Jen-Li Looi

Quantitative Analysis of Mitral Valve Morphology in Mitral Valve Prolapse With Real-Time 3-Dimensional Echocardiography Importance of Annular Saddle Shape in the Pathogenesis of Mitral Regurgitation

Background— Few data exist on the relation of the 3-dimensional morphology of mitral valve and degree of mitral regurgitation (MR) in mitral valve prolapse. Methods and Results— Real-time 3-dimensional transesophageal echocardiography of the mitral valve was acquired in 112 subjects, including 36 patients with mitral valve prolapse and significant MR (≥3+; MR+ group), 32 patients with mitral valve prolapse but no or mild MR (⩽2+; MR− group), 12 patients with significant MR resulting from nonprolapse pathologies (nonprolapse group), and 32 control subjects. The 3-dimensional geometry of mitral valve apparatus was measured with dedicated quantification software. Compared with the normal and MR− groups, the MR+ group had more dilated mitral annulus (P<0.0001), a reduced annular height to commissural width ratio (AHCWR) (P<0.0001) indicating flattening of annular saddle shape, redundant leaflet surfaces (P<0.0001), greater leaflet billow volume (P<0.0001) and billow height (P<0.0001), longer lengths from papillary muscles to coaptation (P<0.0001), and more frequent chordal rupture (P<0.0001). Prevalence of chordal rupture increased progressively with annulus flattening (7% versus 24% versus 42% for AHCWR >20%, 15%–20%, and <15%, respectively; P=0.004). Leaflet billow volume increased exponentially with decreasing AHCWR in patients without chordal rupture (r2=0.66, P<0.0001). MR severity correlated strongly with leaflet billow volume (r2=0.74, P<0.0001) and inversely with AHCWR (r2=0.44, P<0.0001). In contrast, annulus dilatation but not flattening occurred in nonprolapse MR patients. An AHCWR <15% (odds ratio=7.1; P=0.0004) was strongly associated with significant MR in mitral valve prolapse. Conclusion— Flattening of the annular saddle shape is associated with progressive leaflet billowing and increased frequencies of chordal rupture and may be important in the pathogenesis of MR in mitral valve prolapse.Background— Few data exist on the relation of the 3-dimensional morphology of mitral valve and degree of mitral regurgitation (MR) in mitral valve prolapse. Methods and Results— Real-time 3-dimensional transesophageal echocardiography of the mitral valve was acquired in 112 subjects, including 36 patients with mitral valve prolapse and significant MR (≥3+; MR+ group), 32 patients with mitral valve prolapse but no or mild MR (≤2+; MR− group), 12 patients with significant MR resulting from nonprolapse pathologies (nonprolapse group), and 32 control subjects. The 3-dimensional geometry of mitral valve apparatus was measured with dedicated quantification software. Compared with the normal and MR− groups, the MR+ group had more dilated mitral annulus ( P 20%, 15%–20%, and <15%, respectively; P =0.004). Leaflet billow volume increased exponentially with decreasing AHCWR in patients without chordal rupture ( r 2=0.66, P <0.0001). MR severity correlated strongly with leaflet billow volume ( r 2=0.74, P <0.0001) and inversely with AHCWR ( r 2=0.44, P <0.0001). In contrast, annulus dilatation but not flattening occurred in nonprolapse MR patients. An AHCWR <15% (odds ratio=7.1; P =0.0004) was strongly associated with significant MR in mitral valve prolapse. Conclusion— Flattening of the annular saddle shape is associated with progressive leaflet billowing and increased frequencies of chordal rupture and may be important in the pathogenesis of MR in mitral valve prolapse. # Clinical Perspective {#article-title-34}

Dynamic assessment of the changing geometry of the mitral apparatus in 3D could stratify abnormalities in functional mitral regurgitation and potentially guide therapy.

