%-6%.
ACUTE CORONARY SYNDROME
Acute coronary syndrome results from acute plaque rupture or plaque erosion with subsequent thrombosis and occlusion. They are divided into two major categories.
- Non ST elevation myocardial infarction and unstable angina.
- ST elevation myocardial infarction (classical myocardial infarction).
- angina which occurs at rest lasting at least 20 minutes.
- angina that is increasing in frequency and severity.
- post-infarction angina.
- severe pain of new onset (less than one month).
Deep T wave inversion in anterior leads but no ST elevation. Troponin T was positive in this patient
2. ST segment elevation MI (STEMI)
The criteria for AMI in the presence of persistent ST segment elevation.
Acute inferior myocardial infarction (ST segment elevation in inferior leads)The differential diagnosis of chest pain
There are many causes of chest pain; but the following are critical to diagnose:
Other causes of chest pain one needs to consider
- acute pericarditis
- gastro-oesophageal reflux disease
- oesophageal spasm
- gastritis or peptic ulcer disease
- costochondritis (Tietze’s syndrome)
I. Non-ST elevation myocardial infarction
Once a diagnosis of non-ST elevation MI is made, the patient should be admitted to hospital, preferably into a coronary care unit. Any aggravating factors (eg uncontrolled hypertension, cardiac failure, arrhythmias, infection or anaemia) should be treated.
A. Risk stratify the patient according to the TIMI risk score
1 age > 65. 2 greater than 3 coronary disease risk factors 3 coronary artery stenosis > 50%. 4 aspirin in past 7 days 5 elevated cardiac biomarkers 6 severe angina (> 2 episodes in less than 24 hours) 7 ST depression or elevation > 0.5 mm
Each point equals 1; 0–2 equals low risk; 3-4 equals medium risk; 5–7 equals high risk.
B. Drug Management
1. Aspirin (75-150mg) stat and then daily. 2. Clopidogrel 300 mg stat and then 75 mg daily. 3. Anticoagulation. Either unfractionated heparin i.v. (keep PTT 2 x normal) or low molecular weight heparin subcutaneously (Enoxiparin 1 mg/kg). Anticoagulate for at least 48 hours. 4. IV nitrates for pain control; use with caution if there is hypotension or hypovolemia. 5. Beta-blockers if no contraindication is present 6. Glycoprotein 2b3a platelet receptor inhibitors in very high risk individuals, especially if early coronary intervention is planned. 7. Start statin therapy. A modern example is rosuvastatin. 8. Aim to stabilize patient. If chest pain settles quickly and patient at low risk, patient can be managed medically. Plan for an exercise ECG in two weeks. 9. If patient unstable (ongoing chest pain, cardiac failure) or high risk, refer for coronary-angiography and subsequent revascularization.
II. ST elevation myocardial infarction (classical MI)
Once diagnosis is confirmed and other causes of chest pain excluded, the patient needs to be immediately referred to a cardiology unit if possible and admitted to a coronary care unit.
Control cardiac pain
1 IV nitrates very useful 2. Morphine, if no pain relief with nitrates
Measures to limit myocardial infarct size and decrease mortality
- Give to all patients with STEMI where there are
- typical features of STEMI
- time to primary PCI greater than 2 hours or primary PCI not available
- no contraindications to thrombolytic therapy
- Contraindications to thrombolytic therapy are
- recent stroke or surgery
- bleeding disorder
- persistent BP greater than 180mm Hg after pain control
Thrombolytic success to be considered if pain settles, ST segment elevation resolves > 50% and there is haemodynamic stability. Aim to refer these patients for coronary angiography in 24-48 hours.
For thrombolytic failure: Refer the following patients for urgent percutaneous revascularization.
- ongoing severe chest pain
- < 50% ST segment resolution
- haemodynamic instability
- malignant ventricular arrhythmias
Therapy on discharge