Author + information
- Renuka Jain,
- Martin Osranek,
- M. Fuad Jan,
- Lindsey Kalvin,
- Susan Olet,
- Suhail Allaqaband,
- Bijoy Khandheria and
- A. Jamil Tajik
Background: Left ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM) is sensitive to changes in left ventricular (LV) preload, afterload, and contractility; small studies suggest that LVOTO may vary with respiration.
Methods: During routine transthoracic echocardiogram prior to consultation in our HCM Center, we observed LVOTO variation over several heart beats (Panel A, B). We remeasured LVOTO after placement of a respirometer (Panel C, D). We compared clinical variables in the study group to a control group without respiratory variation.
Results: Twenty patients formed the study group, 12 were female, mean age 62.1 yrs ± 13.1, mean septal wall thickness 2.2 cm ± 0.3, all with resting LVOTO. LVOTO was uniformly lowest during inspiration (50.8 mmHg ± 25.6) and highest during expiration (90.1 mmHg ± 41.8), thus an 82.4% ± 39.1 (p=<.0001) change from inspiration to expiration. When compared to controls, the study group was more overweight (mean BMI study 35.1 ± 7.3 vs control 29.1 ± 5.1, p=.0045) and more had sleep-disordered breathing (n=15 study, n=5 control).
Conclusions: Our results are contrary to standard teaching that decreased preload with inspiration will lead to increased LVOTO, and may offer a link between HCM, obesity, and sleep-disordered breathing. We postulate that another mechanism (abnormal lung compliance > ⋄ increased negative intrathoracic pressure > ⋄ increased LV transmural pressure > ⋄ increased LV afterload) overwhelms preload mechanisms in HCM.
Poster Hall, Hall C
Saturday, March 18, 2017, 9:45 a.m.-10:30 a.m.
Session Title: Advances in HCM, PPCM and Other Cardiomyopathies
Abstract Category: 13. Heart Failure and Cardiomyopathies: Clinical
Presentation Number: 1201-278
- 2017 American College of Cardiology Foundation