Nonischemic Mitral Regurgitation Research Articles

Development of left ventricular hypertrophy in a novel porcine model of mitral regurgitation

Objectives. We aimed to develop a porcine model for chronic nonischemic mitral regurgitation (MR) to investigate left ventricular (LV) enlargement and eccentric hypertrophy. Design. Nonischemic MR was induced in 30 pigs by open-chest immobilization of the posterior mitral leaflet by transannular traction sutures that where applied in transmyocardial fashion. A sham operated control group (n = 13) was included. Echocardiographic LV size and heart weight assessed at euthanasia were used to evaluate the development of LV enlargement and eccentric hypertrophy after 8 weeks follow-up. Results. Eight pigs died and seven were excluded due to mediastinal infection (n = 2) or failure to produce MR (n = 5). Thus, 28 pigs were included and were divided into three groups: controls (n = 12), mild MR (mMR; n = 10), and moderate to severe MR (sMR; n = 6). The change in LV internal diameter in diastole (LVIDd) from baseline to follow-up was significantly higher in the sMR group compared to that of the control group (P = 0.0017). Furthermore, LV weight was significantly increased in the mMR (P = 0.047) and the sMR (P = 0.0087) groups compared to that of the control group. Conclusions. A new model for chronic moderate to severe nonischemic MR with development of LV enlargement and eccentric hypertrophy within 8 weeks has been established in pigs.

Invited Commentary

Invited Commentary

Surgery promotes early postoperative changes in left atrial volume and function in non-ischemic symptomatic mitral regurgitation: a three-dimensional echocardiography study

Background: Left Atrial (LA) dilation is associated with a worse prognosis in various clinical situations, including chronic Non-Ischemic Mitral Regurgitation (NIMR). Real time Three-Dimensional Echocardiography (3DE) has allowed a better assessment of LA volume and function. Although LA reverse remodeling has been observed in long-term outcome after surgery in NIMR, little is known about the behavior of LA structure and function in an early post-operative period. We aimed to analyze these aspects with 3DE. Methods: We prospectively studied 43 patients with symptomatic chronic NIMR who underwent valve repair or bioprosthetic valve replacement. LA volumes and function were analyzed before and 30 days after surgery by means of 3DE in all patients, and in a control group of 20 healthy subjects. We studied maximum, minimum and pre-atrial contraction volumes, and calculated total, passive and active LA emptying fractions. Results: Before surgery patients had higher LA volumes (p<0.001), but smaller LA emptying fractions than controls (p<0.01). After surgery, all three LA volumes reduced in both groups. Postoperative increase in active LA emptying fraction also occurred in both groups. Independent predictors of early postoperative LA reverse remodeling were diastolic blood pressure before surgery (Coefficient= - 0.004; p= 0.02), lateral mitral annulus early diastolic velocity (e') (Coefficient=0.02; p=0.008), and a mean transmitral diastolic gradient increment (Coefficient= - 0.035; p < 0.001), but not the surgical technique. Besides, e' was the only variable independently associated with the early recovery of active LA emptying fraction (OR= 1.664, P=0.027). Conclusion: LA reverse remodeling and functional improvement occur soon after surgery of symptomatic chronic NIMR patients, regardless of the surgical technique. Those changes are related to preoperative diastolic blood pressure and an echocardiographic marker of left ventricular diastolic function.

