Angina Flashcards
Pathogenesis of angina is?
The increase in myocardial oxygen demand distal to an atheromatous plaque. In stable angina the atheroma decreases lumen size impeding blood flow.
How does an atheroma lead to an MI?
The surface of the atheroma becomes ulcerated causing intense platelet aggregation, a thrombus forms and completely occludes a coronary artery.
How does an atheroma form?
Irritants such as high LDL, toxins from smoking, high BP causes endothelial dysfunction. LDL moves into the tunica intima. Macrophages envelop LDL and form foam cells. Fibrous cap made up of smooth muscle cells and they add calcium deposits to intima and cap. Blood vessels become crunchy and narrower.
What risk factors are modifiable?
Diabetes (good glycemic control), hypertension, smoking, cholesterol levels.
Non-modifiable risk factors
Age, first degree relative with ischeamic heart disease less than 60 and being male
What investigations would you do?
12 lead ECG, exercise tolerance test, myocardial perfusion scintigraphy, echocardiogram
What would you see on a 12 lead ECG?
Often normal but T wave inversion and ST depression can be seen during an attack
What would you see on the ECG during an exercise tolerance test?
ST depression
How sensitive is the exercise tolerance test?
80%
What test might you use in patients with resistant angina, unstable angina, NSTEMI, strongly positive exercise test, ventricular arrythmias?
Coronary angiography
What blood tests can you do?
FBC, U+E, creatinine, fasting glucose and lipids. TFTs. Creatinine kinase and troponin are only raised if MI occurs
Why do FBCs matter?
Need to exclude anaemia as a cause for chest pain and SOB
Why are TFTs done?
As thyroxicosis increases the work of the heart whilst hypothyroidism increases cholesterol levels
Why are urea and electrolytes done?
To assess renal function
Why is fasting glucose done?
To check for diabetes Normal: 3.9 to 5.5 mmols/l (70 to 100 mg/dl)
Prediabetes or Impaired Glucose Tolerance: 5.6 to 7.0 mmol/l (101 to 126 mg/dl)
Diagnosis of diabetes: more than 7.0 mmol/l (126 mg/dl)
Why are fasting lipids done?
To check the cholesterol to HDL ratio
What are the types of angina?
Stable, unstable, nocturnal and variant
What is the non-pharmacological management?
Risk factor modification
What is advised as management of an attack?
Rest
Take GTN
Take a second dose of GTN after 5 minutes if the pain has not eased.
Take a third dose of GTN after a further 5 minutes if the pain has still not eased.
Call 999 for an ambulance if the pain has not eased after another 5 minutes (ie 15 minutes after onset of pain), or earlier if the pain is intensifying or the person is unwell.
First line drug treatment?
Beta-blocker or CCB (non-dihydropyradines)
If not adequately controlled add what as a second drug?
Ivabradine (funny channel inhibitor reducing HR), Nicorandil (vasodilator to stop vasospasm by inhibiting Rho kinase) or Ranolazine (inhibits by reducing Na entry into Myocytes reducing Ca levels therefore less contractility)
When might angioplasty be done?
Those at high risk of MI and subsequent heart failure
What is the definition of myocardial ischeamia?
Inadequate oxygen delivery to the heart myocardium
