MRI to Evaluate Left Atrial and Ventricular Reverse Remodeling After Restrictive Mitral Annuloplasty in Dilated Cardiomyopathy

Left atrial disease and left atrial reverse remodeling across different stages of heart failure development and progression: a new target for prevention and treatment

The left atrium is a dynamic chamber with peculiar characteristics. Stressors and disease mechanisms may deeply modify its structure and function, leading to left atrial remodelling and disease. Left atrial disease is a predictor of poor outcomes. It may be a consequence of left ventricular systolic and diastolic dysfunction and neurohormonal and inflammatory activation and/or actively contribute to the progression and clinical course of heart failure through multiple mechanisms such as left ventricular filling and development of atrial fibrillation and subsequent embolic events. There is growing evidence that therapy may improve left atrial function and reverse left atrial remodelling. Whether this translates into changes in patient's prognosis is still unknown.

In this review we report current data about changes in left atrial size and function across different stages of development and progression of heart failure. At each stage, drug therapies, lifestyle interventions and procedures have been associated with improvement in left atrial structure and function, namely a reduction in left atrial volume and/or an improvement in left atrial strain function, a process that can be defined as left atrial reverse remodelling and, in some cases, this has been associated with improvement in clinical outcomes. Further evidence is still needed mainly with respect of the possible role of left atrial reverse remodelling as an independent mechanism affecting the patient's clinical course and as regards better standardization of clinically meaningful changes in left atrial measurements. Summarizing current evidence, this review may be the basis for further studies.

Extent and determinants of left ventricular reverse remodeling in patients with secondary mitral regurgitation undergoing MitraClip implantation

Background

In secondary MR, data on left ventricular (LV) remodeling after MitraClip procedure are rare, even this information may impact patient selection. This study investigated changes in LV structure and function by cardiovascular magnetic resonance (CMR) following MitraClip implantation for secondary mitral regurgitation (MR) in order to assess extent and predictors of LV reverse remodeling (LVRR).

Methods and Results

Twenty-nine patients underwent CMR imaging prior to and six months after MitraClip procedure. LVRR was defined by a decrease of LV end-diastolic volume index (LVEDVi) > 15% compared to baseline. According to the definition of LVRR, 34% of patients displayed LVRR at follow-up CMR. Baseline LV stroke volume index (LVSVi), LV ejection fraction (LVEF), LV circumferential strain and MR volume at baseline were predictors of LVRR at follow-up. At second CMR, we detected an improvement in hemodynamic status as illustrated by an increase in effective LVSVi (28 ± 8 ml/m² vs. 33 ± 8 ml/m²; p = 0.053) and cardiac index (2.0 ± 0.5 vs. 2.3 ± 0.5 l/min; p = 0.016), while LVEF and LV strain parameters did not change (p > 0.05). Improvements in effective LVSVi were associated with the decrease of MR volume (r = 0.509; p = 0.018) and MR fraction (r = 0.629; p = 0.002) by MitraClip.

Conclusions

Together, MitraClip implantation is associated with LVRR in one third of patients. Baseline LV function and magnitude of MR are important predictors of LVRR. Improvement of hemodynamic status may be assessed by effective stroke volume index and correlates with the reduction of MR by MitraClip implantation, rather than an increase in LV contractility.

Atrial ectopy after pulmonary vein isolation and left heart reverse remodeling in patients with atrial fibrillation

BACKGROUND

Maintenance of sinus rhythm after pulmonary vein isolation (PVI) for atrial fibrillation (AF) is associated with left atrial (LA) and ventricular (LV) reverse remodeling, although the degree varies among individuals. We hypothesized that frequent premature atrial complex (PAC) after PVI may attenuate the left heart reverse remodeling benefited from maintenance of sinus rhythm.

METHODS

We included 82 AF patients who underwent first-time PVI and 24-h Holter recordings at 6 months after PVI. All patients had no AF recurrence before this time. The number of PAC was categorized into tertiles: <90, 90-488 and >488 PACs/day. All patients underwent two-dimensional echocardiography and serum plasma B-type natriuretic peptide (BNP) measurement before and 6 months after PVI. LA reverse remodeling was defined as ≥15% decrease in LA volume index.