Impact of Severe Mitral Regurgitation on Postoperative Outcomes After Noncardiac Surgery

ObjectivePreoperative cardiac risk assessment scoring systems traditionally do not include valvular regurgitation as a criterion for adverse outcome prediction. We sought to determine the impact of significant mitral regurgitation on postoperative outcomes after planned noncardiac surgeries. MethodsPatients with significant mitral regurgitation (moderate-severe or severe) undergoing noncardiac surgery were identified using surgical and echocardiographic databases at the Cleveland Clinic. The mechanism of mitral regurgitation was identified and classified as ischemic or nonischemic. By using propensity score analysis, we obtained 4 matched controls (patients undergoing noncardiac surgery without mitral regurgitation) for each case. The primary outcome was defined as a composite of 30-day mortality, myocardial infarction, heart failure, and stroke. Secondary outcomes included 30-day mortality, myocardial infarction, heart failure, stroke, and atrial fibrillation. ResultsA total of 298 cases and 1172 controls were included in the study. The incidence of primary outcome was significantly higher among patients with mitral regurgitation (22.2%) compared with controls (16.4%, P=.02). Analysis of the secondary outcomes revealed significant differences in perioperative heart failure (odds ratio, 1.4; 95% confidence interval, 1.02-2.0) and perioperative myocardial infarction (odds ratio, 2.9; 95% confidence interval, 1.2-7.3). Of patients with mitral regurgitation, those with ischemic mitral regurgitation had significantly more events than those with nonischemic mitral regurgitation (39.2% vs 13.3%, P<.001). ConclusionsPatients undergoing noncardiac surgery with significant ischemic mitral regurgitation are at higher risk of a composite adverse postoperative outcome, including short-term mortality, heart failure, myocardial infarction, and stroke.

Usefulness of Preoperative Exercise Tolerance to Predict Late Survival and Symptom Persistence After Surgery for Chronic Nonischemic Mitral Regurgitation

Exercise duration during exercise treadmill testing (ETT) predicts long-term outcome among asymptomatic patients with mitral regurgitation. However, the prognostic value of preoperative exercise duration in patients who undergo mitral valve surgery is unknown. We examined findings among 45 prospectively followed (average 9.2 ± 4.3 years) patients (aged 54.8 ± 12.0 years, 45% men) with chronic isolated severe MR who underwent ETT before mitral valve surgery to test the hypotheses that exercise duration predicts long-term postoperative survival and persistent symptoms within 2 years after operation. During follow-up, 11 patients died; of these, 8 had persistent symptoms. Among patients who exercised >7 minutes, average annual postoperative all-cause and cardiovascular mortality risks were 0.75% (both endpoints) versus 5.4% and 4.8%, respectively, versus those who exercised ≤7 minutes (p= 0.003 all-cause, p= 0.007 cardiovascular). Exercise duration predicted postoperative deaths (p <.02 all cause, p <.04 cardiovascular) even when analysis was adjusted for preoperative variations in age, gender, medications, history of atrial fibrillation, and peak exercise heart rates. Other ETT, echocardiographic, and clinical variables were not independently associated with these outcomes when exercise duration was considered in the analysis. Preoperative exercise duration also predicted postoperative (New York Heart Association functional class ≥II) symptom persistence (p= 0.012), whereas other ETT, echocardiographic and clinical variables did not (NS, all). In conclusion, among patients who undergo surgery for chronic nonischemic mitral regurgitation, preoperative exercise duration, unlike many commonly used descriptors, is useful for predicting postoperative mortality and symptom persistence. Future research should determine whether interventions to improve exercise tolerance before mitral valve surgery can modify these postoperative outcomes.

553 Near Perfect Repair Rate Using Minimally Invasive Surgery for the Treatment of Degenerative Mitral Regurgitation in 200 Consecutive Patients

553 Near Perfect Repair Rate Using Minimally Invasive Surgery for the Treatment of Degenerative Mitral Regurgitation in 200 Consecutive Patients

Assessment of left ventricular function in mitral regurgitation patients using three-dimensional strain and doppler parameters

