Christine Allman

Long-Term Impact of Right Ventricular Septal Versus Apical Pacing on Left Ventricular Synchrony and Function in Patients With Second-or Third-Degree Heart Block

Right ventricular (RV) septal pacing has been advocated as an alternative to apical pacing to avoid long-term detrimental effects. There is conflicting evidence on the benefits of RV septal pacing. Fifty-five subjects (22 normal healthy controls, 17 with RV septal pacing, and 17 with apical pacing) were recruited. Midventricular short-axis left ventricular (LV) circumferential and radial strains were determined. Circumferential and radial strain dyssynchrony and longitudinal systolic dyssynchrony were determined. Echocardiographic determination of pacing sites were compared with electrocardiogram and chest x-ray. Septal pacing is a heterogenous group of different pacing sites, and there was only modest agreement among echocardiogram, electrocardiogram, and chest x-ray. Median pacing durations were 436 days for septal pacing and 2,398 days for apical pacing. Mean QRS duration for apical pacing was longest, followed by septal pacing and control (p <0.001). LV mass index, end-systolic volume index, and ejection fraction were more impaired in septal than in apical pacing (all p values <0.05). Septal pacing was associated with more impaired circumferential strain (p <0.001) and worse LV dyssynchrony than apical pacing and control. In conclusion, standard fluoroscopic and electrocardiographic implantation techniques for RV septal pacing resulted in a heterogenous group of different pacing sites. This heterogenous RV septal pacing group was associated with poorer long-term LV function and greater dyssynchrony than RV apical pacing and control.

Prognostic implications of left atrial volume index in patients in sinus rhythm.

The maximum left atrial volume index (LAVI) has been shown to be of prognostic values, but previous studies have largely been limited to older patients with specific cardiovascular conditions. We examined the independent prognostic values of LAVI in a large unselected series of predominantly younger patients in sinus rhythm followed up for a long period. We evaluated 483 consecutive patients (mean age 47.3 years) using transthoracic echocardiography. The median LAVI was 24 ml/m(2). A primary combined end point of cardiovascular death, stroke, heart failure, myocardial infarction, and atrial fibrillation was sought. We had complete follow-up data for 97.3% of the 483 patients. During a median follow-up of 6.8 years, 86 patients (18.3%) reached the primary end point. Older age, male gender, diabetes, hypertension, hypercholesterolemia, chronic renal failure, a history of myocardial infarction or stroke, a mitral E deceleration time of </=150 ms, and LAVI of >/=24 ml/m(2) were univariate predictors of the primary end point. Event-free survival was significantly lower for patients with a LAVI of >/=24 ml/m(2). Age, a history of stroke, hypertension, chronic renal failure, and male gender were independent clinical predictors. A LAVI of >/=24 ml/m(2) was the only independent echocardiographic predictor (hazard ratio 1.72, 95% confidence interval 1.34 to 2.13, p = 0.018), with the chi-square of the Cox model increased significantly with the addition of the LAVI (p <0.001). The LAVI independently predicted an increased risk of cardiovascular death, heart failure, atrial fibrillation, stroke, or myocardial infarction during a median follow-up of 6.8 years. In conclusion, the prognostic values were incremental to the clinical risks and were valid in a younger, general patient population.

Left ventricular longitudinal and radial synchrony and their determinants in healthy subjects

