Echocardiographic evaluation of mitral geometry in functional mitral regurgitation

Parameters of the mitral apparatus in patients with ischemic and nonischemic dilated cardiomyopathy

The mitral valve apparatus is a complex structure consisting of several coordinating components: the annulus, two leaflets, the chordae tendineae, and the papillary muscles. Due to the intricate interplay between the mitral valve and the left ventricle, a disease of the latter may influence the normal function of the former. As a consequence, valve insufficiency may arise despite the absence of organic valve disease. This is designated as functional or secondary mitral regurgitation, and it arises from a series of distortions to the valve components. This narrative review describes the normal anatomy and the pathophysiology behind the mitral valve changes in ischemic and non-ischemic dilated cardiomyopathies. It also explains the value of a complete multiparametric assessment of this structure. Not only must an assessment include quantitative measures of regurgitation, but also various anatomical parameters from the mitral apparatus and left ventricle, since they carry prognostic value and are predictors of mitral valve repair success and durability.

Predictors of residual mitral regurgitation after left ventricular assist device implantation

Patients with advanced heart failure often have functional mitral regurgitation. Left ventricular assist device implantation improves functional mitral regurgitation through left ventricular unloading. However, residual mitral regurgitation after left ventricular assist device implantation leads to adverse outcomes, and whether patients need concomitant mitral valve surgery is not fully elucidated. Therefore, this study aimed to elucidate the predictors of residual mitral regurgitation and to describe the temporal changes in residual mitral regurgitation. We retrospectively enrolled 15 patients with implantable continuous-flow left ventricular assist device, who had significant mitral regurgitation on echocardiography before left ventricular assist device implantation. Three patients had residual mitral regurgitation (mitral regurgitation color jet area/left atrial area >0.2) 1 month after left ventricular assist device implantation. We investigated factors associated with residual mitral regurgitation and compared patients with or without residual mitral regurgitation. On univariate analysis, mitral valve tethering area and mitral regurgitation vena contracta before left ventricular assist device implantation were significantly associated with residual mitral regurgitation (odds ratio, 1.03; p = 0.036 and odds ratio, 10.45; p = 0.0087). One month after left ventricular assist device implantation, the mean pulmonary capillary wedge pressure and pulmonary artery pressure were higher in patients with residual mitral regurgitation (pulmonary capillary wedge pressure: 11.3 ± 3.5 vs 6.4 ± 3.4 mmHg, p = 0.029 and pulmonary artery pressure: 21.3 ± 4.0 vs 15.9 ± 3.3 mmHg, p = 0.023). However, the mitral regurgitation grading and hemodynamics were not significantly different 6 months after left ventricular assist device implantation. The hospitalization-free survival was not significantly different between the two groups. Mitral valve tethering area and mitral regurgitation vena contracta were predictors of residual mitral regurgitation. Residual mitral regurgitation improved until 6 months after left ventricular assist device implantation and might not affect the prognosis.

Left Ventricular Sphericity Index is a reproducible bedside echocardiographic measure of geometric change between acute phase Takotsubo's syndrome and acute anterior myocardial infarction

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TS and AMI are separate cardiac conditions with similar clinical presentations.

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TS have a higher LVSI than AMI, indicating a more spherical left ventricle.

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LVSI may be utilised acutely to assist differentiation of acute phase TS and AMI.

Background

Left ventricular sphericity index (LVSI) is a simple, quick and reproducible measure to evaluate LV geometric changes. The aim of our study was to evaluate the utility of LVSI as a rapid discrimination tool in two disease processes; Takotsubo’s Syndrome (TS) and Anterior Myocardial Infarction (AMI), in the absence of significant left ventricular systolic dysfunction.

Methods

Consecutive patients with acute phase TS admitted to our institution (Jan 2013 - Dec 2018) were evaluated (n=66). Patients with a comprehensive two-dimensional transthoracic echocardiogram were included in primary analysis (n=50) and age-matched with a cohort of patients with acute anterior AMI (n=50). Appraisal of demographic, clinical and echocardiographic parameters of patients was undertaken. Biplane LVSI was calculated as an average of the short- and long-axis length in the 4- and 2-chamber apical views.

