Jeffrey C. Hill

Direct Ultrasound Measurement of Longitudinal, Circumferential, and Radial Strain Using 2‐Dimensional Strain Imaging in Normal Adults

Current noninvasive techniques used to evaluate left ventricular systolic function are limited by dependence on the angle of insonation (tissue Doppler imaging/TDI) or limited by availability (MRI tagging). We utilized 2‐dimensional speckle strain (ε) imaging (1) to establish normal values for all three ε vectors; (2) to compare circumferential ε values with circumferential shortening (midwall fractional shortening (FSmw); (3) to examine the relationship between left ventricular ε and wall stress; and (4) to compare 2D echocardiographic characteristics by gender. Echocardiography was performed in 60 normal subjects (mean 39 ± 15 years). Small, but significant regional heterogeneity was seen in circumferential ε, but not in radial or longitudinal ε. We found an inverse correlation between circumferential ε and stress (r =−0.29, p<0.05) as well as longitudinal ε and stress (r =−0.11, P < 0.05), though the relationships were not close. We also observed a linear relationship between mean circumferential ε and FSmw (r = 0.29, P < 0.05). In conclusion, (1) 2‐dimensional ε imaging permits measurement of regional systolic ε values in the majority of normal individuals; (2) ε values furnished by this method obey expected stress‐shortening relationships; (3) systolic ε displays minor regional heterogeneity in the circumferential direction; (4) for the first time, a close relationship between FSmw and mean circumferential ε was demonstrated; and (5) there are minor gender‐related differences in LV geometry and function.

Cardiac mechanics in mild hypertensive heart disease: a speckle-strain imaging study.

Background—We hypothesized that abnormalities in regional systolic strain (ϵ) might be present among hypertensive subjects with normal ejection fraction, and, if present, could be used to identify patients at high risk for heart failure. The aim of the current case-control study was to use speckle tracking imaging to identify subclinical global and regional systolic function abnormalities in hypertensive subjects with normal ejection fraction. Methods and Results—Standard 2D Doppler echocardiography, tissue Doppler imaging, and 2D speckle strain imaging were performed in 52 hypertensive subjects with normal ejection fraction and 52 control subjects of similar age. Peak systolic (S′), and diastolic (E′) annular velocities were obtained by tissue Doppler imaging, whereas longitudinal myocardial systolic velocity (Vl) and circumferential, longitudinal, and radial strains (ϵc, ϵl, ϵr) were obtained by speckle tracking. Midwall shortening and peak basal longitudinal strain (ϵl) were used as indices of regional function. Hypertensive subjects had lower velocities—tissue Doppler imaging E′ and S′, and Vl—and evidence of reduced regional function. Surprisingly, however, global ϵ values did not differentiate hypertensive subjects from control subjects. Among hypertensive patients, significant inverse associations were found between left ventricular mass and global longitudinal and circumferential ϵ (both P<0.05). Conclusions—Hypertensive heart disease with normal ejection fraction is associated with reduced myocardial velocities and reduced regional function but normal global ϵ. Our data suggest that velocity abnormalities occur early in hypertension and may be an appropriate target for preventive strategies because they occur before abnormalities in global ϵ.Background— We hypothesized that abnormalities in regional systolic strain (e) might be present among hypertensive subjects with normal ejection fraction, and, if present, could be used to identify patients at high risk for heart failure. The aim of the current case-control study was to use speckle tracking imaging to identify subclinical global and regional systolic function abnormalities in hypertensive subjects with normal ejection fraction. Methods and Results— Standard 2D Doppler echocardiography, tissue Doppler imaging, and 2D speckle strain imaging were performed in 52 hypertensive subjects with normal ejection fraction and 52 control subjects of similar age. Peak systolic (S′), and diastolic (E′) annular velocities were obtained by tissue Doppler imaging, whereas longitudinal myocardial systolic velocity (Vl) and circumferential, longitudinal, and radial strains (ec, el, er) were obtained by speckle tracking. Midwall shortening and peak basal longitudinal strain (el) were used as indices of regional function. Hypertensive subjects had lower velocities—tissue Doppler imaging E′ and S′, and Vl—and evidence of reduced regional function. Surprisingly, however, global e values did not differentiate hypertensive subjects from control subjects. Among hypertensive patients, significant inverse associations were found between left ventricular mass and global longitudinal and circumferential e (both P <0.05). Conclusions— Hypertensive heart disease with normal ejection fraction is associated with reduced myocardial velocities and reduced regional function but normal global e. Our data suggest that velocity abnormalities occur early in hypertension and may be an appropriate target for preventive strategies because they occur before abnormalities in global e. Received September 26, 2008; accepted July 21, 2009. # CLINICAL PERSPECTIVE {#article-title-2}

Left atrial volume and geometry in healthy aging: the Cardiovascular Health Study.

