Relative merits of left ventricular dyssynchrony, left ventricular lead position, and myocardial scar to predict long-term survival of ischemic heart failure patients undergoing cardiac resynchronization therapy.

BACKGROUND: The relative merits of left ventricular (LV) dyssynchrony, LV lead position, and myocardial scar to predict long-term outcome after cardiac resynchronization therapy remain unknown and were evaluated in the present study. METHODS AND RESULTS: In 397 ischemic heart failure patients, 2-dimensional speckle tracking imaging was performed, with comprehensive assessment of LV radial dyssynchrony, identification of the segment with latest mechanical activation, and detection of myocardial scar in the segment where the LV lead was positioned. For LV dyssynchrony, a cutoff value of 130 milliseconds was used. Segments with <16.5% radial strain in the region of the LV pacing lead were considered to have extensive myocardial scar (>50% transmurality, validated in a subgroup with contrast-enhanced magnetic resonance imaging). The LV lead position was derived from chest x-ray. Long-term follow-up included all-cause mortality and hospitalizations for heart failure. Mean baseline LV radial dyssynchrony was 133±98 milliseconds. In 271 patients (68%), the LV lead was placed at the latest activated segment (concordant LV lead position), and the mean value of peak radial strain at the targeted segment was 18.9±12.6%. Larger LV radial dyssynchrony at baseline was an independent predictor of superior long-term survival (hazard ratio, 0.995; P=0.001), whereas a discordant LV lead position (hazard ratio, 2.086; P=0.001) and myocardial scar in the segment targeted by the LV lead (hazard ratio, 2.913; P<0.001) were independent predictors of worse outcome. Addition of these 3 parameters yielded incremental prognostic value over the combination of clinical parameters. CONCLUSIONS: Baseline LV radial dyssynchrony, discordant LV lead position, and myocardial scar in the region of the LV pacing lead were independent determinants of long-term prognosis in ischemic heart failure patients treated with cardiac resynchronization therapy. Larger baseline LV dyssynchrony predicted superior long-term survival, whereas discordant LV lead position and myocardial scar predicted worse outcome.

Cardiac resynchronization therapy in paediatric and congenital heart disease patients.

The number of patients with congenital heart disease (CHD) has significantly increased over the last decades. The CHD population has a high prevalence of heart failure during late follow-up and this is a major cause of mortality. Cardiac resynchronization therapy (CRT) may be a promising therapy to improve the clinical outcome of CHD and paediatric patients with heart failure. However, the CHD and paediatric population is a highly heterogeneous group with different anatomical substrates that may influence the effects of CRT. Echocardiography is the mainstay imaging modality to evaluate CHD and paediatric patients with heart failure and novel echocardiographic tools permit a comprehensive assessment of cardiac dyssynchrony that may help selecting candidates for CRT. This article reviews the role of CRT in the CHD and paediatric population with heart failure. The current inclusion criteria for CRT as well as the outcomes of different anatomical subgroups are evaluated. Finally, echocardiographic assessment of mechanical dyssynchrony in the CHD and paediatric population and its role in predicting response to CRT is comprehensively discussed.

A rare cause of cardiac tamponade.

Cardiac tamponade is a life-threatening condition which must be quickly diagnosed and treated. This medical urgency can have several possible causes. We report the case of a 59-year-old patient presenting with a cardiac tamponade caused by extramedullary haematopoiesis due to myelofibrosis.

Transcatheter aortic valve implantation: role of multi-detector row computed tomography to evaluate prosthesis positioning and deployment in relation to valve function.

