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.

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.

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.

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 Anterior mitral leaflet length and mitral annulus diameter impact the echocardiographic outcome after isolated myectomy

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Mateusz Kuć ◽  
Magdalena Kumor ◽  
Mariusz Kłopotowski ◽  
Maciej Dąbrowski ◽  
Natalia Kopyłowska-Kuć ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Left Ventricle ◽  
Mitral Regurgitation ◽  
Nyha Class ◽  
Mitral Annulus ◽  
Outflow Tract ◽  
Mitral Leaflet ◽  
Anterior Mitral Leaflet ◽  
Anterior Posterior ◽  
Annulus Diameter

Abstract Background Myectomy remains the standard surgical treatment of patients with hypertrophic cardiomyopathy (HOCM). New surgical methods developed in the last decades mainly address the mitral valve and are controversial because of their conflicting assumptions. This study assesses the influence of anterior mitral valve leaflet (AML) length and the anterior-posterior diameter of the mitral annulus (MAD) on dynamic left ventricle outflow tract obstruction and mitral regurgitation (MR) after extended myectomy. Methods We retrospectively analysed the transthoracic echocardiograms (TTE) of 36 patients. AML length and MAD were obtained from TTE performed before the operation. The greatest maximal left ventricle outflow tract (LVOT) gradient and MR registered in follow-up were analysed. After surgery, patients were divided into two groups; those with moderate or milder MR and/or an LVOT gradient < 30 mmHg (responders), and those with more than moderate MR and/or an LVOT gradient ≥30 mmHg (non-responders). Results Patients in responders group had significantly longer AML: 32.3 ± 2.3 mm vs 30.0 ± 3.8 mm (p = 0.03) [parasternal long axis view – PLAX view], 25.9 ± 2.3 mm vs 23.5 ± 2.7 mm (p = 0.008) [four chamber view - 4CH view] and larger anterior-posterior mitral annulus diameter 28.1 ± 2.8 mm vs 25.4 ± 3.2 mm (p = 0.011) than those in non-responders group. Among all analysed patients longer anterior mitral leaflet was correlated with lower postoperative LVOT gradient when measured in PLAX view (p = 0.02) and lower degree of MR due to systolic anterior motion (SAM) when measured in 4CH view (p = 0.009). Greater [AML x mitral annulus] ratio correlated with lower postoperative LVOT gradient in both projections: 4CH (p = 0.025), PLAX (p = 0.012). There was significant reduction in NYHA Class after surgery (p = 0.000). There were no significant differences in NYHA class after surgery (p = 0.633) neither in NYHA class reduction (p = 0.475) between patients divided into responders and non-responders group according to echocardiographic parameters. Conclusions Patients with a longer AML and a greater diameter of the mitral annulus are less likely to have mitral regurgitation due to residual SAM and increased LVOT gradient after an extended myectomy. Division of patients according to echocardiographic criteria into responders and non-responders was not in concordance with clinical improvement. Trial registration Retrospective study. Approved by ethics committee (IK-NPIA-0021-21/1763/19) at 16.01.2019.

scholarly journals Clinical importance of left atrial infiltration in cardiac transthyretin amyloidosis

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
F Bandera ◽  
R Martone ◽  
L Chacko ◽  
S Ganesananthan ◽  
JA Gilbertson ◽  
...  
Keyword(s):  
Left Atrial ◽  
Speckle Tracking ◽  
Contractile Function ◽  
Clinical Importance ◽  
Transthyretin Amyloidosis ◽  
Funding Sources ◽  
Atrial Contraction ◽  
Congo Red Staining ◽  
Distinctive Phenotype ◽  
Normal Architecture

