Severe Functional Mitral Regurgitation Research Articles

Possible Left Circumflex Artery Obstruction in a Cardioband Transcatheter Mitral Annuloplasty Caused by Coronary Kinking During Cinching

A 70-year-old woman presented with dyspnea in New York Heart Association functional class III. Transesophageal echocardiography revealed severe functional central mitral regurgitation (MR) due to annular dilatation with calcification of the posterior leaflet ([Figure 1A][1], [Online Video 1][2]).

600.56 Clinical Outocomes of Percutaneous Mitral Valve Repair with MitraClip for the Management of Functional Mitral Regurgitation

To evaluate the safety and efficacy of percutaneous mitral valve repair for the management of functional mitral insufficiency. Severe functional mitral regurgitation (FMR) is present in 25–30% of patients with heart failure and is an independent predictor of mortality and hospitalizations in

Papillary Muscle Tugging Approximation for Functional Mitral Regurgitation

The surgical approach is challenging for patients with severe functional mitral regurgitation with nonischemic/ischemic dilated cardiomyopathy who are unsuitable forheart transplantation or ventricular assist device implantation. We developed a new surgical treatment named papillary muscle tugging approximation combined with mitral valve replacement. This technique is safe and feasible, with excellent midterm outcomes.

Progression and Challenges of Medical Treatment in Severe Functional Mitral Regurgitation: Case Report of 41-Year-Old Woman

Progression and Challenges of Medical Treatment in Severe Functional Mitral Regurgitation: Case Report of 41-Year-Old Woman

Left Ventricular Pseudoaneurysmectomy and Mitral Valve Replacement 30 Years after Blunt Polytrauma

Left ventricular (LV) pseudoaneurysms are the consequence of cardiac rupture, usually contained by adherent pericardium or fibrous scar tissue. They represent, from a functional point of view, the acquired blood-filled spaces that are external to the cardiac chambers but communicating with the ventricle. They can occur after transmural myocardial infarction or, albeit less frequently, post-traumatically. This cardiac disease has been a topic of discussion since the pioneering days of heart surgery. We present a case of a posttraumatic LV pseudoaneurysm, in which the causative blunt trauma happened 30 years prior to the onset of symptoms. Severe functional mitral regurgitation (FMR) resulted from leaflet tethering and partial rupture of the posteromedial papillary muscle complex.

Lessons from MITRA-FR and COAPT studies: Can we hope for an indication for severe functional mitral regurgitation in systolic heart failure?

Lessons from MITRA-FR and COAPT studies: Can we hope for an indication for severe functional mitral regurgitation in systolic heart failure?

Functional mitral regurgitation determinants in dilated cardiomyopathy

Functional mitral regurgitation (FMR) is a frequent condition in the setting of dilated cardiomyopathy (DCM) and its physiopathological mechanisms are complex. The aim of this study was to determine the influence of left ventricular remodeling and mechanical dyssynchrony on the occurrence of FMR in non ischemic DCM. Prospective study involving 52 patients (mean age = 57 ± 10 years, sex-ratio = 1.8) with non ischemic DCM. Two groups were compared: the group with FMR (group MR + = 31 patients) and that without FMR (group MR- = 21 patients). Mean QRS duration was 141 ± 29 ms, 63% of patients had complete left bundle branch block (LBBB), with no significant difference between the 2 groups. Echocardiographic parameters representing left ventricular systolic function were similar in 2 groups except for cardiac output which was lower in the group MR+ (3.3 ± 1l/min vs. 4 ± 1,3l/min. P = 0.02). For mitral deformation indices, tenting area (3.6 ± 1 cm 2 vs. 2,5 ± 0.8 cm 2 ; P = 0.005) and tenting height (1,5 ± 0.3 cm vs. 1 ± 0.2 cm; P < 0.001) were significantly larger in group MR+. For dyssynchrony indices, only temporal longitudinal dyssynchrony was associated to FMR ( P = 0.04). In the group MR+, more criteria of intraventricular dyssynchrony were noted (3.4 ± 1.4) than in-group MR- (2.4 ± 1.4; P = 0.01). FMR severity was well correlated to tenting area ( r = 0.66; P < 0.001) and tenting height ( r = 0,67; P < 0.01). However, parameters representing left ventricular systolic and diastolic function were not good determinants of FMR severity and dyssynchrony indices were not at all associated to FMR severity. This study showed that only the mitral deformation indices were well correlated to both the presence and the severity of FMR. Left ventricular remodeling indices were not good determinants of FMT. However, the intra ventricular dyssynchrony indices were associated to the presence of FMR and not to its severity.