AIMS: Aortic regurgitation after transcatheter aortic valve implantation (TAVI) is one of the most frequent complications. However, the underlying mechanisms of this complication remain unclear. The present evaluation studied the anatomic and morphological features of the aortic valve annulus that may predict aortic regurgitation after TAVI. METHODS AND RESULTS: In 53 patients with severe aortic stenosis undergoing TAVI, multi-detector row computed tomography (MDCT) assessment of the aortic valve apparatus was performed. For aortic valve annulus sizing, two orthogonal diameters were measured (coronal and sagittal). In addition, the extent of valve calcifications was quantified. At 1-month follow-up after procedure, MDCT was repeated to evaluate and correlate the prosthesis deployment to the presence of aortic regurgitation. Successful procedure was achieved in 48 (91%) patients. At baseline, MDCT demonstrated an ellipsoid shape of the aortic valve annulus with significantly larger coronal diameter when compared with sagittal diameter (25.1 +/- 2.4 vs. 22.9 +/- 2.0 mm, P < 0.001). At follow-up, MDCT showed a non-circular deployment of the prosthesis in six (14%) patients. Moderate post-procedural aortic regurgitation was observed in five (11%) patients. These patients showed significantly larger aortic valve annulus (27.3 +/- 1.6 vs. 24.8 +/- 2.4 mm, P = 0.007) and more calcified native valves (4174 +/- 1604 vs. 2444 +/- 1237 HU, P = 0.005) at baseline and less favourable deployment of the prosthesis after TAVI. CONCLUSION: Multi-detector row computed tomography enables an accurate sizing of the aortic valve annulus and constitutes a valuable imaging tool to evaluate prosthesis location and deployment after TAVI. In addition, MDCT helps to understand the underlying mechanisms of post-procedural aortic regurgitation.

Time course of global left ventricular strain after acute myocardial infarction.

AIMS: The purpose of the present study was to assess the evolution of left ventricular (LV) function after acute myocardial infarction (AMI) using global longitudinal peak systolic strain (GLPSS) during 1 year follow-up. In addition, patients were divided in groups with early, late, or no improvement of LV function and predictors of recovery of LV function were established. METHODS AND RESULTS: A total of 341 patients with AMI were evaluated. Two-dimensional echocardiography was performed at baseline, 3, 6, and 12 months. At baseline, LV function was assessed with traditional parameters and GLPSS. Global longitudinal peak systolic strain was re-assessed at 3, 6, and 12 months. Improvement of LV function was based on GLPSS and was observed in 72% of the patients. No differences were observed between patients with early and late improvement. The left anterior descending coronary artery as culprit vessel, peak cardiac troponin T level, diastolic function, and baseline GLPSS were identified as independent predictors of recovery of LV function. CONCLUSION: Improvement of LV systolic function occurred in the majority of patients during follow-up. Global longitudinal peak systolic strain, left anterior descending coronary artery as culprit vessel, peak cardiac troponin T level, and diastolic function were independent predictors of recovery of LV function. Quantification of GLPSS may be of important value for the prediction of recovery of LV function in patients after AMI.

Why, how and when do we need to optimize the setting of cardiac resynchronization therapy?

Current cardiac resynchronization therapy (CRT) devices allow manipulation of the atrioventricular (AV) and interventricular (VV) timings in order to maximize the left ventricular (LV) performance. Multiple echocardiographic and non-echocardiographic methods have been proposed to optimize AV and VV intervals but no consensus has been reached on which methodology should preferably be used. Furthermore, different physiologic conditions, such as rest and exercise, may markedly change LV loading conditions, and therefore an optimal setting determined at rest may be different during exercise. The present article reviews current methodologies to optimize AV and VV interval and discuss why, when and how optimization of these delays may be performed based on current evidence. Moreover, an overview of the results of the multicenter trials on AV and VV intervals optimization is provided.

The role of non-invasive imaging in patient selection.

Cardiac resynchronization therapy (CRT) is an established therapy for patients with advanced heart failure, depressed left ventricular (LV) function and wide QRS complex. A substantial amount of patients do not respond to CRT. Recent studies suggest that assessment of mechanical dyssynchrony may allow identification of potential CRT responders. In addition, presence of scar tissue and venous anatomy may play a role in the selection of candidates. This article summarizes the role of non-invasive cardiac imaging modalities addressing these issues in the selection of CRT candidates.

Noninvasive evaluation of coronary sinus anatomy and its relation to the mitral valve annulus: implications for percutaneous mitral annuloplasty.