RESULTS

There was no significant difference in the baseline characteristics among the PAC tertiles except for sex. Six months after PVI, LA volume index, LV mass index, and serum BNP levels were significantly decreased in lower and middle PAC tertiles (all P < .05), whereas no significant changes were observed in upper PAC tertile. Frequency of LA reverse remodeling was significantly lower in upper tertile of PAC compared with middle and lower tertiles (22.2%, 57.1%, and 59.3%, P < .001). Baseline LA volume index, changes in LV mass index, and the frequency of PAC were independently associated with LA reverse remodeling (all P < .05).

CONCLUSIONS

Frequent PAC after PVI was associated with less left heart reverse remodeling in AF patients even without AF recurrence.

Pre-Procedural Serum Atrial Natriuretic Peptide Levels Predict Left Atrial Reverse Remodeling After Catheter Ablation in Patients With Atrial Fibrillation

OBJECTIVES

This study aimed to investigate the role of atrial natriuretic peptide (ANP) levels to predict left atrial (LA) reverse remodeling in atrial fibrillation (AF) patients.

BACKGROUND

Although LA reverse remodeling after radiofrequency catheter ablation (RFCA) for AF was reported to be associated with favorable outcomes and improvement of LA and left ventricular function, the predictor has not been extensively evaluated.

METHODS

This study included 104 consecutive patients who underwent RFCA for AF. All patients underwent multidetector computed tomography examination and laboratory tests, including measurement of ANP, plasma B-type natriuretic peptide (BNP), and high-sensitivity C-reactive protein (hs-CRP) levels before and 6 months after RFCA. The study population was divided according to the extent of the decrease in the LA volume index at follow-up; responders were defined as patients who exhibited a ≥15% decrease in the LA volume index.

RESULTS

At follow-up, 49 patients (47%) were classified as responders. Pre-procedural serum ANP and BNP levels were significantly higher in the responders than in the nonresponders (both p < 0.01). In the responders, a significant decrease was observed in the log ANP, log BNP, and log hs-CRP levels from baseline to follow-up (all p < 0.01). Multivariate linear regression analysis revealed that log ANP levels before RFCA and maintenance of sinus rhythm during follow-up were independent predictors of LA reverse remodeling (both p < 0.01).

CONCLUSIONS

In this study, 47% of the patients exhibited LA reverse remodeling after RFCA for AF, with a concomitant improvement in serum ANP, BNP, and hs-CRP levels. The pre-procedural ANP level and maintenance of sinus rhythm were independently associated with LA reverse remodeling.

Preoperative left ventricular ejection fraction and left atrium reverse remodeling after mitral regurgitation surgery

Background

Left atrium enlargement has been associated with cardiac events in patients with mitral regurgitation (MR). Left atrium reverse remodeling (LARR) occur after surgical correction of MR, but the preoperative predictors of this phenomenon are not well known. It is therefore important to identify preoperative predictors for postoperative LARR.

Methods

We enrolled 62 patients with chronic severe MR (prolapse or flail leaflet) who underwent successful mitral valve surgery (repair or replacement); all with pre- and postoperative echocardiography. LARR was defined as a reduction in left atrium volume index (LAVI) of ≥25%. Stepwise multiple regression analysis was used to identify independent predictors of LARR.

Results

LARR occurred in 46 patients (74.2%), with the mean LAVI decreasing from 85.5 mL/m² to 49.7 mL/m² (p <0.001). These patients had a smaller preoperative left ventricular systolic volume (p =0.022) and a higher left ventricular ejection fraction (LVEF) (p =0.034). LVEF was identified as the only preoperative variable significantly associated with LARR (odds ratio, 1.086; 95% confidence interval, 1.002–1.178). A LVEF cutoff value of 63.5% identified patients with LARR of ≥25% with a sensitivity of 71.7% and a specificity of 56.3%.