INTRODUCTION In functional mitral regurgitation (FMR), effective regurgitant orifice area (EROA) displays a dynamic pattern. The impact of dynamic changes of annulus dysfunction and leaflets tenting on phasic EROA was explored with real-time three-dimensional transesophageal echocardiography (RT3D-TEE). METHODS RT3D-TEE was performed in 52 FMR patients and 30 controls. Mitral annulus dimensions and leaflets tenting were measured throughout systole (TomTec, Germany). Phasic EROA was measured by proximal isovelocity surface area (PISA) method. RESULTS Mitral annulus had the minimal area and an oval shape with saddle configuration during early systole in controls, which enlarged and became round and flattened towards mid and late systole (P<0.05). In contrast, annulus in FMR was significantly larger, rounder and flatter (P<0.001), which further dilated and became more flattened at late systole (P<0.05 vs control). Leaflet tenting height in FMR decreased in mid systole and remains unchanged towards late systole. The leaflet tenting volume peaked at early and late systole with a mid-systolic trough in both FMR and controls. But tenting volume of patients with FMR was significantly larger than that of controls (all P<0.001 vs control in whole systole). Further analysis demonstrated that early tenting volume (β value=0.053, P<0.05) was a predictor of early EROA, whereas late tenting volume (β value=0.031, P<0.05) and late annular displacement velocity were predictors of late EROA. CONCLUSIONS The early and late peak EROAs of FMR was primarily contributed by tenting volume at early systole and late systole respectively. These findings would be of value to consider in interventions aimed at reducing the severity of FMR.

Diagnosis of cleft mitral valve using real-time 3-dimensional transesophageal echocardiography

Isolatedcleftmitralvalveisararecauseofcongenitalmitralregurgi-tation (MR). Most commonly, the cleft involves the anterior leaflet ofthe mitral valve as seen in atrioventricular canal defects, although iso-lated cleft on the posterior lea flet has been described [1,2]. Real-time3-dimensional transesophageal echocardiography (RT3D-TEE) allowsvisualization of the mitral valve in any desired plane orientation. Ithelps in defining the extent and location of the pathology, and deter-miningthemechanismandseverityofvalvulardysfunction[3].Perhapsmore important, it provides essential information to cardiac surgeonsbyallowingthemtovisualizethelocationandextentofcomplexmitralvalvelesions,especiallywhencommissuralpathologyorcleftsarepres-ent. This information has a signi ficant impact on surgical approach. Wereport2caseswhichillustratethediagnosticcapabilitiesofRT3D-TEEinprovidingincrementalinformationofcleftmitralvalve,includingapre-ciseanatomiclocationofthecleftwhichhasanimportantimpactonthesurgical management.A37-year-oldmanwasfoundtohaveaheartmurmuronaroutinehealth check and echocardiography confirmed a primum atrial septaldefect (ASD). Pre-operative two-dimensional (2D) transthoracic(TTE) and transesophageal echocardiography (TEE) demonstrated aprimum ASD with left to right shunt and trace MR (Fig. 1A and B,Movie I and II). The mitral valve appeared unremarkable on 2D TTEor TEE. RT3D-TEE, however, clearly demonstrated the morphologyof the mitral valve is trileaflet from an atrial perspective (the“surgeon” view) (Fig. 1C, Movie III) and the cleft was adjacent tothe ASD (Fig. 1D, Movie IV). Based on the 3DE findings, the surgeondecided to perform a right atriotomy to repair the cleft through theASD. Intraoperative examination through the right atriotomy ap-proach confirmed the primum ASD and the cleft could be seen clearlythroughthe ASD (Fig. 1E). Thecleft mitral valve was repaired throughthe ASD before the primum ASD was closed (Fig. 1F). Post-operative2D- and 3D-TEE showed a competent mitral valve and an intactinter-atrial septum (Fig. 1G and H, Movie V and VI).A 74-year-old man with a history of hypertension has been diag-nosed with MR due to mitral valve prolapse since 2009. He remainedasymptomatic until recently with increasing dyspnoea on exertion.2D-TTE demonstrated a flail posterior mitral leaflet (Fig. 2A, MovieVII). Therefore he was referred for TEE to assess suitability of mitralvalve repair. 2D-TEE revealed a flail P2 segment with an eccentricjet of MR (Fig. 2B and C, Movie VIII and IX). RT3D-TEE clearly demon-strated a flail P2 due to ruptured chordae (Fig. 2D, Movie X). Multiplesites of prolapse of the posterior leaflet with a cleft between P2 andP3 segments were clearly seen on both left atrial and ventricular per-spectives on RT3D-TEE (Fig. 2E and F, Movie XI). There was a left toright shunt on color Doppler suggestive of an atrial septal defect(ASD) (Fig. 2G). A small secundum ASD (Fig. 2was clearly demon-H)strated on RT3D-TEE from the right atrial perspective. He underwentmitral valve repair with an annuloplasty ring, and closure of the cleftand ASD. Post-operative TEE showed trivial MR and no residual ASDshunt (Fig. 2I and J).Our cases highlight the usefulness of RT3D-TEE in providing essen-tial information to the cardiac surgeons by allowing them to visualizethelocationsandextentofcomplexmitralvalvelesionswhichhasasig-nificant impact on surgical approach. 2-dimensional TEE (2D-TEE) canbe used to examine the mitral valve for the presence of cleft using themid-esophageal four-chamber, the mid-esophageal two-chamber andthe transgastric basal short axis views.However, it has been previouslyreported that localizing and confirming the presence of a cleft can bedifficult despite using multiple planes on 2D-TEE [4,5]. In addition, the2Dimagesneedtobeintegratedtocreatea‘mental’3Dimage.Translat-ingthis‘mental’3Dimagetoanon-echocardiographercanbechalleng-ing at times. On the other hand, RT3D-TEE has the ability to display allthe information in one single view. It also allows the examiner to dis-play the beating heart instantaneously in real-time from any spatialangle [6]. This greatly facilitates the communication between the