BACKGROUND: Percutaneous mitral annuloplasty has been proposed as an alternative to surgical annuloplasty. In this respect, evaluation of the coronary sinus (CS) and its relation with the mitral valve annulus (MVA) and the coronary arteries is relevant. The feasibility of evaluating these issues noninvasively with multislice computed tomography was determined. METHODS AND RESULTS: In 105 patients (72 men, age 59+/-11 years), 64-slice multislice computed tomography was performed for noninvasive evaluation of coronary artery disease. Thirty-four patients with heart failure and/or severe mitral regurgitation were included. Three-dimensional reconstructions and standard orthogonal planes were used to assess CS anatomy and its relation with the MVA and circumflex artery. In 71 patients (68%), the circumflex artery coursed between the CS and the MVA with a minimal distance between the CS and the circumflex artery of 1.3+/-1.0 mm. The CS was located along the left atrial wall, rather than along the MVA, in the majority of the patients (ranging from 90% at the level of the MVA to 14% at the level of the distal CS). The minimal distance between the CS and MVA was 5.1+/-2.9 mm. In patients with severe mitral regurgitation, the minimal distance between the CS and the MVA was significantly greater as compared with patients without severe mitral regurgitation (mean 7.3+/-3.9 mm versus 4.8+/-2.5 mm, P<0.05). CONCLUSIONS: In the majority of the patients, the CS courses superiorly to the MVA. In 68% of the patients, the circumflex artery courses between the CS and the mitral annulus. Multislice computed tomography may provide useful information for the selection of potential candidates for percutaneous mitral annuloplasty.

Comparison of left atrial volumes and function by real-time three-dimensional echocardiography in patients having catheter ablation for atrial fibrillation with persistence of sinus rhythm versus recurrent atrial fibrillation three months later.

Real-time 3-dimensional echocardiography (RT3DE) can provide a unique combination of accurate left atrial (LA) volume quantification and rapid, automatic assessment of LA function. The aim of the study was to evaluate the changes in LA volumes and function in patients with atrial fibrillation (AF) undergoing radiofrequency catheter ablation (RFCA) using RT3DE; 57 consecutive patients referred for RFCA were studied. Paroxysmal AF was present in 43 patients (75%) and persistent AF in 14 (25%). After a mean follow-up of 7.9 +/- 2.7 months, patients were divided into 2 groups: successful RFCA (SR group) and recurrence of AF (AF group). RT3DE was performed before, within 3 days, and 3 months after RFCA to assess LA volumes (maximum, minimum, and preA) and LA functions (passive, active, and reservoir). A total of 38 patients (67%) had successful RFCA (SR group). Immediately after RFCA, no significant changes in LA volumes and function were observed. After 3 months, a significant reduction in LA volumes (maximum: 26 +/- 8 to 23 +/- 7 ml/m(2), p <0.01) was noted only in the SR group, with a significant improvement in LA active (22 +/- 8% to 33 +/- 9%, p <0.01) and reservoir functions (116 +/- 45% to 152 +/- 54%, p <0.01). Conversely, the AF group showed a trend towards a deterioration of LA volumes and function. In conclusion, in patients who maintain sinus rhythm after RFCA, a significant reverse remodeling and functional improvement of the left atrium is observed using RT3DE.

Noninvasive imaging of cardiac venous anatomy with 64-slice multi-slice computed tomography and noninvasive assessment of left ventricular dyssynchrony by 3-dimensional tissue synchronization imaging in patients with heart failure scheduled for cardiac resynchronization therapy.

Objectives of this study were to perform a prospective head-to-head comparison between multi-slice computed tomography (MSCT) venography and invasive venography in cardiac resynchronization therapy (CRT) candidates as well as to evaluate the relation between left ventricular (LV) lead position and effect on LV dyssynchrony and immediate response to CRT. Twenty-one consecutive heart failure patients scheduled for CRT implantation were prospectively enrolled to undergo 64-slice MSCT to visualize the venous system, invasive venography during device implantation, and tri-plane tissue synchronization imaging (TSI) before and after implantation. Excellent agreement between MSCT and invasive venography was noted. No significant differences were observed between both techniques regarding vessel diameters. In 12 patients, a match was observed between the area of latest mechanical activation (on TSI) and LV lead position. These patients showed a significant decrease in LV dyssynchrony (43 +/- 7 ms to 11 +/- 9 ms, p <0.0001) with acute reduction in LV end-systolic volume (188 +/- 54 ml to 162 +/- 48 ml, p <0.01) and improvement in LV ejection fraction (22% +/- 9% to 34% +/- 9%, p <0.01). Patients with a mismatch between area of latest activation and LV lead position remained dyssynchronous without improvement in LV function. In conclusion, visualization of major tributaries of the coronary sinus was comparable between invasive venography and MSCT venography. Optimal LV lead positioning in a vein draining the area of latest mechanical activation (determined from tri-plane TSI) resulted in acute improvement of LV dyssynchrony and systolic function after CRT implantation.