Background—The left atrium is a validated marker of clinical and subclinical cardiovascular disease. Left atrial enlargement is often seen among older individuals; however, there are few population-based data regarding normal left atrial size among older persons, especially from those who are healthy, and from women. Furthermore, because the left atrium is a 3D structure, the commonly used parasternal long-axis diastolic diameter often underdiagnoses left atrial enlargement. Methods and Results—We evaluated left atrial size in 230 healthy participants (mean age, 76±5 years) free of prevalent cardiac disease, rhythm abnormality, hypertension, and diabetes selected from the Cardiovascular Health Study, a prospective community-based study of risk factors for cardiovascular disease in 5888 elderly participants. In addition to the standard long-axis measurement, we obtained left atrial superoinferior and lateral diameters and used these dimensions to estimate left atrial volume. These measurements were used to generate reference ranges for determining left atrial enlargement in older men and women, based on the 95% percentiles of the left atrial dimensions in healthy participants, both unadjusted, and after adjustment for age, height, and weight. In healthy elderly subjects, indices of left atrial size do not correlate with age or height but with weight and other measures of body build. Conclusions—These data provide normative reference values for left atrial size in healthy older women and men. The results should be useful for refining diagnostic criteria for left atrial dilation in the older population and may be relevant for cardiovascular risk stratification.Background— The left atrium is a validated marker of clinical and subclinical cardiovascular disease. Left atrial enlargement is often seen among older individuals; however, there are few population-based data regarding normal left atrial size among older persons, especially from those who are healthy, and from women. Furthermore, because the left atrium is a 3D structure, the commonly used parasternal long-axis diastolic diameter often underdiagnoses left atrial enlargement. Methods and Results— We evaluated left atrial size in 230 healthy participants (mean age, 76±5 years) free of prevalent cardiac disease, rhythm abnormality, hypertension, and diabetes selected from the Cardiovascular Health Study, a prospective community-based study of risk factors for cardiovascular disease in 5888 elderly participants. In addition to the standard long-axis measurement, we obtained left atrial superoinferior and lateral diameters and used these dimensions to estimate left atrial volume. These measurements were used to generate reference ranges for determining left atrial enlargement in older men and women, based on the 95% percentiles of the left atrial dimensions in healthy participants, both unadjusted, and after adjustment for age, height, and weight. In healthy elderly subjects, indices of left atrial size do not correlate with age or height but with weight and other measures of body build. Conclusions— These data provide normative reference values for left atrial size in healthy older women and men. The results should be useful for refining diagnostic criteria for left atrial dilation in the older population and may be relevant for cardiovascular risk stratification. Received October 7, 2008; accepted March 31, 2009. # CLINICAL PERSPECTIVE {#article-title-2}

Usefulness of the Pulmonary Arterial Systolic Pressure to Predict Pulmonary Arterial Wedge Pressure in Patients With Normal Left Ventricular Systolic Function

Tissue Doppler imaging combined with transmitral Doppler permits estimation of pulmonary artery wedge pressure (PAWP) in many, but not all, patients, whereas pulmonary artery systolic pressure (PASP) and cardiac output (time-velocity integral method) are routinely measured. It was hypothesized that simple Doppler echocardiographic measurements could be used to estimate PAWP in many patients by rearranging the equation for pulmonary vascular resistance ([mean pulmonary artery pressure - (left atrial pressure/cardiac output)] x 80). Data from 69 patients (mean age 59 +/- 15 years) were reviewed, including cardiac output, transmitral mitral E wave velocity, and lateral tissue Doppler imaging mitral annular early diastolic velocity. PAWP was determined in the 2 ways of (1) measured (PAWPm) using the regression equation PAWPm = 1.91 + (1.24 * transmitral mitral E wave velocity/mitral annular early diastolic velocity) developed and validated by Nagueh, and (2) using a nomogram that we developed to predict PAWP when cardiac output and PASP were known. Moderately strong correlation was found between PASP and PAWPm (r = 0.73), and this correlation improved when excluding patients with pulmonary or liver disease and restricting cardiac output to 3.5 to 6.0 L/min (physiologic range; r = 0.81). Furthermore, the relation between PAWPm and PASP allowed for discrimination of high versus low PAWP: 36 of 37 patients with PASP < or =30 mm Hg had PAWPm < or =15 mm Hg (sensitivity 97%, specificity 47%). Conversely, 9 of 9 patients with PASP > or =40 mm Hg had PAWPm > or =12 mm Hg (sensitivity 100%, specificity 70%). Predicted PAWP correlated well with PAWPm (r = 0.63) and improved when patients with liver or pulmonary disease were excluded (r = 0.83). In conclusion, PASP strongly correlated with PAWP, and this principle can be exploited to rapidly detect patients with low or high PAWP.

