Variables Of Left Ventricular Function Research Articles

Time of day dependent symptom onset is not associated with left ventricular function and myocardial damage after ST-segment elevation myocardial infarction

Abstract Background Circadian processes are suggested to influence ischemic injury in ST-segment elevation myocardial infarction (STEMI). Observational data suspect a circadian dependence of the occurrence of microvascular obstruction (MVO) in patients with STEMI. However, these observations derive from a small sample size and circadian variations in left ventricular function and myocardial damage after STEMI are still a matter of controversy. Purpose We aimed to investigate the association of time of day dependent symptom onset with left ventricular ejection fraction (LVEF), infarct size (IS) and MVO in a large cohort of STEMI patients treated with primary percutaneous coronary intervention (PCI). Methods This observational study investigated acute STEMI patients treated with primary PCI. Cardiac magnetic resonance (CMR) imaging was performed within 1 week after the index event for the determination of left ventricular function and infarct characteristics. The time of symptom onset was used to discriminate patients according to LVEF, IS as well as MVO occurrence and extent over a 24 hours cycle to evaluate circadian behavior. Results In final analysis, 889 acute STEMI patients treated with primary PCI with a delay of 189 [120-315] minutes were included. Median age of the overall cohort was 57 [51-66] years and 17% were female. Median LVEF was 49 [42-55]%, IS assumed 15.5 [8.0-24.7]% of left ventricular myocardial mass (LVMM) and MVO occurred in 57% of STEMI patients. No hourly differences between symptom onset and MVO occurrence (p=0.108), MVO extent (p=0.735), LVEF (p=0.644) and IS (p=0.722) have been evaluated. When comparing 3 hourly segments of symptom onset, no variations in MVO occurrence (p=0.114), MVO extent (p=0.308), LVEF (p=0.547) and IS (p=0.405) were observed. Conclusions No circadian variations in symptom onset and the occurrence and extent of MVO, LVEF and IS were observed in this large cohort of STEMI patients treated with primary PCI. Further research is needed to investigate the complex interplay between circadian processes and ischemic injury in this patient population.

Assessment of aortic valve area on cardiac computed tomography and doppler echocardiography: differences and clinical significance in symptomatic bicuspid aortic stenosis

Abstract Backgrounds This study aimed to investigate the differences and clinical significance of effective orifice area (EOA) on Doppler echocardiography and geometric orifice area (GOA) on cardiac computed tomography (CT) in bicuspid aortic stenosis (AS). Methods One-hundred sixty-three consecutive patients (age 64±10 years, 56.4% men) with symptomatic bicuspid AS who were referred for surgery and underwent both cardiac CT and echocardiography within 3 months were studied. For the aortic valve area, GOACT was measured by multiplanar CT planimetry, and EOAEcho was calculated by continuity equation with Doppler echocardiography. The associations of GOACT and EOAEcho with the patients' symptom scale, biomarkers, and left ventricular (LV) functional variables were comprehensively analyzed. Results There was a significant but modest correlation between EOAEcho and GOACT (r=0.604, p<0.001). Both EOAEcho and GOACT revealed significant correlations with mean pressure gradient and peak transaortic velocity and the coefficients were higher in EOAEcho than GOACT. EOAEcho of 1.05 cm2 and GOACT of 1.25 cm2 correspond to the hemodynamic cut-off values for diagnosing severe AS. EOAEcho was well correlated with patients' symptom scale and log NT-pro BNP, but GOACT was not. In addition, EOAEcho showed higher correlation coefficient with estimated LV filling pressure and LV global longitudinal strain than GOACT. Conclusions Both EOAEcho and GOACT can be used to evaluate the severity of bicuspid AS, however, the threshold for GOACT for diagnosing severe AS should be applied higher than that for EOAEcho. EOAEcho tends to be more correlated with the patients' symptom degree, biomarkers, and LV functional variables than GOACT. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): The Korean Cardiac Research Foundation

Irregular beat-to-beat hemodynamic properties determine left ventricular function during atrial fibrillation

