Ischaemic Heart Disease Flashcards
What is the definition of Ischaemic Heart Disease?
It is a syndrome resulting from myocardial ischamia because of the imbalance between supply and demand of oxygen in the heart
What percentage of patients above 35 years old have asymptotic ischemia?
5%
What is the most commonest form of arrhythmia?
Ventricular fibrillation morning
What are some risk factors for developing IHD?
- Male
- Age
- Smoking
- Family history
- Genetic predisposition
- Diabetes
- High cholesterol
- Obesity
What does DO2 mean?
It is defined as the oxygen delivery
What does VO2 mean?
It is defined as the consumption of oxygen
What causes an increase in oxygen consumption?
- Tachycardia
- Increased preload/afterload
- Increased contractility
What causes a decreases in oxygen consumption?
- Anaemia(low Hb), hypoxia, decreases temperature, increased pH(more alkaline), decreased 2,3 DPG
- Decreased coronary blood flow:
Tachycardia
Diastolic hypotension
Increased hypotension
What are the characteristics of an unstable angina?
- Angina at rest
- Sudden increase in the severity, duration and frequency
- New onset: occurring in less than 2 months
- Associates with ST changes if there’s severe disease
- May occur after myocardial infarction
What are the characteristics of chronic stable angina?
- Usually substernal
- Radiates to the neck and arm
- Gets better with Rest
- Gets worse of exertion
- 50% of the time presents with some sort of occlusion
Which surgery has a high peri-operative mortality?
- Vascular surgery- it automatically becomes more than 5%
What types of surgeries are between 1-5% mortality rate?
- Intraperitoneal
- Intrathoracic
- Orthopedic
- Prostate
How do we treat ischaemic heart disease?
- lifestyle modifications
- correct the risk factors as far as possible
- medication
- correct the coronary lesions CABG/PCA
What do nitrates do?
- dilate the coronary arteries
2. causes relaxation of the vascular smooth muscles
What treatment can we give to treat IHD?
- Nitrates
- Calcium channel blockers
- B-blockers
- ACE-inhibitors
- Combination therapy
In which two cases would we stop aspirin pre-operatively?
- prostate surgery
- neurosurgery
Why do we stop ACE-inhibitors before surgery?
Has a high likelihood of causing hypotension
How do we diagnose myocardial infarction peri-operatively?
- monitor with ECG
- Monitor patients symptoms
- Check troponins every 6 hours
What is the treatment for myocardial infarction peri-operatively?
- oxygen
- aspirin
- morphine
- refer to cardiology for definitive treatment
What does the NYHA-New York Heart Association classification entail?
-It is a classification of heart failure from 1 until 4
What is heart failure?
-The inability to meet the oxygen demand of the heart
What kind of blood flow is in coronary blood vessels?
-low flow high oxygen extraction this is why when some patients exercise they exercise angina, and dyspnea
What is the single most important risk factor for peri-operative myocardial ischaemia and infarction?
Tachycardia because it causes shortened diastole which leads to decreased perfusion of the left ventricle
How can we manage the patients peri-operative risk for myocardial ischaemia?
By offering beta-adrenergic receptor blockers