Objective To interpret the specific dynamic status of mitral regurgitation through the combination of 3D strain and Doppler imaging.Methods Thirty consecutive non-ischemic mitral regurgitation patients〖16 male patients,average(50.72±11.52)years old〗and 30 healthy volunteers〖18 male patients,average(46.86±8.67)years old〗were randomly enrolled as Patient Group and Control Group,respectively.All the subjects received routine,Doppler and 3D echocardiography(Philip IE33,s5-1,X3-1).Velocity time integrity(VTI)at pulmonary artery,aorta and mitral valve,iso-systolic and iso-diastolic time of left ventricle were measured.3D data were analyzed off-line by TOM-TEC 4D LV analysis station to get Systolic Peak Strain(S)of basal(Sb),middle(Sm)and apical segments(Sa)and their time to peak(Tb,Tm and Ta).All the parameters were indexed by body surface area(BSA)or cardiac cycle.Results Systolic peak of 3D strain increased in Patient Group(P<0.05)while Time to Peak 3D strain was delayed(P<0.05)and iso-systolic time was prolonged(P<0.05).Conclusions Peak 3D strain can be influenced by mitral regurgitation and thus is not able to evaluate its left ventricluar function accurately.However,Time to Peak 3D strain and Iso-volumic period are less volume-dependent and may be helpful in follow-up of mitral regurgitation patients.

475 Larger left ventricle size negatively impacts late postoperative left ventricle function following mitral valve repair

475 Larger left ventricle size negatively impacts late postoperative left ventricle function following mitral valve repair

Noninvasive Assessment of Left Ventricular End-Diastolic Pressure with Tissue Doppler Imaging in Patients with Mitral Regurgitation

The ratio of early transmitral flow velocity to mitral annulus early diastolic velocity (E/Ea) is a widely used noninvasive tool to estimate left ventricular end diastolic pressure (LVEDP). The aim of this study was to explore whether E/Ea ratio was a reliable index for the estimation of LVEDP in patients with mitral regurgitation (MR). Sixteen patients with nonischemic MR (primary MR group; 6 male, 58 ± 12 years) 51 patients with ischemic MR (secondary MR group; 29 male, 63 ± 9 years) and 29 patients without MR (control group; 19 male, 53 ± 10 years) were consecutively included. The peak transmitral flow and mitral annular velocities during early diastole were measured. LVEDP was determined invasively by left heart catheterization. Primary and secondary MR groups had significantly higher E/Ea ratios and LVEDP than control group. LVEDP significantly correlated with E/Ea ratio in patients with primary MR, but not in patients with secondary MR. Multiple regression analysis revealed that E/Ea ratio was an independent predictor of LVEDP in patients with primary MR. Ten patients with primary MR had LVEDP ≥15 mmHg. ROC analysis demonstrated cutoff values for E/Ea ratios as >10.5 for lateral mitral annulus (sensitivity: 80%, specificity: 66%, PPV: 80%, NPV: 66%) and as >14 for medial mitral annulus (sensitivity: 90%, specificity: 83%, PPV: 90%, NPV: 83%) to predict primary MR patients with LVEDP ≥15 mmHg. E/Ea ratio is still reliable in estimation of LVEDP in primary MR patients while it is not predictive for LVEDP in secondary MR patients.

Effects of Mitral Valve Surgery on Myocardial Energetics in Patients With Severe Mitral Regurgitation

Hemodynamically significant mitral regurgitation (MR) may alter left ventricular (LV) myocardial energy requirements. The effects of MR and subsequent corrective mitral valve (MV) surgery on myocardial energetics are not well understood. A better understanding of myocardial energetics and the LV responses to changes in preload and afterload may assist with the understanding of mitral regurgitation and its effect on the LV. We sought to determine the effects of MV surgery on forward stroke work, myocardial oxidative metabolism, and myocardial efficiency. Prospectively enrolled patients with chronic, severe, nonischemic mitral regurgitation underwent echocardiography, radionuclide angiography, and C-11 acetate positron emission tomography to measure LV volumes, ejection fraction, and oxidative metabolism before and 1 year after MV surgery. Forward and total stroke work corrected for oxidative metabolism was used to estimate efficiency using the work metabolic index. Fourteen patients (age, 59+/- 8 years) with myxomatous MV were enrolled. One year after MV surgery, there was a reduction in LV end-diastolic and end-systolic volumes (231+/-86 to 131+/-21 mL; P<0.01 and 98+/-53 to 55+/-17 mL; P<0.01). Forward stroke volume increased (58.1+/-15.0 to 75.5+/-23 mL; P<0.01), LV ejection fraction was preserved without a significant change in oxidative metabolism. Forward work metabolic index improved (4.99+/-1.32 x 10(6) to 6.59+/-2.45 x 10(6) mm Hg x mL/m(2); P=0.02). This was not at the expense of total work metabolic index, which was preserved. MV surgery has a beneficial effect on forward stroke volume and forward work metabolic index without adverse effects on oxidative metabolism or total work metabolic index.

