Estimation of left ventricular end-diastolic pressure from Doppler transmitral flow velocity in cardiac patients independent of systolic performance.

In patients with heart disease, changes in left ventricular filling pressures produce alterations in the Doppler transmitral flow velocity and isovolumetric relaxation time. This investigation explored the hypothesis that combining isovolumetric relaxation time with measurements derived from the transmitral flow velocity can be used to estimate left ventricular end-diastolic pressure. Simultaneous Doppler and left ventricular pressure recordings were obtained in 33 patients (24 men with a mean age of 58 +/- 11 years) and an ejection fraction ranging from 15% to 74% (mean 55 +/- 15%). The following Doppler measurements correlated significantly with left ventricular end-diastolic pressure (range 4 to 36 mm Hg): isovolumetric relaxation time (IVRT; r = -0.73), atrial filling fraction (AFF; r = -0.66), deceleration time (DT; r = -0.59), ratio of early transmitral flow velocity to atrial flow velocity (E/A ratio; r = -0.53) and time from termination of mitral flow to the electrocardiographic R wave (MAR; r = 0.37). Combining these measurements into a multilinear regression equation provided a more accurate estimate of end-diastolic pressure (LVEDP; r = 0.80; SEE = 7.4). The equation LVEDP = 46 -0.22 IVRT -0.10 AFF -0.03 DT -(2 divided by E/A) + 0.05 MAR was tested prospectively in 26 additional patients (mean age 55 +/- 11 years; ejection fraction 41 +/- 23%) with simultaneous Doppler and hemodynamic recordings but with the two measurements made independently, in blinded fashion, by additional observers. Estimated and measured end-diastolic pressures correlated well with each other (r = 0.86).(ABSTRACT TRUNCATED AT 250 WORDS)     

Therapeutic benefit of internet-based lifestyle counselling for hypertension

Background

Preventive electronic (e)-counselling has been shown to reduce cardiovascular risk factors. However, heterogeneity in outcomes is commonly reported due to differences in e-protocols. We incorporated key features of an established behavioural therapy, motivational interviewing, to help standardize e-counselling in order to reduce blood pressure in patients with hypertension.

Methods

Subjects (n = 387, mean age = 56 years, 59% female, 72% taking ≥ 1 antihypertensive drug) were diagnosed with stage 1 or 2 hypertension. Subjects were randomized to a 4-month protocol of e-counselling (beta version of the “Blood Pressure Action Plan”, Heart and Stroke Foundation of Canada) vs waitlist control (general e-information on heart-healthy living). Outcomes were systolic, diastolic, and pulse pressures, and total lipoprotein cholesterol after treatment.

Results

Intention to treat analysis did not find a significant group difference in outcomes due to contamination across the 2 arms of this trial. However, per protocol analysis indicated that subjects receiving ≥ 8 e-counselling messages (a priori therapeutic dose) vs 0 e-counselling messages (control) demonstrated greater reduction in systolic blood pressure (mean, −8.9 mm Hg; 95% confidence interval [CI], −11.5 to −6.4 vs −5.0 mm Hg; 95% CI, −6.7 to −3.3, P = 0.03), pulse pressure (−6.1 mm Hg; 95% CI, −8.1 to −4.1 vs −3.1 mm Hg; 95% CI, −4.3 to −1.8, P = 0.02) and total cholesterol (−0.24 mmol/L; 95% CI, −0.43 to −0.06 vs 0.05 mmol/L; 95% CI, −0.06 to 0.16, P = 0.03), but not diastolic blood pressure.

Conclusions

These findings support the merit of evaluating whether e-counselling can improve blood pressure control and reduce cardiovascular risk over the long-term.     

Evolution of cardiac dysfunction in patients with antiphospholipid antibodies and/or antiphospholipid syndrome: A 10-year follow-up study

Objectives

To describe the evolution of valve involvement and myocardial dysfunction over time in patients with systemic lupus erythematosus (SLE) with or without antiphospholipid antibodies (aPL) and/or antiphospholipid syndrome (APS).

Methods

From an initial cohort of 150 patients assessed by transthoracic echocardiography 10 years ago, 17 patients with primary APS (PAPS), 23 with SLE-associated APS (SLE/APS), 19 with SLE positive for aPL without APS, and 23 with SLE negative for aPL were re-evaluated in the present echocardiography study.

