Effect of PTCA and stenting on left ventricular diastolic function in patients with CHD

Effect of PTCA and stenting on left ventricular diastolic function in patients with CHD!050000$河北医科大学第二医院河北医科大学心脏介入中心@傅向华     

Differential systolic and diastolic effects of β-adrenergic stimulation in patients with severe left ventricular dysfunction: A radionuclide ventriculographic study

BACKGROUND: An attenuated inotropic response to beta-adrenergic stimulation has been documented in patients with severely depressed left ventricular (LV) function. Scant data exist regarding the effect of beta-adrenergic stimulation on LV diastolic function in human beings. Our objective was to evaluate the effect of dobutamine infusion on LV systolic and diastolic function in patients with severe ventricular dysfunction. METHODS AND RESULTS: We studied 26 patients (60 +/- 9 years) in stable condition with healed myocardial infarction and LV ejection fraction (EF) less than 35% by radionuclide ventriculography. LVEF, volumes, peak ejection rate (PER), peak filling rate (PFR), and peak systolic pressure-to-end-systolic volume ratio were calculated at the infusion rate of 5 and 10 gamma x kg(-1) x min(-1). At 5 gamma x kg(-1) x min(-1), no changes were observed in heart rate (75 +/- 16 beats/min vs 75 +/- 15 beats/min at rest), LVEF (23% +/- 8% vs 22% +/- 7%), and PER (1.40 +/- 0.48 end-diastolic volume per second [EDV/s] vs 1.30 +/- 0.48 EDV/s); however, a significant increase in PFR was observed (1.11 +/- 0.36 EDV/s vs 0.86 +/- 0.30 EDV/s, P < .01). At 10 gamma x kg(-1) x min(-1), an increase in LVEF (25% +/- 10%, P < .01) and PER (1.60 +/- 0.57 EDV/s, P < .01) was observed; PFR (1.25 +/- 0.36 EDV/s, P < .05) also increased, whereas heart rate (78 +/- 18 beats/min) was unchanged. No significant changes in LV volumes or in indices of LV contraction synchronicity were observed during infusion. Finally, the peak systolic pressure-to-end-systolic volume ratio was unchanged at 5 gamma x kg(-1) x min(-1) and significantly increased at 10 gamma x kg(-1) x min(-1). CONCLUSIONS: In stable patients with ischemic heart disease and severe LV dysfunction, beta-adrenergic stimulation may still induce a positive lusitropic response, despite attenuated inotropic and chronotropic responses; moreover, the effects on diastolic function occur earlier than those on systolic function.     

Quantification of left ventricular regional functions using ECG-gated myocardial perfusion SPECT —validation of left ventricular systolic functions—

OBJECTIVE: We have developed a program to quantify regional left ventricular (LV) function and wall motion synchrony using ECG-gated myocardial perfusion SPECT (MPS). This preliminary study was undertaken to validate the use of this program for estimating regional LV systolic function. METHODS: Patients were subjected to MPS by 99mTc-sestamibi at rest. The study included 20 patients who were confirmed to have a low probability of coronary artery disease (LPG; low probability group), 19 heart disease patients who were examined by MPS and equilibrium radionuclide angiography (ERNA) (ERG; ERNA group), and 24 patients who were examined by MPS and 2-dimensional echocardiography (2DE) (2DEG; 2DE group). The values of the ejection fraction (EF) and peak ejection rate (PER) were estimated. The global functions evaluated by this program were compared with those obtained by ERNA in the ERG. For regional assessment, the reference values of the functional indices were obtained for 17 LV segments in LPG. The Z score, (reference average value of the segment--patient's value of the segment)/reference standard deviation of the segment, was used for the evaluation of regional functions; a score equal to or greater than 2 was defined as abnormal. Semiquantitative visual interpretation of 2DE was used as the standard to assess wall motion. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of these criteria and the relationship between 2DE grading and Z scoring were validated in 2DEG. RESULTS: The values of the global EF and PER evaluated by this program correlated with those determined by ERNA (r = 0.76 and 0.58, respectively; p < 0.005 and 0.01, respectively). The sensitivities of regional EF and PER for segmental wall motion abnormalities were 86.7% and 68.7%, respectively; their specificities were 86.7% and 95.5%, respectively; their PPVs were 64.3% and 79.2%, respectively; and their NPVs were 96.0% and 91.7%, respectively. The Z scores of these indices significantly correlated with the scores determined by 2DE (rs = 0.70 and 0.68, respectively; p < 10(-10)). CONCLUSION: The potential of this program to quantify the regional systolic function was validated.     