Measured posterior annuloplasty for repair of non-ischemic mitral regurgitation. A single unit follow-up☆

The aim of this report is to evaluate short- and long-term outcomes of annuloplasty method of our choice: measured posterior annuloplasty (MPA). MPA is a piece of a Duran ring cut to the length of free-edge of anterior mitral leaflet (AML) and anchored with multiple pledgeted U-sutures from trigone to trigone into the posterior annulus. From 1988 to 2000, 103 consecutive patients with non-ischemic mitral regurgitation were scheduled preoperatively to be repaired by MPA. Preoperative mitral valve regurgitation (MR) grade was 3.8+/-0.5 and decreased to 0.1+/-0.3 (P<0.0001) after repair. One patient was converted to insertion of mechanical prosthesis after grade 3 MR persisted after septal myectomy and MPA. Three patients needed instant revision of the repair one due to SAM and two due to stenosis. No patient had a stenosis or unacceptable (>1) MR after the procedure. There was one operative death (1.0%) and 3 hospital/30-day deaths (2.9%). Sixteen patients (16.3%) expired during the follow-up to 91 months (mean 57.4+/-19.5, median 60 months) none due to failure of MPA. There were no reoperations due to failure of MPA. Three patients had a reoperation, one for dehiscence of reconstruction after P2 resection and two patients due to progression of anterior leaflet degeneration and calcification with 4+ MR. New York Heart Association (NYHA) functional classification decreased from 2.3+/-0.8 to 1.4+/-0.6 (P<0.0001) and only one patient had an increase from II to III. Eighty-eight patients (96.7%) were in NYHA class I-II. Ten patients had an increase of MR from 0 to trace or 1 and one from 0 to 2. Two patients were diagnosed with mild stenosis without need of reoperation. MPA is a durable and stable alternative for repair of non-ischemic mitral regurgitation of different etiologies. The technique gives an objective measure of the length of the band and no patient is left with a significant MR or mitral valve stenosis (MS). First-time success rate is very high and instant repairs few and minor. Freedom of MPA related reoperations is 100%.

The QuantumCor device for treating mitral regurgitation: An animal study

The mitral annular contraction achieved could help reduce mitral regurgitation (MR), and with appropriate modifications, be applied to human subjects providing a potentially effective percutaneous method of valve repair. MR is an important source of morbidity and is an independent predictor of mortality. A variety of percutaneous approaches are being developed to address this issue. We introduce a novel potential method utilizing radiofrequency (RF) energy to heat and shrink the mitral valve annulus in an animal model. In open-heart procedures in 16 healthy sheep (six with naturally occurring MR), we used a malleable probe (QuantumCor, Lake Forest, CA) that conforms to the annular shape to deliver RF energy via a standard generator to replicate a surgical mitral annular ring. Seven sheep were followed chronically and their mitral annulus dimensions measured serially. All sheep underwent intracardiac echocardiography or direct circumferential measurement of the mitral annulus before and after RF therapy. RF therapy was administered in less than 4 min in each case, and the mean anteroposterior (AP) annular distance was reduced by a mean of 23.8% (AP diameter reduction 5.75 +/- 0.86 mm, P < 0.001) acutely. In the six sheep with nonischemic MR, regurgitation was eliminated. Acute histopathology (HP) demonstrated no damage to the leaflets, coronary sinuses, or coronary arteries. At the end of the intended 6-month period of the chronic part of the study, four of the seven animals survived. The four treatment animals showed significant reductions in mitral A-P dimension, with a percent diameter reduction of 26.4% (AP diameter reduction 7 +/- 2.3 mm). The application of RF directly to heat the mitral annulus has resulted in sustained contraction of the annulus in this limited preclinical animal study. With further study and possible modifications, it holds promise for future application in human subjects with MR.