Results

Valvulopathy was detected in 65% of PAPS and 62% of SLE patients with or without aPL. Disease duration [odds ratio (OR), 1.63; 95% confidence interval (CI), 1.13–2.36; p = 0.009 for every 5 years of increase] and presence of SLE/APS (OR, 3.51; 95% CI, 1.27–9.67; p = 0.015) were the only factors associated with the progression of valvular disease in univariate and multivariate analyses. Left ventricular diastolic dysfunction similarly progressed over time, with deceleration time (DT) and isovolumic relaxation time (IVRT) being equally prolonged in each of the four groups (p < 0.05). Right ventricular DT was significantly prolonged in each of the three SLE patient groups (p < 0.001), whereas IVRT increased only in SLE/APS patients (p = 0.040).

Conclusions

Among patients with APS and SLE (with or without aPL), SLE/APS and disease duration were independent factors for valvular disease progression in the present 10-year follow-up echocardiography study. Anticoagulation did not arrest valvular disease progression. Ventricular diastolic dysfunction, primarily of the left ventricle, also progressed over the 10-year period.     

ST peak during primary percutaneous coronary intervention predicts final infarct size,left ventricular function,and clinical outcome

Background and Purpose

One third of patients treated with primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction develop a secondary increase in electrocardiographic ST segment (ST peak) during reperfusion. The purpose was to determine the clinical importance of ST peak during primary PCI.

Methods

A total of 363 patients with ST-elevation myocardial infarction were stratified to no ST peak or ST peak. Final infarct size and ejection fraction (EF) were assessed by cardiovascular magnetic resonance.

Results

Patients with ST peak had a larger infarct size (14% vs 10%; P = .003) and lower EF (53% vs 57%; P = .022). Rates of cardiac mortality (8% vs 3%; P = .047) and cardiac events (cardiac mortality and admission for heart failure; 19% vs 10%; P = .018) were higher among patients with ST peak, but not all-cause mortality (8% vs 5%; P = .46). In a multivariable Cox regression analysis, ST peak remained significantly associated with cardiac events (adjusted hazard ratio, 2.03 [1.08-3.82]).

Conclusion

ST peak during primary PCI is related to larger final infarct size, a reduced EF, and adverse cardiac clinical outcome.     

T-wave inversion and diastolic dysfunction in patients with electrocardiographic left ventricular hypertrophy

Objectives

The aim of this study was to investigate if T-wave inversion (TWI) in the settings of electrocardiogram (ECG)–left ventricular hypertrophy (LVH) is associated with advanced diastolic dysfunction (DD) in subjects with preserved ejection fraction (EF).

Background

Animal studies suggested that an abnormal transmural repolarization sequence from endocardium to epicardium may contribute to DD. However, little is known about abnormal repolarization sequence and DD in humans.

Methods

We studied 231 patients with ECG-diagnosed LVH and with an EF of 50% or greater (measured within 6 months of the index ECG). T-wave inversion was assessed on leads I, aVL, V₄, V₅, or V₆. Diastolic dysfunction was defined based on echocardiographic estimation of the left atrial pressure. We used multiple logistic regression to estimate the odds ratio of DD comparing patients with TWI with those without TWI.

Results

The average age was 65.0 ± 14.2 years, and 61% were women. The mean EF was 61.8% ± 6.6%. Patients with TWIs were more likely to have coronary artery disease (P = .013) and diabetes (P = .007). There was a 5.6-fold increased odds of DD in patients with TWI compared with those without TWI in a model adjusting for sex, age, relative wall thickness, body mass index, hypertension, coronary artery disease, diabetes, hyperlipidemia, and smoking. When comparing different echocardiographic estimates of the left atrial pressure, patients with TWI displayed higher values for septal and lateral E/e′, left atrial volume index, and right ventricular/right atrial peak systolic gradient (P < .01 for each parameter).

Conclusions

T-wave inversion is associated with increased odds of DD in patients with ECG-LVH with preserved systolic function. The reversal of the normal sequence of repolarization manifested on the 12-lead ECG as TWI may be a factor to DD.     

