Ablation of mitral annular and leaflet muscle: effects on annular and leaflet dynamics

2003 ◽  
Vol 285 (4) ◽  
pp. H1668-H1674 ◽  
Author(s):  
Tomasz A. Timek ◽  
David T. Lai ◽  
Paul Dagum ◽  
Frederick Tibayan ◽  
George T. Daughters ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dynamic Geometry ◽  
Mitral Annulus ◽  
Valve Closure ◽  
Mitral Leaflet ◽  
Radiopaque Markers ◽  
Myocardial Fibers ◽  
Video Fluoroscopy ◽  
Leaflet Shape ◽  
Sigmoid Shape

Mitral annular (MA) and leaflet three-dimensional (3-D) dynamics were examined after circumferential phenol ablation of the MA and anterior mitral leaflet (AML) muscle. Radiopaque markers were sutured to the left ventricle, MA, and both mitral leaflets in 18 sheep. In 10 sheep, phenol was applied circumferentially to the atrial surface of the mitral annulus and the hinge region of the AML, whereas 8 sheep served as controls. Animals were studied with biplane video fluoroscopy for computation of 3-D mitral annular area (MAA) and leaflet shape. MAA contraction (MAACont) was determined from maximum to minimum value. Presystolic MAA (PS-MAACont) reduction was calculated as the percentage of total reduction occurring before end diastole. Phenol ablation decreased PS-MAACont (72 ± 6 vs. 47 ± 31%, P = 0.04) and delayed valve closure (31 ± 11 vs. 57 ± 25 ms, P = 0.017). In control, the AML had a compound sigmoid shape; after phenol, this shape was entirely concave to the atrium during valve closure. These data indicate that myocardial fibers on the atrial side of the valve influence the 3-D dynamic geometry and shape of the MA and AML.

scholarly journals Mitral valve opening in the ovine heart

1998 ◽  
Vol 274 (2) ◽  
pp. H552-H563 ◽  
Author(s):  
Matts O. Karlsson ◽  
Julie R. Glasson ◽  
Ann F. Bolger ◽  
George T. Daughters ◽  
Masashi Komeda ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Three Dimensional ◽  
Mitral Annulus ◽  
Posterior Leaflet ◽  
Anterior Leaflet ◽  
Rapid Fall ◽  
Valve Opening ◽  
Radiopaque Markers ◽  
Edge Separation ◽  
Central Cusp

To study the three-dimensional size, shape, and motion of the mitral leaflets and annulus, we surgically attached radiopaque markers to sites on the mitral annulus and leaflets in seven sheep. After 8 days of recovery, the animals were sedated, and three-dimensional marker positions were measured by computer analysis of biplane videofluorograms (60/s). We found that the oval mitral annulus became most elliptical in middiastole. Both leaflets began to descend into the left ventricle (LV) during the rapid fall of LV pressure (LVP), before leaflet edge separation. The anterior leaflet exhibited a compound curvature in systole and maintained this shape during opening. The central cusp of the posterior leaflet was curved slightly concave to the LV during opening. Markers at the border of the “rough zone” were separated by 10 mm during systole. We conclude that coaptation occurs very near the leaflet edges, that the annulus and leaflets move toward their open positions during the rapid fall of LVP, and that leaflet edge separation, the last event in the opening sequence, occurs near the time of minimum LVP.

Motion of both mitral valve leaflets: a cineroentgenographic study in intact dogs

1975 ◽  
Vol 39 (3) ◽  
pp. 359-366 ◽  
Author(s):  
A. G. Tsakiris ◽  
D. A. Gordon ◽  
Y. Mathieu ◽  
L. Irving
Keyword(s):  
Heart Rate ◽  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Mitral Annulus ◽  
Valve Closure ◽  
Time Motion ◽  
Intraventricular Flow ◽  
Radiopaque Markers ◽  
Posterior Cusp ◽  
Opening And Closing

Motion and position of both mitral leaflets were studied in five normal dogs 1–11 wk after radiopaque markers were sutured on the valve cusps and on the mitral annulus. Cinefluorograms and cineangiograms (100–120 frames/s) of left atrium and left ventricle were used to study cusp motion and intraventricular flow patterns, and to detect mitral regurgitation during sinus rhythm (42–184 beats/min) and during isolated atrial or ventricular contractions. Time-motion of both leaflets was similar throughout diastole with the exception of delayed posterior cusp opening. Peak opening and closing speeds, opening and closing times, and time of complete closure, measured from the Q wave of the ECG, were not significantly affected by the variations in heart rate. Diastolic leaflet closure began immediately after opening, while the ventricular cavity was small, and was caused by flow eddies behind the cusps. Isolated ventricular contractions closed the valve leaflets completely and symmetric valve closure was ensured by the different rates of leaflet edge approximation. In contrast, atrial closure was slow, partial, and of very short duration.

