Matteo Bertini

Comparison of Aortic Root Dimensions and Geometries Before and After Transcatheter Aortic Valve Implantation by 2- and 3-Dimensional Transesophageal Echocardiography and Multislice Computed Tomography

Background—3D transesophageal echocardiography (TEE) may provide more accurate aortic annular and left ventricular outflow tract (LVOT) dimensions and geometries compared with 2D TEE. We assessed agreements between 2D and 3D TEE measurements with multislice computed tomography (MSCT) and changes in annular/LVOT areas and geometries after transcatheter aortic valve implantations (TAVI). Methods and Results—Two-dimensional circular (&pgr;×r2), 3D circular, and 3D planimetered annular and LVOT areas by TEE were compared with “gold standard” MSCT planimetered areas before TAVI. Mean MSCT planimetered annular area was 4.65±0.82 cm2 before TAVI. Annular areas were underestimated by 2D TEE circular (3.89±0.74 cm2, P<0.001), 3D TEE circular (4.06±0.79 cm2, P<0.001), and 3D TEE planimetered annular areas (4.22±0.77 cm2, P<0.001). Mean MSCT planimetered LVOT area was 4.61±1.20 cm2 before TAVI. LVOT areas were underestimated by 2D TEE circular (3.41±0.89 cm2, P<0.001), 3D TEE circular (3.89±0.94 cm2, P<0.001), and 3D TEE planimetered LVOT areas (4.31±1.15 cm2, P<0.001). Three-dimensional TEE planimetered annular and LVOT areas had the best agreement with respective MSCT planimetered areas. After TAVI, MSCT planimetered (4.65±0.82 versus 4.20±0.46 cm2, P<0.001) and 3D TEE planimetered (4.22±0.77 versus 3.62±0.43 cm2, P<0.001) annular areas decreased, whereas MSCT planimetered (4.61±1.20 versus 4.84±1.17 cm2, P=0.002) and 3D TEE planimetered (4.31±1.15 versus 4.55±1.21 cm2, P<0.001) LVOT areas increased. Aortic annulus and LVOT became less elliptical after TAVI. Conclusions—Before TAVI, 2D and 3D TEE aortic annular/LVOT circular geometric assumption underestimated the respective MSCT planimetered areas. After TAVI, 3D TEE and MSCT planimetered annular areas decreased as it assumes the internal dimensions of the prosthetic valve. However, planimetered LVOT areas increased due to a more circular geometry.

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.

Findings from left ventricular strain and strain rate imaging in asymptomatic patients with type 2 diabetes mellitus

Regional left ventricular (LV) myocardial functional changes in early diabetic cardiomyopathy have not been well documented. LV multidirectional strain and strain rate analyses by 2-dimensional speckle tracking were used to detect subtle myocardial dysfunction in 47 asymptomatic, male patients (age 57 +/- 6 years) with type 2 diabetes mellitus. The results were compared to those from 53 male controls matched by age, body mass index, and body surface area. No differences were found in the LV end-diastolic volume index (40.7 +/- 8.9 vs 44.1 +/- 7.8 ml/m(2), p = NS), end-systolic volume index (16.0 +/- 4.8 vs 17.8 +/- 4.3 ml/m(2), p = NS), ejection fraction (61.0 +/- 5.5% vs 59.8 +/- 5.3%, p = NS). The transmitral E/A (0.95 +/- 0.21 vs 1.12 +/- 0.32, p = 0.007) and pulmonary S/D (1.45 +/- 0.28 vs 1.25 +/- 0.27, p = 0.001) ratios were more impaired in the patients with diabetes mellitus. Importantly, the diabetic patients had impaired longitudinal, but preserved circumferential and radial systolic and diastolic, function. Diabetes mellitus was an independent predictor for longitudinal strain, systolic strain rate and early diastolic strain rate on multiple linear regression analysis (all p <0.001). In conclusion, the LV longitudinal systolic and diastolic function were impaired, but the circumferential and radial functions were preserved in patients with uncomplicated type 2 diabetes mellitus.