Real-time three-dimensional echocardiography permits quantification of left ventricular mechanical dyssynchrony and predicts acute response to cardiac resynchronization therapy.

OBJECTIVE: To evaluate the value of real-time three-dimensional echocardiography (RT3DE) to predict acute response to cardiac resynchronization therapy (CRT). METHODS: Sixty consecutive heart failure patients scheduled for CRT were included. RT3DE was performed before and within 48 hours after pacemaker implantation to calculate both left ventricular (LV) volumes and LV dyssynchrony. LV dyssynchrony was defined as the standard deviation of the time taken to reach the minimum systolic volume for 16 LV segments (referred to as the systolic dyssynchrony index, SDI). Patients were subsequently divided into acute responders or nonresponders, based on a reduction > or = 15% in LV end-systolic volume immediately after CRT. RESULTS: Four patients (7%) were excluded from further analysis because of either suboptimal apical acquisitions or significant translation artifacts. Out of the remaining 56 patients, 35 patients (63%) were classified as acute responders. Baseline characteristics were similar between responders and nonresponders, except for the SDI, which was larger in responders. Moreover, responders demonstrated a significant reduction of SDI immediately after CRT (from 9.7 +/- 4.1% to 3.6 +/- 1.8%, P < 0.0001), whereas SDI did not change in nonresponders (3.4 +/- 1.8% vs 3.1 +/- 1.1%, NS). ROC curve analysis revealed that a cut-off value for SDI of 5.6% yielded a sensitivity of 88% with a specificity of 86% to predict acute echocardiographic response to CRT (AUC 0.96). CONCLUSION: RT3DE is highly predictive for acute response to CRT (sensitivity 88% and specificity 86%). In addition, RT3DE allows assessment of changes in LV volumes and LV ejection fraction before and after CRT implantation.

Magnetic resonance imaging and computed tomography in assessing cardiac veins and scar tissue.

The success of cardiac resynchronization therapy is influenced by several issues including cardiac venous anatomy and myocardial scar tissue. This article discusses non-invasive imaging modalities that could contribute significantly to the selection process of cardiac resynchronization therapy (CRT) candidates: multi-slice computed tomography to depict the coronary sinus tributaries and magnetic resonance imaging to identify scar tissue.

Nuclear imaging in cardiac resynchronization therapy.

Recently, cardiac resynchronization therapy (CRT) has become implemented in the treatment of patients with severe heart failure. Although the improvement in systolic function after CRT implantation can be considerable, 20%-30% of patients do not respond to CRT. Evidence is accumulating that the presence of left ventricular (LV) dyssynchrony is mandatory for a response to CRT. Since the early 1980s attempts have been made to assess cardiac dyssynchrony with nuclear imaging, and it has been reported recently that information on LV dyssynchrony can be obtained from gated myocardial perfusion SPECT with phase analysis. Other studies with SPECT have shown that extensive scar tissue will limit the response to CRT; similarly, it has been demonstrated that viable tissue (assessed with SPECT) in the target zone for the LV pacing lead (usually the lateral wall) is needed for a response to CRT. Moreover, studies with PET have provided insight into the changes in myocardial perfusion, metabolism, and efficiency after CRT. In the current review, a comprehensive summary is provided on the potential role of nuclear imaging in the selection of heart failure patients for CRT. The value of other imaging techniques is also addressed.

Usefulness of triplane tissue Doppler imaging to predict acute response to cardiac resynchronization therapy.