Conclusions

LARR occurs frequently after mitral valve surgery and is associated with preoperative LVEF higher than 63.5%.

Surgical revascularization is associated with maximal survival in patients with ischemic mitral regurgitation: a 20-year experience

BACKGROUND

The optimal treatment for ischemic mitral regurgitation remains actively debated. Our objective was to evaluate the relationship between ischemic mitral regurgitation treatment strategy and survival.

METHODS AND RESULTS

We retrospectively reviewed patients at our institution diagnosed with significant coronary artery disease and moderate or severe ischemic mitral regurgitation from 1990 to 2009, categorized by medical treatment alone, percutaneous coronary intervention, coronary artery bypass grafting (CABG), or CABG plus mitral valve repair or replacement. Kaplan-Meier methods and multivariable Cox proportional hazards analyses were performed to assess the relationship between treatment strategy and survival, with the use of propensity scores to account for nonrandom treatment assignment. A total of 4989 patients were included: medical treatment alone=36%, percutaneous coronary intervention=26%, CABG=33%, and CABG plus mitral valve repair or replacement=5%. Median follow-up was 5.37 years. Compared with medical treatment alone, significantly lower mortality was observed in patients treated with percutaneous coronary intervention (adjusted hazard ratio, 0.83; 95% confidence interval, 0.76-0.92; P=0.0002), CABG (adjusted hazard ratio, 0.56; 95% confidence interval, 0.51-0.62; P<0.0001), and CABG plus mitral valve repair or replacement (adjusted hazard ratio, 0.69; 95% confidence interval, 0.57-0.82; P<0.0001). There was no significant difference in these results based on mitral regurgitation severity.

CONCLUSIONS

Patients with significant coronary artery disease and moderate or severe ischemic mitral regurgitation undergoing CABG alone demonstrated the lowest risk of death. CABG with or without mitral valve surgery was associated with lower mortality than either percutaneous coronary intervention or medical treatment alone.

Surgical therapy for heart failure

Today's healthcare delivery system is challenged with an escalating number of heart failure patients who have exhausted medical therapy and overwhelmed the limits of organ transplantation. Scientific and technological advances over the last 20 years have now brought new surgical options to this vast patient population, ranging from ventricular restoration surgery to surgical gene therapy and beyond. This article reviews the myriad of surgical options that are available to these patients, their benefits and shortcomings, as well as potential future directions.

Mitral valve geometry and hemodynamics after surgical mitral valve annuloplasty and implications for percutaneous treatment of patients with recurrent mitral regurgitation

The feasibility of transcatheter mitral valve therapy (edge-to-edge or valve-in-ring technique) in patients with significant mitral regurgitation (MR) recurrence after surgical restrictive mitral valve annuloplasty remains unknown. The aim of the present study was to investigate the eligibility for transcatheter mitral valve therapy of high-surgical-risk patients with significant MR recurrence after initial successful restrictive mitral valve annuloplasty. A total of 47 patients (age 67 ± 10 years, 47% men) with significant MR recurrence (effective regurgitant orifice area ≥20 mm², regurgitant volume ≥30 ml/beat, or vena contracta ≥3 mm) after restrictive mitral valve annuloplasty were identified. The long-term outcome of patients dichotomized according to the surgical risk was evaluated. The echocardiographic parameters of mitral valve geometry and hemodynamics at the moment of diagnosis of MR recurrence were assessed to evaluate the eligibility for transcatheter valve therapy. During a median follow-up of 3 years, 23 patients (48.9%) died. The patients with a high-surgical risk (logistic European System for Cardiac Operative Risk Evaluation score ≥20%) had significantly worse long-term survival than those with a low-surgical risk (logistic European System for Cardiac Operative Risk Evaluation score <20%; 50% and 88%, respectively; p = 0.002). All high-surgical-risk patients showed geometric mitral valve features that would allow transcatheter mitral valve therapy (mitral annular area 7 ± 2.0 cm², coaptation length 6 ± 1.6 mm, anterior and posterior mitral leaflet length 24 ± 2.8 mm and 15 ± 3.1 mm, respectively). In conclusion, patients with significant MR recurrence after initial successful restrictive mitral valve annuloplasty and a high risk of redo mitral valve surgery had lower long-term survival rates than patients who could undergo repeat surgery.