Wpływ leku sakubitril/walsartan na funkcjonalną niedomykalność zastawki mitralnej w HFrEF

In the drug therapy of a 65-year-old male with chronic heart failure with reduced ejection fraction, New York Heart Association class III, with numerous co-morbidities including severe functional mitral regurgitation (FMR), in accordance with the 2016 European Society of Cardiology guidelines, angiotensin receptor blocker was replaced with sacubitril/ /valsartan. During further ambulatory observation, significantly reduced FMR was noted. This case report presents the current state of knowledge regarding the broad benefits of using sacubitril/valsartan in everyday clinical practice.

Insights into functional mitral regurgitation using the average pixel intensity method.

Previously we introduced and validated the average pixel intensity (API) method for grading mitral regurgitation (MR) in a heterogeneous MR population. We now investigated the feasibility and added value of the API method more specifically in patients with functional MR (FMR). We consecutively enrolled 283 patients with pure FMR. Transthoracic echocardiography was performed and MR was assessed using the API method and guideline-recommended parameters, including color Doppler, vena contracta width (VCW) and proximal isovelocity surface area (PISA)-based methods. The API method had an applicability of 98% in this FMR cohort, which was significantly higher than VCW (84%) and PISA-based methods (75%). Overall, the API method had significant correlations with direct parameters of FMR severity, ejection fraction, atrial and ventricular dimensions, pulmonary pressures and New York Heart Association class. Analysis of the API dynamics during MR revealed a typical pattern with early and late systolic peaks in API and a midsystolic nadir, which matched the temporal changes of the effective regurgitant orifice (ERO) during FMR. Based on ROC curves of established FMR severity cut-offs, an API value of 125 au was considered the optimal cut-off to determine severe MR. Interestingly, this API severity cut-off is similar to the API severity cut-off for MR in degenerative MR (DMR), despite different EROA/RV cut-offs in current ESC guidelines for FMR and DMR. The API method is an easy, fast and feasible parameter for grading FMR and may complement the multiparametric assessment of FMR in daily clinical practice.

Impact of right heart function on outcome in patients with functional mitral regurgitation and chronic heart failure undergoing percutaneous edge-to-edge-repair.

To evaluate the impact of right ventricular dysfunction (RVD) on outcome after transcatheter mitral valve repair (TMVR) in patients with chronic heart failure (CHF) and severe functional mitral regurgitation (FMR). One hundred thirty patients (median age 72.7 ± 10.7 years; 63.8% male) at high operative risk (LogEuroSCORE 23.8 ± 13.9%) with FMR and CHF (left ventricular ejection fraction 32 ± 7%) were enrolled and separated into two groups according to the RVD. RVD was assessed by the tricuspid annular plane systolic excursion (TAPSE) method (A: TAPSE ≤ 16 mm, n = 58; B: TAPSE > 16 mm, n = 72). The rate of successful reduction of mitral regurgitation (MR ≤2+) by TMVR was similar in both groups (94.6% vs 91.2%; P: n.s.) with low in-hospital major adverse event rates. During a median follow-up period of 10.5 ± 4 months, the Kaplan-Meier analysis revealed a significantly higher all-cause mortality in group A (43.1% vs 23.6%; log-rank P = 0.039) and a significantly higher rate of hospital readmission due to congestive heart failure (56.9% vs 26.4%; log-rank P < 0.001). At long-term follow-up, 25% of patients in group A remained in NYHA functional class IV (none in group B). Preexisting RVD as assessed by TAPSE and Doppler tissue imaging (DTI-S') was an independent predictor of all-cause mortality after TMVR (hazard ratio 2.84; 95% confidence interval 1.15-7.65; P = 0.039; hazard ratio 4.70; 95% confidence interval 1.14-20.21; P = 0.044, respectively). Patients with CHF and RVD were with regard to functional capacity less often responder and showed an unfavorable long-term outcome. Thus, patients with CHF and RVD seem to benefit less frequently from TMVR.