Results

A total of 50 TS patients (64.3±13.7 years, 18% men) were matched with 50 AMI (62.10±12.84 years, 74% men) patients. There was no significant difference in baseline cardiovascular risk factors other than diabetes mellitus (AMI 34% vs TS 17%, p = 0.034). There was also no difference in LV mass (p=0.10) or LVEF (p=0.52) between the two groups. Interestingly, there was a significant difference in mean LVSI between TS (0.60±0.06) vs AMI (0.52±0.07) (p<0.01) reflecting a more spherical shaped left ventricle in the acute TS group.

Conclusions

LVSI is reflective of geometric changes in the left ventricle and may be helpful as a rapid and reproducible diagnostic tool in differentiating between TS and AMI in the acute phase.

Prediction of the ischemic origin of functional mitral regurgitation in patients with systolic heart failure through posterior mitral leaflet angle

BACKGROUND

Differentiating ischemic from non-ischemic functional mitral regurgitationý (FMR) in patients with cardiomyopathy is important in terms of the therapeutic decision-making and prognosis, but might be clinically challenging. In this study, the deformation of mitral valve (MV) indices in the prediction of the etiology of FMR was assessed using 2D transthoracic and tissue Doppler echocardiography.

METHODS

This case-control study was conducted from April 2015 to January 2016 in Imam Reza Hospital in Mashhad, Iran. The participants consisted of 40 patients with ischemic cardiomyopathy (ICM) and 22 with non-ischemic dilated cardiomyopathy (DCM) who referred to the heart failure clinic. Transthoracic echocardiography was performed using the conventional 2D and tissue Doppler imaging (TDI). MV tenting area (TA), coaptation distance (CD), anterior and posterior mitral leaflet angles (AMLA and PMLA), and regional systolic myocardial velocity (Sm) were measured.

RESULTS

There were no significant differences in echocardiographic indices between the two groups, besides Sm and PMLA which were significantly lower and higher, respectively, in ICM subjects in comparison with DCM patients (P = 0.002). PMLA ≥ 40 degrees and Sm ≤ 4 cm/second have a relatively high value for discriminating the ischemic from non-ischemic origin of functional MR in subjects with systolic heart failure (sensitivity: 80.0% and 70.0%, specificity: 73.0% and 77.3%; P = 0.001 and P < 0.001; respectively). Multivariable logistic regression identified PMLA and anterior Sm as major determinants for ischemic MR {Odds ratio (OR) [95% confidence interval (CI)] = 0.89 (0.82-0.96), P = 0.003, OR (95% CI) = 0.29 (0.14-0.60), P = 0.001, respectively}.

CONCLUSION

The present study showed that PMLA and Sm had an independent significant association with the mechanism of FMR. These findings are suggestive of the predictive role of mitral deformation echocardiographic indices in the determination of the etiology of FMR in systolic heart failure.

Effect of cardiac resynchronization therapy on mitral valve geometry: a novel aspect as "reversed mitral remodeling"

Amelioration of the valvular geometry is a possible mechanism for mitral regurgitation (MR) improvement in patients receiving cardiac resynchronization therapy (CRT). We aimed to establish the precise definition, incidence, and predictors of reversed mitral remodeling (RMR), as well as the association with MR improvement and short-term CRT outcome. Ninety-five CRT recipients were retrospectively evaluated for the end-point of "MR response" defined as the absolute reduction in regurgitant volume (RegV) at 6 months. To identify RMR, changes in mitral deformation indices were tested for correlation with MR response and further analyzed for functional and echocardiographic CRT outcomes. Overall, MR response was observed in 50 patients (53%). Among the echocardiographic indices, the change in tenting area (TA) had the highest correlation with the change in RegV (r = 0.653, p < 0.001). The mean TA significantly decreased in MR responders (4.15 ± 1.05 to 3.67 ± 1.01 cm² at 6 months, p < 0.001) and increased in non-responders (3.68 ± 1.04 to 3.98 ± 0.97 cm², p = 0.014). The absolute TA reduction was used to identify patients with RMR (47%) which was found to be associated with higher rates of functional improvement (p = 0.03) and volumetric CRT response (p = 0.036) compared to those without RMR. Non-ischemic etiology and the presence of LBBB independently predicted RMR at multivariate analysis. In conclusion, reduction in TA is a reliable index of RMR, which relates to MR response, and functional and echocardiographic improvement with CRT. LBBB and non-ischemic etiology are independent predictors of RMR.