Caspase-1 deficiency decreases atherosclerosis in apolipoprotein E-null mice

Background

Caspase-1 is a cysteine protease that contributes to mammalian immunity through proteolytic activation of the proinflammatory cytokines, interleukin (IL)-1β and IL-18.

Methods

To determine if caspase-1 deficiency can protect apolipoprotein E-null (Apoe^−/−) mice from atherosclerosis, gender-matched, paired-littermate Apoe^−/− mice with (Casp1^+/+Apoe^−/−) or without (Casp1^−/−Apoe^−/−) a functional caspase-1 (Casp1) gene were fed either a low fat diet for 26 weeks, or a saturated fat and cholesterol-enriched diet for 8 weeks. Plasma lipids and lipoproteins were determined and atherosclerosis was quantified in the aortic sinus and aortic arch.

Results

On either diet, caspase-1 deficiency did not affect total serum cholesterol concentrations and lipoprotein-cholesterol distributions. However, caspase-1 deficiency significantly decreased atherosclerosis in the ascending aorta by 35%-45% in both sexes of mice fed either diet. We further examined atherosclerotic lesions for 2 indices of immune cell activation: Major Histocompatibility Complex (MHC) class II and interferon (IFN)-γ expression. There was a 40%-50% reduction in the number of lesion-associated cells expressing MHC class II from both sexes of Casp1^−/−Apoe^−/− mice compared with Casp1^+/+Apoe^−/− mice and, a significant reduction in lesion-associated IFN-γ in female Casp1^−/−Apoe^−/− compared with their Casp1^+/+Apoe^−/− counterparts.

Conclusions

We conclude that caspase-1 promotes atherosclerosis by enhancing the inflammatory status of the lesion through a mechanism likely involving activation of lesion-associated immune cells and IFN-γ expression.     

Effect of vitamin C on endothelial function in health and disease: A systematic review and meta-analysis of randomised controlled trials

Background

Observational studies indicate that higher vitamin C intake is associated with reduced risk for cardiovascular diseases. However, randomised controlled trials (RCT) examining the effect of vitamin C on endothelial function (EF) have reported inconsistent results. The aims of this systematic review and meta-analysis were to determine the effect of vitamin C supplementation on EF and to investigate whether the effect was influenced by health status, study duration, dose and route of vitamin C administration.

Methods

We searched the Medline, Embase, Cochrane Library, and Scopus databases from inception to May 2013 for studies that met the following criteria: 1) RCT with adult participants, 2) vitamin C administered alone, 3) studies that quantified EF using commonly applied methods including ultrasound, plethysmography and pulse wave analysis.

Results

Pooling the data from 44 clinical trials showed a significant positive effect of vitamin C on EF (SMD: 0.50, 95% CI: 0.34, 0.66, P < 0.001). Stratification of the analysis by health outcome revealed improved EF in atherosclerotic (SMD: 0.84, 95% CI: 0.41, 1.26, P < 0.001), diabetic (SMD: 0.52, 95% CI: 0.21, 0.82, P < 0.001) and heart failure patients (SMD: 0.48, 95% CI: 0.08, 0.88, P < 0.02) after vitamin C supplementation. The effect size appeared to be unaffected by study design, duration, baseline plasma vitamin C concentration or route of administration of vitamin C. The meta-regression showed a significant positive association between vitamin C dose and improvement in EF (β: 0.00011, 95% CI: 0.00001, 0.00021, P = 0.03).

Conclusions

Vitamin C supplementation improved EF. The effect of vitamin C supplementation appeared to be dependent on health status, with stronger effects in those at higher cardiovascular disease risk.PROSPERO Database registration: CRD42013004567, http://www.crd.york.ac.uk/prospero/     

Inhibition of sPLA2 and endothelial function: a substudy of the SPIDER-PCI trial

Background

Inflammation plays an important role in the pathophysiology of atherosclerosis and endothelial dysfunction, and occurs after percutaneous coronary intervention (PCI). We evaluated whether endothelial function is attenuated after PCI and if inhibition of secretory phospholipase A₂ (sPLA₂) activity augments endothelial function and coronary flow reserve (CFR) in these patients.