EFFECT OF PAPILLARY MUSCLE DISPLACEMENT AND ANNULAR DILATION ON DEVELOPMENT OF FUNCTIONAL MITRAL REGURGITATION

Functional mitral regurgitation (FMR) occurs following left ventricle (LV) dysfunction with normal mitral valve (MV) leaflet. The progress and severity of FMR are closely related to LV dilatation, which often results in displacement of the papillary muscles (PMs) and enlargement of the mitral annulus. We investigated the effect of PM displacement and annular dilation on FMR development to better understand the complex intercorrelation between these pathologic alterations leading to FMR. Virtual MV modeling was performed to create a normal human MV, and several different types of PM displacement, annular dilation, and the combination of PM displacement and annular dilation mimicking the pathology of FMR were modeled. Dynamic finite element evaluation of MV function was performed across the complete cardiac cycle for the normal and FMR MV models. PM displacement to both lateral and apical directions revealed markedly reduced leaflet coaptation and large stress distribution in the P2 scallop. Annular dilation greater than 2% demonstrated the occurrence of leaflet malcoaptation and increased stresses near the anterior saddle-horn region. The pathologic MV model with annular dilation combined with PM displacement provides physiologically realistic biomechanical characteristics as the MVs having FMR. Simulation-based biomechanical evaluation of MV pathology related to LV chamber dilatation provides an excellent tool to better understand the pathophysiologic mechanism of FMR.

Predictors of outcome in heart failure patients with severe functional mitral regurgitation undergoing MitraClip treatment

BackgroundThe prognostic predictors of outcome in patients with functional mitral regurgitation (FMR) undergoing MitraClip implantation (MCi) are still poorly known. The aim of our study is to identify the baseline predictors of outcome in FMR patients candidate to MCi. MethodsAll patients with symptomatic moderate-to-severe or severe FMR undergoing MCi at our institution were consecutively and prospectively enrolled. Baseline clinical and instrumental data were collected. Primary endpoint was the occurrence of cardiac death; secondary endpoints were all-cause death and the composite of cardiac death or rehospitalization for heart failure. Results74 patients (mean 71.6 ± 8.3 years) were enrolled. During follow-up (median 416.0 days), the primary endpoint occurred in 15 (20.3%), all-cause death in 26 (35.1%) and the composite endpoint in 25 (33.8%). At multivariate analysis, the left atrial volume index (LAVi; HR:1.02; P = 0.048) and the low peak oxygen uptake (peak VO2; HR:0.73; P = 0.018) increased the risk of cardiac death at follow-up; atrial fibrillation (AF; HR:2.69; P = 0.027) was independently associated to all-cause death and the low level of peak VO2 was an independent predictor of overall mortality (HR:0.70; P < 0.001) as well as of the composite endpoint (HR:0.73; P < 0.001).The ROC analysis identified a peak VO2 cut-off of 10.0 mL/kg/min as the best predictor for the three study endpoints; the best LAVi cut-off for cardiac death was 67 mL/m2. Kaplan-Meier analysis for the individual and combined outcome predictors confirmed their significant stratification ability during follow-up. ConclusionsPeak VO2, along with LAVi and AF, identify FMR patients with the worst prognosis after MCi.

