Impact of right ventricular contractility on left ventricular dyssynchrony in patients with chronic systolic heart failure.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an important therapeutic approach for patients with symptomatic heart failure. The assessment of mechanical dyssynchrony, however, remains an issue. Little data are available regarding the influence of the right ventricle (RV) on left ventricle (LV) mechanical dyssynchrony as assessed by echocardiography. AIMS: We sought to assess the impact of RV contractility on LV function and dyssynchrony. METHODS: A total of 40 patients with congestive heart failure were analyzed. Twenty had RV dysfunction, as defined by a tricuspid annular systolic peak of tissue Doppler (SaRV)<11.5 cm/s, while the remaining 20 had SaRV>11.5 cm/s. All patients underwent echocardiography in order to determine RV function, LV function, and dyssynchrony. RESULTS: The two populations were similar regarding diastolic function, atrio-ventricular conduction and interventricular dyssynchrony. Patients with RV dysfunction showed significantly more severe LV longitudinal dyssynchrony (130±103 ms vs. 62±59 ms; p=0.01). In addition, SaRV (systolic peak recorded at the tricuspid annulus) was correlated with LV longitudinal dyssynchrony (r=0.47; p=0.001). In contrast, LV radial contractility and dyssynchrony (103±110 ms vs. 100±78 ms; p=0.5) were not affected by RV function. CONCLUSION: Quantitative analysis of RV function is important when assessing LV function and dyssynchrony in patients with systolic heart failure. RV function is associated with intra-LV dyssynchrony, particularly when considering longitudinal function.

Left atrial reverse remodeling and cardiac resynchronization therapy for chronic heart failure patients in sinus rhythm.

BACKGROUND: Cardiac resynchronization therapy (CRT), which improves left ventricular (LV) function and reverses LV remodeling, is an established therapy for advanced heart failure with prolonged QRS duration. The aim of this study was to examine whether CRT improves atrial function and induces atrial reverse remodeling. METHODS: A total of 46 patients with heart failure (mean age, 66.7 +/- 10.4 years) who underwent CRT were evaluated with echocardiography before and after 6 months of optimized CRT. Atrial function and LV function were assessed with M-mode, two-dimensional echocardiography, Doppler, tissue Doppler velocity, and strain (epsilon) imaging. LV reverse remodeling was defined as a reduction in LV end-systolic volume of >15%. RESULTS: In responders (n = 23), significant improvements in left atrial (LA) functional, structural, and anatomic remodeling were observed. Maximum LA area and volume decreased, the LA emptying fraction increased, A' increased, and LA epsilon increased from 25.6 +/- 11.0% to 42.6 +/- 10.4% (P < .05 overall). LA reverse remodeling was correlated with baseline LA volume (R = 0.45). Although the correlation was not significant (r = 0.24), LA reverse remodeling was also more frequent in patients with LV reverse remodeling. CONCLUSIONS: In patients with LV remodeling, significant LA reverse remodeling after CRT could be observed and detailed on transthoracic echocardiography.

Selection of patients responding to cardiac resynchronisation therapy: implications for echocardiography.

Echocardiography is an essential facet of monitoring patients with heart failure. However, results of echocardiographic detection and quantification of mechanical dyssynchrony are not currently recommended as grounds for the deployment of biventricular (Biv) resynchronisation therapy. Ten years of research in the field of dyssynchrony within echocardiography have resulted in two negative studies which have, to some extent, discredited this technique. However, the research conducted has at least allowed us to refine our understanding of mechanical dyssynchrony and its management. New quantification techniques and generalised access to digital imagery and processing have renewed hopes that the performance of echocardiography in this field will soon improve. We therefore propose new criteria, to be evaluated as per PROSPECT standard methodology. In the review of the literature presented here, we suggest combining the echocardiography parameters for an individual and physiopathological approach, while waiting for more prospective studies to be conducted before issuing any recommendations.

Argument for a Doppler echocardiography during exercise in assessing asymptomatic patients with severe aortic stenosis.

AIMS: Exercise stress testing (EST) is recommended by guidelines to risk-stratify patients with asymptomatic valvular aortic stenosis (AS), though the role of quantitative exercise-Doppler echocardiography has rarely been studied. This prospective study sought to correlate standard EST results with the haemodynamic measurements made during exercise by Doppler echocardiography. METHODS AND RESULTS: We performed rest and semi-supine exercise Doppler echocardiography in 44 consecutive patients (mean age=68+/-12 years) with aortic valve areas

Mitral regurgitation in dilated cardiomyopathy: value of both regional left ventricular contractility and dyssynchrony.