Cardiac β-adrenergic receptor density and myocardial systolic function in the remote noninfarcted region after prior myocardial infarction with left ventricular remodelling

Purpose

After myocardial infarction (MI), left ventricular (LV) remodelling is observed in noninfarcted LV myocardium. LV remodelling is closely associated with systolic heart failure. Since myocardial dysfunction is related to the downregulation of cardiac postsynaptic beta-adrenergic receptors (β-AR), we hypothesized that a reduction in β-AR density may be manifested in the remote noninfarcted region and such reduction may be related to myocardial systolic dysfunction. Accordingly, we assessed β-AR density with a focus on the remote noninfarcted region.

Methods

Cardiac PET was performed in 15 patients with a prior MI and 10 age-matched healthy controls using ¹¹C-CGP 12177, a radioligand for β-receptors. The maximum number of available specific ¹¹C-CGP 12177 binding sites per gram of tissue was calculated in regions of interest using an established graphical method. LV regional systolic function was assessed based on peak systolic myocardial strain on the LV wall in the longitudinal direction using two-dimensional ultrasound speckle tracking imaging. LV volumes and LV ejection fraction (EF) were also measured.

Results

The LV end-diastolic volume index was significantly larger in patients than in controls (67.8?±?16.9 vs. 49.1?±?12.3?ml/m², p?p?p?Conclusion In the remote noninfarcted region in patients, β-AR downregulation was observed, which was related to deterioration of local myocardial systolic function.     

Does motion analysis in postexercise gated sestamibi SPECT reflect rest left ventricular motion even in severe coronary artery disease?

PURPOSE: Evidence has suggested that postexercise gated Tc-99m sestamibi SPECT (GSPECT) provides combined information about resting wall motion and exercise perfusion. No data have been published about possible differences in wall motion analysis between postexercise and resting GSPECT. METHODS: Fifty patients underwent postexercise (symptom-limited bicycle stress) and rest GSPECT and cardiac catheterization with contrast ventriculography. In 35 patients, additional rest planar Tc-99m RBC radionuclide ventriculography (RNV) was performed. Four observers independently performed left ventricular ejection fraction (LVEF) calculations and visual analysis of regional wall motion (graded in four stages) for all studies. RESULTS: The LVEF calculations in GSPECT revealed a statistically significant difference between postexercise (45.8 +/- 15.7%) and rest (48.0 +/- 16.1%; P < 0.05) determination. Postrest GSPECT LVEF showed a better correlation with LVEF determination performed with contrast ventriculography and RNV than did postexercise GSPECT LVEF. The reduced postexercise wall motion could be shown in segments with exercise-induced ischemia and in those with normal regional perfusion but not in segments with irreversibly abnormal perfusion. CONCLUSIONS: Postexercise GSPECT provides reliable information regarding global wall motion even in severe coronary artery disease, but regional wall motion is underestimated compared with rest GSPECT, because of an imprecise surface detection algorithm in ischemic wall segments and possibly postexercise stunning in severe coronary artery disease.     

Does muscle function and metabolism affect exercise performance in the heat?

It has been suggested that exercise performance in the heat is limited by the degree of hyperthermia, which, in some circumstances, compromises cardiovascular function and/or the central nervous system. However, this review presents evidence that a temperature-induced dysfunction to skeletal muscle contraction may contribute to a reduction in performance during exercise in the heat.     

Does diastolic function evaluated with radionuclide ventriculography predict mortality,hospitalization and the development of new onset heart failure?

