Repercussion of functional mitral regurgitation on reverse remodelling in cardiac resynchronization therapy.

AIMS: Cardiac resynchronization therapy (CRT) reduces the degree of functional mitral regurgitation (FMR). However, FMR has also been associated with a lack of clinical response to CRT. We undertook this study to determine whether the presence of FMR influences the reverse remodelling induced by CRT. METHODS AND RESULTS: We used Doppler echocardiography to assess 20 patients with dilated cardiomyopathy before and 6 months after undergoing CRT. We evaluated the effect of reverse remodelling (reduction > or = 10% in end-systolic volume) according to the presence or absence of important FMR, defined as a regurgitant orifice area (ROA) of > or = 0.20 cm(2). Of the 20 patients (mean age, 64.7 +/- 8.2 years, eight women), 9 had marked FMR (ROA 0.40 +/- 0.12 cm(2)), 6 mild FMR (ROA 0.15 +/- 0.02 cm(2)), and 5 had trivial or no FMR. CRT reduced the presence of mitral regurgitation by 33.3% and induced reverse remodelling in 60% of the patients. A ROA > or = 0.20 cm(2) was associated with a lack of reverse remodelling, despite presenting similar baseline characteristics and a reduction in asynchrony to the other patients. Reverse remodelling was produced in all the other patients, with a significant reduction in end-systolic volume (41.7 +/- 21%; P = 0.003), accompanied by improvement in the ejection fraction (P = 0.003) and myocardial performance index (P = 0.027). CONCLUSION: CRT improved FMR, although the baseline presence of important mitral regurgitation, with a ROA > or = 0.20 cm(2), in patients undergoing CRT was associated with a lack of response in reverse remodelling.     

Mechanism of improvement in mitral regurgitation after cardiac resynchronization therapy.

AIMS: The aim of the current study was to evaluate the relationship between the presence of left ventricular (LV) dyssynchrony at baseline and acute vs. late improvement in mitral regurgitation (MR) after cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Sixty eight patients consecutive (LV ejection fraction 23 +/- 8%) with at least moderate MR (>or=grade 2+) were included. Echocardiography was performed at baseline, 1 day after CRT initiation and at 6 months follow-up. Speckle tracking radial strain was used to assess LV dyssynchrony at baseline. The majority of patients improved in MR after CRT, with 43% improving immediately after CRT, and 20% improving late (after 6 months) after CRT. Early and late responders had similar extent of LV dyssynchrony (209 +/- 115 ms vs. 190 +/- 118 ms, P = NS); however, the site of latest activation in early responders was mostly inferior or posterior (adjacent to the posterior papillary muscle), whereas the lateral wall was the latest activated segment in late responders. CONCLUSION: Current data suggest that the presence of baseline LV dyssynchrony is related to improvement in MR after CRT. LV dyssynchrony involving the posterior papillary muscle may lead to an immediate reduction in MR, whereas LV dyssynchrony in the lateral wall resulted in late response to CRT.     

Effects of cardiac resynchronization therapy on the mechanisms underlying functional mitral regurgitation in congestive heart failure.

AIMS: Functional mitral regurgitation (FMR) improvement induced by cardiac resynchronization therapy (CRT) has been related to left ventricular (LV) remodeling reversal and contractility enhancement. The effects induced by the changes of LV synchronicity indexes on FMR severity have not been investigated. METHODS AND RESULTS: In 30 patients with CRT for heart failure (HF) and QRS>130 ms, LV function parameters, FMR severity as mitral jet regurgitation/left atrial area ratio (JA/LAA) and standard deviation (SD) of the time to the systolic peak velocity at 6-basal and mid-LV segments as asynchrony indexes were evaluated (echo/tissue Doppler) before and 6 months after implant. At follow-up, 15 patients resulted responders to LV reverse remodeling with > or =15% end-systolic volume (ESV) and LV systolic function improvement. Improvement of FMR with > or =15% JA/LAA reduction was observed in 19 patients, 7 were nonresponders to LV reverse remodeling. In patients with > or =15% JA/LAA reduction a significant decrease of LV asynchrony indexes was observed as compared to patients without > or =15% JA/LAA reduction in whom LV asynchrony indexes were increased. Reduction of LV mid-segmental asynchrony was the variable most strongly related to JA/LAA reduction (r(2)=0.697, P<0.01), with good agreement between observed and predicted values (only 1 patient outside the mean+/-2SD). CONCLUSION: These data reveal that CRT can reduce FMR irrespective to LV remodeling reversal; this effect is related to LV asynchrony reduction and further support CRT employment in patients with HF and FMR.     