Frequency and Associated Clinical Features of Functional Tricuspid Regurgitation in Patients With Chronic Atrial Fibrillation

Significant functional tricuspid regurgitation (TR) can develop in some but not all patients with chronic atrial fibrillation (AF). This study sought to identify factors likely to be involved in determining the severity of TR in patients with chronic AF. In this retrospective cohort study of adult patients referred for transthoracic echocardiography for evaluation of AF between 2004 and 2015, we identified 170 patients with chronic AF in the absence of structural or known coronary heart disease. Patients were classified into nonsevere (89 patients) versus severe TR (81 patients) groups based on a comprehensive assessment of color Doppler, spectral Doppler, and morphologic parameters of the tricuspid valve and right side of the heart. Patients with severe TR were significantly older (76 ± 10 vs 70 ± 11, p <0.001), with smaller body surface area (1.7 ± 0.3 m² vs 1.9 ± 0.23 m², p = 0.001) and with female predominance (percentage of men 30% vs 57%, p <0.001). Although comorbidities, use of cardiovascular medications, and left-sided cardiac parameters were statistically indistinguishable between these 2 groups, right-sided cardiac dimensions, tricuspid valve tethering height, and tricuspid valve tethering area were significantly larger in the severe TR group. A comprehensive multivariate logistic regression model (model 1) identified the age, gender, right ventricular systolic pressure, right atrial volume index, and right ventricular end-diastolic area as independent factors associated with TR severity. A simplified logistic regression model using only clinical factors (model 2) confirmed the age, gender, and right ventricular systolic pressure as clinically relevant factors in relation to TR.

Relationship between native papillary muscle T1 time and severity of functional mitral regurgitation in patients with non-ischemic dilated cardiomyopathy

BACKGROUND

Functional mitral regurgitation is one of the severe complications of non-ischemic dilated cardiomyopathy (DCM). Non-contrast native T1 mapping has emerged as a non-invasive method to evaluate myocardial fibrosis. We sought to evaluate the potential relationship between papillary muscle T1 time and mitral regurgitation in DCM patients.

METHODS

Forty DCM patients (55 ± 13 years) and 20 healthy adult control subjects (54 ± 13 years) were studied. Native T1 mapping was performed using a slice interleaved T1 mapping sequence (STONE) which enables acquisition of 5 slices in the short-axis plane within a 90 s free-breathing scan. We measured papillary muscle diameter, length and shortening. DCM patients were allocated into 2 groups based on the presence or absence of functional mitral regurgitation.

RESULTS

Papillary muscle T1 time was significantly elevated in DCM patients with mitral regurgitation (n = 22) in comparison to those without mitral regurgitation (n = 18) (anterior papillary muscle: 1127 ± 36 msec vs 1063 ± 16 msec, p < 0.05; posterior papillary muscle: 1124 ± 30 msec vs 1062 ± 19 msec, p < 0.05), but LV T1 time was similar (1129 ± 38 msec vs 1134 ± 58 msec, p = 0.93). Multivariate linear regression analysis showed that papillary muscle native T1 time (β = 0.10, 95 % CI: 0.05-0.17, p < 0.05) is significantly correlated with mitral regurgitant fraction. Elevated papillary muscle T1 time was associated with larger diameter, longer length and decreased papillary muscle shortening (all p values <0.05).

CONCLUSIONS

In DCM, papillary muscle native T1 time is significantly elevated and related to mitral regurgitant fraction.

Determinants of Atrial Electromechanical Delay in Patients with Functional Mitral Regurgitation and Non-ischemic Dilated Cardiomyopathy

Introduction: Atrial conduction time has important hemodynamic effects on ventricular filling and is accepted as a predictor of atrial fibrillation. In this study we assessed atrial conduction time in patients with non ischemic dilated cardiomyopathy (NIDCMP) and functional mitral regurgitation (MR) and aimed to determine factors predicting atrial conduction time prolongation.

Methods: Sixty five patients with non ischemic dilated cardiomyopathy who have moderate to severe MR and 60 control subjects were included in the study. In addition to conventional echocardiographic measures used to asses left ventricle and MR, atrial electromechanical coupling (time interval from the onset of P wave on surface electrocardiogram [ECG] to the beginning of A wave interval with tissue Doppler echocardiography [PA]), intra- and interatrial electromechanical delay (intra and inter AEMD) were measured.