Brain Natriuretic Peptide Levels Fall Rapidly after Cardioversion of Atrial Fibrillation to Sinus Rhythm

Background: Brain natriuretic peptide (BNP) levels have been reported to fall following cardioversion of atrial fibrillation (AF). The mechanism for the fall in BNP has not been elucidated and the potential confounding effects of sedation have not been investigated. Sedation may alter BNP levels via its effects on loading conditions. Accordingly, we studied whether BNP levels change shortly after cardioversion and attempted to control for possible effects of sedation. Methods: BNP levels were obtained before and after cardioversion in patients with AF and in a control group of patients undergoing intravenous conscious sedation for transesophageal echocardiography. Results: BNP levels dropped (260 ± 255 vs. 190 ± 212 pg/ml, p < 0.05) 40 min after cardioversion, decreasing in 33 of 41 subjects who achieved sinus rhythm. By contrast, mean BNP did not fall in subjects in whom cardioversion was not successful. The change in BNP level was not related to the degree of change in heart rate. No control subject experienced a change in cardiac rhythm; BNP levels increased (195 ± 407 vs. 238 ± 458 pg/ml, p < 0.05) in 18/22 subjects after sedation. Baseline BNP levels were elevated in subjects with AF, and BNP levels were elevated in parallel with heart failure symptoms. Conclusions: The rapid fall in BNP after cardioversion (1) may reflect prompt hemodynamic improvement associated with rhythm change and (2) does not appear to be due to the effects of sedation.

Speckle echocardiographic left atrial strain and stiffness index as predictors of maintenance of sinus rhythm after cardioversion for atrial fibrillation: a prospective study

BackgroundEchocardiographic left atrial (LA) strain parameters have been associated with atrial fibrillation (AF) in prior studies. Our goal was to determine if strain measures [peak systolic longitudinal strain (LAS) and stiffness index (LASt)] changed after cardioversion (CV); and their relation to AF recurrence.Methods and results46 participants with persistent AF and 41 age-matched participants with no AF were recruited. LAS and LASt were measured before and immediately after CV using 2D speckle tracking imaging (2DSI). Maintenance of sinus rhythm was assessed over a 6-month follow up. Mean LAS was lower, and mean LASt higher, in participants with AF before CV as compared to control group (11.9 ± 1.0 vs 35.7 ± 1.7, p<0.01 and 1.31 ± 0.17 vs 0.23 ± 0.01, p<0.01, respectively). There was an increase in the mean LAS immediately after CV (11.9 ± 1.0 vs 15.9 ± 1.3, p<0.01), whereas mean LASt did not change significantly after CV (p=0.62). Although neither LAS nor LASt were independently associated with AF recurrence during the follow-up period, change in LAS after cardioversion (post-CV LAS – pre-CV LAS) was significantly higher among individuals who remained in sinus rhythm when compared to individuals with recurrent AF (3.6 ± 1.1 vs 0.4 ± 0.8, p=0.02).ConclusionsLAS and LASt differed between participants with and without AF, irrespective of the rhythm at the time of echocardiographic assessment. Baseline LAS and LASt were not associated with AF recurrence. However, change in LAS after CV may be a useful predictor of recurrent arrhythmia.

