You will hear these 3 terms multiple times in your career let me simplify them.
1. Myocardial Stunning: Think of a situation as if you are working in the OR as a resident suddenly your attending comes and hits you what will happen to you- You will be stunned and will stop working, stop thinking for some time and at that time you will need support to function properly
similarly if the heart is hit by a reversible insult(ischemia, pressure) it stops working for some time and wont function unless support is provided - Inotropes, Pacing, Baloon pump , ECMO
2. Myocardial Hibernation:(Smart Heart)
Think of Polar bears who hibernate
When the food supply is low polar bear goes sleeping to survive to on low resources and if you happen to go to its cave you will see polar bear not moving at all and from a distance it will look as if he/she is dead. How will you differentiate whether the polar bear is dead or hibernating- challenge it.(Have reliable shoes to help you run before you do that)
similarly when there is chronic low oxygen supply to a wall/walls of heart due to stenosis of the corresponding coronary artery the corresponding wall becomes hypokinetic and on normal echo it will look as if dead. How will you differentiate- try challenging with perfusion scans.
3. Ischaemic preconditioning:(What does not Kill you makes you stronger)
Short periods of ischemia will make the heart stronger to subsequent longer periods of ischemia.
Think of a situation when you are asking your buddy about a tough rotation you are about to start- your buddy tells the horror stories and you will become upset for some time but you will be better able to withstand that rotation
Remember Inhalational anesthetics mimic the effect of Ischemic preconditioning via activating ATP sensitive potassium channels and depleting intracellular calcium so that the heart is better able to withstand periods of ischemia- So may provide better protection from ischemia.
1. Myocardial Stunning: Think of a situation as if you are working in the OR as a resident suddenly your attending comes and hits you what will happen to you- You will be stunned and will stop working, stop thinking for some time and at that time you will need support to function properly
similarly if the heart is hit by a reversible insult(ischemia, pressure) it stops working for some time and wont function unless support is provided - Inotropes, Pacing, Baloon pump , ECMO
2. Myocardial Hibernation:(Smart Heart)
Think of Polar bears who hibernate
When the food supply is low polar bear goes sleeping to survive to on low resources and if you happen to go to its cave you will see polar bear not moving at all and from a distance it will look as if he/she is dead. How will you differentiate whether the polar bear is dead or hibernating- challenge it.(Have reliable shoes to help you run before you do that)
similarly when there is chronic low oxygen supply to a wall/walls of heart due to stenosis of the corresponding coronary artery the corresponding wall becomes hypokinetic and on normal echo it will look as if dead. How will you differentiate- try challenging with perfusion scans.
3. Ischaemic preconditioning:(What does not Kill you makes you stronger)
Short periods of ischemia will make the heart stronger to subsequent longer periods of ischemia.
Think of a situation when you are asking your buddy about a tough rotation you are about to start- your buddy tells the horror stories and you will become upset for some time but you will be better able to withstand that rotation
Remember Inhalational anesthetics mimic the effect of Ischemic preconditioning via activating ATP sensitive potassium channels and depleting intracellular calcium so that the heart is better able to withstand periods of ischemia- So may provide better protection from ischemia.
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