Abstract Background The rapid irregular atrial electrical activity during atrial fibrillation (AF) is associated with an irregular and variable left ventricular (LV) systolic pump function. The effects of cycle length (CL) variations on LV function during AF remain incompletely understood. Purpose To elucidate the physiological mechanisms by which beat-to-beat changes in cycle length affect LV function during AF. We hypothesize that changes in LV preload and afterload cause a large part of the beat-to-beat variability of LV function during AF. Methods Beat-to-beat speckle-tracking echocardiography was performed in 10 patients with persistent AF. In each patient, a hundred consecutive beats were imaged during AF and we evaluated the relation between longitudinal strain in the image plane (4-chamber view) and (pre-)preceding CL in these patients. We used the CircAdapt cardiovascular system model to simulate cardiac mechanics and hemodynamics during AF for each individual patient 1) by imposing the exact irregular sequence of CLs as measured in the patient and 2) by making the atrial myocardium non-contractile. We also simulated generic (i.e. artificially defined) CL sequences (e.g. irregular long CL, irregular short CL) to better understand the determinants of beat-to-beat variations of LV systolic function during AF. Results Generic simulations uncovered the hemodynamic effects of a sudden irregular long or short beat on LV function during the following beat (top). A short beat led to lower LV function in the following beat because of smaller preload, while a longer beat led to larger LV function by Frank-Starling law of contractile myocardium. This CL dependency of LV function was confirmed when analysing clinical data of AF patients (bottom, left). A negative non-linear relation between preceding CL and longitudinal strain was observed (bottom, right). Increased longitudinal strain at high preceding CL (purple box) was explained by a higher preceding EDV (higher preload) (p<0.002). At a given preceding CL, variability in longitudinal strain was explained by the afterload of the preceding beat, with a lower preceding afterload (systolic aortic pressure) leading to higher longitudinal strain (yellow box, p<0.002), but not by changes in preceding preload (non-significant). Conclusions Irregularity in preceding CL leads to changes in LV function through preload and afterload changes. Indeed, as observed in patients during AF, longitudinal LV strain depends non-linearly on the preceding CL. Beat-to-beat changes in preload contribute to variable LV function but changes in afterload also are a key determinant of LV function variability at same preceding CL. Our combined clinical-computational study highlights the variability in longitudinal strain measurement during AF and provides new insight into the physiological mechanisms determining LV function in AF patients. Determinants of LV function in AF Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): NWO-ZonMw, VIDI grant 016.176.340

Impact of mitral regurgitation correction (Mitraclip® vs. surgical repair) on left ventricular myocardial performance according to baseline LVEF

Left ventricular (LV) pressure-strain loops (PSLs) have been recently validated as a non-invasive index of myocardial performance. The present study sought to analyze variation in LV function, myocardial work, and energy dispersion in patients with severe mitral regurgitation undergoing percutaneous mitral valve repair (MitraClip ® system) or mitral valve surgery (MVS). Thirty-two patients (mean age: 71 ± 10 years) with severe MR (18 with ischemic cardiomyopathy, 14 with dilated cardiomyopathy) and a LVEF < 50% undergoing MitraClip ® implantation and 15 patients (mean age: 64 ± 13 years) with primary MR and LVEF > 50% undergoing MVS according to ESC guidelines were included in the study. All patients underwent standard and speckle tracking echocardiography (STE) before MitraClip ® /MVS and at 6-month follow-up. Strain traces and valvular event times were used to calculate LV-PSLs and Global cardiac Work (GW), Positive Work (PW), and Negative work (NW) were therefore obtained. As showed in Table 1 , patients undergoing MVS experienced a decrease in LVEF, mechanical dispersion and an increase in cardiac NW after surgery. In patients undergoing MitraClip ® , a similar result was obtained when baseline LVEF was > 40%, whereas patients having a baseline LVEF < 40% did not experience significant changes in LV performance and mechanical dispersion. In patients with severe MR and a LVEF > 40%, either MitraClip ® or MVS have a negative impact on LV performance. The significant increase in mechanical dispersion and negative work, detected by new STE-derived analysis, provides an interesting explanation of these findings.