Galectin-3 and left ventricular reverse remodelling after surgical mitral valve repair

AIMS

Mitral valve repair in patients with functional mitral regurgitation (FMR) has been associated with beneficial left ventricular (LV) reverse remodelling. Recently, galectin-3 emerged as a marker of myocardial inflammation and fibrosis which may influence LV remodelling after surgery. The aim of the current study was to evaluate the association between pre-operative galectin-3 levels and LV reverse remodelling in heart failure patients with significant FMR who underwent mitral valve repair.

METHODS AND RESULTS

In total, 42 heart failure patients (66 ± 10 years, 69% male) were evaluated. Plasma galectin-3 levels were assessed pre-operatively. Two-dimensional echocardiographic parameters were measured at baseline, and at 6 and 12 months after surgery. LV reverse remodelling was defined as a decrease in LV end-systolic volume ≥15% at 6 months follow-up. In total, 57% of the patients showed LV reverse remodelling. Patients with LV reverse remodelling showed significantly lower pre-operative galectin-3 levels (17.5 ± 5.6 vs. 23.7 ± 9.9 ng/mL, P = 0.009) compared with patients without LV reverse remodelling. In addition, patients with galectin-3 ≤18.2 ng/mL had a six-fold higher probability of showing LV reverse remodelling after surgery as compared with patients with levels >18.2 ng/mL (odds ratio 6.58, 95% confidence interval 1.32-33.33, P = 0.02).

CONCLUSION

High pre-operative plasma galectin-3 is independently associated with the absence of LV reverse remodelling after mitral valve repair. Galectin-3 may be useful to identify heart failure patients who will need additional treatment to obtain beneficial LV reverse remodelling.

Long-term echocardiographic changes in left ventricular size and function following surgery for severe mitral regurgitation

Background

Chronic mitral regurgitation (MR) results in a state of chronic left ventricular (LV) volume overload, resulting in compensatory dilatation. Mitral valve (MV) surgery for regurgitation reduces LV preload but increases LV afterload. Few data are available documenting subsequent changes in LV size and function over time following MV surgery for severe regurgitation in unselected populations.

Material/Methods

Pre- and postoperative echocardiograms (n=454) acquired from 108 consecutive patients with chronic MR who underwent MV surgery were analyzed.

Results

LV diastolic diameter was 4 mm smaller on postoperative compared to preoperative exams, whereas LV fractional shortening (FS) was unchanged. Linear regression analysis showed no change in LV diastolic diameter over time postoperatively, whereas LV FS increased over time following surgery. Improvement in LV FS occurred at an average rate of 1.6% per year (95% CI, 0.2–2.9). Subgroups were small, but the same secular trends were generally noted in groups with or without coronary artery bypass graft surgery (CABGS) and in those with or without mitral leaflet disease.

Conclusions

Following MV surgery for MR, LV diastolic diameter reduces by 2 mm at the time of surgery, but then remains stable over time. Improvement in LV function over time postoperatively was only seen in those without concomitant CABGS, possibly related to less baseline myocardial scarring in this group.

Recovery of right and left ventricular function after acute pulmonary embolism

AIM

To evaluate recovery of cardiac function after acute pulmonary embolism (PE).

MATERIALS AND METHODS

Routine breath-held computed tomography (CT)-pulmonary angiography was performed in patients with suspected PE to confirm or exclude the diagnosis of PE at initial presentation. Electrocardiogram (ECG)-triggered cardiac CT was performed to assess biventricular function. After 6 months, cardiac magnetic resonance imaging (MRI) was performed. In total, 15 consecutive patients with PE and 10 without were studied. A significant change in ventricular volume was defined as a >15% change in end-diastolic or -systolic volumes (EDV, ESV), and significant ventricular function improvement as a >5% increase in ejection fraction (EF) as based on reported cut-off values.