Results: The correlations between inter AEMD and left atrial (LA) size, MR volume, isovolumetric relaxation time (IVRT), deceleration time (DT), systolic pulmonary artery pressure (PAPs), E/A ratio and E/e’ were very poor. Similarly, intra AEMD was not correlated to LA size , MR volume, IVRT, DT, PAPs, E/A ratio and E/e’. However, both inter AEMD and intra AEMD had good correlation with left ventricular mass index, tenting area (TA), tenting distance (TD), coaptation septal distance (CSD), sphericity index (SI).

Conclusion: Prolongation of inter and intra AEMDs were found to be well correlated with parameters reflecting left ventricular and mitral annular remodeling.

Echocardiographic assessment of mitral valve regurgitation, pattern and prevalence, expanding clinical awareness through an institutional survey with the perspective of a quality improvement project

BACKGROUND

Mitral regurgitation (MR) is frequently reported in everyday echocardiograms; accurate assessment is essential for appropriate management and decision making.

OBJECTIVE

We performed a self-audit in order to define the prevalence and pattern of MR and to evaluate methods of assessment with the perspective of developing a quality improvement project.

METHODS AND SETTING

This retrospective analytical study was conducted in a university hospital.

INCLUSION CRITERIA

age more than 18 years and medical records available within the facility, including a "complete" medical history. Using the picture archiving and communication system, we reviewed 961 echocardiograms performed over a 6-month period. The methods of assessment of native mitral valve regurgitation were reported, and also relevant medical data were collected using an electronic archiving system.

RESULTS AND DISCUSSION

Among the 961 patients reviewed, 322 (33.50%) had MR, with variable grades. MR pattern (organic versus functional) was not specified in 49.68% of cases. "Eyeball" assessment and "color jet area" were the most frequently used methods for MR assessment (90.06% and 27.95%, respectively), while "vena contracta" and "flow convergence" methods were rarely implemented (1.55% and 2.17%, respectively). Discussion is made according to current guidelines, while showing the strengths and weaknesses of each method.

CONCLUSION

The prevalence of MR was 33.50%, and in nearly half of cases, the MR pattern was not specified. Qualitative and semi-quantitative methods of assessment were mostly used; quantitative assessment should be implemented more frequently, in accordance with current guidelines. Increasing clinical awareness by creating and implementing a quality improvement project is essential in this context.

Posterior leaflet segment 2 plication in ischemic mitral regurgitation repair

Aim

To evaluate the medium-term results of plication of posterior leaflet segment 2 in addition to ring annuloplasty in patients with functional ischemic mitral regurgitation.

Methods

The study included 136 patients who underwent mitral valve repair with plication of posterior leaflet segment 2 for ischemic mitral regurgitation between 2004 and 2012. The direction and correlation of left ventricle sphericity and tethering area were established by Pearson correlation analysis in patients with or without recurrent mitral regurgitation in the medium term.

Results

Medium-term survival was 91.9% and freedom from moderate or severe mitral regurgitation was 89.6%. In medium-term follow-up, transthoracic echocardiography found a significant decrease in tethering area, coaptation height, and distance between the commissures compared to the pre-surgery values ( p = 0.0001 in all). The distance between the papillary muscles was reduced compared to the pre-surgery period but it was not significant ( p = 0.204). Pearson correlation analysis found no significant correlation between the tethering area and left ventricle sphericity in patients without recurrent mitral regurgitation ( r = 0.15, p = 0.36), a highly positive correlation ( r = 0.44, p < 0.001) in patients with mild recurrent mitral regurgitation, and a moderately positive correlation ( r = 0.71, p < 0.01) in patients with moderate or severe recurrent mitral regurgitation.

Conclusions

The tethering area, coaptation height, and distance between the commissures decreased significantly, thus posterior leaflet segment 2 plication in addition to ring annuloplasty may be the optional procedure to ensure freedom from moderate or severe mitral regurgitation.

Echocardiographic determinants of ischemic mitral regurgitation

OBJECTIVES

It is not clear whether the presence and degree of chronic ischemic mitral regurgitation (IMR) in patients with left ventricular (LV) dysfunction are related to LV dysfunction, local LV remodeling or mitral valve deformation. We sought to establish the strongest determinants of IMR severity in patients with LV dysfunction and IMR.