Takotsubo Cardiomyopathy Due to Systemic Absorption of Intraocular Phenylephrine

We present a case of Takotsubo cardiomyopathy (TTC) with regional variation in left ventricular function precipitated by intraocular injection of phenylephrine. To our knowledge, this is the first described case of TTC occurring in the setting of an intraocular medication. Contrary to the traditional model of the β2-receptor underlying the pathophysiology behind Takotsubo cardiomyopathy, phenylephrine is a pure α1-agonist implicating alternative mechanisms of myocardial injury resulting in a similar clinical phenotype. One should be alert to the possibility of catecholamine induced TTC occurring in patients subject to medications administered via the intraocular route with the potential for significant systemic absorption.

A Patent Ductus Arteriosus Severity Score Predicts Chronic Lung Disease or Death before Discharge

To test the hypothesis that a patent ductus arteriosus (PDA) severity score (PDAsc) incorporating markers of pulmonary overcirculation and left ventricular (LV) diastolic function can predict chronic lung disease or death before discharge (CLD/death). A multicenter prospective observational study was conducted for infants <29 weeks gestation. An echocardiogram was carried out on day 2 to measure PDA diameter and maximum flow velocity, LV output, diastolic flow in the descending aorta and celiac trunk, and variables of LV function using tissue Doppler imaging. Predictors of CLD/death were identified using logistic regression methods. A PDAsc was created and a receiver operating characteristic curve was constructed to assess its ability to predict CLD/death. We studied 141 infants at a mean (SD) gestation and birthweight of 26 (1.4) weeks and 952 (235) g, respectively. Five variables were identified that were independently associated with CLD/death (gestation at birth, PDA diameter, maximum flow velocity, LV output, and LV a' wave). The PDAsc had a range from 0 (low risk) to 13 (high risk). Infants who developed CLD/death had a higher score than those who did not (7.3 [1.8] vs 3.8 [2.0], P < .001). PDAsc had an area under the curve of 0.92 (95% CI 0.86-0.97, P < .001) for the ability to predict CLD/death. A PDAsc cut-off of 5 has sensitivity and specificity of 92% and 87%, and positive and negative predictive values of 92% and 82%, respectively. A PDAsc on day 2 can predict the later occurrence of CLD/death further highlighting the association between PDA significance and morbidity.

Relevance of early poststress variation in left ventricular function studied by gated-SPECT: evaluation in different clinical settings and relationship with angiography results.

Stress-induced ischemia may cause a decrease in left ventricular ejection fraction (EF). We evaluated the variation in early postexercise EF (S-EF) compared with rest EF (R-EF) in different clinical settings to detect ventricular dysfunction. We also correlated ventricular dysfunction with an angiographic score, the Syntax score, in a subgroup of ischemic patients. Gated-SPECT images were acquired 12 min after exercise stress and at rest in 1481 patients. Patients were classified as controls, negative for ischemia, mildly ischemic, moderately/severely ischemic, necrotic, and necrotic with ischemia. Mean end-diastolic volume, end-systolic volume, and EF were compared in each group. The ratio between stress to rest EF was indicated as the functional score. Angiography results were collected for 55% of moderately/severely ischemic patients. Sixty-one angiographies were also completed with Syntax score evaluation. In negative, necrotic, and mildly ischemic patients no differences were found between S-EF and R-EF. An opposite trend was observed in moderately/severely ischemic patients with a decrement of S-EF compared with R-EF (54.80±11.33 vs. 57.79±11.14; P<0.0001). Coronary artery disease was confirmed by angiography in 93% of moderately/severely ischemic patients. In 61 patients who underwent Syntax score evaluation, significant correlation was observed with functional score. Significant decrease in functional score was found in patients with coronary artery bypass graft indication compared with patients with percutaneous coronary intervention or medical indication. Early poststress gated-SPECT acquisition allows the detection of ventricular dysfunction in moderately/severely ischemic disease and provides additional information when directing patients to angiography and revascularization.