Atrial contraction and mitral annular dynamics during acute left atrial and ventricular ischemia in sheep

2002 ◽  
Vol 283 (5) ◽  
pp. H1929-H1935 ◽  
Author(s):  
Tomasz A. Timek ◽  
David T. Lai ◽  
Frederick Tibayan ◽  
George T. Daughters ◽  
David Liang ◽  
...  
Keyword(s):  
Left Ventricle ◽  
Mitral Regurgitation ◽  
Left Atrial ◽  
Contractile Function ◽  
Mitral Annulus ◽  
Balloon Occlusion ◽  
Valve Closure ◽  
Area Reduction ◽  
Atrial Contraction ◽  
Radiopaque Markers

In six sheep, radiopaque markers were placed on the left ventricle (LV), the mitral annulus, the left atrium (LA), and the central edge of both mitral leaflets to investigate the effects of acute LV ischemia on atrial contraction, mitral annular area (MAA), and mitral regurgitation (MR). Animals were studied with biplane videofluoroscopy and transesophageal echocardiography before and during balloon occlusion of the left anterior descending (LAD), distal circumflex (dLCX), and proximal circumflex (pLCX) coronary arteries. MAA and LA area were calculated from the corresponding markers. LAD occlusion did not alter LA area reduction or presystolic MAA reduction, whereas dLCX occlusion resulted in a mild decrease in the former with no change in the latter. Neither occlusion resulted in MR. pLCX occlusion, however, significantly decreased LA area and presystolic MAA reduction and resulted in increased end-diastolic MAA, delayed valve closure from end diastole, and MR. Decreased atrial contractile function, as observed during acute posterolateral ischemia, is linked to diminished presystolic mitral annular reduction, a larger mitral annular size at end diastole, and MR.

scholarly journals Mechanistic Insights Into Posterior Mitral Leaflet Inter-Scallop Malcoaptation During Acute Ischemic Mitral Regurgitation

Circulation ◽  
2002 ◽  
Vol 106 (12_suppl_1) ◽  
Author(s):  
David T. Lai ◽  
Frederick A. Tibayan ◽  
Truls Myrmel ◽  
Tomasz A. Timek ◽  
Paul Dagum ◽  
...  
Keyword(s):  
Mitral Regurgitation ◽  
High Speed ◽  
Lateral Displacement ◽  
Three Dimensional ◽  
Mitral Annulus ◽  
Left Ventricular ◽  
Ischemic Mitral Regurgitation ◽  
Posterior Leaflet ◽  
Mitral Leaflet ◽  
Posterior Mitral Leaflet

Background Three-dimensional dynamics of the 3 individual scallops within the posterior mitral leaflet during acute ischemic mitral regurgitations have not been previously measured. Methods Radiopaque markers were sutured to the mitral annulus, papillary muscle tips, and leaflet edges in 13 sheep. Immediately postoperatively, under open-chest conditions, 3-D marker coordinates were obtained using high-speed biplane videofluoroscopy before and during echocardiographically verified acute ischemic mitral regurgitation produced by occlusion of the left circumflex coronary artery. Results During acute ischemic mitral regurgitation, at end systole, the anterolateral edge of the central scallop was displaced 0.8±0.9 mm laterally and 0.9±0.6 mm apically away from the anterolateral scallop; such displacement correlated with lateral displacement of the lateral annulus (R 2 =0.7, SEE=0.7 mm, P <0.001) and movement of the right lateral annulus away from the nonischemic anterior papillary tip (R 2 =0.6, SEE=0.8 mm, P =0.002), respectively. End-systolic displacement of the posteromedial edge of the central scallop was 1.4±0.9 mm anteriorly and 0.9±0.6 mm laterally away from the posteromedial scallop, corresponding to anterior displacement of the mid-lateral annulus (R 2 =0.5, SEE=1.0 mm, P <0.001). Conclusions Malcoaptation of the scallops within the posterior leaflet during acute left ventricular ischemia is a novel observation. The primary geometric mechanism underlying scallop malcoaptation in acute ischemic mitral regurgitation was annular dilatation, which hindered leaflet coaptation by drawing the individual scallops apart. These findings support the use of annular reduction in the repair of ischemic mitral regurgitation and also suture closure of prominent subcommissures between posterior leaflet scallops.