OBJECTIVE The reference values and impact of physiologic variables on echocardiographic quantification of left ventricular (LV) synchrony in a large series of healthy persons are unknown. This study prospectively investigated the impact of age, gender, and other physiologic parameters on LV longitudinal and radial synchrony. METHODS LV longitudinal systolic and diastolic synchrony using tissue Doppler imaging were measured as the standard deviation of times to 12 regional peak myocardial systolic Sm (SDTs) and early diastolic Em (SDTe) velocities in 122 healthy volunteers (age 19-68 years, 64 men). By using 2-dimensional speckle tracking, radial synchrony was measured as the standard deviation of times to 6 regional peak strain (SDTrepsilon) in the short-axis papillary muscle level. Longitudinal systolic synchrony was also measured as the standard deviation of times to 12 regional peak strain (SDTlepsilon). RESULTS The mean QRS duration and LV ejection fraction were 87 +/- 12 msec and 61% +/- 5.5%, respectively. The mean SDTs and SDTe were 37.1 +/- 17.4 msec and 17.3 +/- 6.7 msec, respectively. Gender and the mean Sm velocity from the 6 basal LV segments were independent predictors of SDTs, whereas the isovolumic relaxation time and mean Em velocity independently predicted SDTe. The mean SDTrepsilon was 19.2 +/- 14.6 msec. SDTrepsilon did not correlate with any clinical or echocardiographic parameters. The mean SDTlepsilon was 40.4 +/- 11.8 msec. Isovolumic relaxation time, pulmonary S/D ratio, and mean Sm independently predicted SDTlepsilon. There was no correlation between LV longitudinal and radial synchrony. Intraobserver and interobserver variability analyses showed the highest correlation for SDTs compared with SDTrepsilon and SDTlepsilon. CONCLUSION This study establishes normal reference ranges for LV systolic and diastolic synchrony measured with tissue Doppler velocity-based and 2-dimensional speckle tracking-based methods in a large group of healthy subjects of both genders across a wide age group. SDTs is gender specific and dependent on global LV systolic function, whereas SDTe is dependent on global LV diastolic function. Two-dimensional speckle-derived radial synchrony is independent of any clinical and echocardiographic variables but has higher intraobserver and interobserver variability compared with SDTs. LV longitudinal synchrony does not correlate with radial synchrony.

Comparison of Myocardial Tissue Velocities Measured by Two-Dimensional Speckle Tracking and Tissue Doppler Imaging

Myocardial velocities have prognostic implications, and transmitral E wave to mitral annular early diastolic tissue velocity ratio (E/Em) is utilized to estimate left ventricular (LV) end-diastolic pressure (EDP). There are no reference values for 2-dimensional (2D) speckle tracking myocardial velocities (S2D, E2D, A2D), and it is unknown if they are comparable with color tissue Doppler imaging (TDI). Predictors of E/E2D ratios are unknown and E/E2D has not been validated with LVEDP. The myocardial velocities of 142 subjects were measured by TDI and 2D speckle tracking. Mean E/Em and E/E2D were calculated as transmitral E wave to mean 6 basal early diastolic myocardial velocities using TDI and 2D speckle tracking respectively, and compared with LVEDP during catheterizations (n = 20). Mean E2D was lower but mean S2D and A2D were higher than TDI (all p <0.001). When TDI sample volume was tracked throughout the cardiac cycle, this directional difference was no longer apparent with S2D, E2D, and A2D higher than TDI (all p <0.05). Age, systolic blood pressure, LV ejection fraction, and mean S2D were independent correlates of E/E2D. Receiver-operator characteristic analysis showed E/E2D (p = 0.03), not E/Em, identified elevated LVEDP (> or =12 mm Hg). E/E2D of 11.6 had 83% sensitivity and 70% specificity to predict elevated LVEDP. In conclusion, TDI and 2D speckle tracking myocardial velocities are not comparable due to angle independency and ability for tissue tracking with the latter. LV systolic function, age, and afterload are independent correlates of E/E2D. Only E/E2D identifies elevated LVEDP, and an E/E2D of 11.6 has the optimal sensitivity and specificity.