Comparative assessment of left ventricular function variables determined via cardiac computed tomography and cardiac magnetic resonance imaging in dogs

To evaluate the accuracy and reproducibility of left ventricular (LV) volumetric and function variables determined via contrast-enhanced cardiac CT and cardiac MRI in healthy dogs. 10 healthy Beagles. Cardiac MRI and cardiac CT were performed in anesthetized Beagles; both examinations were conducted within a 2-hour period. Cardiac MRI was performed with a 3.0-T magnet, and contrast-enhanced cardiac CT was performed with a 64-row detector CT machine. Data sets were acquired during apnea with simultaneous ECG gating. Short-axis images were created to determine functional variables via the Simpson method. Cardiac CT values for mean end-diastolic and end-systolic LV volumes had excellent correlation (r = 0.95) with cardiac MRI measurements, whereas LV stroke volume (r = 0.67) and LV ejection fraction (r = 0.75) had good correlations. The only variable that differed significantly between imaging modalities was end-diastolic LV volume. For each pair of values, Bland-Altman analysis revealed good limits of agreement. The 3-D modalities cardiac CT and cardiac MRI were excellent techniques for use in assessing LV functional variables. Similar results were obtained for LV volume and function variables via both techniques. The major disadvantage of these modalities was the need to anesthetize the dogs for the examinations.

Cardiac Dysfunction in Pneumovirus-Induced Lung Injury in Mice

To determine biventricular cardiac function in pneumovirus-induced acute lung injury in spontaneously breathing mice. Experimental animal study. Animal laboratory. C57Bl/6 mice. Mice were inoculated with the rodent pneumovirus, pneumonia virus of mice. Pneumonia virus of mice-infected mice were studied for right and left ventricular function variables by high-field strength (7 Tesla) cardiac MRI at specific time points during the course of disease compared with baseline. One day before and at peak disease severity, pneumonia virus of mice-infected mice showed significant right and left ventricular systolic and diastolic volume changes, with a progressive decrease in stroke volume and ejection fraction. No evidence for viral myocarditis or viral presence in heart tissue was found. These findings show adverse pulmonary-cardiac interaction in pneumovirus-induced acute lung injury, unrelated to direct virus-mediated effects on the heart.

How many systolic and diastolic variables must be measured in elderly patients with symptoms of heart failure?

Objectives: To explore the concordance and the feasibility of obtaining systolic or diastolic variables of left ventricular function in elderly patients with heart failure symptoms. Methods: One hundred twenty four patients with symptoms of heart failure (mean age 77 years, 70% females) were included in a cross-sectional, explorative study. Nineteen echocardiographic variables (7 systolic and 12 diastolic) were measured. Results: Overall, feasibility ranged from 93% to 100% for 15 variables and was 48% for mitral regurgitation dp/dt(MRdp/dt), 66% for the difference between pulmonary AR-dur and mitral A-dur, 81% for the ratio between early and late mitral inflow velocity (E/A), and 76% for tissue Doppler imaging late dia-stolic velocity (TDI A’). Concordance was very good/ good in 83% and poor/missing in 17% of systolic variables, whereas it was very good/good for 67% of diastolic variables and poor/missing for 33%. Factor analysis reduced systolic variables to two factors that explained 69% of the total variance in systolic function. Conclusions: Low feasibility for some and questionable concordance of especially diastolic variables questions the rationale for routinely measuring a high number of echocardigraphic variables. The results of the factor analysis further strengthen the possibility of reducing the number of measured variables. The clinical value of such a reduction needs to be validated.

Myocardial Perfusion Imaging Is a Strong Predictor of Death in Women

We sought to assess the prognostic value and risk classification improvement using contemporary single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) to predict all-cause mortality. Myocardial perfusion is a strong estimator of prognosis. Evidence published to date has not established the added prognostic value of SPECT-MPI nor defined an approach to detect improve classification of risk in women from a developing nation. A total of 2,225 women referred for SPECT-MPI were followed by a mean period of 3.7 ± 1.4 years. SPECT-MPI results were classified as abnormal on the presence of any perfusion defect. Abnormal scans were further classified as with mild/moderate reversible, severe reversible, partial reversible, or fixed perfusion defects. Risk estimates for incident mortality were categorized as <1%/year, 1% to 2%/year, and >2%/year using Cox proportional hazard models. Risk-adjusted models incorporated clinical risk factors, left ventricular ejection fraction (LVEF), and perfusion variables. All-cause death occurred in 139 patients. SPECT-MPI significantly risk stratified the population; patients with abnormal scans had significantly higher death rates compared with patients with normal scans, 13.1% versus 4.0%, respectively (p < 0.001). Cox analysis demonstrated that after adjusting for clinical risk factors and LVEF, SPECT-MPI improved the model discrimination (integrated discrimination index = 0.009; p = 0.02), added significant incremental prognostic information (global chi-square increased from 87.7 to 127.1; p < 0.0001), and improved risk prediction (net reclassification improvement = 0.12; p = 0.005). SPECT-MPI added significant incremental prognostic information to clinical and left ventricular functional variables while enhancing the ability to classify this Brazilian female population into low- and high-risk categories of all-cause mortality.