心脏再同步治疗超反应的预测因子分析

目的 心脏再同步治疗（CRT）能明显改善患者临床症状,逆转心肌重构,称之为CRT超反应.本文主要分析CRT术后,患者超反应的预测因子.方法 采用回顾性研究,2005年1月至2010年6月共有124例随访资料完整的CRT或心脏再同步治疗除颤器（CRT-D）纳入分析,分为超反应组及其他反应组.并在CRT术后第6个月随访时,进行临床评估及超声心动图评价.心功能（NYHA分级）提高≥1级,左心室射血分数（LVEF） ≥0.45或增加2倍以上称为超反应.结果 两组患者在基线状态除QRS时限[（160.2±36.1）ms对（139.6±32.5）ms,P=0.01],完全左束支阻滞比例（95％对82％,P=0.02）、心力衰竭症状出现时间[（21.0±14.6）个月对（36.0±25.3）个月,P=0.02]差异有统计学意义外,其余参数在基线状态差异无统计学意义;有17％的患者出现超反应.6个月随访时超反应组与其他反应组在心功能分级、脑钠肽（BNP）、QRS时限、LVEF及因心力衰竭住院率方面有明显改善.结论 完全左柬支阻滞及心力衰竭症状出现较短的患者CRT反应较好.     

Baseline QRS width and mitral regurgitation behavior after cardiac resynchronization therapy among patients with dilated cardiomyopathy

BackgroundThe effect of cardiac resynchronization therapy (CRT) on functional mitral regurgitation (FMR) is reflected on both clinical and echocardiographic response. We sought to assess the behavior of FMR and the response to CRT implantation in relation to the baseline width of the QRS complex among patients with dilated cardiomyopathy (DCM).Patients and methodsThis is a prospective observational case-control study, including forty patients with advanced DCM who had left bundle branch block (LBBB), QRS ⩾ 130 ms (group 1) and 10 patients with QRS < 130 ms (group 2) both with echocardiographic evidence of dyssynchrony and subjected to CRT in our center.ResultsEvidence of response to CRT at 6 months, was observed in 31 patients (77.5%) of group 1 Vs 2 (20%) patients of group 2 (p. 0.001). MR improvement was higher among responders to CRT in 31/33 (93.9%) Vs 2/17 patients (11.7%) of the non responders (p. 0.003). FMR improvement was observed in 31 patients of group 1 (77.5%) Vs 2 patients of group 2 (20%) p. value 0.001.ConclusionAmong patients with DCM, the degree of FMR regression after CRT seems to be more clear in patients with a baseline QRS width ⩾130 ms and this seems to be associated with better response of the patients to CRT.     

Selecting patients for cardiac resynchronization therapy: electrical or mechanical dyssynchrony?

Cardiac resynchronization therapy (CRT) markedly reduces morbidity and mortality in patients with heart failure and prolonged QRS duration. Landmark trials have included over 4000 patients based on their electrocardiogram. A few small, observational, non-randomized, single centre studies of short duration have suggested that echocardiographic measurement of mechanical dyssynchrony may better identify patients likely to benefit from CRT. We objectively review the meaning and measurement of electrical and mechanical dyssynchrony, the strengths and weaknesses of echocardiographic indices of dyssynchrony, and the controversial issue of predicting response to treatment. We conclude that proposals to alter current guidelines for patient selection, and include echocardiography, are misguided. Echocardiographic assessment will only become credible and applicable to clinical practice once used to select patients for large prospective randomized trials which show an improvement in clinical outcome.     

心脏再同步治疗超反应的预测因素研究

目的 寻找心脏再同步治疗（CRT）超反应可能的预测因素.方法 将66例植入CRT的患者分为超反应组和非超反应组,通过组间比较、Logistic回归分析以及绘制受试者工作（ROC）曲线等方法寻找CRT超反应的独立预测因子,并评价其预测价值.结果 超反应患者中男性、右束支阻滞少,左束支阻滞多,植入术前左心室舒张末内径（LVEDD）小,术后QRS时限短,但只有术前LVEDD是CRT超反应的独立预测因子,术前LVEDD≤68.5 mm预测CRT超反应的敏感性为84.6%,特异性为76.9%.结论 植入术前左心室较小的CRT治疗患者更容易从这一器械治疗中获益.     

Percutaneous mitral valve repair: A new treatment for mitral regurgitation

Mitral valve disease affects more than 4 million people in the United States. The gold standard of treatment in these patients is surgical repair or replacement of the valve with a prosthesis. The MitraClip (Abbott Vascular, Menlo Park, CA) is a new technology, which offers an alternative to open surgical repair or replacement via a minimally invasive route. We present an evidence-based clinical update that provides an overview of this technology as it relates to managing patients with significant mitral regurgitation. This review article is particularly useful to noninterventional cardiologists and interventional cardiologists who will be managing patients with this novel technology in increased volumes over the next decade but who do not perform this procedure.     