Management of asymptomatic patients with severe non-ischaemic mitral regurgitation. Are practices consistent with guidelines?

For asymptomatic patients with severe mitral regurgitation, guidelines recommend surgery in selected patients. However, little is known on how the current practice fits with guidelines. Of the 5001 patients prospectively included in the Euro Heart Survey on valvular heart disease, 877 had isolated mitral regurgitation and 546 had severe mitral regurgitation (grade >or=3/4 with Doppler echocardiography). Of them, 101 were asymptomatic and had non-ischaemic mitral regurgitation. The decision to refer the patients to surgery or not operate was analysed by comparing patient characteristics with American College of Cardiology/American Heart Association guidelines. Coronary angiography was performed in 21 out of 33 patients (64%) who were considered for surgery. Catheterisation was performed in 27 patients (27%). A decision to operate was taken in 33 patients (33%). Decisions to refer to surgery or not were in accordance with guidelines in 63 patients (62%). Regarding discordant decisions, intervention was considered 'over-used' in 9 patients (9%) and 'under-used' in 29 patients (29%), of whom 24 had a class I or IIa indication for surgery. Of the 68 non-operated patients, 44 (65%) received at least one drug with haemodynamic effect. In asymptomatic patients with severe mitral regurgitation, preoperative coronary angiography seems under-used and cardiac catheterisation is frequently used. Regarding the decision to operate or not, a large number of patients were not referred to surgery even though they fulfilled recommendation for surgery. Thus, to avoid too late surgical referral, implementation of existing guidelines should be improved.

Evolving Concepts and Technologies in Mitral Valve Repair

Over the past few decades, it has become apparent that mitral valve repair is preferable to mitral valve replacement for the majority of patients undergoing surgery for mitral regurgitation (MR). The advantages of mitral valve repair include low rates of thromboembolism, resistance to endocarditis, excellent late durability reported for as long as 25 years, and no need for anticoagulation in the majority of patients.1–5 Because of these advantages of repair over replacement, the threshold for performing mitral valve repair has been lowered to include patients with MR who have early symptoms or even those who are asymptomatic, assuming that the chance of successful repair is ≥90% according to the latest American College of Cardiology/American Heart Association guidelines.6,7 Recently, surgeons have evaluated new techniques to further improve mitral valve repair, and cardiologists and surgeons are increasingly interested in the potential for percutaneous approaches to mitral valve repair.8 Myxomatous MR affects 1% to 2% of the population and therefore is a common pathology for mitral valve surgery, but the complexity of the operation may be difficult, which leads to generally low rates of repair. In a recent review, only 44.3% of patients in the United States who required mitral valve surgery for MR received a mitral valve repair,9 and in the Euro Heart Survey, repair rates were similarly low (46.5%).10 The goals of mitral repair are to maintain leaflet mobility, remodel the annulus, and allow normal coaptation of the anterior and posterior leaflets. Recent advances in techniques and new concepts for mitral repair are important to cardiologists and other clinicians interested in the management of patients with mitral valve disease. Accordingly, an improved understanding of these concepts will aid in the development of innovative techniques to create safe, durable, reliable, and reproducible mitral valve repair techniques, both …

