Agreement is poor among current criteria used to define response to cardiac resynchronization therapy.

BACKGROUND: Numerous criteria believed to define a positive response to cardiac resynchronization therapy have been used in the literature. No study has investigated agreement among these response criteria. We hypothesized that the agreement among the various response criteria would be poor. METHODS AND RESULTS: A literature search was conducted with the keywords "cardiac resynchronization" and "response." The 50 publications with the most citations were reviewed. After the exclusion of editorials and reviews, 17 different primary response criteria were identified from 26 relevant articles. The agreement among 15 of these 17 response criteria was assessed in 426 patients from the Predictors of Response to Cardiac Resynchronization Therapy (PROSPECT) study with Cohen's kappa-coefficient (2 response criteria were not calculable from PROSPECT data). The overall response rate ranged from 32% to 91% for the 15 response criteria. Ninety-nine percent of patients showed a positive response according to at least 1 of the 15 criteria, whereas 94% were classified as a nonresponder by at least 1 criterion. kappa-Values were calculated for all 105 possible comparisons among the 15 response criteria and classified into standard ranges: Poor agreement (kappa< or =0.4), moderate agreement (0.4 or =0.75). Seventy-five percent of the comparisons showed poor agreement, 21% showed moderate agreement, and only 4% showed strong agreement. CONCLUSIONS: The 26 most-cited publications on predicting response to cardiac resynchronization therapy define response using 17 different criteria. Agreement between different methods to define response to cardiac resynchronization therapy is poor 75% of the time and strong only 4% of the time, which severely limits the ability to generalize results over multiple studies.

Prognostic value of the shock index along with transthoracic echocardiography in risk stratification of patients with acute pulmonary embolism.

The initial clinical presentation and echocardiography have key roles in risk stratification of patients with acute pulmonary embolism (PE). To assess the value of shock index and echocardiographic abnormalities as predictors of in-hospital complications and mortality, echocardiographic features of 159 patients diagnosed with acute PE were reviewed. A shock index > or =1, independent of echocardiographic findings, was associated with increased in-hospital mortality. Regardless of shock index, moderate to severe right ventricular (RV) hypokinesis and a ratio of RV to left ventricular (LV) end-diastolic diameter >1 was significantly associated with in-hospital mortality and demonstrated the best predictive values for short-term outcomes. The sensitivity and negative predictive value of diastolic LV impairment (E/A wave <1), RV hypokinesis, RV/LV >1, and end-diastolic RV diameter >3 cm for in-hospital mortality were 100%. Systolic pulmonary artery pressure (PAP) was higher in patients who died before discharge. A cut-off point >50 mm Hg for systolic PAP was significantly associated with increased in-hospital death. In conclusion, among conventional echocardiographic abnormalities attributed to RV dysfunction (E/A wave <1, RV hypokinesis, RV/LV >1, RV end-diastolic diameter >3 cm, and interventricular septal flattening), moderate to severe RV hypokinesis and RV/LV >1 have better predictive values for short-term outcomes of patients with acute PE. In addition, a shock index > or =1 and systolic PAP >50 mm Hg could also be helpful in the triage of these patients.

Electrocardiographic score and short-term outcomes of acute pulmonary embolism.

Risk stratification of patients with a diagnosis of acute pulmonary embolism (PE) is crucial in deciding appropriate management. An electrocardiographic (ECG) scoring system may potentially be useful in identifying patients at high risk of increased hospital morbidity and mortality from acute PE. Electrocardiography and echocardiography of 159 patients with a diagnosis of acute PE using ventilation/perfusion scan or spiral computed tomographic scan at 2 Emory-affiliated hospitals were reviewed. The 21-ECG score was compared with the presence or absence of right ventricular (RV) dysfunction and the 2 major end points of complicated in-hospital course or death. ECG score was significantly higher in patients with RV dysfunction (p <0.001) and a complicated in-hospital course (p <0.05). Although the ECG score was higher in nonsurvivors, it was not significantly different. Based on receiver-operator characteristic curves, an ECG score > or =3 could predict RV dysfunction with sensitivity, specificity, and positive and negative predictive values of 76%, 82%, 76%, and 86%, respectively. An ECG score > or =3 could predict a complicated in-hospital course and mortality with sensitivities of 58% and 59%, specificities of 60% and 58%, positive predictive values of 16% and 10%, and negative predictive values of 89% and 95%, respectively. In conclusion, the current 21-ECG scoring system can predict RV dysfunction in patients with acute PE well. However; its ability to predict an adverse in-hospital course is limited. Nevertheless, an ECG score <3 predicts better short-term outcome in these patients.