AIMS: Mitral regurgitation (MR) is common and independently predicts mortality in patients with left ventricular (LV) systolic dysfunction. Its management remains challenging because of the complexity and variety of potential mechanisms implicated. We sought to determine which LV functional characteristics are the most important determinants of the severity of the MR associated with dilated cardiomyopathies. METHODS AND RESULTS: We performed echocardiographic studies in 87 consecutive patients with dilated cardiomyopathy. The degree of MR was quantified according to guidelines. LV, left atrial and mitral annulus dimensions, mitral valve tenting, estimated filling pressures, regional myocardial contractility, and dyssynchrony (using regional strain (epsilon) analysis) were recorded too. Determinants of significant MR was thus assessed using multivariate models. Mitral regurgitant volume correlated with mitral annulus diameter (P<0.001), mitral valve tenting height (P<0.001), LV volumes (P=0.004), LV ejection fraction, mid-lateral wall peak of epsilon (P=0.01), and its delay (P<0.001). That inter-relation between the mitral annulus, the ventricle shape, contractility, and dyssynchrony was founded in the multivariate analysis. As a matter of fact, the model predicting the best the MR volume (R=0.78) included: mitral annulus diameter, dyssynchrony, tenting heigh and contractility of the LV mid-lateral wall (measured by epsilon). CONCLUSION: The MR of the dilated cardiomyopathy is multifactorial. Our data suggest that analysing only LV geometry and mitral orifice is insufficient to correctly describe functional MR determinant. LV contractility and dyssynchrony are essential too.

Prolonged heparin and vitamin K antagonist regimen for early non-obstructive thrombosis of mechanical mitral valve prostheses.

BACKGROUND AND AIM OF THE STUDY: Transesophageal echocardiography (TEE) has been used to document the incidence of non-obstructive thrombosis (NOT) after mechanical prosthetic mitral valve replacement (MVR). The postoperative occurrence and unpredictable evolution of NOT complicate its management. The study aim was to examine the safety and efficacy of prolonged, combined administration of heparin and vitamin K antagonists (VKA) recommended for this indication. METHODS: All patients who underwent mechanical prosthetic MVR between July 1999 and December 2004 at the authors' institution were systematically studied with TEE immediately after surgery. Patients who presented with > or = 5 mm NOT were treated with combined heparin and VKA until TEE-confirmed resolution of the thrombus. RESULTS: Among 256 patients who underwent 263 MVRs (seven reinterventions), 47 (17.9%) presenting with > or = 5 mm NOT received combined heparin and VKA for between 7 and 115 days (median 17 days). No thromboembolic or hemorrhagic events or deaths were observed during this period of observation. Four patients were treated with danaparoid and VKA because of thrombocytopenia induced by heparin before the diagnosis of NOT. Over a mean follow up of 39 months, one patient died from cancer and another from the sequelae of a stroke. In total, there were five NOT recurrences, three of which were complicated by embolic events without sequelae within eight months, and one by a recurrent stroke. In addition, three patients without demonstrable NOT recurrence suffered transient ischemic attacks. CONCLUSION: Among this small sample of patients, combined heparin and VKA was well tolerated and effective, and could prevent reoperation or thrombolysis. These observations may warrant further study in a larger patient population.

Resting echocardiographic assessments of left atrial function and filling pressure interest in the understanding of exercise capacity in patients with chronic congestive heart failure.

OBJECTIVE: Doppler echocardiography is well recognized as the primary noninvasive imaging technique to assess global and regional cardiac function. Cardiopulmonary exercise testing has become a powerful tool to predict outcome in chronic heart failure (CHF). We looked for cardiac determinants, using resting echocardiographic parameters, of exercise tolerance in patients with CHF. METHODS: Transthoracic echocardiography and standardized cardiopulmonary exercise testing were performed in 75 patients (59 +/- 11 years) with CHF, New York Heart Association functional class II to III. Systolic and diastolic function, filling pressures, and left ventricular, right ventricular, and left atrial (LA) regional function were assessed using Doppler tissue velocities and strain values. RESULTS: Maximal workload (86 +/- 41 W) and peak oxygen (14.6 +/- 3.1 mL/min/kg) correlated with left ventricular filling pressure estimates (E/Ea and E/Vp) but also with end-diastolic pulsed Doppler tissue velocity at the mitral annulus (Aa), LA volume, and regional LA function assessed by strain analysis. In multivariate analysis, maximum workload and peak oxygen were shown to correlate with right ventricular peak strain, although Aa and E/Ea were the best predictors of exercise capacity. CONCLUSION: Capacity to exercise in patients with CHF is understandable by resting echocardiography. Filling pressures, and LA and right ventricular functions, are its cardiac best determinants. Adding Aa peak velocity in resting echocardiographic evaluation of patients with CHF is found useful.

Assessment of longitudinal and radial ventricular dyssynchrony in ischemic and nonischemic chronic systolic heart failure: a two-dimensional echocardiographic speckle-tracking strain study.