Abstract Funding Acknowledgements Type of funding sources: None. INTRODUCTION  The clinical significance of left atrial (LA) involvement in ATTR amyloidosis cardiomyopathy (ATTR-CM) has not been characterized. The aims of this study were to characterize: (1)LA pathology in explanted ATTR-CM hearts; (2)LA mechanics using echocardiographic speckle-tracking in a large cohort of ATTR-CM patients; (3)to study the association with mortality. METHODS AND RESULTS Congo red staining and immunohistochemistry was performed to assess the presence, type and extent of amyloid and associated changes in 5 explanted ATTR-CM atria. Echo speckle-tracking was used to assess LA reservoir, conduit, contractile function and stiffness in 906 ATTR-CM patients (551 wt-ATTR-CM;93 T60A-ATTR-CM;241 V122I-ATTR-CM;21 other). There was extensive ATTR amyloid infiltration in the 5 atria with loss of normal architecture, vessels remodelling, capillary disruption and subendocardial fibrosis. Echo speckle-tracking in 906 ATTR-CM patients demonstrated increased atrial stiffness [median(25th-75th quartile) 1.83(1.15-2.92)] that remained independently associated with prognosis, after adjusting for known predictors (lnLA stiff:HR = 1.26,CI 1.07-1.57;p = 0.009). There was substantial impairment of the three phasic functional atrial components [reservoir 8.86(5.94-12.97)%; conduit 6.5(4.53-9.28)%; contraction function 4.0(2.29-6.56)%]. Atrial contraction was absent in 21.6% of patients whose ECG showed sinus rhythm (SR)-"atrial electro-mechanical dissociation"(AEMD). AEMD was associated with poorer prognosis compared to SR patients with effective mechanical contraction (p &lt; 0.0001). AEMD conferred a similar prognosis to patients in AF. CONCLUSION The phenotype of ATTR-CM includes significant infiltration of the atrial walls with progressive loss of atrial function and increased stiffness, which is a strong independent predictor of mortality. AEMD emerged as a distinctive phenotype identifying patients in SR with poor prognosis. Abstract Figure.

scholarly journals Pathogenesis of Mitral Regurgitation in Tachycardia-Induced Cardiomyopathy

Circulation ◽  
2001 ◽  
Vol 104 (suppl_1) ◽  
Author(s):  
Tomasz A. Timek ◽  
Paul Dagum ◽  
David T. Lai ◽  
David Liang ◽  
George T. Daughters ◽  
...  
Keyword(s):  
Mitral Regurgitation ◽  
Dilated Cardiomyopathy ◽  
Transesophageal Echocardiography ◽  
Angular Displacement ◽  
Mitral Annulus ◽  
Valve Closure ◽  
Lateral Direction ◽  
Systolic Volume ◽  
End Diastolic Volume ◽  
Tachycardia Induced Cardiomyopathy

Background Dilated cardiomyopathy is often associated with mitral regurgitation (MR), or so-called functional MR, the mechanism of which continues to be debated. We studied the valvular and ventricular 3D geometric perturbations associated with MR in an ovine model of tachycardia-induced cardiomyopathy (TIC). Methods and Results Nine sheep underwent myocardial marker implantation in the left ventricle (LV), mitral annulus, and mitral leaflets. After 5 to 8 days, the animals were studied with biplane videofluoroscopy (baseline), and mitral competence was assessed by transesophageal echocardiography. Rapid ventricular pacing (180 to 230 bpm) was subsequently initiated for 15±6 days until the development of TIC and MR, whereupon biplane videofluoroscopy and transesophageal echocardiography studies were repeated. LV volume was calculated from the epicardial marker array. Valve closure time was defined as the time after end diastole when the distance between leaflet edge markers reached its minimal plateau. TIC resulted in increased LV end-diastolic volume ( P =0.001) and LV end-systolic volume ( P =0.0001) and greater LV sphericity ( P =0.02). MR increased significantly (grade 0.2±0.3 versus 2.2±0.9, P =0.0001), as did mitral annulus area (817±146 versus 1100±161 mm 2 , P =0.0001) and mitral annulus septal-lateral diameter (28.2±3.5 versus 35.1±2.6 mm, P =0.0001). Time of valve closure (70±18 versus 87±14 ms, P =0.23) and angular displacement of both the anterior (29±5° versus 27±3°, P =0.3) and posterior (55±15° versus 44±11°, P =0.13) leaflet edges relative to the mitral annulus after valve closure did not change, but leaflet edge separation after closure increased (5.2±0.9 versus 6.8±1.2 mm, P =0.019). Conclusions MR in TIC resulted from decreased leaflet coaptation secondary to annular dilatation in the septal-lateral direction. These data support the use of annular reduction procedures, such as rigid, complete ring annuloplasty, to address functional MR in patients with dilated cardiomyopathy.