Left ventricular systolic dysfunction (LVSD) in asymptomatic patients is associated with the development of heart failure (HF) and the degree of LVSD predicts prognosis. Whether left ventricular diastolic dysfunction (LVDD) predicts the development of HF or mortality is not known. Our objective was to investigate the predictive value of LVDD evaluated by radionuclide ventriculography (RN). All patients referred for RN during a 12 month period were included. Medical records were reviewed to determine characteristics of the patients at the time of RN and events occurring during a 5 year follow-up. Data from 195 patients were analysed. During the follow-up period 49 patients (25.1%) died, 41 (21.0%) were admitted to hospital and 25 (12.3%) developed HF. An ejection fraction (EF) <40% was associated with mortality (relative risk (RR), 2.04; P=0.001) and hospital admissions (RR, 1.33; P=0.002). Patients who developed subsequent HF had, on average, lower EF at baseline. In a multivariate analysis the lower the EF the more likely patients were to develop new onset HF (odds ratio, 0.92; 95% CI 0.88-0.97; P=0.003). LVDD evaluated with peak filling rate and time to peak filling rate was not associated with any of the outcomes. However, a higher proportion of patients with pre-existing HF at the time of the RN had abnormal LVDD than patients with no HF. LVDD evaluated by RN is associated with symptoms of HF at the time of assessment but is not a good predictor of mortality, hospitalization or new onset HF. EF remains a better predictor of outcomes.     

Left ventricular function in physiologic and pathologic hypertrophy in Sprague–Dawley rats

Objective

The aim of this study was to design a high intensity swimming training and two-kidney, one-clip (2K1C) hypertension protocol in Sprague–Dawley (SD) rats and to use current echocardiography techniques to examine the differential diagnosis between physiological and pathological left ventricular hypertrophy.

Methods

One group of SD rats performed swimming training at high intensive swimming training (HIGH) for eight weeks. In animals of the other arm of the study, a 2KIC hypertension was created and maintained for eight weeks.

Results

After eight weeks, all rats were studied by standard and tissue Doppler echocardiography. The heart weight/body weight ratio (HW/BW) of 2K1C and HIGH rats increased by 16% and 42%, respectively. Echocardiography showed increased septal and posterior wall thickness in both the 2K1C and HIGH rats. Left ventricular increased by 35 and 41% respectively. Left ventricular diameters, stroke volumes, cardiac output, and ejection fractions were unchanged in either group. Mitral inflow showed a decrease in late-wave velocity, thus increasing the E/A ratio in HIGH rats. However, mitral inflow showed an increase in late-wave velocity, thus decreasing the E/A ratio in 2K1C rats. There was a significant increase in Ea and early diastolic (Em)/late diastolic (Am) in HIGH rats in basal septum and lateral mitral valve annulus. And there was a significant increase in Am, which led to a significant decrease of Em/Am in 2K1C rats. No significant change occurred in pulmonary vein systolic velocity and diastolic velocity, in either of the three animal groups. However, there was significant increase in atrial reversal velocity in HIGH rats.

Conclusions

Doppler echocardiographic parameters of LV diastolic function can be of diagnostic importance for discrimination between pathologic and physiologic LV hypertrophy.     

Do electrocardiographic changes with adenosine myocardial perfusion imaging predict ischaemia in patients with left ventricular hypertrophy?

BACKGROUND: Electrocardiographic (ECG) changes during adenosine myocardial perfusion imaging (MPI) correlate with severe coronary artery disease and the presence of collaterals. However, the significance of these changes during adenosine MPI in patients with left ventricular hypertrophy (LVH) on baseline electrocardiogram is less well understood. OBJECTIVE: To evaluate whether ECG changes on adenosine MPI predict ischaemia in patients with LVH. METHODS: We reviewed retrospectively 454 consecutive patients who had undergone adenosine MPI at our institution. The baseline electrocardiogram was reviewed to determine whether or not LVH was present. All patients were administered adenosine at 140 microg x kg x min for a total of 6 min and Tc-sestamibi was injected at 3 min into the protocol. None of the patients underwent any form of exercise during the stress test. RESULTS: Of the 146 patients with LVH, 10 had stress ECG changes suggestive of ischaemia and 40 had evidence of ischaemia on MPI. Similarly, of the 308 patients without LVH, 43 had stress ECG changes suggestive of ischaemia and 68 had ischaemia on MPI. The sensitivity and specificity of stress ECG changes in predicting ischaemia on perfusion in patients with LVH were 12.5% and 95.3%, respectively, with a positive predictive value of 50% and a negative predictive value of 74.3%. CONCLUSION: ECG changes suggestive of ischaemia in patients with LVH are very specific for ischaemia on MPI, and their significance is similar to that in patients without LVH.     