Quantitative Analysis of Mitral Valve Morphology in Mitral Valve Prolapse Using Real-Time Three-Dimensional Echocardiography: Importance of Annular Saddle-Shape in Pathogenesis of Mitral Regurgitation

Background— Few data exist on the relation of the 3-dimensional morphology of mitral valve and degree of mitral regurgitation (MR) in mitral valve prolapse. Methods and Results— Real-time 3-dimensional transesophageal echocardiography of the mitral valve was acquired in 112 subjects, including 36 patients with mitral valve prolapse and significant MR (≥3+; MR+ group), 32 patients with mitral valve prolapse but no or mild MR (⩽2+; MR− group), 12 patients with significant MR resulting from nonprolapse pathologies (nonprolapse group), and 32 control subjects. The 3-dimensional geometry of mitral valve apparatus was measured with dedicated quantification software. Compared with the normal and MR− groups, the MR+ group had more dilated mitral annulus (P<0.0001), a reduced annular height to commissural width ratio (AHCWR) (P<0.0001) indicating flattening of annular saddle shape, redundant leaflet surfaces (P<0.0001), greater leaflet billow volume (P<0.0001) and billow height (P<0.0001), longer lengths from papillary muscles to coaptation (P<0.0001), and more frequent chordal rupture (P<0.0001). Prevalence of chordal rupture increased progressively with annulus flattening (7% versus 24% versus 42% for AHCWR >20%, 15%–20%, and <15%, respectively; P=0.004). Leaflet billow volume increased exponentially with decreasing AHCWR in patients without chordal rupture (r2=0.66, P<0.0001). MR severity correlated strongly with leaflet billow volume (r2=0.74, P<0.0001) and inversely with AHCWR (r2=0.44, P<0.0001). In contrast, annulus dilatation but not flattening occurred in nonprolapse MR patients. An AHCWR <15% (odds ratio=7.1; P=0.0004) was strongly associated with significant MR in mitral valve prolapse. Conclusion— Flattening of the annular saddle shape is associated with progressive leaflet billowing and increased frequencies of chordal rupture and may be important in the pathogenesis of MR in mitral valve prolapse.Background— Few data exist on the relation of the 3-dimensional morphology of mitral valve and degree of mitral regurgitation (MR) in mitral valve prolapse. Methods and Results— Real-time 3-dimensional transesophageal echocardiography of the mitral valve was acquired in 112 subjects, including 36 patients with mitral valve prolapse and significant MR (≥3+; MR+ group), 32 patients with mitral valve prolapse but no or mild MR (≤2+; MR− group), 12 patients with significant MR resulting from nonprolapse pathologies (nonprolapse group), and 32 control subjects. The 3-dimensional geometry of mitral valve apparatus was measured with dedicated quantification software. Compared with the normal and MR− groups, the MR+ group had more dilated mitral annulus ( P 20%, 15%–20%, and <15%, respectively; P =0.004). Leaflet billow volume increased exponentially with decreasing AHCWR in patients without chordal rupture ( r 2=0.66, P <0.0001). MR severity correlated strongly with leaflet billow volume ( r 2=0.74, P <0.0001) and inversely with AHCWR ( r 2=0.44, P <0.0001). In contrast, annulus dilatation but not flattening occurred in nonprolapse MR patients. An AHCWR <15% (odds ratio=7.1; P =0.0004) was strongly associated with significant MR in mitral valve prolapse. Conclusion— Flattening of the annular saddle shape is associated with progressive leaflet billowing and increased frequencies of chordal rupture and may be important in the pathogenesis of MR in mitral valve prolapse. # Clinical Perspective {#article-title-34}