Chronic intermittent hypobaric hypoxia protects the heart against ischemia/reperfusion injury through upregulation of antioxidant enzymes in adult guinea pigs.

To investigate the protection and the anti-oxidative mechanism afforded by chronic intermittent hypobaric hypoxia (CIHH) against ischemia/reperfusion (I/R) injury in guinea pig hearts. Adult male guinea pigs were exposed to CIHH by mimicking a 5000 m high altitude (p(B)=404 mmHg, p(O2)=84 mmHg) in a hypobaric chamber for 6 h/day for 28 days. Langendorff-perfused isolated guinea pig hearts were used to measure variables of left ventricular function during baseline perfusion, ischemia and the reperfusion period. The activity and protein expression of antioxidant enzymes in the left myocardium were evaluated using biochemical methods and Western blotting, respectively. Intracellular reactive oxygen species (ROS) were assessed using ROS-sensitive fluorescence. After 30 min of global no-flow ischemia followed by 60 min of reperfusion, myocardial function had better recovery rates in CIHH guinea pig hearts than in control hearts. The activity and protein expression of superoxide dismutase (SOD) and catalase (CAT) were significantly increased in the myocardium of CIHH guinea pigs. Pretreatment of control hearts with an antioxidant mixture containing SOD and CAT exerted cardioprotective effects similar to CIHH. The irreversible CAT inhibitor aminotriazole (ATZ) abolished the cardioprotection of CIHH. Cardiac contractile dysfunction and oxidative stress induced by exogenous hydrogen peroxide (H(2)O(2)) were attenuated by CIHH and CAT. These data suggest that CIHH protects the heart against I/R injury through upregulation of antioxidant enzymes in guinea pig.Acta Pharmacologica Sinica (2009) 30: 947-955; doi: 10.1038/aps.2009.57; published online 22 June 2009.

Inducible nitric oxide synthase contributes to intermittent hypoxia against ischemia/reperfusion injury1

To investigate the role of inducible nitric oxide synthase (iNOS)-derived nitric oxide (NO) in the cardioprotection of intermittent hypoxia (IH) against ischemia/reperfusion (I/R) injury. Langendorff-perfused isolated rat hearts were used to measure variables of left ventricular function during baseline perfusion, ischemia, and reperfusion period. Nitrate plus nitrite (NOx) content in myocardium was measured using a biochemical method. iNOS mRNA and protein expression in rat left ventricles were detected using reverse transcription polymerase chain reaction (RT-PCR) and Western blot, respectively. Myocardial function recovered better in IH rat hearts than in normoxic control hearts. The iNOS-selective inhibitor aminoguanidine (AG) (100 micromol/L) significantly inhibited the protective effects of IH, but had no influence on normoxic rat hearts. The baseline content of NOx in IH hearts was higher than that in normoxic hearts. After 30 min ischemia, the NOx level in normoxic hearts increased compared to the corresponding baseline level, whereas there was no significant change in IH hearts. However, the NOx level in IH hearts was still higher than that of normoxic hearts during ischemia and reperfusion period. AG 100 micromol/L significantly diminished the NOx content in IH and normoxic hearts during ischemia and reperfusion period. The baseline levels of iNOS mRNA and protein in IH hearts were higher than those of normoxic hearts. Compared to the corresponding baseline level, iNOS mRNA and protein levels in normoxic rat hearts increased and those in IH rat hearts decreased after reperfusion. The addition of AG 100 micromol/L significantly decreased iNOS mRNA and protein expression in IH rat hearts after I/R. IH upregulated the baseline level of iNOS mRNA and protein expression leading to an increase in NO production, which may play an important role in the cardiac protection of IH against I/R injury.