Methods

In the sPLA₂ Inhibition to Decrease Enzyme Release After Percutaneous Coronary Intervention (SPIDER-PCI) study, patients undergoing elective PCI were randomized to receive Varespladib (Anthera Pharmaceuticals Inc, San Mateo, CA), an inhibitor of sPLA₂, or placebo 3-5 days prior to PCI and for 5 days after PCI. In this substudy, endothelial function was assessed in 31 patients by flow-mediated dilation (FMD) before treatment and on the day after PCI, while taking study medication. During the PCI procedure, CFR was assessed using a Doppler guide wire.

Results

Baseline and procedural characteristics were comparable in both groups and sPLA2 activity was similar at baseline. After PCI, sPLA₂ activity decreased only in the Varespladib group (2.9 ± 0.9 to 0.5 ± 0.4 ng/mL), and high-sensitivity C-reactive protein (hsCRP) increased by more than 100% in both groups. FMD at baseline was 3.66 ± 2.45% (Varespladib) and 3.37 ± 1.73% (placebo) with nonsignificant increase in both groups after PCI. The effect of Varespladib on FMD, adjusted for pre-PCI FMD by linear regression, was −1.16 ± 1.68%; P = 0.5. CFR was 2.45 ± 0.66 and 2.77 ± 0.85 in the Varespladib and placebo groups, respectively (P = 0.36).

Conclusions

Systemic endothelial function is not reduced after elective PCI despite eliciting acute inflammatory response. Acute inhibition of sPLA₂ activity with Varespladib does not affect endothelial or microvascular function after PCI.     

La onda R prominente en V1 pero no en V2 es un signo específico de infarto transmural lateral grande

Introduction and objectives

In the absence of right ventricular hypertrophy or bundle-branch block, a prominent R wave in V₁ or V₂ is considered to reflect a lateral myocardial infarction. We investigated the differences in infarct location, size and transmural extent between patients with prominent R wave in V₁ and those with prominent R wave in V₂.

Methods

We studied 50 patients with a previous first infarction involving left ventricular inferior and/or lateral wall at contrast-enhanced magnetic resonance.

Results

A prominent R wave in V₁ was present in 8 patients (16%), in V₂ in 23 (46%). At magnetic resonance, the infarction involved the inferior wall in 11 patients (22%), the lateral wall in 6 (12%), and both walls in 33 patients (66%). The sensitivity of a prominent R wave in V₁ in detecting a lateral infarction was low (17.9%), while the specificity was high (90.9%). The sensitivity and specificity of a prominent R wave in V₂ were 46.2% and 54.5%, respectively. In patients with a prominent R wave in V₁, infarct size and lateral and transmural extent were greater than in patients without this pattern (P<.005, <.001, and <.05, respectively); conversely, infarct size and transmural extent in the inferior wall and in its basal-posterior segment were not significantly different. In patients with a prominent R wave in V₂, infarct size, lateral and transmural extent were not different from patients without this pattern.

Conclusions

Only a prominent R wave in V₁ is a specific sign of large and transmural lateral infarction.Full English text available from:www.revespcardiol.org     

Heart failure survival score in patients with Chagas disease: correlation with functional variables

Introduction and objectives

Chagas disease is a prevalent cause of heart failure in Latin America, and its prognosis is worse than other etiologies. The Heart Failure Survival Score has been used to assess prognosis in patients with heart failure; however, this score has not yet been studied in patients with Chagas cardiopathy.

Methods

The Heart Failure Survival Score was calculated in 55 patients with severe left ventricular systolic dysfunction due to Chagas disease. Correlations were assessed between the Heart Failure Survival Score and variables obtained from, cardiopulmonary exercise tests, quality-of-life measures, and 6-minute walking tests.

Results

Patients were distributed among New York Heart Association classes II–IV; 89% were taking angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, 62% were taking beta-blockers, 86% were taking diuretics, and 74% were taking aldosterone receptor blockers. The mean Heart Failure Survival Score was 8.75 (0.80). The score correlated well with cardiopulmonary test variables such as peak oxygen uptake (0.662; P<.01), oxygen uptake at the anaerobic threshold (0.644; P<.01), ventilation carbon dioxide efficiency slope (−0.417; P<.01), oxygen pulse (0.375; P<.01), oxygen uptake efficiency slope (0.626; P<.01), 6-minute walking test (0.370; P<.01), left ventricle ejection fraction (0.650; P=.01), and left atrium diameter (−0.377; P<.01). There was also a borderline significant correlation between the Heart Failure Survival Score and quality of life (−0.283; P<.05).