Displacements and strains in the costal diaphragm of the dog

1994 ◽  
Vol 76 (1) ◽  
pp. 223-229 ◽  
Author(s):  
A. M. Boriek ◽  
T. A. Wilson ◽  
J. R. Rodarte
Keyword(s):  
Chest Wall ◽  
Three Dimensional ◽  
Small Displacement ◽  
Lung Capacity ◽  
Muscle Shortening ◽  
Residual Capacity ◽  
Three Bundles ◽  
Radiopaque Markers ◽  
Video Fluoroscopy ◽  
Principal Strains

Radiopaque markers were attached at 1- to 2-cm intervals along three nearby muscle bundles to cover rectangular regions of the mid-costal diaphragms of seven dogs. The markers were tracked by biplane video fluoroscopy during spontaneous breathing (SB), mechanical ventilation with the same tidal volume (MV), and at inflation to total lung capacity (TLC) in the prone and supine positions. The three-dimensional positions of the markers at functional residual capacity (FRC), at end inspiration during SB and MV, and at TLC were determined, and the strains in the plane of the diaphragm relative to FRC were calculated. The principal strains were found to lie nearly along the muscle bundle direction and perpendicular to it. The principal strains along the muscle bundles, which describe muscle shortening, were uniform among the three bundles and uniform along the bundle for MV. For SB, in the prone and supine positions, shortening was approximately 30% greater in the middle of the bundle than near the central tendon and chest wall. Although the tidal volumes were the same for SB and MV, the shortening was larger for SB. The strains perpendicular to the bundle direction were not significantly different from zero. It appears that, for the loads that occur during tidal breathing, the diaphragm is inextensible in the direction perpendicular to the muscle direction. There is a very small displacement of the costal diaphragm at its insertion on the chest wall. The displacement at the central tendon is primarily a result of muscle shortening and rotation of the arc of the muscle around its insertion on the chest wall.

Coordinate-Free Analysis of Mitral Valve Dynamics in Normal and Ischemic Hearts

Circulation ◽  
2000 ◽  
Vol 102 (suppl_3) ◽  
Author(s):  
Paul Dagum ◽  
Tomasz A. Timek ◽  
G. Randall Green ◽  
David Lai ◽  
George T. Daughters ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Color Doppler ◽  
Mitral Annulus ◽  
Left Ventricular ◽  
Free System ◽  
Ring Annuloplasty ◽  
3D Geometry ◽  
Valve Function ◽  
Valve Dynamics ◽  
Radiopaque Markers

Background —The purpose of this investigation was to study mitral valve 3D geometry and dynamics by using a coordinate-free system in normal and ischemic hearts to gain mechanistic insight into normal valve function, valve dysfunction during ischemic mitral regurgitation (IMR), and the treatment effects of ring annuloplasty. Methods and Results —Radiopaque markers were implanted in sheep: 9 in the ventricle, 1 on each papillary tip, 8 around the mitral annulus, and 1 on each leaflet edge midpoint. One group served as a control (n=7); all others underwent flexible Tailor partial (n=5) or Duran complete (n=6) ring annuloplasty. After an 8±2-day recovery, 3D marker coordinates were measured with biplane videofluoroscopy before and during posterolateral left ventricular ischemia, and MR was assessed by color Doppler echocardiography. Papillary to annular distances remained constant throughout the cardiac cycle in normal hearts, during ischemia, and after ring annuloplasty with either type of ring. Papillary to leaflet edge distances similarly remained constant throughout ejection. During ischemia, however, the absolute distances from the papillary tips to the annulus changed in a manner consistent with leaflet tethering, and IMR was observed. In contrast, during ischemia in either ring group, those distances did not change from preischemia, and no IMR was observed. Conclusions —This analysis uncovered a simple pattern of relatively constant intracardiac distances that describes the 3D geometry and dynamics of the papillary tips and leaflet edges from the dynamic mitral annulus. Ischemia perturbed the papillary-annular distances, and IMR occurred. Either type of ring annuloplasty prevented such changes, preserved papillary-annular distances, and prevented IMR.

