Pharmacological Treatment of IHD Part 1 Flashcards

1
Q

Treating Imbalance in supply and demand of myocardial oxygen

A

Demand increases: work rate and work load

Supply decreases: thrombus, atheroma, vasoconstriction

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2
Q

Regulation for coronary blood flow

A

Endothelium - derived relaxing factor - NO
Sheer stress causes influx of calcium, which turns CTP->cGMP, which causes relaxation of smooth muscle
Dephosphorylating myosin LC-PO4 also relaxes smooth muscle

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3
Q

Regulation of Cardiac Workload

A

End diastolic volume (preload) regulated b sympathetic system and RAAS (contractility of venules) and just RAAS (H2O and Na+ retention)
Heart Rate (symp NS/Ca2+)
Contractility (symp NS/Ca2+)
Lateral peripheral resistance (symp NS, RAAS)

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4
Q

Stable Angina

A

Predictable pattern of pain, during exercise, relieved by rest
Treatment: decrease work load and/or increase blood supply and treat risk factors
Nitrates do both e.g. GTN, but
Side effects: postural hypotension, headache, dizziness

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5
Q

Reflex Tachycardia

A

Due to activation of SNS - if treatment causes it, use a beta blocker to block effects of SNS
Beta blockers decrease frequency and force of contraction, decreasing cardiac output
Also inhibit renin release from kidney, so inhibit RAAS
Side Effects: bronchoconstriction, fatigue, contraindicated in patients with peripheral vascular disease
E.g. bisoprolol

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6
Q

Ca2+ channel antagonists

A

Decrease frequency and force of contraction
Leads to decreasing cardiac workload
Leads to increasing dilation of arterioles
Used when Beta blockers are contraindicated

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7
Q

Frequency and force of contration

A

CCBs can reduce heart beat by blocking L type channels in SA and AV nodes
This slows rate of depolarisation and reduces rate of AP generation
Also decreases force of contraction by reducing Ca2+ entry through L type channels

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8
Q

Ivabradine

A

Blocks the pacemaker current (Ih/f - funny current) in the nodal tissue of the heart
It decreases Na+ entry through If channels - slows rate of depolarisation of the SA nodal cells and reduce firing frequency and heart rate - doesn’t directly alter force of contraction
Side effects: luminous phenomena (Ih) in retina, blurred vision, dizziness
Alternatives: long-acting nitrate (isosorbide mononitrate), nicorandil, ranolazine

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