Comparison of mitral annulus geometry between patients with ischemic and non-ischemic functional mitral regurgitation: implications for transcatheter mitral valve implantation

BackgroundTranscatheter mitral valve replacement (TMVR) is a new therapeutic option for high surgical risk patients with mitral regurgitation (MR). Mitral valve (MV) geometry quantification is of paramount importance for success of the procedure and transthoracic 3D echocardiography represents a useful screening tool. Accordingly, we sought to asses MV geometry in patients with functional MR (FMR) that would potentially benefit of TMVR, focusing on the comparison of mitral annulus (MA) geometry between patients with ischemic (IMR) and non ischemic mitral regurgitation (nIMR).MethodsWe retrospectively selected 94 patients with severe FMR: 41 (43,6%) with IMR and 53 (56,4%) with nIMR. 3D MA analysis was performed on dedicated transthoracic 3D data sets using a new, commercially-available software package in two moments of the cardiac cycle (early-diastole and mid-systole). We measured MA dimension and geometry parameters, left atrial and left ventricular volumes.ResultsMaximum (MA area 10.7 ± 2.5 cm2 vs 11.6 ± 2.7 cm2, p > 0.05) and the best fit plane MA area (9.9 ± 2.3 cm2 vs 10.7 ± 2.5 cm2, p > 0.05, respectively) were similar between IMR and nIMR. nIMR patients showed larger mid-systolic 3D area (9.8 ± 2.3 cm2 vs 10.8 ± 2.7 cm2, p < 0.05) and perimeter (11.2 ± 1.3 cm vs 11.8 ± 1.5 cm, p < 0.05) with longer and larger leaflets, and wider aorto-mitral angle (135 ± 10° vs 141 ± 11°, p < 0.05). Conversely, the area of MA at the best fit plane did not differ between IMR and nIMR patients (9 ± 1.1 cm2 vs 9.9 ± 1.5 cm2, p > 0.05).ConclusionsPatients with ischemic and non-ischemic etiology of FMR have similar maximum dimension, yet systolic differences between the two groups should be taken into account to tailor prosthesis’s selection.Trial registrationN.A.

Effect of Functional Mitral Regurgitation on Outcome in Patients Receiving Cardiac Resynchronization Therapy for Heart Failure

Functional mitral regurgitation (FMR) is common in heart failure (HF), and negatively impacts prognosis. Cardiac resynchronization therapy (CRT) can improve FMR, but the long-term changes in and impact of FMR after CRT are still unclear. The present study investigated the prevalence, evolution and impact on mortality of FMR before and after CRT in patients with HF. A total of 1,313 patients (66 ± 11 years, 77% male, 59% ischemic heart disease) treated with CRT were evaluated. Patients were divided into 4 groups of FMR according to the evolution at 6 months after CRT: no or mild FMR at baseline which remained unchanged at 6 months (grade 0-1 FMR unchanged, n = 609 [51%]), no or mild FMR which worsened to moderate to severe (grade 0-1 FMR worsened, n = 66 [6%)]), moderate to severe FMR which improved to no or mild (grade 2-4 improved, n = 209 [18%]), and moderate to severe FMR which remained unchanged (grade 2-4 unchanged, n = 309 [26%]). Over a mean follow-up of 51 ± 38 months, 297 (25%) patients died. Those with baseline FMR grade 0-1 which remained unchanged at 6-month follow-up, as well as baseline FMR grade 2-4 which improved, had lower mortality rates than patients with 6-month FMR grade 2-4 regardless of baseline FMR grade (p <0.001). Baseline FMR grade 2-4 that remained unchanged at 6-month follow-up was associated with increased mortality, independent of the clinical and left ventricular volumetric responses to CRT (hazard ratio, 1.77; 95% confidence interval, 1.41-2.22, p <0.001). In conclusion, moderate to severe FMR at baseline which remains unchanged at 6 months after CRT implantation is strongly associated with long-term mortality in patients with HF.