Subclinical Cardiac Dysfunction Detected by Strain Imaging During Breast Irradiation With Persistent Changes 6 Weeks After Treatment

PURPOSE To evaluate 2-dimensional strain imaging (SI) for the detection of subclinical myocardial dysfunction during and after radiation therapy (RT). METHODS AND MATERIALS Forty women with left-sided breast cancer, undergoing only adjuvant RT to the left chest, were prospectively recruited. Standard echocardiography and SI were performed at baseline, during RT, and 6 weeks after RT. Strain (S) and strain rate (Sr) parameters were measured in the longitudinal, circumferential, and radial planes. Correlation of change in global longitudinal strain (GLS % and Δ change) and the volume of heart receiving 30 Gy (V30) and mean heart dose (MHD) were examined. RESULTS Left ventricular ejection fraction was unchanged; however, longitudinal systolic S and Sr and radial S were significantly reduced during RT and remained reduced at 6 weeks after treatment [longitudinal S (%) -20.44 ± 2.66 baseline vs -18.60 ± 2.70* during RT vs -18.34 ± 2.86* at 6 weeks after RT; longitudinal Sr (s(-1)) -1.19 ± 0.21 vs -1.06 ± 0.18* vs -1.06 ± 0.16*; radial S (%) 56.66 ± 18.57 vs 46.93 ± 14.56* vs 49.22 ± 15.81*; *P<.05 vs baseline]. Diastolic Sr were only reduced 6 weeks after RT [longitudinal E Sr (s(-1)) 1.47 ± 0.32 vs 1.29 ± 0.27*; longitudinal A Sr (s(-1)) 1.19 ± 0.31 vs 1.03 ± 0.24*; *P<.05 vs baseline], whereas circumferential strain was preserved throughout. A modest correlation between S and Sr and V30 and MHD was observed (GLS Δ change and V30 ρ = 0.314, P=.05; GLS % change and V30 ρ = 0.288, P=.076; GLS Δ change and MHD ρ = 0.348, P=.03; GLS % change and MHD ρ = 0.346, P=.031). CONCLUSIONS Subclinical myocardial dysfunction was detected by 2-dimensional SI during RT, with changes persisting 6 weeks after treatment, though long-term effects remain unknown. Additionally, a modest correlation between strain reduction and radiation dose was observed.

Comparison of Left Ventricular Dyssynchrony by Two-Dimensional Speckle Tracking Versus Tissue Doppler Imaging in Patients With Non-ST-Elevation Myocardial Infarction and Preserved Left Ventricular Systolic Function

Assessment of left ventricular (LV) dyssynchrony after myocardial infarction has prognostic value. There were no reference ranges for 2-dimensional (2D) speckle tracking synchrony, and it was unclear whether color tissue Doppler imaging and 2D speckle tracking synchrony indexes were comparable. One hundred twenty-two healthy volunteers and 40 patients with non-ST-elevation myocardial infarction (NSTEMI) had LV systolic and diastolic synchrony, defined as the SD of time to peak systolic (2D-SDTs) and early diastolic (2D-SDTe) velocities in the 12 basal and mid segments using 2D speckle tracking, respectively. Mean 2D-SDTs and 2D-SDTe were 29.4 +/- 16.1 and 14.2 +/- 6.1 ms in healthy subjects, respectively. Gender and mean 2D systolic velocity independently predicted 2D-SDTs, and mean 2D early diastolic velocity independently predicted 2D-SDTe. Bland-Altman analysis showed suboptimal agreement between 2D speckle tracking and tissue Doppler imaging dyssynchrony indexes. 2D speckle tracking showed lower coefficients of variation for time to peak systolic and early diastolic velocities than tissue Doppler imaging. There were no significant differences in coefficients of variation for 2D speckle tracking systolic and diastolic synchrony for high versus low frame rates. Patients with NSTEMI had significantly lower ejection fraction, but higher LV mass and wall stress than healthy subjects. Only 2D-SDTs was significantly higher in patients with NSTEMI compared with healthy subjects (37.1 +/- 22.5 vs 29.4 +/- 16.1 ms; p = 0.02). In conclusion, 2D-SDTs was gender specific and influenced by global systolic function, and 2D-SDTe was influenced by global diastolic function. 2D speckle tracking and tissue Doppler imaging dyssynchrony indexes were not comparable. 2D speckle tracking may be a more sensitive discriminator of LV systolic dyssynchrony than tissue Doppler imaging.

