Ever wondered why Takotsubo Cardiomyopathy occurs in SAH?
This exotic Japanese term has more to offer than just a cool name.
56 yo comes to ED with SAH, HH4, gets coiled & is admitted to NeuroICU. Echo tech was performing Echo while I was rounding & saw this on the screen.
This exotic Japanese term has more to offer than just a cool name.
56 yo comes to ED with SAH, HH4, gets coiled & is admitted to NeuroICU. Echo tech was performing Echo while I was rounding & saw this on the screen.
Takotsubo = Apical hypokinesis & ballooning aka Broken heart syndrome- more like broken brain as far as I’m concerned !!
This name after a characteristic shape of Left ventricle resembling the shape of a pot used to trap Octopus.
This name after a characteristic shape of Left ventricle resembling the shape of a pot used to trap Octopus.
A few theories have been proposed but catecholamine surge is still debated yet widely cited- explained here:
A)⬆️ICP👉Excessive catecholamine surge
B)Differential effect of catecholamine on myocardium
Let’s understand each concept & at the end it’ll all make sense
A)⬆️ICP👉Excessive catecholamine surge
B)Differential effect of catecholamine on myocardium
Let’s understand each concept & at the end it’ll all make sense
A)
Any catastrophic neurological🤕can cause sudden⬆️in circulatory catecholamines due to activation of Hypothalamus-pituitary-adrenal (HPA) axis. But the key factor is SUDDEN- like in aSAH.
Any catastrophic neurological🤕can cause sudden⬆️in circulatory catecholamines due to activation of Hypothalamus-pituitary-adrenal (HPA) axis. But the key factor is SUDDEN- like in aSAH.
In 1993,Shivalkar et al (8419012) performed experiment where they placed epidural Foley in dogs & infused same total amount of saline to cause⬆️ICP f/b measurement of epinephrine.
Group 1(Left)👉3 boluses of saline👉sudden⬆️ICP
Group 2(Right)👉slow infusion of saline👉slow⬆️ICP
Group 1(Left)👉3 boluses of saline👉sudden⬆️ICP
Group 2(Right)👉slow infusion of saline👉slow⬆️ICP
Measurement of circulating epinephrine levels, were 1000x baseline in group 1 and 200x in group 2.
Group 1👉 1000x baseline⬆️of epinephrine
Group 2👉 200x baseline⬆️of epinephrine
**SUDDEN EXPLOSIVE⬆️IN ICP (aSAH) HAS MORE HEMODYNAMIC IMPACTS THAN SLOW SUSTAINED⬆️ICP**
Group 1👉 1000x baseline⬆️of epinephrine
Group 2👉 200x baseline⬆️of epinephrine
**SUDDEN EXPLOSIVE⬆️IN ICP (aSAH) HAS MORE HEMODYNAMIC IMPACTS THAN SLOW SUSTAINED⬆️ICP**
B)
🧠has immense control over🫀through autonomic nerves. But🗝️here is to understand the DISTRIBUTION.
Sympathetic innervation of ventricle is heterogeneous.
Sympathetic nerves concentration👉base>>apex👉gradient of ventricular tissue catecholamines from base>>apex. (482037)
🧠has immense control over🫀through autonomic nerves. But🗝️here is to understand the DISTRIBUTION.
Sympathetic innervation of ventricle is heterogeneous.
Sympathetic nerves concentration👉base>>apex👉gradient of ventricular tissue catecholamines from base>>apex. (482037)
Kawano et al (12644879) studied autonomic nerve distribution in healthy autopsied hearts by histochemical analysis for AChE (parasympathetic) & Tyrosine Hydroxylase-TH (sympathetic) in the nerve endings.
Amongst many other findings, they made 3 main observations: (🗝️*P<0.05, **P<0.01, ***P<0.005)
1.Overall, atria are richer in innervation than ventricles.
2.Right heart has slightly richer innervation than the left.
3.Both ventricles, Basal area are richer than apical area.
1.Overall, atria are richer in innervation than ventricles.
2.Right heart has slightly richer innervation than the left.
3.Both ventricles, Basal area are richer than apical area.
In 2008, Lyon (18094670) established B2 Adrenergic receptors (B2AR) have concentration gradient👉 Base<<Apex.
Conversely, sympathetic innervation👉base>>apex
**LV APEX IS MORE RESPONSIVE TO CIRCULATING CATECHOLAMINES DUE TO⬆️⬆️SYMPATHETIC NERVE ENDINGS:B2AR RATIO👉BASE<<APEX**
Conversely, sympathetic innervation👉base>>apex
**LV APEX IS MORE RESPONSIVE TO CIRCULATING CATECHOLAMINES DUE TO⬆️⬆️SYMPATHETIC NERVE ENDINGS:B2AR RATIO👉BASE<<APEX**
Based on rat models:
At⬆️⬆️concentration, Epinephrine causes B2AR signal change from Gs (+ve inotropic)👉Gi (-ve inotropic)
LV apex being more responsive to Epi than base👉hypokinetic
LV base being less responsive to same Epi concentration remians ++inotropic
**Takotsubo**
At⬆️⬆️concentration, Epinephrine causes B2AR signal change from Gs (+ve inotropic)👉Gi (-ve inotropic)
LV apex being more responsive to Epi than base👉hypokinetic
LV base being less responsive to same Epi concentration remians ++inotropic
**Takotsubo**
Bottomline:
✅Aneurysmal rupture & sudden⬆️ICP👉surge in catecholamines
✅Hypersensitivity of apical myocardium👉B2AR signaling form Gs to Gi
✅Apical myocardium more responsive than base at same epinephrine concentration
❤️🔥❤️🔥End result is Takotsubo❤️🔥❤️🔥
✅Aneurysmal rupture & sudden⬆️ICP👉surge in catecholamines
✅Hypersensitivity of apical myocardium👉B2AR signaling form Gs to Gi
✅Apical myocardium more responsive than base at same epinephrine concentration
❤️🔥❤️🔥End result is Takotsubo❤️🔥❤️🔥
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