Transient elevation of high-sensitive troponinT after Cardioband implantation.

The Cardioband system enables percutaneous surgical-like direct mitral valve annuloplasty and, thereby, repair of severe functional mitral valve regurgitation (MR) in patients with advanced systolic heart failure (HF) and dilation of the left ventricular (LV) annulus. Since the device is anchored by screws in the LV annulus, limited myocardial injury is likely to occur. Five patients (Society of Thoracic Surgeons score: 2.7 ± 0.7%) with severe HF (LV ejection fraction [LVEF]: 17 ± 1%; LV end-diastolic diameter [LVEDD]: 71 ± 3 mm) were treated with the Cardioband (sizes C-F) receiving 14-17screws in the LV annulus region. Myocardial injury was monitored by measuring high-sensitive cardiac troponinT (hsTnT) levels and by echocardiography. All patients showed significant periprocedural increase in hsTnT levels. Peak hsTnT concentration was reached between day1 and day6 (593 ± 141 pg/ml). None of the patients showed clinical signs of myocardial infarction, ST-segment elevation, new onset of deteriorated myocardial wall motion, or new ventricular tachycardia. hsTnT levels normalized in all patients after 14days (hsTnT on day0: 34 ± 6 pg/ml vs. hsTnT on day14: 36 ± 6 pg/ml; p = 0.604). This nonischemic hsTnT kinetics was compared to asixth patient who experienced proximal damage of the left circumflex artery (LCX) and ST-segment elevation during the Cardioband procedure, followed by immediate repair of the LCX, avoiding structural damage of the LV. Cardioband implantation is accompanied by significant elevation of hsTnT without causing structural myocardial damage or clinical symptoms such as worsening of LV function, new-onset LV regions exhibiting reduced wall motion, or ventricular tachycardia.

Transcatheter Repair of Functional Mitral Regurgitation in Heart Failure Patients - A Meta-Analysis of 23 Studies on MitraClip Implantation.

The aim of this study was to investigate long-term survival, clinical status, and echocardiographic findings of patients with severe functional mitral regurgitation (FMR) undergoing MitraClip (MC) treatment and to explore the role of baseline features on outcome. Methods and Results: Randomized and observational studies of FMR patients undergoing MC treatment were collected to evaluate the overall survival, New York Heart Association (NYHA) class and echocardiographic changes after MC treatment. Baseline parameters associated with mortality and echocardiographic changes were also investigated. Across 23 studies enrolling 3,253 patients, the inhospital death rate was 2.31%, whereas the mortality rate was 5.37% at 1 month, 11.87% at 6 months, 18.47% at 1 year and 31.08% at 2 years. Mitral regurgitation Grade <3+ was observed in 92.76% patients at discharge and in 83.36% patients at follow-up. At follow-up, 76.63% of patients NYHA Class I-II and there were significant improvements in left ventricular (LV) volume, ejection fraction, and pulmonary pressure. Atrial fibrillation (AF) had a significant negative effect on 1-year survival (β=0.18±0.06; P=0.0047) and on the reduction in LV end-diastolic and end-systolic volumes (β=-1.05±0.47 [P=0.0248] and β=-2.60±0.53 [P=0.0024], respectively). MC results in durable reductions in mitral regurgitation associated with significant clinical and echocardiographic improvements in heart failure patients. AF negatively affects LV reverse remodeling and 1-year survival after MC treatment.