scholarly journals The loss of left atrial contractile function predicts worse outcome in HFrEF: a speckle tracking study

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
GE Mandoli ◽  
MC Pastore ◽  
G Benfari ◽  
M Setti ◽  
L Maritan ◽  
...  
Keyword(s):  
Sinus Rhythm ◽  
Left Atrial ◽  
Speckle Tracking ◽  
Longitudinal Strain ◽  
Contractile Function ◽  
Global Longitudinal Strain ◽  
Left Ventricular ◽  
Volume Index ◽  
Systolic Pulmonary Artery Pressure ◽  
Atrial Contraction

Abstract Funding Acknowledgements Type of funding sources: None. Background in chronic heart failure (HF), high cardiac pressure induces a progressive remodeling of small pulmonary arteries up to pulmonary hypertension development. At the end of left atrial (LA) conduit function, pulmonary and left heart end-systolic pressures equalize. This might affect LA systole. Purpose we investigated whether peak atrial contraction strain (PACS), measured by speckle tracking echocardiography (STE), was independently associated with outcome in HF with reduced ejection fraction(HFrEF). Methods 168 outpatients with HFrEF and sinus-rhythm referred to our echo-labs were prospectively enrolled. After clinical and echocardiographic evaluation, off-line STE analysis was performed. The endpoints were cardiovascular (CV) death and HF hospitalization respectively. Spline knotted survival model identified the optimal cut-off value for PACS. Results The 152 included patients were stratified based on PACS &lt; 8%(n = 76) or PACS≥8%(n = 76). Mean age was 61 ± 12, mean EF was 30 ± 9%. Characteristics of the two groups are presented in Table 1. Over a mean follow-up of 3.41 ± 1.9 years, 117 events (51 CV death, 66 HF hospitalizations) were collected. By univariate and multivariate Cox analysis, global PACS emerged as a strong and independent predictor of CV death and HF hospitalization, even after adjusting for age, sex, LV strain, E/e’, LA volume index (HR 0.6 per 5 unit decrease in PACS). Kaplan Meier curves showed a sustained divergence in event-free survival rates for the two groups (Fig.1). Conclusions The reduction of PACS significantly and independently affects CV outcome in HFrEF. Although limited to patients with sinus rhythm, it could offer additive prognostic information for HFrEF patients. Table 1 Variable PACS &lt; 8 PACS ≥ 8 P value Age 61.5± 11.4 61.8 ± 12.7 0.4 NYHA class &gt;2 26% (n = 39) 11% (n = 17) &lt;0.0001 NT pro BNP 2293.7 ± 1636 1335 ± 242 0.04 E/E’ ratio 16.1 ± 9.09 12.1 ± 7.09 0.0015 LV GLS -7.28 ± 3.4 -10.17 ± 3.2 &lt;0.001 sPAP 40.5 ± 13.7 30.3 ± 9.3 &lt;0.0001 LAVI 64.4 ± 20.4 45.5 ± 15.8 &lt;0.0001 PALS 9.8 ± 4.9 20.2 ± 7 &lt;0.0001 E, peak early diastolic “E” wave; E’, medium velocity of early mitral annulus descent; GLS, global longitudinal strain; LAVI, left atrial volume index; LV, left ventricular; PACS, peak atrial contraction strain; PALS, peak atrial longitudinal strain; sPAP, systolic pulmonary artery pressure. Abstract Figure. Fig.1

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