Intramural Left Atrial Hematoma Complicating Catheter Ablation for Atrial Fibrillation

![Figure][1] [![Graphic][3] ][3] A 52-year-old woman became hypotensive during radiofrequency ablation for paroxysmal atrial fibrillation. She received heparin 5,000 IU after transseptal puncture, and continued as an infusion to maintain an activated clotting time of 270 s during the

Three-dimensional echocardiography for cor triatriatum in adults

Cor triatriatum is a very rare congenital abnormality. In this malfor- mation the left atrium (LA) is divided by a fibromuscular membrane into an upper (supero-posterior) chamber containing the pulmonary veins and their confluence and a lower (infero-anterior) chamber hous- ing the true LA and left atrial appendage. The two chambers generally communicate through one or more openings in the intra-atrial mem- brane. The age at presentation and clinical symptoms is related to the degree of pulmonary venous obstruction. In the majority of cases it is diagnosed in neonatal period or early infancy, whereas adult cases are veryrareandtendtobe asymptomaticbecausethedividingmembranes are often non-obstructive. Atrial septal defect or patent foramen ovale is present in 70-80% of patients with cor triatriatum (1-3). Three- dimensional echocardiography (3DE) provides additional information such as the morphology, the size, and the number of openings of the dividing membrane and its spatial relationship to pulmonary veins, left atrial appendage and inter-atrial septum. We report 3 cases of non-obstructive cor triatriatum in adults whereby 3DE provides incre- mental information about the membrane, its relation to adjacent struc- tures and associated cardiac anomalies.