METHODS

We prospectively performed transthoracic echocardiography for 135 patients (mean age = 60.76 ± 9.69 years, 71.9% male) with LV dysfunction (ejection fraction ≤ 50%) and coronary artery disease (70% stenosis in ≥ 1 coronary artery and no myocardial infarction during the previous 16 days). Global and local LV remodeling and mitral deformity indices were measured. Using the vena contracta, MR severity was graded as no regurgitation; mild; moderate; and severe.

RESULTS

Mild regurgitation was found in 45 (33.3%) patients, moderate in 71 (52.6%), severe in 6 (4.4%), and no regurgitation in 13 (9.6%). By linear logistic multivariable analysis, the major echocardiographic determinants of MR severity were tenting area (TA), sphericity index (LV systolic length/width), and C-septal (distance between the leaflet coaptation and the septum). TA was best related to coaptation depth and annulus diameter. Mitral annular diameter was best correlated with left atrial surface area (r = 0.630, p < 0.001).

CONCLUSION

TA was significantly correlated with annulus diameter and, along with sphericity index and C-septal, were the independent echocardiographic determinants of MR severity. These findings warrant consideration when performing mitral valve repairs for patients with IMR.

Determinants of functional mitral regurgitation severity in patients with ischemic cardiomyopathy versus nonischemic dilated cardiomyopathy

AIMS

Functional mitral regurgitation (MR) is prevalent among patients with left ventricular (LV) dysfunction and is associated with a poorer prognosis. Our aim was to assess the primary determinants of MR severity in patients with ischemic cardiomyopathy (ICM) and nonischemic dilated cardiomyopathy (DCM).

METHODS AND RESULTS

Patients with functional MR secondary to ICM (n = 55) and DCM (n = 48) were prospectively enrolled. Effective regurgitant orifice (ERO) area, global LV remodeling, regional wall-motion abnormalities, and mitral apparatus deformity indices were assessed utilizing conventional and tissue Doppler echocardiography. ICM patients had more severe MR compared with DCM patients despite similar ejection fraction and functional status (ERO = 0.16 ± 0.08 cm(2) vs. ERO = 0.12 ± 0.70 cm(2) , respectively, P = 0.002). Regional myocardial systolic velocities in mid-inferior and mid-lateral wall were negatively correlated with ERO in ICM and DCM patients, respectively. Multivariate analysis identified coaptation height as the only independent determinant of ERO in both groups. In a subset of ICM patients (n = 9) with relatively high ERO despite low coaptation height, a higher prevalence of left bundle branch block was detected (88.9% vs. 46.7%, P = 0.02).

CONCLUSIONS

Functional MR severity was chiefly determined by the extent of mitral apparatus deformity, and coaptation height can provide a rapid estimation of MR severity in heart failure patients. Additional contributory mechanisms in ICM patients include depressed myocardial systolic velocities in posteromedial papillary muscle attaching site and evidence of global LV dyssynchrony.

Quantitation of the mitral tetrahedron in patients with ischemic heart disease using real-time three-dimensional echocardiography to evaluate the geometric determinants of ischemic mitral regurgitation

BACKGROUND

Ischemic mitral regurgitation (IMR) is common in ischemic heart disease and results in poor prognosis. However, the exact mechanism of IMR has not been fully elucidated.

HYPOTHESIS

Quantitation of the mitral tetrahedron using three-dimentianl (3D) echocardiography is capable of evaluating the geometric determinants and mechanisms of IMR.

METHODS

Forty patients with a history of ST-elevation myocardial infarction at least 6 months earlier were studied. Parameters of mitral deformation and global left ventricular (LV) function and shape were evaluated by 2-dimensional echocardiography. The effective regurgitant orifice (ERO) of IMR was obtained by the quantitative continuous-wave Doppler technique. Three-dimensional (3D) echocardiography was applied to assess the mitral tetrahedron.

RESULTS

Mitral valvular tenting area (P < 0.001), mitral annular area (P = 0.032), dilation of the LV in diastole, impairment of the LV ejection fraction, and volume of the spherically shaped LV in systole were greater in patients with an ERO ≥20 mm(2) than in those with an ERO <20 mm(2). In the mitral tetrahedron, only the interpapillary muscle roots distance showed a significant difference (P = 0.004). Multivariate analysis with the logistic regression model showed the systolic mitral tenting area (odds ratio [OR]: 280.49, 95% confidence interval [CI]: 4.59-1.72 × 10(4), P = 0.007) and interpapillary muscle distance (OR: 1.50, 95% CI: 1.03-2.19, P = 0.036) to be independent factors in predicting significant IMR (ERO ≥20 mm(2)).