Usefulness of the peak velocity difference by tissue Doppler imaging technique as an effective predictor of response to cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) improves symptoms and functional status in heart failure patients; however, current selection criteria need improvement. A novel tissue Doppler imaging parameter, the peak velocity difference (PVD), defined as the greatest difference in time to peak velocity between any of 6 left ventricular regions, may better select responders to CRT. Subjects were divided into 2 groups based on the PVD. Clinical and echocardiographic parameters significantly improved in subjects with dyssynchrony by the baseline PVD and had a better overall response to CRT.

Quantification of left ventricular regional myocardial function using two-dimensional speckle tracking echocardiography in healthy volunteers--a multi-center study.

BACKGROUND: Although two-dimensional speckle tracking (2DST) has been validated in animal and early clinical studies for quantitative evaluation of myocardial motion and contractility, there are only limited measurements in large healthy population to be used as reference data, which severely restricts its clinical application. This study aimed at determining the age-specific normal values of left ventricular (LV) longitudinal, circumferential and radial strain in healthy adults. METHODS: We studied 228 healthy subjects (109 males, mean age 44 ± 15 years, range 18-78 years). Their LV longitudinal, circumferential and radial strains were measured by 2DST at basal, middle and apical levels of parasternal short-axis and apical 2-, 4- and 3-chamber views. The effects of age, gender and echocardiographic machines (52 patients had measurements obtained by both GE and Philips machines) on these parameters were also evaluated. RESULTS: The longitudinal and circumferential strains were -20.4 ± 3.4% and -22.9 ± 3.1%, respectively with higher values being observed at basal than apical segments. On the contrary, the radial strain which ranged 42.6 ± 12.9% decreased towards apical segments. The longitudinal strain declined, the circumferential strain rose and the radial strain remained similar during aging. Adult females had slightly higher circumferential and longitudinal strains than males (23 ± 3% vs -22 ± 3%, -21 ± 3% vs -20 ± 3% respectively; both p<0.01). Strains measured by the 2 different echo machines had good correlations but Phillips-assessed strains (longitudinal and circumferential) were 10% higher than GE measurements. Inter- and intra-observer variabilities were acceptable. CONCLUSIONS: Strain measurements by 2DST echocardiography varies with age, gender and echocardiographic vendors in healthy adults. These findings are important to differentiate between health and disease and to assess the severity of disease.

Effect of age and gender on left ventricular rotation and twist in a large group of normal adults--a multicenter study.

BACKGROUND: The newly developed 2-dimensional speckle tracking imaging (2D-STI) allows assessment of left ventricular (LV) rotation and twist. The aims of the present study are to establish normal values and to examine the effect of aging and gender on these parameters. METHODS: We studied 228 healthy subjects (109 males, mean age 44 ± 15 years, ranged 18-78 years). LV longitudinal and circumferential strain, rotation and twist were assessed by 2D-STI at basal, middle and apical levels of parasternal short-axis and apical 2-, 4- and 3-chamber views. RESULTS: The mean global LV longitudinal and circumferential strains were -20.4 ± 3.4% and -22.9 ± 3.1%, respectively. Of the 2,736 segments analyzed, 110 (8%) and 128 (9.4%) segments did not have optimal images for the assessment of basal and apical rotation. The basal rotation (-9.6 ± 2.5°) was significantly lower than apical rotation (11.2 ± 4.3°, p<0.0001) with a mean LV twist of 20.5 ± 4.5°. The longitudinal strain decreased with aging, which was accompanied by significant augmentations in circumferential strain, LV rotation and twist. There was no gender difference for rotational and twist measurements which had acceptable inter and intra-observer variabilities. CONCLUSIONS: Evaluation of LV rotation and twist are feasible with 2D-STI. Older age rather than gender seems to augment global LV rotation and twist. This may be the compensatory mechanism as a result of aging-related decline in subendocardial function. These data can serve as the references for further evaluation of pathological myocardial motions in various cardiovascular diseases.