scholarly journals Isolated Cleft of the Posterior Mitral Leaflet in 8 Year Old Patient

2021 ◽  
pp. 1-2
Author(s):  
Merjema Karavdic ◽  
◽  
Mirza Halimic ◽  
Keyword(s):  
Mitral Valve ◽  
Clinical Importance ◽  
Mitral Annulus ◽  
Long Term Results ◽  
Posterior Leaflet ◽  
Mitral Leaflet ◽  
Posterior Mitral Leaflet ◽  
Endocardial Cushion Defect ◽  
Congenital Mitral Regurgitation

Cleft of the mitral valve is a rare cause of the congenital mitral regurgitation. Isolated cleft is uncommon finding and is more often found associated with some form of endocardial cushion defect. Cleft of the septal leaflet is found much more often than the defect in the posterior leaflet. Mitral clefts can extend to the mitral annulus or they can be less ''deep'' and show only minor regurgitation. Clinical importance of the isolated cleft of the mitral valve (ICMV) is that it can be successfully corrected by surgery and that it can have good long-term results.

scholarly journals Annular Height-to-Commissural Width Ratio of Annulolasty Rings In Vivo

Circulation ◽  
2005 ◽  
Vol 112 (9_supplement) ◽  
Author(s):  
Tomasz A. Timek ◽  
Julie R. Glasson ◽  
David T. Lai ◽  
David Liang ◽  
George T. Daughters ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Left Ventricle ◽  
Mammalian Species ◽  
Mitral Annulus ◽  
Width Ratio ◽  
Native Valve ◽  
Radiopaque Markers ◽  
Duran Ring ◽  
Flexible Ring

Background— A “saddle-shaped” mitral annulus with an optimal ratio between annular height and commissural diameter may reduce leaflet and chordal stress and is purported to be conserved across mammalian species. Whether annuloplasty rings maintain this relationship is unknown. Methods and Results— Twenty-three adult sheep underwent implantation of radiopaque markers on the left ventricle and mitral annulus. Eight animals underwent implantation of a Carpentier-Edwards Physio ring, 7 underwent a Medtronic Duran flexible ring, and 8 served as controls. Animals were studied with biplane videofluoroscopy 7 to 10 days postoperatively. Annular height and commissural width (CW) were determined from 3D marker coordinates, and annular height:CW ratio (AHWCR) was calculated. Annular height was similar in Control and Duran animals but significantly lower in the Physio group at end diastole (8.4±3.8, 6.7±2.3, and 3.4±0.6 mm, respectively, for Control, Duran, and Physio; ANOVA=0.005) and at end systole (14.5±6.2, 10.5±5.5, and 5.8±2.5 mm, respectively, for Control, Duran, and Physio; ANOVA=0.004). Both ring groups reduced CW significantly relative to Control. AHCWR did not differ between Control and Duran but was lower in Physio (23±11%, 24±7%, and 12±2% at end diastole and 42±17%, 37±17%, and 21±10% at end systole, respectively, for Control, Duran, and Physio, respectively; ANOVA <0.05 for both). Conclusions— Mitral annular height and AHWCR of the native valve were unchanged by a Duran ring, whereas the Physio ring led to a lower AHWCR. Theoretically, such a flexible annuloplasty ring may provide better leaflet stress distribution by maintaining normal AHWCR.

Bringing Dynamic Geometry to Three Dimensions

2015 ◽  
pp. 68-99
Author(s):  
Nicholas H. Wasserman
Keyword(s):  
Teaching And Learning ◽  
Spatial Reasoning ◽  
Mathematics Classroom ◽  
Three Dimensional ◽  
Dynamic Geometry ◽  
State Standards ◽  
Three Dimensions ◽  
Two Dimensional ◽  
The Common ◽  
K 12

Contemporary technologies have impacted the teaching and learning of mathematics in significant ways, particularly through the incorporation of dynamic software and applets. Interactive geometry software such as Geometers Sketchpad (GSP) and GeoGebra has transformed students' ability to interact with the geometry of plane figures, helping visualize and verify conjectures. Similar to what GSP and GeoGebra have done for two-dimensional geometry in mathematics education, SketchUp™ has the potential to do for aspects of three-dimensional geometry. This chapter provides example cases, aligned with the Common Core State Standards in mathematics, for how the dynamic and unique features of SketchUp™ can be integrated into the K-12 mathematics classroom to support and aid students' spatial reasoning and knowledge of three-dimensional figures.

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