This study evaluated the value of triplane tissue Doppler imaging (TDI) to predict acute response after cardiac resynchronization therapy (CRT). Forty-nine patients scheduled for CRT underwent triplane echocardiography with simultaneous TDI acquisition before and 48 hours after implantation. A 3-dimensional left ventricular (LV) volume was generated and LV volumes and ejection fraction were calculated. A parametric imaging technique, tissue synchronization imaging, was applied to portray the area of latest mechanical activation. LV dyssynchrony was quantitatively analyzed by evaluating time from QRS onset to peak myocardial velocity in 12 LV segments from the triplane dataset. Acute response was defined as > or =15% decrease in LV end-systolic volume. Receiver-operating characteristic curves of dyssynchrony parameters were analyzed to identify predictors of response to CRT. Acute response was observed in 47% of patients. Responders had a significantly larger extent of LV dyssynchrony at baseline compared with nonresponders. Optimal prediction of acute response to CRT was obtained with the SD of time delays in all LV segments (sensitivity 91%, specificity 85%). In conclusion, 3-dimensional TDI echocardiography permits parametric and quantitative analyses of LV dyssynchrony and assessment of LV volumes and ejection fraction. LV dyssynchrony parameters, derived from the triplane TDI dataset, were highly predictive for acute volumetric response to CRT.

Triplane tissue Doppler imaging to evaluate mechanical dyssynchrony before and after cardiac resynchronization in a patient with congenitally corrected transposition of the great arteries.

We report the case of a 13-year-old girl with congenitally corrected transposition of the great arteries. Since the implantation of a conventional pacemaker for acquired complete atrioventricular block, the patient experienced increased heart failure symptoms. Using triplane tissue Doppler imaging, significant intraventricular dyssynchrony induced by unilateral pacing and associated with diminished exercise capacity was demonstrated. A biventricular pacemaker was successfully implanted transvenously, leading to synchronous activation of the systemic ventricle and improved exercise capacity.

Maximum oxygen uptake at peak exercise in elderly patients with coronary artery disease and preserved left ventricular function: the role of inflammation on top of tissue Doppler-derived systolic and diastolic function.

BACKGROUND: Several studies have shown that longitudinal systolic function and left ventricular filling pressures, as assessed with tissue Doppler imaging, predict exercise capacity. AIM: The aim of this study was to evaluate whether natriuretic peptides and inflammatory parameters can independently predict maximum oxygen uptake at peak exercise (VO2max) on top of tissue Doppler imaging-derived markers. METHODS: We evaluated 142 patients (age 70 +/- 6 years, 77% men) with known or suspected coronary artery disease and a preserved left ventricular ejection fraction (> or = 50%). All patients underwent bicycle spiroergometry, and N-terminal pro-B-type natriuretic peptide levels were determined. Cytokines (IL-6 and soluble tumor necrosis factor receptors 1 and 2) and high-sensitivity C-reactive protein were measured as inflammatory markers. Tissue Doppler imaging was applied to evaluate peak long axis systolic velocities (Sm) and early mitral annulus velocities (E'). Ratio of early transmitral flow (E) to E' was assessed as marker of left ventricular filling. Analysis of variance, comparing VO2max quartiles, was used to determine univariate predictors and linear regression to determine multivariate VO2max predictors. RESULTS: Average VO2max was 18.5 +/- 5.7 mL/kg per minute (range 6-36.6). Compared with the highest quartile, patients with low VO2max were more frequently women (P < .0001). N-terminal pro-B-type natriuretic peptide and cytokine levels were significantly higher in the lower VO2max categories. Longitudinal myocardial velocities increased, and E/E' decreased along with increasing VO2max. In multivariate linear regression analysis, VO2max was independently predicted by sex, glucose, Sm, E/E', and cytokine levels. CONCLUSION: Maximum oxygen uptake at peak exercise in patients with known or suspected coronary artery disease and preserved systolic function was independently predicted by inflammatory makers on top of tissue Doppler-derived systolic and diastolic function.

Fasting blood glucose levels are related to exercise capacity in patients with coronary artery disease.