Optimisation of atrioventricular delay during exercise improves cardiac output in patients stabilised with cardiac resynchronisation therapy.

BACKGROUND: Atrioventricular (AV) delay in cardiac resynchronisation therapy (CRT) recipients are typically optimised at rest. However, there are limited data on the impact of exercise-induced changes in heart rate on the optimal AV delay and left ventricular function. METHODS AND RESULTS: The authors serially programmed AV delays in 41 CRT patients with intrinsic sinus rhythm at rest and during two stages of supine bicycle exercise with heart rates at 20 bpm (stage I) and 40 bpm (stage II) above baseline. The optimal AV delay during exercise was determined by the iterative method to maximise cardiac output using Doppler echocardiography. Results were compared to physiological change in PR intervals in 56 normal controls during treadmill exercise. The optimal AV delay was progressively shortened (p<0.05) with escalating exercise level (baseline: 123±26 ms vs. stage I: 102±24 ms vs stage II: 70±22 ms, p<0.05). AV delay optimisation led to a significantly higher cardiac output than without optimisation did during stage I (6.2±1.2 l/min vs. 5.2±1.2 l/min, p<0.001) and stage II (6.8±1.6 l/min vs. 5.9±1.3 l/min, p<0.001) exercise. A linear inverse relationship existed between optimal AV delays and heart rates in CRT patients (AV delay=241-1.61×heart rate, R2=0.639, p<0.001) and healthy controls (R2=0.646, p<0.001), but the slope of regression was significantly steeper in CRT patients (p<0.001). CONCLUSIONS: Haemodynamically optimal AV delay shortened progressively with increasing heart rate during exercise, which suggests the need for programming of rate-adaptive AV delay in CRT recipients.

Variability in tissue Doppler echocardiographic measures of dyssynchrony is reduced with use of a larger region of interest.

BACKGROUND: Doppler tissue imaging (DTI)-based dyssynchrony parameters failed to predict response to cardiac resynchronization therapy (CRT) in the multicenter Predictors of Response to Cardiac Resynchronization Therapy (PROSPECT) trial. Large variability during the interpretation of DTI data was one of several factors thought to contribute to this failure. In this study, the authors hypothesized that using larger regions of interest (ROIs) to generate velocity curves from Doppler tissue images would significantly reduce the variability of DTI dyssynchrony parameters. METHODS: The variability of 3 ROI sizes (6 x 6, 18 x 6, and 30 x 6 mm) was compared in 30 patients undergoing CRT. Variability due to manual ROI placement was determined for each ROI size by placing 3 ROIs in each myocardial segment, 6mm apart from one another. Thus, 3 velocity curves were generated for each segment and each ROI size. Four published dyssynchrony parameters were calculated from all permutations of the 3 ROI positions per segment. A mean modified coefficient of variation was calculated for each parameter and ROI size. RESULTS: The 6 x 6 mm ROI had a mean coefficient of variation of 27%. The 18 x 6 and 30 x 6 mm ROIs had significantly lower coefficients of variation (17% and 14%, respectively) than the 6 x 6 mm ROI (P < .01 for both). The 30 x 6 mm ROI also reduced the diagnostic inconsistency of dyssynchrony parameters by 44% (P = .024) compared with the 6 x 6 mm ROI. CONCLUSION: Using a 30 x 6 mm ROI instead of a 6 x 6 mm ROI to quantify tissue Doppler dyssynchrony reduces variability by 47% and diagnostic inconsistency by 44%. The authors recommend using a 30 x 6 mm ROI in future trials to minimize variability.