Regional timing of myocardial shortening is related to prestretch from atrial contraction: assessment by high temporal resolution MRI tagging in humans.

Earlier studies have shown substantial nonuniformity in normal left ventricular (LV) myocardial function concerning both the degree of shortening and timing of shortening. We hypothesized that nonuniform LV function may be related to nonuniform prestretch induced by atrial contraction. Eleven healthy human subjects were studied using MRI myocardial tagging and strain analysis. The amount of circumferential prestretch was assessed in 30 LV segments. Prestretch was defined as the difference in strain between end diastole (at ECG R wave) and diastasis. Furthermore, both the degree of shortening (quantified as peak circumferential shortening, peak systolic shortening rate, and amount of postsystolic shortening) and timing of shortening (quantified as the onset time of shortening and time to peak shortening) were assessed. LV prestretch was found to be nonuniform, with the highest values in the lateral wall. The amount of segmental prestretch correlated significantly with peak shortening (r = 0.79), peak shortening rate (r = 0.50), amount of postsystolic shortening (r = 0.67), onset time of shortening (r = -0.57), and time to peak shortening (r = 0.71) (P < 0.001 for each of these relations). These relations may be explained by regional differences in wall stress or by a regional Frank-Starling effect. The correlation between timing of shortening and prestretch demonstrates that mechanical timing is not determined by electrical phenomena alone. In conclusion, regional variation in LV function correlates with the nonuniform prestretch from atrial contraction.

Stress-related variations in left ventricular function as assessed with gated myocardial perfusion SPECT

Background There is inconsistency in reported patient characteristics associated with differences in basal and poststress left ventricular function (delta ejection fraction [ΔEF]) assessed by gated single photon emission computed tomography (SPECT). This inconsistency may therefore hamper adequate interpretation. In this study we first determined the reproducibility of serial gated SPECT–assessed left ventricular function. Second, we determined whether left ventricular ejection fraction (LVEF) assessed directly after stress reflects basal LVEF and, if not, what patient characteristics were associated with this discrepancy in LVEF. Methods and results Serial reproducibility of technetium 99m tetrofosmin gated SPECT–assessed LVEF in 22 patients showed a mean difference between two sequential measurements at rest of 0.09% EF units, with a 95% limit of agreement (2 SDs) at 5.8% EF units. In 229 patients Tc-99m tetrofosmin gated SPECT was performed after stress and at rest. Independent predictors of ΔEF were the presence of scintigraphically proven ischemia (standardized coefficient, −1.256; P = .003) and difference in heart rate at the time of acquisition (standardized coefficient, 0.121; P = .001). Conclusions Gated SPECT–assessed LVEF at rest is reproducible under standard clinical conditions. However, LVEF assessed after stress does not represent LVEF at rest in patients with scintigraphically proven ischemia and in patients with increased heart rate after stress compared with heart rate at rest.

Acoustic quantification indexes of left ventricular size and function: Effects of signal averaging

Background: The aim of this study was to evaluate the clinical utility of using signal-averaged acoustic quantification (SAAQ) waveforms for improved assessment of left ventricular (LV) size and function. Methods and Results: Four separate protocols were performed in 47 subjects. SAAQ waveforms were used to assess alterations in LV function induced by dobutamine (15 μg/kg per minute) and esmolol (200 μg/kg per minute) in eight normal subjects. Subsequently, we analyzed SAAQ waveforms obtained in 12 patients with LV dysfunction secondary to dilated cardiomyopathy and 12 age-matched normal subjects. Finally, we developed computer software for monitoring of LV function on the basis of continuous acquisition and repeated analysis of SAAQ waveforms. We compared the interbeat variability in indexes of LV function obtained from raw AQ and SAAQ during 10 minutes of steady-state monitoring in eight patients undergoing transesophageal echocardiography. The feasibility of long-term monitoring in the intensive care setting was then studied in seven patients undergoing abdominal surgery. Our analysis tracked variations in LV function induced by dobutamine and esmolol. Significant differences in all measured indexes were found between normal subjects and patients with dilated cadiomyopathy. Signal averaging during steady-state monitoring significantly reduced the interbeat variability of all indexes (21% to 42%). In the operating room, the SAAQ monitoring system tracked hemodynamic changes in close agreement with invasive measurements. Conclusions: SAAQ allows fast and easy quantification of LV function and can track hemodynamic trends in the operating room setting. (J Am Soc Echocardiogr 1998;11:792-802.)