Alterations in multidirectional myocardial functions in patients with aortic stenosis and preserved ejection fraction: a two-dimensional speckle tracking analysis

AIMS To identify changes in multidirectional strain and strain rate (SR) in patients with aortic stenosis (AS). METHODS AND RESULTS A total of 420 patients (age 66.1 ± 14.5 years, 60.7% men) with aortic sclerosis, mild, moderate, and severe AS with preserved left ventricular (LV) ejection fraction [(EF), ≥50%] were included. Multidirectional strain and SR imaging were performed by two-dimensional speckle tracking. Patients were more likely to be older (P < 0.001) and at a worse New York Heart Association functional class (P < 0.001) with increasing AS severity. There was a progressive stepwise impairment in longitudinal, circumferential, and radial strain and SR with increasing AS severity (all P < 0.001). The myocardial dysfunction appeared to start in the subendocardium with mild AS, to mid-wall dysfunction with moderate AS, and eventually transmural dysfunction with severe AS. Aortic valve area, as a measure of AS severity, was an independent determinant of multidirectional strain and SR on multiple linear regressions. CONCLUSIONS Patients with AS have evidence of subclinical myocardial dysfunction early in the disease process despite normal LVEF. The myocardial dysfunction appeared to start in the subendocardium and progressed to transmural dysfunction with increasing AS severity. Symptomatic moderate and severe AS patients had more impaired multidirectional myocardial functions compared with asymptomatic patients.

Myocardial steatosis and biventricular strain and strain rate imaging in patients with type 2 diabetes mellitus.

Background— Magnetic resonance spectroscopy can quantify myocardial triglyceride content in type 2 diabetic patients. Its relation to alterations in left (LV) and right (RV) ventricular myocardial functions is unknown. Methods and Results— A total of 42 men with type 2 diabetes mellitus were recruited. Exclusion criteria included hemoglobin A1c >8.5%, known cardiovascular disease, diabetes-related complications, or blood pressure >150/85 mm Hg. Myocardial ischemia was excluded by a negative dobutamine stress test. LV and RV volumes and ejection fraction were quantified by magnetic resonance imaging. LV global longitudinal and RV free wall longitudinal strain, systolic strain rate, and diastolic strain rate were quantified by echocardiographic speckle tracking analyses. Myocardial triglyceride content was quantified by magnetic resonance spectroscopy and dichotomized on the basis of the median value of 0.76%. The median age was 59 years (25th and 75th percentiles, 54 and 62 years). Median diabetes diagnosis duration was 4 years, and median glycohemoglobin level was 6.2% (25th and 75th percentiles, 5.9% and 6.8%). There were no differences in LV and RV end-diastolic and end-systolic volume indexes and ejection fraction between patients with high (≥0.76%) and those with low (<0.76%) myocardial triglyceride content. However, patients with high myocardial triglyceride content had greater impairment of LV and RV myocardial strain and strain rate. The myocardial triglyceride content was an independent correlate of LV and RV longitudinal strain, systolic strain rate, and diastolic strain rate. Conclusions— High myocardial triglyceride content is associated with more pronounced impairment of LV and RV functions in men with uncomplicated type 2 diabetes mellitus.

Phrenic stimulation: a challenge for cardiac resynchronization therapy.