Differentiation of hypertrophic cardiomyopathy and cardiac amyloidosis from other causes of ventricular wall thickening by two-dimensional strain imaging echocardiography.

Hypertension is the most common cause of left ventricular (LV) hypertrophy. However, multiple causes can lead to LV hypertrophy, each of which has different histological and mechanical properties. To assess the value of a novel speckle-tracking echocardiographic measurement of myocardial strain and strain rate in defining the mechanical properties of LV hypertrophy, 20 patients with asymmetric hypertrophic cardiomyopathy, 24 patients with secondary LV hypertrophy, 12 patients with biopsy-proved confirmed cardiac amyloidosis, and 22 age-matched healthy asymptomatic volunteers were studied. Patients with amyloidosis had severe diastolic dysfunction, and myocardial deformation was significantly decreased. The new technique allowed cardiac amyloid to be easily differentiated from the other categories. In patients with hypertrophic cardiomyopathy, there was segmental myocardium dysfunction as assessed by strain imaging. LV global systolic velocity and radial displacement were higher, and abnormal relaxation was more frequent, in the group with secondary LV hypertrophy than in normal controls. In conclusion, the observations from strain parameters derived from speckle tracking were consistent with the known underlying pathology of each condition, which speaks to the value of strain imaging. Cardiac amyloid profoundly alters all strain parameters, and analysis of these parameters could aid in the diagnosis.

Effects of region of interest tracking on the diagnosis of left ventricular dyssynchrony from Doppler tissue images.

BACKGROUND: Left ventricular dyssynchrony is often diagnosed by comparing velocity curves from Doppler tissue images of two or more myocardial regions. Velocity curves are generated by placing sample volumes or regions of interest (ROIs) within the myocardium. ROIs need to be manually relocated to maintain a midmyocardial location as the heart moves, but are frequently left in a stationary position. The error caused by use of a stationary ROI may affect the diagnosis of dyssynchrony, but this has not been quantified. OBJECTIVE: We hypothesized that using a stationary ROI to quantify dyssynchrony from Doppler tissue images would affect the diagnosis of dyssynchrony in patients with heart failure. METHODS: We quantified dyssynchrony in 18 patients with heart failure using 4 published dyssynchrony parameters: septal-to-lateral delay, maximum difference in the basal 2- or 4-chamber times to peak, SD of the 12 basal and midwall times to peak, and cross-correlation delay (XCD). Each dyssynchrony parameter was measured using both tracked and stationary ROIs. RESULTS: Use of a stationary ROI did not change the diagnosis of dyssynchrony when using XCD. However, ROI tracking changed the diagnosis of dyssynchrony in 17%, 11%, and 17% of patients when using septal-to-lateral delay, maximum difference in the basal 2- or 4-chamber times to peak, and SD of the 12 basal and midwall times to peak, respectively. XCD showed the lowest percent difference between tracked and stationary ROIs (4 +/- 9% vs 22 +/- 53%, 50 +/- 167%, and 12 +/- 30%, respectively, for septal-to-lateral delay, maximum difference in the basal 2- or 4-chamber times to peak, and SD of the 12 basal and midwall times to peak). CONCLUSION: Manual ROI tracking is required when using conventional time-to-peak parameters to diagnose dyssynchrony. XCD diagnosis of dyssynchrony can be performed accurately with a stationary ROI.

Cross-correlation quantification of dyssynchrony: a new method for quantifying the synchrony of contraction and relaxation in the heart.

