Stay Connected. Manage Your Care.
Access your health information anytime and anywhere, at home or on the go, with MyHealth.
- Message your clinic
- View your lab results
- Schedule your next appointment
- Pay your bill
The MyHealth mobile app from Stanford Health Care puts all your health information at your fingertips and makes managing your health care simple and quick.
Guest Services
24/7
We are available to assist you
whenever you need it. Give us a call at
650-498-3333 or
PHYSICIAN HELPLINE
Have a question? We're here to help! Call 1-866-742-4811
Monday - Friday, 8 a.m. - 5 p.m.
REFER A PATIENT
Fax 650-320-9443
Track your patients' progress and communicate with Stanford providers conveniently and securely.
Abstract
Conventional surgical thinking indicates that mitral annular (MA) size reduction plays a key role in mitral valve closure, and most MA size and shape changes are thought to occur during left ventricular (LV) systole. The influences of left atrial (LA) and LV systole on MA size and shape, however, remain debated.Eight radiopaque markers were placed equidistantly around the MA and imaged using high-speed simultaneous biplane videofluoroscopy in seven closed-chest, sedated sheep before and during asynchronous LV pacing. Marker images were used to compute the three-dimensional coordinates of each marker every 16.7 ms throughout the cardiac cycle, allowing calculation of three-dimensional MA area, septal-lateral (SL) dimension, and commissure-commissure (CC) dimension under control and LV pacing conditions. Maximum MA area occurred in early diastole, and minimum MA area near end-diastole; maximum area reduction was 12+/-1% (P< or =.001). Interestingly, 89+/-3% of area reduction occurred before LV systole. During this "presystolic" period, SL decreased by 8+/-1% and CC by 2+/-1%; the SL/CC ratio fell from 0.73+/-0.02 to 0.69+/-0.01 (P< or =.005), indicating a less circular shape at end-diastole. With LV pacing, total MA area reduction was similar (13+/-2 versus 12+/-1%, P=NS versus control); however, all MA area reduction occurred during LV systole with minimum MA area occurring at end-systole. Presystolic shortening in both SL and CC dimensions was lost, and presystolic ellipticalization disappeared.Changes in MA size and shape coincident with LA systole included area reduction and shape change prior to the onset of LV contraction. These presystolic changes vanished when LA systole was absent (LV pacing). Thus, LA systole plays a pivotal role in MA size reduction and shape alteration. The unexpected timing of these MA dynamics should be taken into account during mitral valve reparative procedures.
View details for PubMedID 9386085