BACKGROUND: Current guidelines recommend a QRS greater than or equal to 120 milliseconds to select candidates for cardiac resynchronization therapy. However, ischemic and nonischemic cardiomyopathies are two different entities and they might be selected following different approaches. We sought, thus, after a validation the new 2-dimensional (2D) speckle-tracking strain (STS) against color Doppler tissue imaging (DTI)-strain (S) to compare the different correlation between electrical and mechanical dyssynchrony (DYS) in ischemic and nonischemic cardiomyopathies. METHODS: We measured: (1) QRS duration; (2) mechanical interventricular DYS (the difference between preaortic and prepulmonary ejection times); (3) left intraventricular DYS (the SD of time-to-peak of longitudinal DTI-S); and (4) longitudinal and radial 2D-STS in the basal and middle segments of lateral and septal left ventricular walls in 95 patients with chronic heart failure caused by ischemic (n = 49) or nonischemic (n = 46) heart disease. Twelve healthy control subjects were also explored. RESULTS: Mechanical interventricular DYS was correlated (DTI-S: P < .001) with QRS-duration, but not in ischemic heart disease. DTI-S and 2D-STS measurements were correlated (R = 0.6, P < .001) in the overall population. Longitudinal 2D-S DYS was correlated with QRS duration in patients with nonischemic, (P = .003) but not with ischemic heart disease, whereas radial 2D-S DYS was correlated with QRS width in both subgroups (r = 0.48, P = .003, and r = 0.43, P = .003, respectively). CONCLUSIONS: The profile of DYS is influenced by the underlying cause of heart failure. The 2D-STS is a new tool for cardiac DYS assessment. Its ability to measure both longitudinal and radial intraventricular DYS is noteworthy.

Concordance between mechanical and electrical dyssynchrony in heart failure patients: a function of the underlying cardiomyopathy?

BACKGROUND: Cardiac resynchronization therapy (CRT) improves heart failure (HF) symptoms through a reduction of cardiac mechanical dyssynchrony. Mechanical dyssynchrony is currently estimated by electrical dyssynchrony (QRS duration). It is known that electrical and mechanical dyssynchrony are not well correlated in HF patients. However, there is limited information about whether this relationship might be influenced by the underlying cardiomyopathy. METHODS: Doppler echocardiography was performed in 88 patients presenting with heart failure due to ischemic (n = 42) or nonischemic (n = 46) heart disease, left ventricular ejection fraction <40%, New York Heart Association class II-IV, regardless of their QRS duration. Interventricular dyssynchrony was assessed by the time interval between preaortic and prepulmonary ejection times. Intraventricular dyssynchrony was ascertained by (1) the delay between the earliest and the latest peak negative longitudinal strain recorded in the basal and mid-segments of the lateral and septal walls (TMinMax) and (2) the standard deviation of time-to-peak in the same segments (SDdys). RESULTS: The correlation coefficient between QRS duration and mechanical interventricular dyssynchrony was r = 0.47 (P < 0.001) in patients with nonischemic disease and nonsignificant in patients with ischemic disease. Similarly, the correlation coefficient between QRS duration and mechanical intraventricular dyssynchrony was significant in patients with nonischemic disease (r = 0.37, P = 0.01 for TMinMax; r = 0.42, P = 0.003 for SDdys) and nonsignificant in patients with ischemic disease. CONCLUSION: The concordance between electrical dyssynchrony assessed by QRS duration and mechanical dyssynchrony assessed by myocardial strain is dependent upon the underlying cardiomyopathy. This observation may improve our understanding of the various responses observed in CRT patients.

Acute effects of biventricular pacing on right ventricular function assessed by tissue Doppler imaging.

AIMS: The benefits of cardiac resynchronization therapy (CRT) on functional status, left ventricular (LV) remodelling and survival in patients with drug-refractory congestive heart failure (CHF), LV systolic dysfunction, and wide QRS have been demonstrated in randomized trials. However, the impact of CRT on right ventricular (RV) function, an independent prognostic factor in CHF remains questionable. This study examined the acute effects of various pacing modes on RV function in recipients of CRT systems. METHODS AND RESULTS: Echocardiographic examinations were performed in 15 patients (median age: 67 years, range 49-78), to compare RV function during atrial (AAI), RV and LV pacing, and biventricular (BiV) pacing, in random order. At baseline, the median LV ejection fraction was 20% (range 10-35) and the median LV end-diastolic diameter was 78 mm (range 62-85). Right ventricular function was impaired, with a median 36% fractional shortening of RV surfaces (7-59). Tissue Doppler systolic peak of velocity (Sa) recorded at the tricuspid annulus increased significantly from 9.9 cm/s (range 4.7-16.5) during AAI pacing, 10 cm/s (range 5.4-20.3) during RV pacing, and 11.7 cm/s (range 4.6-16.7) during LV pacing to 12.6 cm/s (range 6.6-19.1) during BiV pacing (P < 0.01). Trends toward improvements in other indices of RV function, particularly myocardial performance index and systolic excursion of the tricuspid annulus, were also observed. CONCLUSIONS: This short-term study showed a significant improvement in RV systolic function during BiV pacing compared with AAI, RV, or LV pacing in CRT recipients.

