The

• Ischemic heart disease (IHD)


  Condition in which there is an inadequate supply of blood and oxygen to a portion of the myocardium; Typically occurs when there is an imbalance between myocardial oxygen supply and demand
• Ischemic heart disease may present as

  • Angina
  • Unstable angina
  • Myocardial infarction

  
• Acute coronary syndrome


  Term that encompasses both unstable angina and myocardial infarction

  
• Angina pectoris


  Symptom complex caused by transient myocardial ischemia, which occurs whenever there is an imbalance between myocardial oxygen supply and demand

  
• Causes of angina


  • Atherosclerosis
  • Aortic valve disease (mainly stenosis)
  • Hypertrophic cardiomyopathy
  • Vasculitis or aortitis
  • Coronary artery spasm
  • Syndrome X

  
• Coronary artery spasm


  May coexist with atherosclerosis, especially in unstable angina, but may occur as an isolated phenomenon in less than 1% of cases, in patients with normal coronary arteries on angiography

  
• Variant angina


  Angina resulting from coronary artery spasm, when accompanied by transient ST elevation on the ECG

  
• Syndrome X


  Constellation of typical angina on effort, objective evidence of myocardial ischaemia on stress testing, and normal coronary arteries on angiography

  
• Syndrome X


  • Many of these patients are women and the mechanism of their symptoms is often unclear; It carries a good prognosis but may respond to anti-anginal therapy
• Stable angina


  Characterised by central chest pain, discomfort or breathlessness that is predictably precipitated by exertion or other forms of stress, and is promptly relieved by rest
• Warm-up angina


  Discomfort comes when patient starts walking and does not return despite greater effort
• Angina decubitus


  Angina that occurs at rest while the patient is recumbent

  
• Nocturnal angina


  Patient may be awakened at night by typical chest discomfort and dyspnea
• Physical examination


  • Frequently unremarkable but should include a careful search for evidence of valve disease, important risk factors, left ventricular dysfunction, manifestations of arterial disease, and unrelated conditions that may exacerbate angina
• Electrocardiogram (ECG)


  May be normal in patients with typical angina pectoris, but there may also be signs of an old myocardial infarction; Repolarization abnormalities, LVH and disturbances of cardiac rhythm or intraventriction are suggestive of IHD; Dynamic ST-segment and T-wave changes that accompany episodes of angina pectoris and disappear thereafter are more specific

  
• Exercise ECG


  Planar or downsloping ST segment depression of 1 mm or more is indicative of ischaemia; Up-sloping ST depression is less specific; False-positive results can occur with digoxin therapy, left ventricular hypertrophy, bundle branch block and WPW syndrome; However, exercise testing may be normal in a significant proportion of patients (False-negative)
• Stress echocardiography


  May show a regional wall hypokinesia in the left ventricle during stress, indicating ischemia
• Myocardial perfusion scanning


  A perfusion defect present during stress but not at rest provides evidence of reversible myocardial ischaemia; A persistent perfusion defect seen during both phases is usually indicative of previous MI
• CT coronary arteriography


  Used to document the presence or absence of CAD in patients with suspected angina

  
• Coronary angiography


  Provides detailed anatomical information about the extent and nature of CAD; Usually performed when coronary artery bypass graft surgery or percutaneous coronary intervention is being considered
• Cardiac biomarkers (serum troponin, CK-MB) are usually not used in patient with stable angina (but it is highly indicated in patient with acute coronary syndrome)
• Non-specific investigations


  • Complete blood count (anemia)
  • Blood sugar
  • Urinalysis (sugar, albumin, urea)
  • Lipid profile
  • Renal function test (blood urea, serum creatinine)
  • Thyroid function test
  • Chest X-ray
  • High-sensitivity C-reactive protein (CRP)
• Principles of management


  • Careful assessment of the extent and severity of arterial disease
  • Identification and treatment of risk factors
  • Advice on smoking cessation
  • Introduction of drug treatment for symptom control
  • Identification of high-risk patients for treatment to improve life expectancy
• Antiplatelet therapy


  All patients with angina secondary to CAD should receive antiplatelet therapy; Low-dose (75 mg) aspirin should be prescribed for all patients and continued indefinitely; Clopidogrel (75 mg daily) is an equally effective alternative if aspirin causes dyspepsia or other side effects
• Statin


  All patients should be prescribed a statin (Rosuvastitin, Atorvastatin, Simvastatin), even if cholesterol is normal
• Nitrates


  Act directly on vascular smooth muscle to produce venous and arteriolar dilatation; Help angina by lowering preload and afterload, which reduces myocardial oxygen demand, and by increasing myocardial oxygen supply through coronary vasodilatation; Sublingual GTN is indicated for acute attacks; Isosorbide dinitrate and isosorbide mononitrate can be given by mouth; Continuous nitrate therapy can cause pharmacological tolerance but this can be avoided by a 6–8-hour nitrate-free period, best achieved at night
• Beta-blockers


  Lower myocardial oxygen demand by reducing heart rate, BP and myocardial contractility; A once-daily cardioselective preparation is preferable; Non-selective β-blockers may aggravate coronary vasospasm; Beta-blockers should not be withdrawn abruptly, as rebound effects may precipitate dangerous arrhythmias, worsening angina or MI
• Calcium channel antagonists


  Lower myocardial oxygen demand by reducing BP and myocardial contractility; Diltiazem and Verapamil can be used as monotherapy; Dihydropyridine calcium antagonists may cause a reflex tachycardia, so it is best to use them in combination with a β-blocker; Calcium channel antagonists must be used with care in patients with poor LV function
• Potassium channel activator (Nicorandil)

  Acts as a vasodilator with effects on the arterial and venous systems, and has the advantage that it does not exhibit the tolerance seen with nitrates
• Ion channel antagonist (Ivabradine)


  Induces bradycardia by modulating ion channels in the sinus node; Does not inhibit myocardial contractility and appears to be safe in patients with heart failure
• Ranolazine


  Inhibits the late inward sodium current in coronary artery smooth muscle cells, with a secondary effect on calcium flux and vascular tone, reducing angina symptoms
• Percutaneous coronary intervention (PCI)


  Involves passing a fine guidewire across a coronary stenosis under radiographic control and using it to position a balloon, which is then inflated to dilate the stenosis; Can be combined with deployment of a coronary stent
• Coronary artery bypass grafting (CABG)

  The internal mammary arteries, radial arteries or reversed segments of the patient's own saphenous vein can be used to bypass coronary artery stenosis; Usually involves major surgery under cardiopulmonary bypass but, in some cases, grafts can be applied to the beating heart ('off-pump' surgery); Arterial grafts have a much better long-term patency rate
• Survival is improved by CABG in symptomatic patients with left main stem stenosis, three-vessel coronary disease when the LAD, CX and right coronary arteries are involved, or two-vessel disease involving the proximal LAD coronary artery
• Prognosis of CAD


  • Related to the number of diseased vessels and the degree of left ventricular dysfunction; A patient with single-vessel disease and good left ventricular function has a 5-year survival of more than 90%, while a patient with severe left ventricular dysfunction and extensive three-vessel disease has a 5-year survival of less than 30% unless revascularisation is performed; Symptoms are a poor guide to prognosis, since spontaneous improvement in angina due to the development of collateral vessels is common; Nevertheless, the 5-year mortality of patients with severe angina (CCS angina scale III or IV) is nearly double that of patients with mild symptoms