Prognostic implications of left ventricular dyssynchrony early after non-ST elevation myocardial infarction without congestive heart failure

AIMS To determine independent predictors of left ventricular (LV) dyssynchrony after non-ST elevation myocardial infarction (NSTEMI) and prognostic value of combining dyssynchrony parameters for long-term LV dysfunction. METHODS AND RESULTS Left ventricular dyssynchrony assessments were performed in 100 NSTEMI patients followed-up for 1 year using a composite dyssynchrony score. Early LV dyssynchrony was independently predicted by the presence of significant proximal left circumflex artery (LCx) stenosis and global systolic dysfunction. Left ventricular end-diastolic volume index decreased with time and was independently determined by a lower number of diseased vessels and the absence of early dyssynchrony. Left ventricular end-systolic volume index decreased with time and was independently determined by the absence of early dyssynchrony, lower number of diseased vessels, and revascularization. Left ventricular ejection fraction increased with time and was independently determined by the absence of early dyssynchrony, lower number of diseased vessels, and revascularization. The composite dyssynchrony score was an independent determinant of a persistently dilated LV and low LVEF at follow-up. CONCLUSION After NSTEMI, proximal LCx stenosis and impaired LV function independently predicted LV dyssynchrony. The composite dyssynchrony score had prognostic value and identified patients with persistently dilated and impaired LV on follow-up.

Impact of Diabetes and Increasing Body Mass Index Category on Left Ventricular Systolic and Diastolic Function

Background: Diabetes and obesity are both worldwide growing epidemics, and both are independently associated with increased risk for heart failure and death. The aim of this study was to examine the additive detrimental effect of both diabetes and increasing body mass index (BMI) category on left ventricular (LV) myocardial systolic and diastolic function. Methods: The present retrospective multicenter study included 653 patients (337 with type 2 diabetes and 316 without diabetes) of increasing BMI category. All patients had normal LV ejection fractions. LV myocardial systolic (peak systolic global longitudinal strain and peak systolic global longitudinal strain rate) and diastolic (average mitral annular e′ velocity and early diastolic global longitudinal strain rate) function was quantified using echocardiography. Results: Increasing BMI category was associated with progressively more impaired LV myocardial function in patients with diabetes (P < .001). Patients with diabetes had significantly more impaired LV myocardial function for all BMI categories compared with those without diabetes (P < .001). On multivariate analysis, both diabetes and obesity were independently associated with an additive detrimental effect on LV myocardial systolic and diastolic function. However, obesity was associated with greater LV myocardial dysfunction than diabetes. Conclusion: Both diabetes and increasing BMI category had an additive detrimental effect on LV myocardial systolic and diastolic function. Furthermore, increasing BMI category was associated with greater LV myocardial dysfunction than diabetes. As they frequently coexist together, future studies on patients with diabetes should also focus on obesity. HIGHLIGHTSDiabtetics have more impaired LV function in all categories of BMI than controls.BMI and diabetes are independent predictors of impaired LV myocardial function.Increasing BMI and diabetes have an additive detrimental effect on LV function.

Long-term outcomes in patients with restrictive filling following ST-segment elevation myocardial infarction.

This study evaluated the effect of restrictive filling pattern (RFP) on 5‐year outcomes in patients following ST‐segment elevation myocardial infarction (STEMI). A hundred STEMI patients treated either by rescue or primary percutaneous coronary intervention with an echocardiogram performed within 6 weeks of STEMI comprised the study group. Creatinine kinase (CK) and left ventricular ejection fraction were independent determinants of RFP, and RFP was an independent predictor of cardiac and all‐cause mortality at median follow up of 5 years.