A randomized comparison of permanent septal versus apical right ventricular pacing: short-term results.

OBJECTIVES: This study compared chronic right ventricular (RV) pacing at the septum versus apex. BACKGROUND: Chronic RV apical pacing may be detrimental to ventricular function. This randomized, pilot study examined whether, compared with apical, permanent septal pacing preserves cardiac function. METHODS: Ablation of the atrioventricular junction for permanent AF, followed by implantation of a DDDR pacemaker connected to two ventricular leads was performed in 28 patients. One lead screwed into the septum and another placed at the apex were connected to the atrial and ventricular port, respectively. Septum or apex was paced by programming AAIR or VVIR modes, respectively. Patients were randomly assigned, 4 months later, to pacing at one site for 3 months, and crossed over to the other for 3 months. New York Heart Association class, QRS width and axis, left ventricular ejection fraction (LVEF), exercise duration, and peak oxygen uptake were measured. Results in patients with LVEF > 45% and < or = 45% were compared. RESULTS: Septal pacing was associated with shorter QRS (145 +/- 4 msec vs 170 +/- 4 msec, P < 0.01) and normal axis (40 degrees +/- 10 degrees vs -71 +/- 4 degrees , P < 0.01). At 3 months, among patients with baseline LVEF < or = 45%, LVEF was 42 +/- 5% after septal pacing versus 37 +/- 4% after apical pacing (P < 0.001). CONCLUSION: In contrast to RV apical pacing, chronic RV septal pacing preserved LVEF in patients with baseline LVEF < or = 45%.

Clinical and electrocardiographic predictors of a positive response to cardiac resynchronization therapy in advanced heart failure.

AIMS: Cardiac resynchronization therapy (CRT) is an effective treatment for refractory congestive heart failure (CHF). However, up to 30% of patients do not respond to CRT. The aim of this study was to identify clinical and electrocardiographic (ECG) predictors of a positive response to CRT. METHODS AND RESULTS: This retrospective study included 139 consecutive patients successfully implanted with a CRT device (mean age, 68+/-9 years, 113 men). At baseline, 69% of patients were in New York Heart Association (NYHA) functional class III, and 31% in class IV, mean left ventricular ejection fraction was 21+/-6%, and mean QRS duration was 188+/-28 ms. In each patient, left and right ventricular leads were placed to attain the shortest QRS duration during biventricular stimulation. Patients were classified at 6 months as responders to CRT (n=100) if they were alive, they had not been re-hospitalized for management of CHF, and the NYHA class had decreased by 1 point, and/or peak VO(2) or 6 min hall-walk increased by >10%. All others were classified as non-responders (n=38; one patient was lost to follow-up). Uni- and multivariate logistic regression analyses were performed to detect a pre- or intra-operative predictor of a positive response to CRT. Among multiple demographic, clinical, and ECG variables, the amount of QRS shortening (DeltaQRS) associated with biventricular stimulation was the only independent predictor of a positive (37+/-23 ms) vs. negative (11+/-23 ms) response to CRT (P<0.001). CONCLUSION: A positive response to CRT was observed in 73% of patients at 6 months and predicted only by DeltaQRS.

Suspected pacemaker or defibrillator transvenous lead infection. Prospective assessment of a TEE-guided therapeutic strategy.

AIMS: The aim of this prospective study was to assess the clinical value of a management strategy principally based on the results of multiplane transoesophageal echocardiography (TEE) in patients with suspected lead infection. METHODS AND RESULTS: Seventy-seven consecutive patients were included. Based on Duke's modified criteria, PTLI was considered as definite in 54 patients (70%) and possible in 23 patients (30%). Nineteen patients with a diagnosis of possible infection, as defined by bacteraemia without abnormal TEE images and without evidence of pacemaker pocket infection, were treated by antibiotics alone. In all other cases, the pacing material was totally removed. During a mean follow-up time of 3.1+/-2.5 years, 21 patients (27%) died, mostly from cardiovascular causes. Only one patient died from infection and there was only one case of delayed infection recurrence in an other localization. No significant differences in outcome were observed between explanted and non-explanted patients. CONCLUSIONS: The results observed confirm that early and total explantation of pacing material has to be done in patients with bacteraemia and abnormal images at TEE. But conversely conservation of the pacing system can be proposed to patients with bacteraemia but without abnormal images at TEE provided prolonged antibiotic treatment is given.