Left ventricular systolic dyssynchrony in acute decompensated heart failure

Acute decompensated heart failure (ADHF) is a common and potentially fatal condition. Acute ischemia, hypertensive crisis, fluid retention, mitral regurgitation and tachyarrhythmias can precipitate ADHF, yet very often no clinical trigger was apparent [1]. Left ventricular systolic dyssynchrony (LVSD) is important in the pathogenesis of heart failure [2], yet evaluation of LVSD is usually performed in stable clinical conditions. Patients can have transient episodes of LVSD leading to acute elevation of LV filling pressure and pulmonary edema. Recent studies revealed that LVSD can change dynamically with exercise [3] and pharmacological stress [4,5]. Herein, acute LVSD may be a hidden triggering mechanism for ADHF. Echocardiography with tissue Doppler imaging (TDI) during episodes of ADHF can provide a better appreciation of acute LVSD. To test the hypothesis that patients who presented with ADHF may have more LVSD than those who had chronic stable heart failure (CSHF) without recent exacerbation, we prospectively performed echocardiography with TDI in 145 HF subjects, including 84 consecutive patients presented with ADHF (defined as acute respiratory distress with clinical and/or radiographic evidence of pulmonary edema; LV ejection fraction b 50%) requiring hospitalization, comparing them to 61 CSHF patients identified from outpatient database who had no HF exacerbation or hospitalization in the past 6 months. Patients with acute coronary syndrome, primary valvular disease, atrial fibrillation, and pacemaker implantation were excluded. Echocardiography (Vivid 7, VingmedGeneral Electric, Horten, Norway) was performed within 48 h of ADHF admission. Color-coded TDI (frame rate optimized to 100 Hz or higher) was used to assess LVSD. Myocardial velocity curves were reconstituted offl ine using the 12-segment (6-basal 6-mid) model[3] .T ime to peak systolicvelocityduringejection(Ts) wasmeasured foreachsegmentwith reference to the onset of QRS complex. The standard deviation of Ts (TsSD) of the 12 LV segments was calculated to evaluate LVSD. Significant LVSD was defined as Ts-SD N 33 ms as previously published [2] .L ongitudinal myocardial function was assessed by averaging the peak myocardial systolic (mean Sm) and early diastolic (mean Em) velocities at the 6 basal segments. LV and left atrial dimensions were measured according to guideline recommendations [6]. The effective regurgitant orifice (ERO) of any mitral regurgitation was calculated by the proximal isovelocity surface area method [7]. Group comparisons were performed by independent students t test or Pearson χ 2 test as appropriate. Pearson

Intravenous fluid administration to rule out migration of Amplatzer septal occluder

A 22-year-old woman with a history of closure of secundum atrialseptal defect (ASD) with 22 mm Amplatzer septal occluding device in2002 presented for a follow-up transthoracic echocardiography. Thediagnosis was made when a heart murmur was detected at the ageof 13 and transthoracic echocardiography performed at that stagedemonstratedalargesecundumASDwithaleftto rightshuntcausingdilatation of the right atrium and right ventricle. She remainedasymptomatic after the procedure. Transthoracic echocardiographydemonstrated a normal sized right ventricle with preserved rightventricular function. Agitated saline injection via the right antecubitalvein revealed a mild right-to-left intra-cardiac shunting (Fig. 1A,arrows). Both left and right atrial discs at the inferior portion of thedeviceappearedprotrudingintotherightatrium,raisingthepossibilityof device migration across the inter-atrial septum (Fig. 1BandC,arrows;Video1).500 mLof0.9%normalsalinewasadministeredintra-venously within 10 to 15 min in order to increase the right atrialvolume and to straighten the inter-atrial septum. The 2 discs at thelower portion of the device were clearly seen attaching to differentsides the inter-atrial septum (Fig. 1D, arrow; Video 2), excludingerosion/migration of the device.Transcatheter ASD occlusion has become an alternative to surgicalprocedure using cardiopulmonary bypass in recent years. Majority ofASD closure devices become fully endothelialized within severalmonths after deployment and thus, pose little risk of erosion or migra-tion. This complication is rare but death from such mechanical compli-cation remains a concern. Erosion events associated with the ASDclosure device have occurred at the roof of the right or left atrium orat the atrial junction with the aorta, causing hemopericardium,tamponade or aortic fistula [1,2]. The reasons for erosion are unknown,but several risk factors have been proposed including absent or defi-cient superior-anterior rim, device-sizing, and/or device straddling ofthe aorta [2–4]. Deformation of the device at the aortic root at 24 hpost procedure and early pericardial effusion have been proposed asearly risk factors [5].The possible explanation for enhanced detection of attachment ofthe device to the rims of the inter-atrial septum in our case appears torest on the changes in the right atrial volume. By increasing the rightatrial volume with fluid bolus, the inter-atrial septum stretches outand thus the device could be clearly seen attaching to the postero-inferior rim of the atrial septum. This case illustrates the usefulness ofgiving saline bolus intravenously to enhance detection of the device tothe rims of the inter-atrial septum.The authors of this manuscript have certified that they complywith the Principles of Ethical Publishing in the International Journalof Cardiology.Supplementary data to this article can be found online at http://dx.doi.org/10.1016/j.ijcard.2013.01.180.AcknowledgementDr Looi acknowledges support from the Overseas FellowshipAward from the National Heart Foundation New Zealand.References