BACKGROUND: Quantification of left ventricular dyssynchrony using Doppler tissue imaging may improve selection of patients who will benefit from cardiac resynchronization therapy. Most methods used to quantify dyssynchrony use a time-to-peak analysis, which is quantitatively simplistic and requires manual identification of systole and selection of peak velocities. METHODS: We developed and tested a new, highly automatable dyssynchrony parameter, cross-correlation delay (XCD), that does not require identification of systole or manual selection of peak systolic velocities. XCD uses all velocity data points from 3 consecutive beats (approximately 420 points). We tested XCD on 11 members of a positive control group (responders to cardiac resynchronization therapy with a >or=15% reduction in left ventricular end-systolic volume) and 12 members of a negative control group (normal 12-lead electrocardiogram and 2-dimensional echocardiogram findings). We compared XCD to septal-to-lateral delay in time-to-peak (SLD), maximum difference in the basal 2- or 4-chamber times to peak (MaxDiff), and SD of the 12 basal and midwall times-to-peak (Ts-SD). RESULTS: XCD and Ts-SD were significantly different between the positive and negative control groups (both P

Speckle-tracking strain echocardiography for detecting cardiac dyssynchrony in a canine model of dyssynchrony and heart failure.

Multiple echocardiographic criteria have been proposed to diagnose mechanical dyssynchrony in patients with heart failure without being validated against a model of cardiac dyssynchrony with heart failure. This study examines which of these methods can detect dyssynchrony in a canine model. Adult mongrel dogs underwent His-bundle ablation and right-ventricular pacing for 4 wk at either 110 bpm to induce dyssynchrony without heart failure (D group, n = 12) or 170 bpm to induce dyssynchrony with heart failure (DHF group, n = 9). To induce heart failure with narrow QRS, atria were paced at 190 bpm for 4 wk (HF group, n = 8). Tissue Doppler imaging (TDI) and two-dimensional echocardiography were performed at baseline and at end of study. Standard deviation of time to peak systolic velocity (color-coded TDI), time to peak S wave on pulse-wave TDI, time to peak radial and circumferential strain by speckle-tracking analysis (E(rr) and E(cc), respectively), and septal-to-posterior wall motion delay on M mode were obtained. In D group, only E(rr) and E(cc) were increased by dyssynchrony. In contrast, all the echocardiographic parameters of dyssynchrony appeared significantly augmented in the DHF group. Receiver-operator curve analysis showed good sensitivity of E(rr) (90%) and E(cc) (100%) to detected dyssynchrony without heart failure and excellent sensitivity and specificity of E(rr) and E(cc) to detect dyssynchrony with heart failure. Radial strain by speckle tracking is more accurate than TDI velocity to detect cardiac dyssynchrony in a canine model of dyssynchrony with or without heart failure.

The use of the SonoSite ultrasound device for intraoperative evaluation of the aorta.

OBJECTIVE: Neurologic complications remain a significant cause of morbidity and mortality in cardiac surgery. Risk factors for neurologic injuries include the presence of atheromatous disease in the aorta. Epiaortic ultrasound has been shown to be superior in detecting the extent and location of atheromatous disease. The SonoSite Corporation (Bothell, WA) has recently introduced an affordable, portable, high-resolution ultrasound device. This new device was compared with the Hewlett-Packard Sonos 5550 ultrasound device (currently manufactured by Philips, Andover, MA) to determine suitability for this purpose. DESIGN: Prospective, serial comparison of 2 devices. SETTING: University hospital. PARTICIPANTS: Fifty consecutive cardiac surgery patients. INTERVENTIONS: Intraoperative epiaortic ultrasound images were obtained using a SonoSite 180 Plus ultrasound device and a Hewlett-Packard Sonos 5500 ultrasound device. Three observers graded recorded images based on extent of atheromatous disease. MEASUREMENTS AND MAIN RESULTS: Two patients were excluded because of errors in recording images. For the 48 remaining patients, consensus (median) grades had an observed agreement of 93.6% compared with a chance agreement of 67.7%. This correlates to a kappa value of 0.80 or near-excellent agreement. CONCLUSIONS: The near-excellent agreement of the 2 devices is acceptable, thus providing a unique opportunity to expand the use of epiaortic ultrasound imaging.