Segmental analysis of color kinesis images: new method for quantification of the magnitude and timing of endocardial motion during left ventricular systole and diastole.

We describe a method for objective assessment of left ventricular (LV) endocardial wall motion based on Color Kinesis, a new echocardiographic technique that color-encodes pixel transitions between blood and myocardial tissue. We developed a software that analyzes Color Kinesis images and provides quantitative indices of magnitude and timing of regional endocardial motion. Images obtained in 12 normal subjects were used to evaluate the variability in each index. Esmolol, dobutamine, and atropine were used to track variations in LV function in 14 subjects. Objective evaluation of wall motion was tested in 20 patients undergoing dobutamine stress testing. Regional fractional area change, displacement, and radial shortening were displayed as histograms and time curves. Global function was assessed by calculating magnitude and timing of peak ejection or filling rates and mean time of ejection or filling. Patterns of endocardial motion were consistent between normal subjects. Fractional area change and peak ejection rate decreased with esmolol and increased with dobutamine. Time to peak ejection and mean time of contraction were prolonged with esmolol and shortened with dobutamine. Using atropine, we proved that our findings with dobutamine were not secondary to its chronotropic effects. Dobutamine induced regional wall motion abnormalities in 10 patients in 38 segments diagnosed conventionally. Segmental analysis detected abnormalities in 36 of these 38 segments and in an additional 5 of 322 segments. Analysis of Color Kinesis images allows fast, objective, and automated evaluation of regional wall motion sensitively enough to evaluate clinical dobutamine stress data. This method has significant potential in the diagnosis of myocardial ischemia.

Ischemia During Ambulatory Monitoring as a Prognostic Indicator in Patients With Stable Coronary Artery Disease

To assess long-term prognostic significance of transient ischemia in patients with documented coronary artery disease and stable symptoms and to examine the relation between transient ischemia and the site of angiographic disease progression following acute cardiac events. Cohort study with a mean+/-SD follow-up of 51.5+/-23.8 months. Ambulatory patients with stable coronary artery disease, assigned to medical therapy. A total 221 patients (173 men; mean age, 60.8 years) were recruited. Of the 221 patients, 101 (45.7%) had single-vessel, 86 (38.9%) had 2-vessel, and 34 (15.4%) had 3-vessel disease. A total of 135 had a positive exercise test for ischemia, and mean+/-SD resting left ventricular ejection fraction (LVEF) was 49.8%+/-11.4%. Using conventional criteria, patients were prospectively stratified as low risk for continued medical therapy (single-vessel disease, 2-vessel disease with negative exercise test, or LVEF> or =40%; n=189 [85.5%]) or high risk for continued medical therapy (multivessel disease with ischemia and/or left ventricular dysfunction; n=32 [14.5%]). Ambulatory ST-segment monitoring, treadmill exercise testing, radionuclide ventriculography, and coronary angiography. Demographic, clinical, ambulatory monitoring, treadmill exercise, and left ventricular function variables as independent predictors of acute (cardiac death, myocardial infarction, or unstable angina) or all (including revascularization) cardiac events in the overall and the low-risk population. None of the clinical or noninvasive measures of ischemia were of prognostic significance in the overall or the low-risk group. The only significant independent predictor of outcome in all patients for all events, including revascularization, was the number of diseased vessels (X2=13.5 [df=1]; P<.001). Exclusion of vessel disease resulted in conventional risk stratification as the most significant predictor of outcome from all events in all patients (X2= 10.3 [df= 1]; P=.001). In the low-risk group, the number of diseased vessels was the only predictor for all events (X2=4.6; P=.03). For acute cardiac events, none of the variables tested were of prognostic significance. Based on the frequency of events in the low-risk patients, a 2-fold increase in the rate of cardiac events in patients with transient ischemia compared with those without transient ischemia during ambulatory monitoring could be excluded with greater than 85% power and alpha of .05. Of 30 patients suffering acute nonfatal cardiac events during follow-up, angiography was performed in 27, revealing significant progression of coronary disease in 24 (88.8%) and the development of new significant lesions at sites remote from previously significant lesions in 20 (74%) cases. These new lesions were equally likely to occur in those with or without transient ischemia at initial assessment. Acute cardiac events in predominantly low-risk stable angina patients with confirmed coronary disease are unpredictable, and those more likely to suffer such an event cannot be identified by the detection of ambulatory ischemia. Acute nonfatal cardiac events result predominantly from the development of significant new coronary lesions, not initially severe enough to cause ischemia. Patients categorized as high risk for long-term medical therapy have an increased rate of cardiac events (mainly revascularization) when compared with low-risk patients.