Background—Phrenic stimulation (PS) may hinder left ventricular (LV) pacing. We prospectively observed its prevalence in consecutive patients with cardiac resynchronization therapy (CRT) devices. Methods and Results—In the years 2003 to 2006, 197 patients received a CRT device. PS and LV threshold measurements were carried out at implantation and at 6-month follow-up. LV reverse remodeling was assessed by echocardiography before implantation and at follow-up. LV lead placement was lateral/posterolateral in 86% of patients. Both PS and LV reverse remodeling occurred most frequently at the lateral/posterolateral LV pacing sites (P<0.001). PS was detected in 73 (37%) of patients and was clinically relevant in 41 (22%). The detection of PS at implantation had a poor sensitivity, as it occurred only in left lateral or sitting position in 27 patients. Ten patients (5%) underwent repeated surgery and 4 (2%) had their CRT turned off because of PS. At follow-up, we could manage PS noninvasively in 32 patients with a small PS-LV threshold difference: in 20 by cathode programmability (3 also thanks to automatic management of LV output) and in 12 (without cathode programmability) by programming the LV output as threshold +1 V. Conclusions—PS may seriously hinder CRT. A bipolar LV lead and cathode programmability are mandatory to avoid PS by changing the LV pacing vector at target sites for CRT. LV stability at target sites despite PS should also be pursued by these means. The automatic adjustment of LV pacing output is complementary in patients with a small PS-LV threshold difference.Background— Phrenic stimulation (PS) may hinder left ventricular (LV) pacing. We prospectively observed its prevalence in consecutive patients with cardiac resynchronization therapy (CRT) devices. Methods and Results— In the years 2003 to 2006, 197 patients received a CRT device. PS and LV threshold measurements were carried out at implantation and at 6-month follow-up. LV reverse remodeling was assessed by echocardiography before implantation and at follow-up. LV lead placement was lateral/posterolateral in 86% of patients. Both PS and LV reverse remodeling occurred most frequently at the lateral/posterolateral LV pacing sites ( P <0.001). PS was detected in 73 (37%) of patients and was clinically relevant in 41 (22%). The detection of PS at implantation had a poor sensitivity, as it occurred only in left lateral or sitting position in 27 patients. Ten patients (5%) underwent repeated surgery and 4 (2%) had their CRT turned off because of PS. At follow-up, we could manage PS noninvasively in 32 patients with a small PS-LV threshold difference: in 20 by cathode programmability (3 also thanks to automatic management of LV output) and in 12 (without cathode programmability) by programming the LV output as threshold +1 V. Conclusions— PS may seriously hinder CRT. A bipolar LV lead and cathode programmability are mandatory to avoid PS by changing the LV pacing vector at target sites for CRT. LV stability at target sites despite PS should also be pursued by these means. The automatic adjustment of LV pacing output is complementary in patients with a small PS-LV threshold difference. Received December 14, 2008; accepted June 10, 2009. # CLINICAL PERSPECTIVE {#article-title-2}

Left Atrial Strain Predicts Reverse Remodeling After Catheter Ablation for Atrial Fibrillation

OBJECTIVES The purpose of this study was to assess left atrial (LA) strain during long-term follow-up after catheter ablation for atrial fibrillation and to find predictors for LA reverse remodeling. BACKGROUND The association between LA reverse remodeling and improvement in LA strain after catheter ablation has not been investigated thus far. METHODS In 148 patients undergoing catheter ablation for atrial fibrillation, LA volumes and LA strain were assessed with echocardiography at baseline and after a mean of 13.2 ± 6.7 months of follow-up. The study population was divided according to LA reverse remodeling at follow-up: responders were defined as patients who exhibited 15% or more reduction in maximum LA volume at long-term follow-up. Left atrial systolic (LAs) strain was assessed with tissue Doppler imaging. RESULTS At follow-up, 93 patients (63%) were classified as responders, whereas 55 patients (37%) were nonresponders. At baseline, LAs strain was significantly higher in the responders as compared with the nonresponders (19 ± 8% vs. 14 ± 6%; p = 0.001). Among the responders, a significant increase in LAs strain was noted from baseline to follow-up (from 19 ± 8% to 22 ± 9%; p < 0.05), whereas no change was noted among the nonresponders. LAs strain at baseline was an independent predictor of LA reverse remodeling (odds ratio: 1.813; 95% confidence interval: 1.102 to 2.982; p = 0.019). CONCLUSIONS In the present study, 63% of the patients exhibited LA reverse remodeling after catheter ablation for atrial fibrillation, with a concomitant improvement in LA strain. LA strain at baseline was an independent predictor of LA reverse remodeling.

Acute effects of right ventricular apical pacing on left ventricular synchrony and mechanics.

Background—Chronic right ventricular (RV) apical pacing has a detrimental effect on left ventricular (LV) function. However, the acute effects of RV apical pacing on LV mechanics remain unclear. The purpose of the study was to assess the acute impact of RV apical pacing on global LV function, evaluating LV contraction synchrony and LV shortening and twist, using 2D speckle-tracking strain imaging. Methods and Results—A group of 25 patients with structural normal hearts referred for electrophysiological study were studied. Two-dimensional echocardiography was performed at baseline and during RV apical pacing at the time of the electrophysiological study. Changes in LV synchrony and mechanics (longitudinal shortening and twist) were assessed using speckle-tracking strain imaging. In addition, 25 controls matched by age, sex, and LV function were studied during sinus rhythm. The group of patients (44±12 years, 10 men) and the group of controls (48±3 years, 8 men) showed comparable LV synchrony, LV longitudinal shortening, and LV twist at baseline. However, during RV apical pacing, a more dyssynchronous LV contraction was observed in the patients (from 21 ms [Q1:10, Q3:53] to 91 ms [Q1:40, Q3:204], P<0.001) together with an impairment in LV longitudinal shortening (from −18.3±3.5% to −11.8±3.6%, P<0.001) and in LV twist (from 12.4±3.7° to 9.7±2.6°, P=0.001). Conclusions—During RV apical pacing, an acute induction of LV dyssynchrony is observed. In addition, LV longitudinal shortening and LV twist are acutely impaired.