Is abnormal iodine-123-MIBG kinetics associated with left ventricular dysfunction in patients with diabetes mellitus?

BACKGROUND: Although autonomic neuropathy is frequently recognized in patients with diabetes mellitus, it is uncertain whether cardiac sympathetic neuropathy may play a role in the development of diabetic cardiomyopathy. METHODS AND RESULTS: In 10 control subjects and 61 patients with diabetes mellitus who did not have coronary artery disease, cardiac sympathetic function and left ventricular ejection fraction (LVEF) were evaluated by using iodine-123-metaiodobenzylguanidine (MIBG) imaging and echocardiography, respectively. Dynamic acquisitions and planar images obtained 15 and 150 minutes after injection were used as a means of measuring early and late myocardial uptake and clearance rates of MIBG from the heart. Eight patients with an LVEF less than 50% demonstrated a lower late myocardial MIBG uptake (0.0043% +/- 0.0017% vs. 0.0024% +/- 0.0009%/pixel, P = .002) and a higher clearance rate (22.9% +/- 17.7% vs. 49.3% +/- 12.2%, P<.0001) than the 53 patients with an LVEF of 50% or greater, although the age, sex, type of diabetes mellitus, and frequency of neuropathy, retinopathy, and nephropathy were not significantly different between the 2 subgroups. The LVEF correlated weakly but significantly with early and late myocardial uptake and clearance rate (r = 0.277, P = .03; r = 0.421, P = .001; r = 0.382, P = .002; respectively) in patients with diabetes mellitus. CONCLUSION: Marked MIBG abnormalities are associated with left ventricular dysfunction in patients with diabetes mellitus. However, long-term follow-up of patients with diabetes mellitus who have marked MIBG abnormalities and normal LVEF will be required to determine whether these patients would demonstrate systolic dysfunction earlier than patients without an MIBG abnormality.     

Does aging adversely affect muscle mitochondrial function?

Muscle oxidative function appears to decline with aging, and evidence suggests that this is related to reduced synthesis of mitochondrial and other muscle proteins. Causes for these events may include mtDNA damage or reduced mtDNA copy numbers, reduced oxidative enzyme activities and ATP production, and increased proton leak.     

Does hypoxia impair ovarian function in Bolivian women indigenous to high altitude?

Fertility appears to be reduced in at least some high altitude populations relative to their counterparts at lower elevations. Inferring from the difficulties with reproduction of newcomers to high altitude and from animal experiments, it has been hypothesized that this apparent reduction is the result of hypoxia acting to reduce fecundity and/or increase fetal loss. In humans, however, several behavioral as well as biological factors may affect fertility levels. These many factors have been organized by demographers into a framework of seven proximate determinants that includes fecundability (the monthly probability of conception) of which successful ovulation is one component. To test whether ovarian function is impaired in women indigenous to high altitude, we measured salivary progesterone (P) in a sample (n = 20) of Quechua women (aged 19-42 years) residing at 3,100 m. It was found that mean luteal P = 179 pmol/L and mean midluteal P = 243 pmol/L, levels that fall about midway in the range of known values for several populations and are higher than some lower altitude populations. These findings suggest that hypoxia does not appear to significantly impair ovarian function in those with lifelong residence at high altitude. There are, however, several factors common to many high altitude populations that may act to reduce fecundability and fertility including intercourse patterns (affected by marriage and migration practices), prolonged lactation, dietary insufficiency, and hard labor.     

Assessment of left ventricular function by gated myocardial perfusion and gated blood-pool SPECT: Can we use the same reference database?