CONCLUSIONS

3D echocardiography can be effectively applied in measuring the mitral tetrahedron and evaluating the mechanism of IMR. Mitral valvular tenting and interpapillary muscle distance are 2 independent factors of significant IMR.

Regional changes in coaptation geometry after reduction annuloplasty for functional mitral regurgitation

BACKGROUND

While it is known that band annuloplasty for functional mitral regurgitation (FMR) improves leaflet coaptation, the effect on regional coaptation geometry has not previously been well defined. We used three-dimensional transesophageal echocardiography (3D-TEE) to analyze the regional effects of semirigid band annuloplasty on annular geometry and leaflet coaptation zones of patients with FMR.

METHODS

Sixteen patients with severe FMR underwent a semirigid band annuloplasty. Intraoperative full volume 3D-TEE datasets were acquired pre valve and post valve repair. Offline analysis assessed annular dimensions and regional coaptation zone geometry. The regions were defined as R1 (A1-P1), R2 (A2-P2), and R3 (A3-P3); coaptation distance, coaptation depth, and coaptation length were measured in each region. Differences were analyzed with repeated measures within a general linear model.

RESULTS

Band annuloplasty decreased mitral regurgitation grade from 3.7 to 0.1 (scale 0 to 4). Annular septolateral dimension (p<0.01) and coaptation distance (p<0.01) decreased significantly in all regions. Likewise, anterior and posterior leaflet coaptation lengths increased in all regions (p<0.01 and p=0.05, respectively), with region 2 showing the greatest increase (p=0.01). Changes in coaptation depth were not significant.

CONCLUSIONS

Semirigid band annuloplasty for FMR produces significant regional remodeling of leaflet coaptation zones, with region 2 showing the greatest increase in leaflet coaptation length. This regional analysis of annular geometry and leaflet coaptation creates a framework to better understand the mechanisms of surgical success or failure of annuloplasty for FMR.

Cardiac resynchronization therapy guided by late gadolinium-enhancement cardiovascular magnetic resonance

BACKGROUND

Myocardial scarring at the LV pacing site leads to incomplete resynchronization and a suboptimal symptomatic response to CRT. We sought to determine whether the use of late gadolinium cardiovascular magnetic resonance (LGE-CMR) to guide left ventricular (LV) lead deployment influences the long-term outcome of cardiac resynchronization therapy (CRT).

METHODS

559 patients with heart failure (age 70.4 ± 10.7 yrs [mean ± SD]) due to ischemic or non-ischemic cardiomyopathy underwent CRT. Implantations were either guided (+CMR) or not guided (-CMR) by LGE-CMR prior to implantation. Fluoroscopy and LGE-CMR were used to localize the LV lead tip and and myocardial scarring retrospectively. Clinical events were assessed in three groups: +CMR and pacing scar (+CMR+S); CMR and not pacing scar (+CMR-S), and; LV pacing not guided by CMR (-CMR).

RESULTS

Over a maximum follow-up of 9.1 yrs, +CMR+S had the highest risk of cardiovascular death (HR: 6.34), cardiovascular death or hospitalizations for heart failure (HR: 5.57) and death from any cause or hospitalizations for major adverse cardiovascular events (HR: 4.74) (all P < 0.0001), compared with +CMR-S. An intermediate risk of meeting these endpoints was observed for -CMR, with HRs of 1.51 (P = 0.0726), 1.61 (P = 0.0169) and 1.87 (p = 0.0005), respectively. The +CMR+S group had the highest risk of death from pump failure (HR: 5.40, p < 0.0001) and sudden cardiac death (HR: 4.40, p = 0.0218), in relation to the +CMR-S group.

CONCLUSIONS

Compared with a conventional implantation approach, the use of LGE-CMR to guide LV lead deployment away from scarred myocardium results in a better clinical outcome after CRT. Pacing scarred myocardium was associated with the worst outcome, in terms of both pump failure and sudden cardiac death.