Quantitative Analysis of Mitral Valve Morphology in Mitral Valve Prolapse With Real-Time 3-Dimensional EchocardiographyClinical Perspective: Importance of Annular Saddle Shape in the Pathogenesis of Mitral Regurgitation

Background— Few data exist on the relation of the 3-dimensional morphology of mitral valve and degree of mitral regurgitation (MR) in mitral valve prolapse. Methods and Results— Real-time 3-dimensional transesophageal echocardiography of the mitral valve was acquired in 112 subjects, including 36 patients with mitral valve prolapse and significant MR (≥3+; MR+ group), 32 patients with mitral valve prolapse but no or mild MR (⩽2+; MR− group), 12 patients with significant MR resulting from nonprolapse pathologies (nonprolapse group), and 32 control subjects. The 3-dimensional geometry of mitral valve apparatus was measured with dedicated quantification software. Compared with the normal and MR− groups, the MR+ group had more dilated mitral annulus (P<0.0001), a reduced annular height to commissural width ratio (AHCWR) (P<0.0001) indicating flattening of annular saddle shape, redundant leaflet surfaces (P<0.0001), greater leaflet billow volume (P<0.0001) and billow height (P<0.0001), longer lengths from papillary muscles to coaptation (P<0.0001), and more frequent chordal rupture (P<0.0001). Prevalence of chordal rupture increased progressively with annulus flattening (7% versus 24% versus 42% for AHCWR >20%, 15%–20%, and <15%, respectively; P=0.004). Leaflet billow volume increased exponentially with decreasing AHCWR in patients without chordal rupture (r2=0.66, P<0.0001). MR severity correlated strongly with leaflet billow volume (r2=0.74, P<0.0001) and inversely with AHCWR (r2=0.44, P<0.0001). In contrast, annulus dilatation but not flattening occurred in nonprolapse MR patients. An AHCWR <15% (odds ratio=7.1; P=0.0004) was strongly associated with significant MR in mitral valve prolapse. Conclusion— Flattening of the annular saddle shape is associated with progressive leaflet billowing and increased frequencies of chordal rupture and may be important in the pathogenesis of MR in mitral valve prolapse.Background— Few data exist on the relation of the 3-dimensional morphology of mitral valve and degree of mitral regurgitation (MR) in mitral valve prolapse. Methods and Results— Real-time 3-dimensional transesophageal echocardiography of the mitral valve was acquired in 112 subjects, including 36 patients with mitral valve prolapse and significant MR (≥3+; MR+ group), 32 patients with mitral valve prolapse but no or mild MR (≤2+; MR− group), 12 patients with significant MR resulting from nonprolapse pathologies (nonprolapse group), and 32 control subjects. The 3-dimensional geometry of mitral valve apparatus was measured with dedicated quantification software. Compared with the normal and MR− groups, the MR+ group had more dilated mitral annulus ( P 20%, 15%–20%, and <15%, respectively; P =0.004). Leaflet billow volume increased exponentially with decreasing AHCWR in patients without chordal rupture ( r 2=0.66, P <0.0001). MR severity correlated strongly with leaflet billow volume ( r 2=0.74, P <0.0001) and inversely with AHCWR ( r 2=0.44, P <0.0001). In contrast, annulus dilatation but not flattening occurred in nonprolapse MR patients. An AHCWR <15% (odds ratio=7.1; P =0.0004) was strongly associated with significant MR in mitral valve prolapse. Conclusion— Flattening of the annular saddle shape is associated with progressive leaflet billowing and increased frequencies of chordal rupture and may be important in the pathogenesis of MR in mitral valve prolapse. # Clinical Perspective {#article-title-34}