Association between diffuse myocardial fibrosis by cardiac magnetic resonance contrast-enhanced T(1) mapping and subclinical myocardial dysfunction in diabetic patients: a pilot study.

Background— Diabetic patients have increased interstitial myocardial fibrosis on histological examination. Magnetic resonance imaging (MRI) T1 mapping is a previously validated imaging technique that can quantify the burden of global and regional interstitial fibrosis. However, the association between MRI T1 mapping and subtle left ventricular (LV) dysfunction in diabetic patients is unknown. Methods and Results— Fifty diabetic patients with normal LV ejection fraction (EF) and no underlying coronary artery disease or regional macroscopic scar on MRI delayed enhancement were prospectively recruited. Diabetic patients were compared with 19 healthy controls who were frequency matched in age, sex and body mass index. There were no significant differences in mean LV end-diastolic volume index, end-systolic volume index and LVEF between diabetic patients and healthy controls. Diabetic patients had significantly shorter global contrast-enhanced myocardial T1 time (425±72 ms vs. 504±34 ms, P<0.001). There was no correlation between global contrast-enhanced myocardial T1 time and LVEF (r=0.14, P=0.32) in the diabetic patients. However, there was good correlation between global contrast-enhanced myocardial T1 time and global longitudinal strain (r=−0.73, P<0.001). Global contrast-enhanced myocardial T1 time was the strongest independent determinant of global longitudinal strain on multivariate analysis (standardized &bgr;=−0.626, P<0.001). Similarly, there was good correlation between global contrast-enhanced myocardial T1 time and septal E′ (r=0.54, P<0.001). Global contrast-enhanced myocardial T1 time was also the strongest independent determinant of septal E′ (standardized &bgr;=0.432, P<0.001). Conclusions— A shorter global contrast-enhanced myocardial T1 time was associated with more impaired longitudinal myocardial systolic and diastolic function in diabetic patients.

Global Longitudinal Strain Predicts Long-Term Survival in Patients with Chronic Ischemic Cardiomyopathy

Background— Left ventricular (LV) global longitudinal strain (GLS) is a measure of the active shortening of the LV in the longitudinal direction, which can be assessed with speckle-tracking echocardiography. The aims of this evaluation were to validate the prognostic value of GLS as a new index of LV systolic function in a large cohort of patients with chronic ischemic cardiomyopathy and to determine the incremental value of GLS to predict long-term outcome over other strong and well-established prognostic factors. Methods and Results— A total of 1060 patients underwent baseline clinical evaluation and transthoracic echocardiography. Median age was 66.9 years (interquartile range, 58.4, 74.2 years); 739 (70%) were men. The median follow-up duration for the entire patient population was 31 months. During the follow-up, 270 patients died and 309 patients reached the combined end point (all-cause mortality and heart failure hospitalization). Compared with survivors, patients who died (270, [25%]) had larger LV volumes (P<0.05), lower LV ejection fraction (P=0.004), higher wall motion score index (P=0.001), and greater impairment of LV GLS (P<0.001). After dichotomizing the population on the basis of the median value of LV GLS (−11.5%), patients with an LV GLS ⩽−11.5% had superior outcome compared with patients with an LV GLS >−11.5% (log-rank &khgr;2, 13.86 and 14.16 for all-cause mortality and combined end point, respectively, P<0.001 for both). On multivariate analysis, GLS was independently related to all-cause mortality (hazard ratio per 5% increase, 1.69; 95% confidence interval, 1.33–2.15; P<0.001) and combined end point (1.64; 95% confidence interval, 1.32–2.04; P<0.001). Conclusions— The assessment of LV GLS with speckle-tracking echocardiography is significantly related to long-term outcome in patients with chronic ischemic cardiomyopathy.