Cardiac resynchronization therapy guided by late gadolinium-enhancement cardiovascular magnetic resonance

BACKGROUND

Myocardial scarring at the LV pacing site leads to incomplete resynchronization and a suboptimal symptomatic response to CRT. We sought to determine whether the use of late gadolinium cardiovascular magnetic resonance (LGE-CMR) to guide left ventricular (LV) lead deployment influences the long-term outcome of cardiac resynchronization therapy (CRT).

METHODS

559 patients with heart failure (age 70.4 ± 10.7 yrs [mean ± SD]) due to ischemic or non-ischemic cardiomyopathy underwent CRT. Implantations were either guided (+CMR) or not guided (-CMR) by LGE-CMR prior to implantation. Fluoroscopy and LGE-CMR were used to localize the LV lead tip and and myocardial scarring retrospectively. Clinical events were assessed in three groups: +CMR and pacing scar (+CMR+S); CMR and not pacing scar (+CMR-S), and; LV pacing not guided by CMR (-CMR).

RESULTS

Over a maximum follow-up of 9.1 yrs, +CMR+S had the highest risk of cardiovascular death (HR: 6.34), cardiovascular death or hospitalizations for heart failure (HR: 5.57) and death from any cause or hospitalizations for major adverse cardiovascular events (HR: 4.74) (all P < 0.0001), compared with +CMR-S. An intermediate risk of meeting these endpoints was observed for -CMR, with HRs of 1.51 (P = 0.0726), 1.61 (P = 0.0169) and 1.87 (p = 0.0005), respectively. The +CMR+S group had the highest risk of death from pump failure (HR: 5.40, p < 0.0001) and sudden cardiac death (HR: 4.40, p = 0.0218), in relation to the +CMR-S group.

CONCLUSIONS

Compared with a conventional implantation approach, the use of LGE-CMR to guide LV lead deployment away from scarred myocardium results in a better clinical outcome after CRT. Pacing scarred myocardium was associated with the worst outcome, in terms of both pump failure and sudden cardiac death.

Predictors of mitral regurgitation recurrence in patients with heart failure undergoing mitral valve annuloplasty

Restrictive mitral annuloplasty is a surgical treatment option for patients with heart failure (HF) and functional mitral regurgitation (MR). However, recurrent MR has been reported at mid-term follow-up. The aim of the present study was to identify the echocardiographic predictors of recurrent MR in patients with HF undergoing mitral annuloplasty. During a mean follow-up of 2.6 +/- 1.6 years, 109 patients with HF (49% ischemic and 51% idiopathic dilated cardiomyopathy) who had undergone mitral valve repair were followed up (of 122 total patients). The severity of MR was quantified, and the following parameters were measured before intervention and at the mid-term follow-up examination: left ventricular (LV) and left atrial volumes and dimensions, LV sphericity index, mitral annular area, and mitral valve geometry parameters. At mid-term follow-up, 21 patients presented with significant MR (grade 2 to 4), and 88 patients had only MR grade 0 to 1. Both groups of patients had had a similar preoperative MR grade, mitral annular area, and LV volume and dimension. In contrast, patients with recurrent MR had had increased preoperative posterior and anterior leaflet angles, tenting height, tenting area, and LV sphericity index compared to the patients without recurrent MR. Of the different parameters of mitral and LV geometry, the distal mitral anterior leaflet angle (hazard ratio 1.48, 95% confidence interval 1.32 to 1.66, p <0.001) and posterior leaflet angle (hazard ratio 1.13, 95% confidence interval 1.07 to 1.19, p <0.001) were independent determinants of MR at mid-term follow-up. In conclusion, in patients with HF of ischemic or idiopathic etiology and functional MR, distal mitral leaflet tethering and posterior mitral leaflet tethering were associated with recurrent MR after restrictive mitral annuloplasty.

What is treatment success in cardiac resynchronization therapy?

Cardiac resynchronization therapy (CRT) is an established treatment for symptomatic patients with heart failure, a prolonged QRS duration, and impaired left ventricular (LV) function. Identification of ‘responders’ and ‘non-responders’ to CRT has attracted considerable attention. The response to CRT can be measured in terms of symptomatic response or clinical outcome, or both. Alternatively, the response to CRT can be measured in terms of changes in surrogate measures of outcome, such as LV volumes, LV ejection fraction, invasive measures of cardiac performance, peak oxygen uptake, and neurohormones. This review explores whether these measures can be used in assessing the symptomatic and prognostic response to CRT. The role of these parameters to the management of individual patients is also discussed.