The purpose of this study was to compare left ventricular (LV) volume and ejection fraction (LVEF) measurements obtained with electrocardiographic gated single-photon emission computed tomographic (SPECT) myocardial perfusion imaging (GS-MPI) with those obtained with gated SPECT cardiac blood-pool imaging (GS-pool). Fifteen patients underwent GS-MPI with technetium-99m-tetrofosmin and GS-pool with technetium-99m-erythrocyte, within a mean interval of 8 +/- 3 days. Eight patients had suspected dilated cardiomyopathy and seven patients had angiographically significant coronary artery disease. End-diastolic volume (EDV), end-systolic volume (ESV) and LVEF measurements were estimated from GS-MPI images by means of Cedars-Sinai automatic quantitative program and from GS-pool images by the threshold technique. Mean differences between GS-MPI and GS-pool in EDV, ESV and LVEF measurements were -2.8 +/- 10.5 ml [95% confidence interval (CI): -8.6 +/- 3.0 ml], 2.6 +/- 7.3 ml (CI: -1.4 +/- 6.6 ml) and -2.3 +/- 5.1% (CI: -5.1 +/- 0.6%), respectively. No significant difference in the mean differences from 0 was found for EDV, ESV or LVEF measurements. Bland-Altman plots revealed no trend over the measured LV volumes and LVEF. For all parameters, regression lines approximated lines of identity. The excellent agreement between GS-MPI and GS-pool measurements suggests that, for estimation of LV volumes and LVEF, these two techniques may be used interchangeably and measurements by one method can serve as a reference for the other.     

Does walking strategy in older people change as a function of walking distance?

This study investigates whether the spatio-temporal parameters of gait in the elderly vary as a function of walking distance. The gait pattern of older subjects (n=27) over both short (SWD<10 m) and long (LWD>20 m) walking was evaluated using an ambulatory device consisting of body-worn sensors (Physilog). The stride velocity (SV), gait cycle time (GCT), and inter-cycle variability of each parameter (CV) were evaluated for each subject. Analysis was undertaken after evaluating the errors and the test-retest reliability of the Physilog device compared with an electronic walkway system (GaitRite) over the SWD with different walking speeds. While both systems were highly reliable with respect to the SV and GCT parameters (ICC>0.82), agreement for the gait variability was poor. Interestingly, our data revealed that the measured gait parameters over SWD and LWD were significantly different. LWD trials had a mean increase of 5.2% (p<0.05) in SV, and a mean decrease of 3.7% (p<0.05) in GCT compared with SWD trials. Although variability in both the SV and GCT measured during LWD trials decreased by an average of 1% relative to the SWD case, the drop was not significant. Moreover, reliability for gait variability measures was poor, irrespective of the instrument and despite a moderate improvement for LWD trials. Taken together, our findings indicate that for valid and reliable comparisons, test and retest should be performed under identical distance conditions. Furthermore, our findings suggest that the older subjects may choose different walking strategies for SWD and LWD conditions.     

Does increased physical activity in school affect children's executive function and aerobic fitness?

This study seeks to explore whether increased PA in school affects children's executive function and aerobic fitness. The “Active school” study was a 10‐month randomized controlled trial. The sample included 449 children (10‐11 years old) in five intervention and four control schools. The weekly interventions were 2×45 minutes physically active academic lessons, 5×10 minutes physically active breaks, and 5×10 minutes physically active homework. Aerobic fitness was measured using a 10‐minute interval running test. Executive function was tested using four cognitive tests (Stroop, verbal fluency, digit span, and Trail Making). A composite score for executive function was computed and used in analyses. Mixed ANCOVA repeated measures were performed to analyze changes in scores for aerobic fitness and executive function. Analysis showed a tendency for a time×group interaction on executive function, but the results were non‐significant F(1, 344)=3.64, P=.057. There was no significant time×group interaction for aerobic fitness. Results indicate that increased physical activity in school might improve children's executive function, even without improvement in aerobic fitness, but a longer intervention period may be required to find significant effects.     

Can left ventricular end-diastolic volumes be estimated with prospective ECG-gated CT coronary angiography?

Background

With the goal of minimizing patient radiation exposure, many centres have adopted prospective ECG-gated computed tomographic coronary angiography. Since image acquisition occurs only during ventricular diastasis, the ability to measure left ventricular (LV) ejection fraction (EF) and LV volumes has been lost. Given that LV volumes have prognostic value, the ability to estimate LV end diastolic volume (EDV) may be clinically desirable.