Percutaneous Treatment for Mitral Regurgitation: The QuantumCor System

Percutaneous edge-to-edge techniques and annuloplasty have been used to treat mitral regurgitation (MR). However, neither intervention can be performed reliably a second time and, with annuloplasty, a foreign body is left behind. The mitral and tricuspid annuli are areas of dense collagen (Fig. 1); treatment with radiofrequency (RF) energy in sheep reduces their size, and can be repeated without affecting the coronary sinus. RF energy may also be used in leaflet procedures. Our aim was to improve mitral valve competence using techniques that can be incorporated into a minimally invasive approach. In open-heart procedures in 16 healthy sheep (6 with naturally occurring MR), we used a malleable probe (QuantumCor, Inc., Lake Forest, CA) that conforms to the annular shape to deliver RF energy via a standard generator to replicate a surgical mitral annular ring. Four segments of the posterior mitral valve annulus were treated while on cardiopulmonary support via a left thoracotomy with access via the atrial appendage. Seven sheep were followed chronically. All sheep underwent intracardiac echocardiography (ICE) or direct circumferential measurement of the mitral annulus before and after RF therapy. RF therapy was administered in less than 4 minutes in each case, and the mean anteroposterior (AP) annular distance was reduced by a mean of 5.75 +/- 0.86 mm (23.8% reduction, P< 0.001). In the 6 sheep with nonischemic MR, regurgitation was eliminated. Acute histopathology (HP) demonstrated no damage to the leaflets, coronary sinuses, or coronary arteries. At 30 days, the AP distance continued to be reduced in the 7 surviving sheep (mean 5.0 +/- .6 mm, 21.4% reduction, P< 0.001). In a sheep model, RF energy applied for less than 4 minutes per case at subablative temperatures in four quadrants of the posterior mitral valve annulus reduced the AP and circumferential annular distances significantly, and eliminated nonischemic MR. Results will need to be confirmed in follow-up studies to determine safety and efficacy. RF energy administered as a novel, percutaneous method of mitral valve annuloplasty may have the potential to reduce morbidity and mortality associated with current surgical techniques.

Left atrial remodelling early after mitral valve repair for degenerative mitral regurgitation

Objective:Left atrial (LA) size is an important predictor of outcome after mitral valve replacement in patients with symptomatic chronic mitral regurgitation (MR). Data on LA remodelling after mitral valve repair...

Prognostic Value of Exercise Tolerance Testing in Asymptomatic Chronic Nonischemic Mitral Regurgitation

In many heart diseases, exercise tolerance testing (ETT) has useful functional correlates and/or prognostic value. However, its predictive value in mitral regurgitation (MR) is undefined. To determine whether ETT descriptors predict death or indications for mitral valve surgery in patients with MR, we prospectively followed, for 7 +/- 3 end-point-free years, a cohort of 38 patients with chronic severe nonischemic MR who underwent modified Bruce ETT; all lacked surgical indications at study entry. Their baseline exercise descriptors were also compared with those from 46 patients with severe MR who, at entry, already had reached surgical indications. End points during follow-up in the cohort included sudden death (n = 1), heart failure symptoms (n = 2), atrial fibrillation (n = 4), left ventricular (LV) ejection fraction <60% (n = 2), LV systolic dimensions > or =45 mm (n = 12) and >40 mm (n = 11), LV ejection fraction <60% plus LV systolic dimensions > or =45 mm (n = 3), and heart failure plus LV systolic dimensions > or =45 mm plus LV ejection fraction <60% (n = 1). In univariate analysis, exercise duration (p = 0.004), chronotropic response (p = 0.007), percent predicted peak heart rate (p = 0.01), and heart rate recovery (p <0.02) predicted events; in multivariate analysis, only exercise duration was predictive (p <0.02). Average annual event risk was fivefold lower (4.62%) with an exercise duration > or =15 versus <15 minutes (average annual risk 23.48%, p = 0.004). Relative risks in patients with and without exercise-inducible ST-segment depression were comparable (< or =1.3, p = NS) whether defined at entry and/or during follow-up. Exercise duration, but not prevalence of exercise-inducible ST-segment depression, was lower (p <0.001) in patients with surgical indications at entry versus initially end-point-free patients. In conclusion, in asymptomatic patients with chronic severe nonischemic MR and no objective criteria for operation, progression to surgical indications generally is rapid. However, those with excellent exercise tolerance have a relatively benign course. Exercise-inducible ST-segment depression has no prognostic value in this population.

