Role of the papillary muscle in opening and closure of the mitral valve

1980 ◽  
Vol 238 (3) ◽  
pp. H348-H354 ◽  
Author(s):  
M. Marzilli ◽  
H. N. Sabbah ◽  
T. Lee ◽  
P. D. Stein
Keyword(s):  
Mitral Valve ◽  
Papillary Muscle ◽  
Left Atrial ◽  
Left Ventricular ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Dimensional Changes ◽  
Opening And Closing ◽  
Isovolumic Relaxation

Dimensional changes of the left ventricular anterolateral papillary muscle of six open-chest dogs were measured continuously throughout the cardiac cycle in order to evaluate the role of the papillary muscle in opening and closing of the mitral valve. Dimensional changes were measured with ultrasonic dimension gauges. Maximal shortening and maximal elongation of the papillary muscle followed maximal shortening and elongation of a segment of the free wall of the left ventricle by 65 +/- 6 (SE) ms. Maximal elongation of the papillary muscle occurred 25 +/- 2 ms after the onset of ejection. Maximal shortening of the papillary muscle occurred 68 +/- 5 ms after the aortic incisura and 10 +/- 2 ms after the crossover of left ventricular and left atrial pressure. The papillary muscle shortened 14 +/- 4%. The percentage of papillary muscle shortening that occurred after the aortic incisura was 39 +/- 7%, and the percentage of shortening that occurred after the crossover of left ventricular and left atrial pressure was 3 +/- 1%. The observed shortening of the papillary muscle throughout left ventricular isovolumic relaxation suggests that the papillary muscle may have a role in opening the mitral valve. Conversely, elongation of the papillary muscle in the late portion of diastole appears necessary to permit proper closure of the mitral valve leaflets.

scholarly journals The Effect of Furosemide on Left Atrial Pressure in Dogs with Mitral Valve Regurgitation

2011 ◽  
Vol 25 (2) ◽  
pp. 244-250 ◽  
Author(s):  
S. Suzuki ◽  
T. Ishikawa ◽  
L. Hamabe ◽  
D. Aytemiz ◽  
H. Huai-Che ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Left Atrial ◽  
Mitral Valve Regurgitation ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Valve Regurgitation

Myocardial performance and collateral flow after transient coronary occlusion in exercising dogs

1979 ◽  
Vol 237 (4) ◽  
pp. H520-H527
Author(s):  
M. V. Cohen ◽  
T. Yipintsoi
Keyword(s):  
Stroke Volume ◽  
Left Atrial ◽  
Exercise Group ◽  
Left Ventricular ◽  
Treadmill Running ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Collateral Flow ◽  
Group I ◽  
Group Ii

Fourteen dogs with prior constriction of the left circumflex (LCf) coronary artery were studied at rest and during treadmill running. Hemodynamics were measured before and after a 1-min LCf occlusion. Coronary and collateral flows were quantitated during occlusion both at rest and during exercise. Group I consisted of 4 dogs with resting collateral flow exceeding one-half (average 78%) of normal flow, and group II consisted of 10 dogs with collateral flows less than one-half (average 30%) of normal. At rest LCf occlusion caused no hemodynamic changes in group I, but stroke volume fell significantly in group II. During running, collateral flow after LCf occlusion doubled in group I, and there was only a small rise in left atrial pressure to 18 mmHg. In group II, collateral flow increased by 50% during running and actually decreased in 4 dogs. Significant cardiac failure developed as stroke volume halved, and left atrial pressure rose to an average 30 mmHg. Therefore exercise-induced depression of left ventricular function in the ischemic heart can be correlated to the amount of coronary collateral flow.

Characteristics and outcomes of patients with normal left atrial pressure undergoing transcatheter mitral valve repair

Heart ◽  
2020 ◽  
Vol 106 (12) ◽  
pp. 898-903 ◽  
Author(s):  
Jason R Sims ◽  
Guy S Reeder ◽  
Mayra Guerrero ◽  
Mohamad Alkhouli ◽  
Vuyisile T Nkomo ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Mitral Valve Repair ◽  
Left Atrial ◽  
Multivariable Analysis ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
Valve Repair ◽  
Transcatheter Mitral Valve Repair ◽  
V Wave ◽  
Regurgitant Orifice Area

ObjectiveA subset of patients at the time of transcatheter mitral valve repair (TMVR) will have normal left atrial pressure (LAP) (<13 mm Hg) despite having severe mitral regurgitation (MR). The goal of this study was to determine clinical characteristics and outcomes in patients with normal LAP undergoing TMVR.MethodsA single-centre retrospective cohort of consecutive patients who underwent transcatheter edge-to-edge mitral valve clip and continuous LAP monitoring between 5/1/2014 and 5/1/2018 was analysed. One-year mortality was compared by Kaplan–Meier survival curves. Multivariable analysis was performed to identify predictors of normal LAP and 1 year mortality.ResultsOf the 204 patients undergoing TMVR, 65% were men and the mean age was 81. Of these patients, 31 (15%) had normal LAP (mean LAP 10.5 mm Hg, mean V wave 16.5 mm Hg) and 173 had elevated LAP (mean LAP 19 mm Hg, mean V wave 32.5 mm Hg). The prevalence of severe MR was not different between groups, although the normal LAP group had significantly lower effective regurgitant orifice area and regurgitant volume. Other notable baseline characteristics including prior cardiac surgery, atrial fibrillation, hypertension, diabetes, congestive heart failure, body mass index, mechanism of MR and ejection fraction were similar between groups. However, there was an increased prevalence of chronic lung disease (CLD) (45.2% vs 17.3%, p<0.001) in the normal LAP group. On multivariate analysis, the only significant predictor of normal LAP was the presence of CLD (OR 4.79 (1.83–12.36), p=0.001) and 1-year mortality was significantly higher in the normal LAP group (32.3% vs 12.7%, p=0.006). After adjustment for comorbidities, normal LAP was no longer a predictor of 1-year mortality (RR 1.62 (0.64–4.06), p=0.32); however, CLD (RR 3.44 (1.37–8.67), p=0.01) remained a statistically significant predictor.ConclusionNormal LAP at the time of TMVR is associated with a higher incidence of CLD which independently predicts increased 1-year mortality. In patients with CLD and apparently severe MR, measurement of LAP may help identify those with lower likelihood of benefit from TMVR.

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