RESULTS

Right and left ventricular (RV and LV) EDV and ESV changed non-significantly (<1.3%) in the patients without PE, indicating good comparability of those values measured by CT and MRI. PE patients with baseline normal RV function (RVEF ≥ 47%) revealed a >5% improvement in the RVEF (+5.4 ± 3.1%) due to a decrease in the RVESV. Patients with baseline abnormal RV function showed a >5% improvement in the RVEF (+14 ± 15%) due to decreases in both the RVESV and RVEDV. Furthermore, the LVEDV increased in this latter patient group.

CONCLUSIONS

The present study demonstrated an improvement in RV function in the majority of patients with PE, independent of baseline RV function. The degree of RV and LV recovery was dependent on the severity of baseline RV dysfunction.

Atrioventricular reverse remodeling after valve repair for chronic severe mitral regurgitation: 1-year follow-up

BACKGROUND

Chronic severe mitral regurgitation is associated with poor clinical outcome because chronic volume overload leads to hemodynamic changes and left ventricular and left atrial remodeling. Few data are available regarding left atrial volume index regression (LAVIR) and left ventricular mass index regression (LVMIR) after valve surgery for mitral regurgitation. We aimed to identify predictive correlates of LAVIR and LVMIR and to assess the relationship between these regressions.

HYPOTHESIS

Volume overload in chronic severe mitral regurgitation may influence left atrial and ventricular remodeling and reverse remodeling.

METHODS

Eighty-five patients who underwent valve repair for severe chronic mitral regurgitation were consecutively enrolled. Plasma N-terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP) and echocardiographic measurements were performed before surgery, before discharge, and at 12 months after surgery. LAVIR and LVMIR were assessed using serial echocardiography.

RESULTS

There were significant decreases in left ventricular mass index (LVMI; from 125.9 ± 31.3 g/m² to 94.8 ± 28.6 g/m², P = 0.001) and left atrial volume index (LAVI; from 75.3 ± 33.5 mL/m² to 41.7 ± 16.0 mL/m², P = 0.001) after surgery. Preoperative LAVI positively correlated with preoperative LVMI (r = 0.437, P = 0.001) and LAVIR positively correlated with LVMIR (r = 0.347, P = 0.001). In multivariate stepwise linear regression analysis, preoperative LAVI, age, hypertension, and atrial fibrillation were independently predictive of LAVIR, and preoperative LVMI, hypertension, and NT-proBNP were independently predictive of LVMIR.

CONCLUSIONS

Volume overload in chronic severe mitral regurgitation may influence left ventricular remodeling and reverse remodeling, as well as left atrial remodeling and reverse remodeling. Preoperative lower LAVI, younger age, absence of hypertension, and absence of atrial fibrillation may predict LAVIR, and preoperative lower LVMI, lower NT-proBNP levels, and absence of hypertension may predict LVMIR after surgery for chronic severe mitral regurgitation.

CMR for Assessment of Diastolic Function

Prevalence of heart failure with preserved left ventricular ejection fraction amounts to 50% of all cases with heart failure. Diagnosis assessment requires evidence of left ventricular diastolic dysfunction. Currently, echocardiography is the method of choice for diastolic function testing in clinical practice. Various applications are in use and recommended criteria are followed for classifying the severity of dysfunction. Cardiovascular magnetic resonance (CMR) offers a variety of alternative applications for evaluation of diastolic function, some superior to echocardiography in accuracy and reproducibility, some being complementary. In this article, the role of the available CMR applications for diastolic function testing in clinical practice and research is reviewed and compared to echocardiography.

Changes in mitral annular geometry and dynamics with ß-blockade in patients with degenerative mitral valve disease

BACKGROUND

remodeling of the mitral annulus contributes to progression of mitral regurgitation (MR). In patients with moderate-to-severe MR, short-term treatment with β-blockers has been shown to increase left ventricular (LV) end-diastolic and end-systolic volume, and this could deleteriously increase mitral valve annular dimensions. The objective of this study was to quantify the effects of a short duration of β-blocker treatment on mitral annular dimensions and dynamics in patients with MR due to primary degenerative valve disease.