Papillary Muscle Dyssynchrony-Mediated Functional Mitral Regurgitation: Mechanistic Insights and Modulation by Cardiac Resynchronization

ObjectivesThis study sought to define interpapillary muscle dyssynchrony as a major contributing factor in functional mitral regurgitation (FMR) and prove the reversibility of FMR by interpapillary muscle resynchronization. BackgroundMechanistic features of FMR include papillary muscle displacement due to left ventricular remodeling. Intraventricular conduction delay might further augment this condition by introducing interpapillary muscle dyssynchrony. MethodsWe enrolled 269 chronic heart failure with reduced ejection fraction patients with conduction delay and comprehensively assessed dyssynchrony by complementary echocardiographic techniques covering the entire spectrum of dyssynchrony. ResultsPatients with severe FMR had markedly increased interpapillary longitudinal dyssynchrony (160 ms [interquartile range (IQR): 120 to 200 ms]) compared with those with moderate (70 ms [IQR: 40 to 110 ms]), no, or mild FMR (60 ms [IQR: 30 to 100 ms]; p < 0.001). Increased interpapillary muscle dyssynchrony was correlated with regurgitant volume (r = 0.50; p < 0.001) and vena contracta width (r = 0.49; p < 0.001). Restoration of longitudinal papillary muscle synchronicity by cardiac resynchronization therapy was correlated with FMR regression, as reflected by the reduction in regurgitant volume (r = 0.46; p < 0.001) and vena contracta width (r = 0.58; p < 0.001). Conversely, the improvement of FMR was associated with improved interpapillary radial (p = 0.006) and longitudinal (p < 0.001) dyssynchrony. The improvement of dyssynchrony-mediated FMR signified a better prognosis compared with no improvement in FMR during the 8-year follow-up period even after comprehensive adjustment by a bootstrap-selected confounder model (adjusted hazard ratio: 0.41; 95% confidence interval: 0.18 to 0.91; p = 0.028). The results remained virtually unchanged after adjustment for left bundle branch block. ConclusionsIntraventricular dyssynchrony introduces unequal contraction by papillary muscle bearing walls, which has an adverse effect on FMR. Cardiac resynchronization therapy can effectively restore interpapillary balance and thus create a less tented leaflet configuration, resulting in a clinically meaningful reduction of FMR. The restoration of papillary muscle synchronicity in dyssynchrony-mediated FMR translates into a significantly better prognosis.

Predictors of mortality in ischaemic versus non-ischaemic functional mitral regurgitation after successful transcatheter mitral valve repair using MitraClip: results from two high-volume centres.

Transcatheter edge-to-edge mitral valve repair using the MitraClip has been widely performed in surgical high-risk patients with reduced left ventricular systolic function and severe functional mitral regurgitation (FMR). Ischaemic heart disease is the leading aetiology of heart disease worldwide. We aimed to assess the clinical implications of ischaemic aetiology in patients with severe FMR who underwent MitraClip implantation. From two high-volume centres in Germany, we retrospectively compared the clinical outcomes and clinical predictors of all-cause mortality after MitraClip implantation in patients with ischaemic (I-FMR) and non-ischaemic FMR (NI-FMR). In the overall FMR cohort (n = 575), there were 336 (58%) patients with I-FMR and 239 (42%) with NI-FMR. There was no significant difference in survival between the two groups (log-rank p = 0.78). In a multivariable Cox regression analysis of all-cause mortality, different predictors were observed for either group. In I-FMR patients, decreasing tricuspid annular systolic excursion [adjusted hazard ratio (HRadj) 1.06, 95% confidence interval (95% CI) 1.01-1.14 /1mm, p = 0.028] and increasing logistic EuroSCORE (HRadj 1.02, 95% CI 1.00-1.03, p = 0.037) were independent predictors, whereas in NI-FMR patients, NT-pro BNP (HRadj 1.05, 95% CI 1.02-1.08, p = 0.001) and age (HRadj 1.06, 95% CI 1.01-1.11, p = 0.013) were independently predictive of mortality. Despite the similar survival between ischaemic and non-ischaemic FMR, different predictors of all-cause mortality were demonstrated. Further clinical studies are mandated to focus on each FMR subgroup with stratification by ischaemic origin.

Haemodynamic effects of percutaneous mitral valve edge-to-edge repair in patients with end-stage heart failure awaiting heart transplantation.