Changes in systolic left ventricular function in isolated mitral regurgitation. A strain rate imaging study

The aim of the present study is to understand the changes in left ventricular (LV) regional systolic deformation based on strain rate (SR) imaging in patients with isolated mitral regurgitation (MR). Progressive LV dilatation and irreversible myocardial damage as a result of chronic isolated MR are important causes of morbidity and mortality in patients following valve surgery. To date, there is no specific diagnostic method to detect subclinical changes in systolic function before irreversible dysfunction occurs. Seventy-seven individuals were studied: 54 asymptomatic patients (age 56 +/- 12) with isolated non-ischaemic MR divided into three groups: mild, moderate, and severe and 23 healthy subjects. All underwent a standard echo examination and a tissue Doppler study. A mathematical study was carried out to predict how SR should alter with increasing dimensions and due to irreversible myocardial damage. Radial as well as longitudinal peak systolic SR was significantly decreased in patients with severe MR compared to the other groups (LV posterior wall: P = 0.0006, septum: P = 0.0004, LV lateral wall: P = 0.0003). From both modelling and in our patients, deformation correlated inversely with LV end-diastolic diameter and end-systolic diameter (ESD). Deformation measurements (corrected for increased geometry) enabled the identification of patients classically referred to as at risk of irreversible myocardial damage (ESD > or = 4.5 cm). In patients with a wide range of MR, deformation remains unchanged due to a balance of increased dimensions and increased stroke volume. Only when contractility is expected to change, deformation will significantly decrease. SR imaging indices, corrected for geometry, might potentially be useful in detecting subclinical deterioration in LV function in asymptomatic patients with severe MR.

The role of left ventricular long axis contraction in patients with asymptomatic non-ischemic mitral valve regurgitation and normal systolic function

Background Several indices have been proposed in order to better evaluate chronic mitral regurgitation, however, none of them is unique, thus underlying the diagnostic deficiency. We aimed to investigate the role of long axis contraction in both ventricles in patients with non-ischemic asymptomatic mitral regurgitation (MR). Methods Eighty-nine patients (40 men, mean age 59.9 ± 13.5 years) with non-ischemic asymptomatic MR along with 50 healthy controls were studied. An echocardiographic, including tissue Doppler imaging study, an exercise radionuclide cineangiography and a cardiac catheterization were also performed. Results Fifty of 89 patients (56.2%) had a normal response of left ventricular (LV) ejection fraction on exercise. LV end-diastolic diameter and volume index were significantly higher in patients with an impaired LV response. Moreover, systolic wave maximal velocity and systolic wave slope both at the lateral wall and at the inter-ventricular septum were significantly lower in patients with an impaired LV response. Systolic wave maximal velocity at the lateral wall was the index that best predicted LV response to exercise; while a cutoff value of 9.5 cm/s predicted an impaired LV response with a sensitivity of 96% and a specificity of 100%. MR as defined by the width of vena contracta, was mild/moderate in 78% of patients with a systolic wave maximal velocity at the lateral wall > 9.5 cm/s and severe in 69.2% of patients with a velocity < 9.5 cm/s. Conclusion In patients with asymptomatic non-ischemic MR, the evaluation of LV long axis contraction at rest can unmask a subnormal LV functional status.

523 Mitral valve repair with or without ring insertion in patients with non-ischemic mitral regurgitation and preoperatively depressed left ventricular function. A Doppler echocardiography study

523 Mitral valve repair with or without ring insertion in patients with non-ischemic mitral regurgitation and preoperatively depressed left ventricular function. A Doppler echocardiography study