METHODS AND RESULTS

twenty-five patients with moderate-to-severe degenerative MR and normal LV systolic function were studied in a double-blind crossover experiment using a β1-selective adrenergic blocker and placebo administered for 14±3 days. Cardiac MRI images were acquired after each treatment period to quantify mitral annular dimensions. At end diastole, there was no change in annular area (1659±331 versus 1632±299 mm(2); P<0.19), annular perimeter (154.3±16.4 versus 152±13.9 mm; P<0.13), septal-lateral (SL) dimension (38.0±5 versus 39.0±4.5 mm; P<0.15), or annular height (9.8±3.8 versus 9.5±2.5 mm; P<0.53). β-blockade resulted in significant end-diastole decreases in commissure-commissure dimension (48.9±4.6 versus 47.2±4.0 mm; P<0.01) and eccentricity (1.3±0.2 versus 1.2±0.1; P<0.01). At end systole (ES), β-blockade conferred a small, but significant decrease in annular perimeter (161.0±19.3 versus 156.8±16.9 mm; P<0.04) and eccentricity (1.2±0.1 versus 1.1±0.1; P<0.02), and the SL dimension significantly increased (41.5±5.7 versus 43.0±5.3 mm; P<0.03). Commissure-commissure dimension, annular area, and annular height at ES were not significantly different.

CONCLUSIONS

despite significant increases in LV end-diastolic and end-systolic volume, short-term β-blocker treatment of patients with moderate-to-severe MR reduced or preserved all mitral annular dimensions except SL at ES.

Assessment of cardiac remodeling in asymptomatic mitral regurgitation for surgery timing: a comparative study of echocardiography and magnetic resonance imaging

Background

Early surgery is recommended for asymptomatic severe mitral regurgitation (MR), because of increased postoperative left ventricular (LV) dysfunction in patients with late surgery. On the other hand, recent reports emphasized a "watchful waiting" process for the determination of the proper time of mitral valve surgery. In our study, we compared magnetic resonance imaging (MRI) and transthoracic echocardiography to evaluate the LV and left atrial (LA) remodeling; for better definitions of patients that may benefit from early valve surgery.

Methods

Twenty-one patients with moderate to severe asymptomatic MR were evaluated by echocardiography and MRI. LA and LV ejection fractions (EFs) were calculated by echocardiography and MRI. Pulmonary veins (PVs) were measured from vein orifices in diastole and systole from the tangential of an imaginary circle that completed LA wall. Right upper PV indices were calculated with the formula; (Right upper PV diastolic diameter- Right upper PV systolic diameter)/Right upper PV diastolic diameter.

Results

In 9 patients there were mismatches between echocardiography and MRI measurements of LV EF. LV EFs were calculated ≥60% by echocardiography, meanwhile < 60% by MRI in these 9 patients. Severity of MR evaluated by effective regurgitant orifice area (EROA) didn't differ with preserved and depressed EFs by MRI (p > 0.05). However, both right upper PV indices (0.16 ± 0.06 vs. 0.24 ± 0.08, p: 0.024) and LA EFs (0.19 ± 0.09 vs. 0.33 ± 0.14, p: 0.025) were significantly decreased in patients with depressed EFs when compared to patients with normal EFs.

Conclusions

MRI might be preferred when small changes in functional parameters like LV EF, LA EF, and PV index are of clinical importance to disease management like asymptomatic MR patients that we follow up for appropriate surgery timing.

Different substrates of non-sustained ventricular tachycardia in post-infarction patients with and without left ventricular dilatation

BACKGROUND

We investigated the relationship between nonsustained ventricular tachycardia (NSVT) and left ventricular (LV) dilatation, function, remodeling, and scar tissue extent in patients with previous myocardial infarction (MI).