Left ventricular systolic and diastolic function assessed with two-dimensional and Doppler echocardiography in “white coat” hypertension

Objectives. The aim of this study was to investigate left ventricular function in subjects with “white coat” hypertension, defined as office arterial diastolic pressure ≥90 and ambulatory daytime pressure < 140/90mm Hg.Background. The white coat arterial pressure response may, by influencing left ventricular function, have a confounding effect in studies of heart disease.Methods. Two-dimensional and Doppler echocardiography, combined with the calibrated subclavian arterial pulse tracing, were used to assess variables of left ventricular function in 26 subjects with white coat hypertension, as well as 22 subjects with previously untreated ambulatory hypertension (office arterial diastolic pressure ≥90 and <115 mm Hg and ambulatory daytime diastolic pressure ≥90 mm Hg) and 32 normotensive subjects.Results. In subjects with white coat hypertension, systolic arterial pressure during the echocardiographic examination was significantly higher than ambulatory daytime systolic pressure. This pressure response was positively related to the ratio of the systolic to diastolic pulmonary venous flow peak velocities and to the peak velocity of flow reversion during atrial systole; it was inversely related to the ratio of early to late mitral flow peak velocities. Left ventricular stroke volume, ejection fraction and velocity of circumferential fiber shortening did not differ in the study groups, but left ventricular external work and end-systolic wall stress were increased in the white coat group.Conclusions. The arterial pressure response in subjects with white coat hypertension is associated with increased left ventricular external work, increased end-systolic wall stress and alterations of left ventricular filling but normal ejection fraction and velocity of circumferential fiber shortening.

Factors associated with cognitive recovery after cardiopulmonary resuscitation

A range of neuro-cognitive sequelae, from mild intellectual impairments to brain death, have been reported in survivors of aborted sudden cardiac death. To determine to what extent, if any, factors associated with cardiopulmonary resuscitation, left ventricular function, and mood state are related to outcomes in five cognitive areas, namely orientation, attention, memory, reasoning, and motor performance. Repeated measures were used to assess cognitive outcomes in 45 sudden cardiac arrest survivors over the 6 months following cardiopulmonary resuscitation. A battery of neuro-psychological tests was used to assess cognitive outcomes and psychological status over time. The relationship of the cardiopulmonary resuscitation, left ventricular function, and psychological variables to cognitive outcomes were assessed at each data point. The independent variables included time to cardiopulmonary resuscitation, time to defibrillation, duration of cardiopulmonary resuscitation, time to awakening, ejection fraction, New York Heart Association Class I to IV, tension, anger, and depression. During hospitalization 38 of the 45 survivors (84%) had mild to severe deficits in one or more cognitive areas; 19 of 38 survivors (50%) continued to be impaired in one or more cognitive areas at 6 months. Of these, all had mild to severe deficits in at least one aspect of memory, with delayed recall the most frequent impairment. Time to awakening accounted for a unique portion of the variance in orientation and memory outcomes over time. The left ventricular function variables accounted for a significant portion of the variance in motor speed. Our results suggest that half of the long-term survivors of aborted sudden cardiac death are cognitively intact 6 months after resuscitation but that 25% have moderate to severe impairment in memory, which could hamper and/or preclude the resumption of prearrest roles.