Response of functional mitral regurgitation in nonischemic cardiomyopathy to left bundle branch pacing

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Early results after mitral valvuloplasty for pure mitral regurgitation

In this study we present the results of 105 consecutive patientswith pure mitral regurgitation who underwent surgical treatment.In all patients mitral regurgitation was associated with mitralvalve prolapse: 54 patients underwent mitral valvuloplasty and51 patients mitral valve replacement. Clinical assessment and echocardiography were used as follow-upcriteria at one year after surgery. After mitral valvuloplasty,NYH A decreased from 2.7±0.8 to 1.1±0.7 (P<0.01)and workload capacity increased from 65±28% to 96±25%(P<0.001); left endsystolic atrial dimension and enddiastolicdimension decreased from 6.2±0.8 to 4.8±1.2 cm(P<0.001) and from 7.2±1.3 to 5.9±0.8 cm (P<0.01);ventricular contraction fraction did not change significantly. After mitral valve replacement, clinical and echocardiographicimprovement was significant but less remarkable than after valvuloplasty;ventricular contraction fraction fell from 39±7% to 29±8%in contrast to patients undergoing mitral valvuloplasty in whomno significant change occurred. Complications were rare in both groups though only a minorityof patients undergoing mitral valvuloplasty received anticoagulants.We conclude that mitral valvuloplasty in patients with puremitral regurgitation associated with mitral valve prolapse givesexcellent results, particularly regarding left ventricular functionwhen compared with the patients after mitral valve replacement.     

Early results after mitral valvuloplasty for pure mitral regurgitation

In this study we present the results of 105 consecutive patientswith pure mitral regurgitation who underwent surgical treatment.In all patients mitral regurgitation was associated with mitralvalve prolapse: 54 patients underwent mitral valvuloplasty and51 patients mitral valve replacement. Clinical assessment and echocardiography were used as follow-upcriteria at one year after surgery. After mitral valvuloplasty,NYH A decreased from 2.7±0.8 to 1.1±0.7 (P<0.01)and workload capacity increased from 65±28% to 96±25%(P<0.001); left endsystolic atrial dimension and enddiastolicdimension decreased from 6.2±0.8 to 4.8±1.2 cm(P<0.001) and from 7.2±1.3 to 5.9±0.8 cm (P<0.01);ventricular contraction fraction did not change significantly. After mitral valve replacement, clinical and echocardiographicimprovement was significant but less remarkable than after valvuloplasty;ventricular contraction fraction fell from 39±7% to 29±8%in contrast to patients undergoing mitral valvuloplasty in whomno significant change occurred. Complications were rare in both groups though only a minorityof patients undergoing mitral valvuloplasty received anticoagulants.We conclude that mitral valvuloplasty in patients with puremitral regurgitation associated with mitral valve prolapse givesexcellent results, particularly regarding left ventricular functionwhen compared with the patients after mitral valve replacement.     

Very long term follow-up of cardiac resynchronization therapy: clinical outcome and predictors of mortality

BACKGROUND: Cardiac resynchronization therapy (CRT) improves symptoms, left ventricular ejection fraction (LVEF) and survival in patients with heart failure and wide QRS, however, long term clinical outcome is unknown. AIMS: To identify predictors of mortality and evaluate the effects of CRT after long term follow-up. METHODS: Consecutive patients treated with CRT between 1997 and 2002 were included. We collected clinical information from patient files. Patients who were still alive underwent echocardiography and clinical evaluation. RESULTS: We included 179 patients (median age 65.5 years, 144 male). Median follow-up for survival was 4.0 years. Mortality at one and five years was 15% and 53%, respectively. Predictors of mortality were, ischaemic heart disease (IHD), higher NYHA class and lower LVEF (<22.5%) at baseline, and no improvement in NYHA class at early follow-up. NYHA class remained stable from early to long term follow-up after a median of 5.1 years. In patients with non-IHD median LVEF increased significantly from early to long term follow-up (39% vs. 50% p=0.007). CONCLUSION: Predictors of mortality in patients with CRT are IHD, lower LVEF and higher NYHA class at baseline, and no symptomatic response to CRT. After 5 years follow-up, clinical effects are sustained, and in patients with non-IHD further improvements in LVEF are observed.     

Mitral regurgitation and cardiac resynchronization therapy

Secondary mitral regurgitation (MR) is frequent in patients with severely depressed left ventricular function. It increases mortality, and decreases exercise capacity. Its main mechanisms are multifactorial, related to apical and outward displacement of the papillary muscles, secondary to an enlarged and a more spherical left ventricle, causing increased subvalvar traction; mitral annular dilatation; and poor contraction of the left ventricle, with a slowed rate of rise of intraventricular pressure and slow closure of the leaflets. Since mechanical dyssynchrony is a major contributor factor to secondary MR, cardiac resynchronization therapy (CRT) could be considered as an alternative therapeutic option for MR, alone or in combination with surgical correction. Effects of CRT on secondary MR are acute and long-term, due to the reverse remodeling of the left ventricle. CRT reduces systolic MR by 30-40%, both at rest and during exercise, and abolishes diastolic MR, by increase of the closing forces and decrease of the tethering forces, acting on the mitral valve; decrease of the mitral annular dilatation represents a minor mechanism. Patients more likely to benefit should have moderate-to-severe MR (but not too severe), of nonischemic etiology, and high interpapillary muscles dyssynchrony. Effects are similar in patients with sinus rhythm and in patients with atrial fibrillation, and in patients with broad and narrow QRS complexes, provided that they have similar extent of dyssynchrony. Biventricular mode is the pacing modality of choice.