Cardiac Mechanics in Mild Hypertensive Heart DiseaseCLINICAL PERSPECTIVE: A Speckle-Strain Imaging Study

Background—We hypothesized that abnormalities in regional systolic strain (ϵ) might be present among hypertensive subjects with normal ejection fraction, and, if present, could be used to identify patients at high risk for heart failure. The aim of the current case-control study was to use speckle tracking imaging to identify subclinical global and regional systolic function abnormalities in hypertensive subjects with normal ejection fraction. Methods and Results—Standard 2D Doppler echocardiography, tissue Doppler imaging, and 2D speckle strain imaging were performed in 52 hypertensive subjects with normal ejection fraction and 52 control subjects of similar age. Peak systolic (S′), and diastolic (E′) annular velocities were obtained by tissue Doppler imaging, whereas longitudinal myocardial systolic velocity (Vl) and circumferential, longitudinal, and radial strains (ϵc, ϵl, ϵr) were obtained by speckle tracking. Midwall shortening and peak basal longitudinal strain (ϵl) were used as indices of regional function. Hypertensive subjects had lower velocities—tissue Doppler imaging E′ and S′, and Vl—and evidence of reduced regional function. Surprisingly, however, global ϵ values did not differentiate hypertensive subjects from control subjects. Among hypertensive patients, significant inverse associations were found between left ventricular mass and global longitudinal and circumferential ϵ (both P<0.05). Conclusions—Hypertensive heart disease with normal ejection fraction is associated with reduced myocardial velocities and reduced regional function but normal global ϵ. Our data suggest that velocity abnormalities occur early in hypertension and may be an appropriate target for preventive strategies because they occur before abnormalities in global ϵ.Background— We hypothesized that abnormalities in regional systolic strain (e) might be present among hypertensive subjects with normal ejection fraction, and, if present, could be used to identify patients at high risk for heart failure. The aim of the current case-control study was to use speckle tracking imaging to identify subclinical global and regional systolic function abnormalities in hypertensive subjects with normal ejection fraction. Methods and Results— Standard 2D Doppler echocardiography, tissue Doppler imaging, and 2D speckle strain imaging were performed in 52 hypertensive subjects with normal ejection fraction and 52 control subjects of similar age. Peak systolic (S′), and diastolic (E′) annular velocities were obtained by tissue Doppler imaging, whereas longitudinal myocardial systolic velocity (Vl) and circumferential, longitudinal, and radial strains (ec, el, er) were obtained by speckle tracking. Midwall shortening and peak basal longitudinal strain (el) were used as indices of regional function. Hypertensive subjects had lower velocities—tissue Doppler imaging E′ and S′, and Vl—and evidence of reduced regional function. Surprisingly, however, global e values did not differentiate hypertensive subjects from control subjects. Among hypertensive patients, significant inverse associations were found between left ventricular mass and global longitudinal and circumferential e (both P <0.05). Conclusions— Hypertensive heart disease with normal ejection fraction is associated with reduced myocardial velocities and reduced regional function but normal global e. Our data suggest that velocity abnormalities occur early in hypertension and may be an appropriate target for preventive strategies because they occur before abnormalities in global e. Received September 26, 2008; accepted July 21, 2009. # CLINICAL PERSPECTIVE {#article-title-2}

ATRIAL STRAIN BY 2D SPECKLE TRACKING OUTPERFORMS ATRIAL VOLUME IN IDENTIFYING HYPERTENSIVE PATIENTS WITH DIASTOLIC DYSFUNCTION: PP.8.336

Background: Left atrial (LA) dilation is considered a marker of diastolic dysfunction (DD). However LA size is affected by loading conditions (e.g. overweight, physical excercise, mild mitral regurgitation), and dilation might also be found in individuals with normal LV diastolic function. LA deformation by 2D Speckle Strain Imaging (2DSI) is a novel method to analyze LA diastolic function, which might improve the ability of identifying DD in hypertensives (HTN). Methods: 39 HTN with grade 1–2 DD (76 ± 14yrs; 72%females) and 66 healthy volunteers (NLS; 44 ± 16yrs; 55%females) underwent standard echocardiography with complete evaluation of diastolic function and LA 2DSI. LA volume was calculated by the area-length method. Gender-specific ASE recommended partition values were used to define LA dilation. Receiver operating curves were used to compare the accuracy of LA volume and LA2DSI in differentiating HTN with DD from NLS. Results: HTN were older and more often women as compared to NLS (both p < 0.05). In analysis of covariance, adjusting for covariates, HTN showed reduced LA 2DSI (23.8 ± 8.2% vs 43.0 ± 11.1%) and higher LA volume (58 ± 27 mL vs 41 ± 14 mL), resulting in a higher prevalence of LA dilation (38% vs 12%; all p < 0.01). Comparison of ROC suggested a significantly better performance of LA 2DSI, as compared to LA volume, in differentiating HTN with DD from NLS (AUC = 0.89 vs 0.68; p = 0.001). In details, an LA 2DSI partition value of 26% demonstrated 75% specificity and 76% sensitivity in identifying HTN with DD. Figure 1. No caption available. Conclusion: Reduced LA diastolic function by 2DSI is often found in HTN patients and is associated with increased LA volume. Presence of LA 2DSI < 26% is significantly more accurate than presence of LA dilation in differentiating HTN with DD from normal controls. Further studies are needed to verify the prognostic superiority of LA 2DSI.