Quantitative Analysis of Mitral Valve Morphology in Mitral Valve Prolapse With Real-Time 3-Dimensional EchocardiographyClinical Perspective

Background— Few data exist on the relation of the 3-dimensional morphology of mitral valve and degree of mitral regurgitation (MR) in mitral valve prolapse. Methods and Results— Real-time 3-dimensional transesophageal echocardiography of the mitral valve was acquired in 112 subjects, including 36 patients with mitral valve prolapse and significant MR (≥3+; MR+ group), 32 patients with mitral valve prolapse but no or mild MR (⩽2+; MR− group), 12 patients with significant MR resulting from nonprolapse pathologies (nonprolapse group), and 32 control subjects. The 3-dimensional geometry of mitral valve apparatus was measured with dedicated quantification software. Compared with the normal and MR− groups, the MR+ group had more dilated mitral annulus (P<0.0001), a reduced annular height to commissural width ratio (AHCWR) (P<0.0001) indicating flattening of annular saddle shape, redundant leaflet surfaces (P<0.0001), greater leaflet billow volume (P<0.0001) and billow height (P<0.0001), longer lengths from papillary muscles to coaptation (P<0.0001), and more frequent chordal rupture (P<0.0001). Prevalence of chordal rupture increased progressively with annulus flattening (7% versus 24% versus 42% for AHCWR >20%, 15%–20%, and <15%, respectively; P=0.004). Leaflet billow volume increased exponentially with decreasing AHCWR in patients without chordal rupture (r2=0.66, P<0.0001). MR severity correlated strongly with leaflet billow volume (r2=0.74, P<0.0001) and inversely with AHCWR (r2=0.44, P<0.0001). In contrast, annulus dilatation but not flattening occurred in nonprolapse MR patients. An AHCWR <15% (odds ratio=7.1; P=0.0004) was strongly associated with significant MR in mitral valve prolapse. Conclusion— Flattening of the annular saddle shape is associated with progressive leaflet billowing and increased frequencies of chordal rupture and may be important in the pathogenesis of MR in mitral valve prolapse.Background— Few data exist on the relation of the 3-dimensional morphology of mitral valve and degree of mitral regurgitation (MR) in mitral valve prolapse. Methods and Results— Real-time 3-dimensional transesophageal echocardiography of the mitral valve was acquired in 112 subjects, including 36 patients with mitral valve prolapse and significant MR (≥3+; MR+ group), 32 patients with mitral valve prolapse but no or mild MR (≤2+; MR− group), 12 patients with significant MR resulting from nonprolapse pathologies (nonprolapse group), and 32 control subjects. The 3-dimensional geometry of mitral valve apparatus was measured with dedicated quantification software. Compared with the normal and MR− groups, the MR+ group had more dilated mitral annulus ( P 20%, 15%–20%, and <15%, respectively; P =0.004). Leaflet billow volume increased exponentially with decreasing AHCWR in patients without chordal rupture ( r 2=0.66, P <0.0001). MR severity correlated strongly with leaflet billow volume ( r 2=0.74, P <0.0001) and inversely with AHCWR ( r 2=0.44, P <0.0001). In contrast, annulus dilatation but not flattening occurred in nonprolapse MR patients. An AHCWR <15% (odds ratio=7.1; P =0.0004) was strongly associated with significant MR in mitral valve prolapse. Conclusion— Flattening of the annular saddle shape is associated with progressive leaflet billowing and increased frequencies of chordal rupture and may be important in the pathogenesis of MR in mitral valve prolapse. # Clinical Perspective {#article-title-34}