METHODS AND RESULTS

Eighty-two patients (ages 64+/-10 years) with first previous MI were referred for 24-hour electrocardiogram recording and cine and delayed enhancement (DE) cardiac magnetic resonance (CMR). LV volumes, ejection fraction, systolic wall thickening, sphericity index, and core and peri-infarctual areas of scar tissue by CMR were evaluated. LV dilatation was observed in 39 patients. Episodes of NSVT were recorded in 32 patients: 23 with LV dilatation and 9 without. In the entire population, NSVT was related to ejection fraction, LV volumes, LV mass, and sphericity index; end-systolic volume (P=.001) resulted in the only independent predictor at multivariate analysis. In patients without LV dilatation, the occurrence of NSVT was only positively related with percentage of contracting segments with DE (P=.008). Conversely, in patients with LV dilatation, increase in LV mass (P=.020) and end-systolic volume (P=.038) were independent predictors of NSVT.

CONCLUSIONS

Necrotic and viable myocardium coexistence within the same wall segments predicted occurrence of NSVT in patients without LV dilatation, whereas LV mass and end-systolic volume were predictors of NSVT in those with LV dilatation.

Regional wall motion abnormalities and scarring in severe functional ischemic mitral regurgitation: A pilot cardiovascular magnetic resonance imaging study

OBJECTIVES

To relate cardiovascular magnetic resonance-derived segmental wall motion and myocardial scarring and determine whether they are associated with postoperative mitral regurgitation following coronary artery bypass grafting and annuloplasty for severe functional ischemic mitral regurgitation.

METHODS

From January 2001 to October 2006, 29 patients with grade >or=3+ chronic functional ischemic mitral regurgitation were studied using cardiovascular magnetic resonance. Wall motion abnormality was graded for 17 standard left ventricular myocardial segments (0 = none, 1+ = hypokinesis, 2+ = severe hypokinesis, 3+ = akinesis, 4+ = dyskinesis), as was degree of hyperenhancement (scarring). Postoperative mitral regurgitation was assessed longitudinally by 71 transthoracic echocardiograms.

RESULTS

Wall motion abnormalities grade >or=2+ were present in most myocardial segments (median 13). Scar >25% was present in a median of 3 segments, and 44% of those were in the territory of the posterior papillary muscle. Nearly all segments (95%) with >25% scar had >or=2+ wall motion abnormality. Although 90% of patients had no mitral regurgitation at hospital discharge, by 6 months, 34% had mitral regurgitation grade >or=2+. There was little association between wall motion abnormality and recurrence of mitral regurgitation (P > .1). Seventy percent of patients with scar >25% in the posterior papillary muscle region exhibited postoperative mitral regurgitation of grade >or=2+ by 6 months, compared with 15% with score <or=25% (P = .07).

CONCLUSIONS

In a pilot study of cardiovascular magnetic resonance imaging in severe functional ischemic mitral regurgitation, severity of posterior papillary muscle region scarring correlated with decreased segmental wall motion and mitral regurgitation early after coronary revascularization and annuloplasty. Routinely assessing scar burden may identify patients for whom annuloplasty alone is insufficient to eliminate mitral regurgitation.

Structural and functional remodeling of the left atrium: clinical and therapeutic implications for atrial fibrillation

Left atrial (LA) structural and functional remodeling reflects a spectrum of pathophysiological changes that have occurred in response to specific stressors. These changes include alterations at the levels of ionic channels, cellular energy balance, neurohormonal expression, inflammatory response, and physiologic adaptations. There is convincing evidence demonstrating an important pathophysiological association between LA remodeling and atrial fibrillation (AF). Measures that will prevent, attenuate, or halt these processes of LA remodeling may have a major public health impact with respect to the epidemic of AF. In this review, we describe the mechanisms involved in LA remodeling and highlight the existing and potential therapeutic options for its reversal, and implications for AF development.

Mitral regurgitation and left ventricular dyssynchrony: implications for treatment

Cardiac resynchronisation therapy may provide an alternative treatment for mitral regurgitation in patients unsuitable for surgery.