Abnormal Cardiovascular Responses During Orthostatic Hypotension in Cardiac Amyloidosis Revealed by Semi-Sitting/Standing Stress Echocardiography
Mai Iwataki, Hajime Miki, Takeshi Onoue, Yasufumi Nagata, Robert A Levine, Yutaka Otsuji, Masaharu Kataoka · 2026
Read Abnormal Cardiovascular Responses During Orthostatic Hypotension in Cardiac Amyloidosis Revealed by Semi-Sitting/Standing Stress Echocardiography by Mai Iwataki, Hajime Miki, Takeshi Onoue, Yasufumi Nagata, Robert A Levine, Yutaka Otsuji, Masaharu Kataoka (2026) in the Tower of Babel, a free online library of public-domain works preserved in clean, searchable text. No sign-up. The full text is served as a plain-text file at a predictable URL, where text is present: https://antarctic-labs.com/tower-of-babel/pmc-13616552.txt.
Description
Fainting on standing is common when protein deposits stiffen the heart, but the mechanics stay unclear. Mai Iwataki and co-authors used ultrasound imaging while volunteers and patients sat up and stood, comparing six healthy people, five patients with cardiac amyloidosis but no fainting, and four with both. The standing stress test let them watch heart, arteries, and veins react in real time.
The fainting group showed a broad failure to compensate. Heart rate rose too little, blood pressure fell, the heart's squeeze did not strengthen, and output dropped sharply. Stranger still, vessel resistance fell when it should rise, and a large vein widened instead of narrowing. The authors suggest every limb of the response falters at once, and that standing ultrasound can expose the pattern.
Catalog record
| CREATOR | Mai Iwataki, Hajime Miki, Takeshi Onoue, Yasufumi Nagata, Robert A Levine, Yutaka Otsuji, Masaharu Kataoka |
|---|---|
| YEAR | 2026 |
| COLLECTION | PAPERS |
| FORMAT | TXT |
| FILE SIZE | 22 KB |
| VERSION | 1.0 |
| LICENSE | CC BY 4.0 |
| RIGHTS | CC BY |
| SOURCE | Europe PMC |