Objective

We sought to predict LV EDV using CT coronary angiography (CTA) images obtained during ventricular diastasis.

Methods

Consecutive patients who underwent retrospective ECG-gated CTA were enrolled. Images were reconstructed at the 75% phase and at end-diastole. LV and left atrial (LA) volumes were measured.

Results

A total of 153 consecutive patients were analyzed (mean age = 56.7 ± 11.2 years; men = 56.2%). The mean LV EDV and EF were 144.4 ± 40.2 mL and 63.4 ± 9.9%, respectively. There appeared to be a very strong linear relationship between the 75% phase LV volume and LV EDV with an R² of 0.993. Using LV and LA volumes at the 75% phase, a prediction model of LV EDV was developed (LV EDV = (1.021 × 75% phase LV volume) + (0.259 × 75% phase LA volume), adjusted R² = 0.995).

Conclusion

LV EDV can be estimated using CTA data obtained during ventricular diastasis. Further studies are needed to demonstrate that such estimates of LV EDV have incremental prognostic value over coronary artery disease severity assessment with prospective ECG-gated CTA.     

Monitoring effects of α-human atrial natriuretic polypeptide (α-hANP) on left ventricular function in patients with essential hypertension with a cardiac probe

The effects of -hANP on left ventricular function were studied with a cardiac probe in ten patients with essential hypertension. Our data showed that intravenous administration of -hANP significantly elevated left ventricular function. At 5 min, the elevation of EF, RCO, ER, RSV, PFR were 13.23% (P<0.02), 12.7 (P<0.02), 0.618 (P<0.02), 0.133 (P<0.05), 0.283 (P<0.01), respectively. At 10 min, the increase of EF, ER, were 11.07% (P<0.02) and 0.233 (P<0.01), respectively. Atriopeptin significantly reduced systolic and diastolic blood pressure from 2 min to 20 min (P<0.001–0.05).Supported by IAEA Grant No. 4062/RI/RB     

Does exertional heat stress impact gastrointestinal function and symptoms?

ObjectivesExertional-heat stress generates a thermoregulatory strain that exacerbates splanchnic hypoperfusion and sympathetic drive, but the effects on gastrointestinal function are poorly defined. The study aimed to determine the effects of exertional-heat stress on gastric myoelectrical activity, orocecal transit time (OCTT), and gastrointestinal symptoms (GIS).DesignRandomised cross-over study.MethodsEndurance runners (n = 16) completed 2 h of running at 60 % V?O_2max in 35 °C (HOT) and 22 °C (TEMP) ambient conditions. Surface electrogastrography (cEGG) was recorded pre- and post-exercise to determine gastric myoelectrical activity, a lactulose challenge was used to determine OCTT, and GIS were recorded using a modified visual analogue scale tool.ResultsPost-exercise T_re [HOT:38.8(38.5 to 39.0)°C and TEMP:38.1(37.8 to 38.4)°C] and Δ T_re [HOT:2.2(2.0 to 2.4)°C and TEMP:1.5(1.2 to 1.8)°C] was higher on HOT compared to TEMP (p < 0.001). Normal gastric myoelectrical cycle frequency reduced (p = 0.010) on HOT [? 11.7(? 20.8 to ? 2.6)%], but this decrease did not differ (p = 0.058) from TEMP [? 2.7(? 8.3 to 3.0)%]. Bradygastria increased post-exercise on both trials (HOT:11.3(2.3 to 20.4)%, p = 0.030; and TEMP:7.4(2.1 to 12.6)%, p = 0.009). OCTT did not differ between trials (p = 0.864) with transit response classified as very slow on both HOT (99(68 to 131)min) and TEMP (98(74 to 121)min). GIS incidence was higher on HOT (88 %) compared to TEMP (81 %), in accordance with greater total-GIS and upper-GIS severity (p = 0.005 and p = 0.033, respectively).ConclusionsRunning for 2 h at 60 % V?O_2max in either hot or temperate ambient conditions instigates perturbations in myoelectrical activity and OCTT, with GIS incidence and severity greater in hot conditions.