BACKGROUND AND AIM: Previous studies have demonstrated reduced exercise capacity in patients with diabetes mellitus. This study evaluated the relationship between fasting blood glucose (FBG) levels and exercise capacity in patients with coronary artery disease (CAD). METHODS: We evaluated 986 consecutive patients with CAD referred for bicycle spiroergometry combined with gated myocardial perfusion imaging. Maximum oxygen consumption (VO2max) and maximal watts were measured. Patients were divided into 4 FBG categories: < 100 mg/dL (n = 611), 100 to 109 mg/dL (n = 144), 110 to 125 mg/dL (n = 102), and > or = 126 mg/dL (n = 129). Differences in clinical characteristics, exercise hemodynamics, perfusion imaging, and univariate as well as multivariate predictors of exercise capacity were determined. RESULTS: Maximal watts and VO2max were significantly lower (P < .0001) in patients with higher FBG levels and were related to FBG values in univariate and multivariate analyses. Left ventricular volumes and ejection fractions did not differ between the FBG categories. Myocardial perfusion imaging showed a comparable degree of ischemia in the 4 FBG groups. However, patients with higher FBG levels had higher heart rate and blood pressure values at rest resulting in a higher rate-pressure product (values in the 4 FBG groups 8299 +/- 2051, 8733 +/- 2008, 9558 +/- 2583, and 9588 +/- 2468 beat/min x mm Hg, P < .0001), suggesting increased myocardial oxygen consumption per unit time at rest. CONCLUSION: Exercise capacity in patients with CAD is related to FBG levels. Patients with impaired fasting glucose or an FBG level > or = 126 mg/dL reached lower peak watts and lower VO2max values. This could be attributed to a higher myocardial oxygen consumption per unit time at rest and the inability to adapt their coronary flow adequately to higher metabolic demands during maximal exercise.

Effect of ischemic mitral regurgitation on the ratio of early transmitral flow velocity to mitral annulus early diastolic velocity in patients with stable coronary artery disease.

The present study evaluated the prevalence of ischemic mitral regurgitation (MR) in a large population of patients with documented coronary artery disease who had been referred for echocardiography and assessed whether ischemic MR is an independent determinant of echocardiographically estimated left ventricular (LV) filling pressures. We studied 849 consecutive patients with coronary artery disease (67 +/- 10 years; 76% men) without organic valvular disease. Ischemic MR was semiquantitatively graded as absent or trace or grades 1 to 3/4 by assessment of the color flow jet in relation to the left atrium in multiple orthogonal views. The ratio of early transmitral flow velocity to mitral annulus early diastolic velocity was determined to estimate LV filling pressures. Ischemic MR was absent in 25% of patients and 28% had grade > or = 2 ischemic MR. Only 18% of patients with preserved LV function had a significant ischemic MR, but up to 66% of patients with poor LV function had grade > or = 2 MR. The ratio of early transmitral flow velocity to mitral annulus early diastolic velocity was independently predicted by age, gender, LV ejection fraction, and ischemic MR severity. Even mild ischemic MR was associated with an increase in this noninvasive marker of LV filling pressures.

Diabetes and impaired fasting glucose as predictors of morbidity and mortality in male coronary artery disease patients with reduced left ventricular function.

OBJECTIVES: To evaluate the prognostic value of impaired fasting glucose and diabetes mellitus in male patients with coronary artery disease and poor left ventricular function. METHODS AND RESULTS: From a prospective database on patients referred for gated myocardial perfusion imaging between 1998 and 2002 all male patients with a history of coronary artery disease and poor left ventricular function were selected. Poor function was defined as left ventricular ejection fraction < or = 40%. Subjects were classified as non-diabetics with fasting blood glucose levels < 110 mg/dL, non-diabetics with impaired fasting glucose (fasting blood glucose between 110 and 125 mg/dL) and diabetics. Median follow-up was 2.7years. End points were all-cause mortality, cardiac death and hospitalization for heart failure. One hundred and sixty patients were selected (age 65 +/- 9 years and left ventricular ejection fraction 29 +/- 8%). In univariate analysis atrial fibrillation, NYHA class, glycaemia and diabetes mellitus discriminated between survivors and non-survivors. In Cox multivariate regression analysis for all-cause mortality only NYHA class and diabetes mellitus remained significant. Kaplan Meier analysis showed that diabetics had the worst survival and non-diabetics with glucose < 110 mg/dL had the best survival. Non-diabetics with impaired fasting glucose had intermediate survival. Analysis for cardiac death/hospitalization for heart failure showed similar results. CONCLUSION: In male patients with coronary artery disease and impaired left ventricular function diabetes mellitus and fasting glucose are strongly predictive of poor outcome. Diabetics have the worst prognosis but non-diabetics with impaired fasting glucose also are at higher risk compared to nondiabetics with low fasting blood glucose.