NON INVASIVE EVALUATION OF MYOCARDIAL STIFFNESS IN ARTERIAL HYPERTENSION: PP.22.348

Background: Heart failure with preserved ejection fraction (HFPEF) is frequent in hypertension in the absence of preceding myocardial infarction and is attributed to abnormal myocardial stiffness (MS), altering the physiological pressure/volume relationship. A direct non-invasive measure of MS is still a challenge. Methods: Using standard transthoracic Doppler-echocardiography and tissue-Doppler, we generated a single point LV end-diastolic (ED) pressure (P)/volume (V) ratio as an estimate of MS in 59 normotensive and 64 hypertensive subjects (18–91 yrs). ED-P was calculated as LV pressure before atrial contraction (estimated by E/E’ ratio) + peak atrio-ventricular gradient at the atrial contraction (from peak A velocity). ED-P/V was 0.15 ± 0.05 in normotensive subjects and the value of 0.20 (90th percentile) defined increased MS. We also generated P/V loops for subjects with (n = 33) or without (n = 90) increased ED-P/V, by assuming: 1) P at mitral opening = 5 mmHg; 2) End of isometric contraction corresponding to aortic diastolic P; 3) Peak-systolic P = cuff systolic P occurring at 2/3 of LV empting; 4) End-systolic P estimated as: mean cuff P*0.98 + 11, corresponding to the time of end-systolic V. Results: Subjects with high ED-P/V (n = 33, 82% hypertensive) exhibited higher ejection fraction and relative wall thickness with lower midwall shortening, stroke volume and stroke work (see figure) than those with normal ED-P/V (all p < 0.0001) and similar LV mass. Conclusions: Thus, a CV phenotype at high risk of HFPEF corresponds to a high non-invasively determined single-beat ED-P/V ratio as an estimate of increased myocardial stiffness. This method might identify hypertensive patients at high risk of HFPEF. Figure 1. No caption available.

INCREASED LEFT VENTRICULAR MASS IN HYPERTENSIVE MEN IS MORE STRONGLY RELATED TO CENTRAL THAN TO BRACHIAL BLOOD PRESSURE CONTROL: PP.3.99

Background: Cardiovascular risk in hypertension (HTN) has been shown to be more strongly related to central systolic blood pressure (c-SBP) than to brachial (cuff) systolic blood pressure (b-SBP). We examined the relation of left ventriculat (LV) mass and LV hypertrophy (H) with BP control defined by both b-SBP and c-SBP. Methods: Ninety-one patients without diabetes or prevalent cardiovascular disease (80% HTN, 42% men, 57 ± 15yrs), underwent standard 2D echocardiography and blood pressure measurement using a commercially available device (HEM-9000AI, Omron Healthcare Co., Kyoto, Japan). Central SBP was derived from the SBP2 peak according to a previously invasively validated equation. Results: Nine patients were excluded due to sinus arrhythmia or suboptimal BP curve recording. The remaining 82 patients (56 ± 15yrs, 27.7 ± 4.6Kg/m2; 65 HTN of which 72% treated) were dichotomized according to the presence of uncontrolled HTN (SBP ± 140mmHg) by b-SBP and by c-SBP.Higher prevalence of uncontrolled HTN was found when classification was made according to c-SBP (52.4%) as compared to b-SBP (41.5%; p < 0.001), with poor agreement between the two methods (kappa score = 0.54). Analysis of the whole population showed that uncontrolled HTN (by b-SBP or c-SBP) was associated with higher values of LV mass index and relative wall thickness (p < 0.01). However, in men (n = 37) classification by b-SBP was unable to identify differences among group with controlled vs. uncontrolled HTN in either LV mass or LVH prevalence (p = NS). In fact, classification based on c-SBP showed significantly higher values of LV mass index in patients with uncontrolled BP (43 ± 11 g/m2.7) compared to those with controlled BP (37 ± 8 g/m2.7). Figure 1. No caption available. Accordingly, prevalence of LVH was significantly higher in uncontrolled HTN when the classification was based on c-SBP (30 vs 6% p = 0.05). Conclusions: compared to b-SBP, c-SBP better identifies hypertensive men with increased LV mass and LVH, and may be of incremental value in risk stratification.