Patients with SAH were found to have myocardial necrosis. But instead of being centered around coronary arteries, it was found near intracardiac nerves!
The damage appeared neural, not ischemic, in origin.
9/ The question then becomes: how does bleeding into the subarachnoid space lead to sympathetic activation?
To answer this question, we need to examine adjacent structures that might be susceptible to injury after SAH.
10/ The hypothalamus is one structure adjacent to the subarachnoid space.
Given its role in the autonomic nervous system, one hypothesis suggests that hypothalamic irritation after SAH leads to sympathetic activation and cerebral T-waves.
11/ This is supported by animal studies from the 1960s showing that direct electrical stimulation of the hypothalamus leads to ECG changes (including TWI).
12/ Another structure that may be affected by SAH is the insular cortex, an area that lies buried in the sylvian fissure beneath the frontoparietal and temporal lobes.
🔑The insular cortex also plays a role in sympathetic regulation.
14/ Additional support for the sympathetic activation hypothesis comes from another condition associated with elevated catecholamines and deep/inverted T-waves:
15/ Cerebral T-waves in subarachnoid hemorrhage are just one example where sympathetic activation leads to deep TWI.
In the coming days, I'll add some other examples of what might be more accurately termed "sympathetic T-waves".
16/16
☞ Subarachnoid hemorrhage is associated with deep/inverted "cerebral T-waves"
☞ Cerebral T-waves are the result of sympathetic activation, either from injury to the hypothalamus and/or insular cortex
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3/ Although an increasing severity is bone marrow infiltration by plasma cells
is associated with worsening anemia, leukocyte and platelet counts remain stable.
This suggests something beyond the replacement of hematopoietic cells is responsible.
1/10
Does epinephrine improve outcomes in patients with cardiac arrest?
This is a question with a complex answer. This thread is only meant to scratch the surface and is a follow-up to a recent tweetorial on the use of epinephrine for cardiac arrest.
2/ Although epinephrine has been used for decades questions about its ability to improve outcomes have been around for just as long.