Cardiovascular Therapeutics Flashcards
IHD
Ischaemic Heart Disease
Angina or MI
Greatest risk factor for chronic heart failure
IHD as the cardiomyocytes become dysfunctional
Risk factors for developing heart disease
Male Gender Family History Ethinicity Smoking - Most important Diabetes Hypercholesterolaemia Hypertension Sedentary Lifestyle Obesity
Stable Angina
Atherosclerosis in coronary artery, limiting heart’s ability to respond to increased demand
Symptoms on exertion but relieved by rest
Unstable Angina
Plaque rupture and formation of a non-occlusive thromboembolism or vasospasm
Symptoms at rest
ECG Diagnosis of Angina
ST-Depression
Angiography
Needed for definitive diagnosis of angina
Insert catheter into radial artery and advance it up into coronary circulation
Insert radio-opaque dye and X-ray heart
This would show the narrowing seen in IHD
Management of Angina
Lifestyle
- Stop smoking
- Exercise
- Diet
- Weight
Coronary artery bypass grafting
Angioplasty & Stenting
PTCA
Percutaneous Transluminal Coronary Angioplasty
Angioplasty with a stent
Primary treatment of heart attack in the UK
STEMI
ST Elevation Myocardial Infarction
GTN
Glyceryl Trinitrate (Drug to treat angina)
Releases NO in blood, leading to vasodilation as it activates guanylyl cyclase and releases cGMP
Major effect is venodilation that reduces pre-load, reducing work on heart and thus angina symptoms
Delivery of GTNs
As a spray under the tonguethat either prevents attacks or can relieve one
Risk of oral Nitrates
Prolonged exposure can reduce effectiveness; tolerance is developed
How to clinically overcome nitrate tolerance
Aim for a nitrate free period; 2 doses rather than 3 per day
Beta-blockers
Selective B1 Adrenoceptor blockers
First choice drugs for prevention of IHD
Negative Inotropic and chronotropic effects reducing cardiac work and preventing symptoms
When does coronary flow occur and how do beta-blockers affect this
Coronary flow only occurs during diastole
By slowing the heart, the diastolic period will be increased, as will the time for coronary blood flow
General effects of Beta-Blockers
Anti-arrhythmic effects and reduce the risk of myocardial infarction.
Calcium channel blockers
Vasodilators and improve coronary blood flow, so prevent symptoms of IHD
Types of Calcium Channel Blockers with example
Rate-limiting Agents (e.g. Verapamil)
Dihydropyridines (e.g. Amlodipine)
Rate Limiting Agents Ca2+ Channel Blockers
Act on the heart and have myocardial depressant actions
- Used as a substitute for beta-blockers in AFib as they have a similar effect
Dihydropyridines
Selective Ca2+ channel blockers that are selective for vascular smooth muscle and lead to vasodilatation
Ace Inhibitors
Reduces mortality of patients with IHD
Potassium Channel Activators
Nicorandil - combined NO donor and activator of ATP sensitive K-Channels
Opens K+ channels, letting K+ leave cells leading to hyperpolarisation and making them less excitable - Vasodilation
Target is ATP-sensitive K+ channel
Ivabradine
Inhibits If channels (Pacemaker Na/K currents in the SAN)
Reduces heart rate
(Might be potassium channel activators)