AimsFunctional mitral regurgitation is complicating end‐stage heart failure and potential heart transplantation by increasing pulmonary artery pressures. The aim of the present study was to investigate feasibility and haemodynamic effects of percutaneous mitral valve edge‐to‐edge repair using the MitraClip™ device in patients with end‐stage heart failure awaiting heart transplantation.Methods and resultsIn this retrospective study, we identified nine patients suffering from end‐stage heart failure listed for heart transplantation in whom moderate–severe or severe functional mitral regurgitation was recognized and treated with percutaneous mitral valve edge‐to‐edge repair. Twenty‐two patients listed for heart transplantation and presenting with moderate–severe or severe functional mitral regurgitation treated in the pre‐MitraClip™ era served as controls. Patients were analysed at two separate time points: MitraClip™ group: pre‐procedure and post‐procedure (follow‐up: 215 ± 53 days) and control group: study entry with recognition of moderate–severe or severe functional mitral regurgitation (follow‐up: 197 ± 47 days). Percutaneous mitral valve edge‐to‐edge repair with the MitraClip™ was feasible and safe in our high‐risk end‐stage heart failure population. The intervention resulted in significant reduction of mitral regurgitation (grade 3.0 [0.5] to 1.5 [0.5]; P = 0.009), left atrial diameter (51 mm [16] to 49 mm [4]; follow‐up MitraClip™ vs. control group P = 0.0497), pulmonary artery pressures (sPA 50 mmHg [15] to 45 mmHg [10]; P = 0.02; mPA 34 mmHg [8] to 30 mmHg [10]; P = 0.02), and New York Heart Association class (3.5 [1.0] to 3.0 [0.5]; P = 0.01) and improved mixed‐venous oxygen saturation (57% [11] to 55% [7]; follow‐up MitraClip™ vs. control group P = 0.02). No changes in the control group were observed.ConclusionsMitraClip™ implantation as ‘bridge‐to‐transplant’ strategy in patients with end‐stage heart failure and severe functional mitral regurgitation awaiting heart transplantation is feasible and appears to result in favourable haemodynamic effects.

Impact of atrial fibrillation on improvement of functional mitral regurgitation in cardiac resynchronization therapy

Functional mitral regurgitation (FMR) and atrial fibrillation (AF) are frequent heart failure (HF) complications. Cardiac resynchronization therapy (CRT) can improve FMR; however, little is known about the influence of AF on FMR improvement. The purpose of this study was to investigate the mechanisms and impact of baseline AF on FMR improvement after CRT. CRT recipients with HF, AF, or sinus rhythm (SR) at baseline with moderate or severe FMR, were included from an ongoing registry. Left atrial (LA), mitral annular (MA), and left ventricular (LV) dimensions were evaluated echocardiographically. FMR improvement was defined as ≥1 grade decrease from baseline to 6-month follow-up. Clinical and echocardiographic measurements were performed at baseline and 6-month follow-up. A total of 419 patients (age 66 ± 8 years; 73% male) were analyzed. At 6-month follow-up, FMR improved in 145 patients (45.6%) with SR vs 31 of AF patients (30.7%) (P = .011). Despite similar LV reverse remodeling at 6 months after CRT (LV end-systolic volume decreased by 32.1 ± 43.2 mL in the SR group and by 27.7 ± 6.3 mL in those with AF; P = .353), patients with SR exhibited smaller LA volumes (63.0 ± 26.5 mL vs 103.1 ± 41.0mL; P <.001) and MA diameters (42.3 ± 5.6 mm vs 46.1 ± 5.8 mm; P <.001) compared to AF patients. FMR improvement is more common in CRT recipients in SR vs AF, despite a similar degree of LV remodeling. LA volume and MA diameter are greater in the AF group, causing the negative impact of AF on FMR improvement in CRT, as well as indicating a potential therapeutic target (ie, AF rhythm control).