Conclusions

In heart failure patients with Chagas disease, the Heart Failure Survival Score correlated well with the main prognostic functional test variables.Full English text available from:www.revespcardiol.org     

Relation of impaired left ventricular filling to systolic midwall mechanics in hypertensive patients with normal left ventricular systolic chamber function: the Losartan Intervention for Endpoint Reduction in Hypertension (LIFE) study

Background

Patients with hypertensive left ventricular (LV) hypertrophy commonly have diastolic dysfunction with preserved LV ejection fraction. LV systolic midwall shortening (MWS) may be impaired in hypertensive patients with normal LV ejection fraction. However, it is unclear whether impaired LV filling is related to depressed systolic midwall mechanics.

Methods

Echocardiographic measures of LV diastolic filling and systolic performance were compared in 632 unmedicated patients with stage II or III hypertension and LV hypertrophy determined by electrocardiogram, with LV ejection fraction >55% and <2+ mitral regurgitation.

Results

Stress-corrected LV MWS, an index of myocardial contractility, was lower in patients with abnormal as opposed to normal LV filling patterns (98% ± 12% vs 102% ± 10%, P < .001) and in patients with prolonged as opposed to normal isovolumic relaxation time (IVRT) (98% ± 13% vs 101% ± 12%, P = .014). Stress-corrected MWS was <85% of predicted levels in more patients with abnormal LV filling patterns (11.8% vs 6.3%) or with long IVRT (≥105 msec) (34% vs 21%, both P < .05). In regression analyses, lower stress-corrected MWS and higher LV mass were independent correlates of longer IVRT, while lower stress-corrected MWS was the only independent correlate of prolonged mitral valve deceleration time (P = .017). Higher LV mass had strong, statistically independent relationships to longer IVRT (by 0.3 g/msec) and decreased stress-corrected MWS (by 0.5 g/%; both P < .0001), independent of body size and age.

Conclusion

In patients with moderate hypertension and target organ damage who have normal LV ejection fraction, impaired early diastolic LV relaxation (abnormal E/A ratio, prolonged IVRT and deceleration time) is associated with impaired LV systolic midwall mechanics independent of higher LV mass.     

Longitudinal study of cardiac remodelling in rabbits following infarction

Background

Cardiac remodelling following myocardial infarction (MI) is a complex, dynamic process. There have been few longitudinal studies of these changes.

Methods

A 2-dimensional transthoracic echocardiography was performed on 20 rabbits, before and 1, 2, 4, 8, and 12 weeks after MI (n = 14) and twice for controls (n = 6). Chronic left ventricular (LV) infarct size was histologically characterized and correlated with mechanical function. A linear mixed model was used to analyze longitudinal and infarct size-related changes in LV end-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF), sphericity, circumferential strain, and wall motion score index.

Results

Mean LV infarct size was 28.9% ± 9.3%. After MI, rapid remodelling occurred in LVESV, LVEF, and sphericity for 2 weeks and LVEDV for 4 weeks, with slower changes afterwards. LV infarct size correlated with LVESV (r = 0.76), LVEDV (r = 0.71), and LVEF (r = 0.69). Larger infarcts resulted in greater LVESV dilation (P = 0.04) and faster LVEDV (P < 0.01), LVEF (P < 0.01), and sphericity (P < 0.01) remodelling. Apical global circumferential strain and wall motion score index increased for 1 week, then stabilized, regardless of infarct size, and apical global circumferential strain was correlated with apical infarction (r = 0.58). Additionally, regional circumferential strain decreased in segments with severe (> 80%) infarction more quickly (P < 0.01) and by a greater degree (P = 0.04) compared with segments with minor (< 20%) infarction.

Conclusions

The most dynamic remodelling of cardiac function in this model occurred during the first 4 weeks, stabilizing thereafter, with changes maintained up to 12 weeks. Infarct size affected both the early rate and long-term extent of mechanical remodelling.     

Intervención fisioterápica preventiva del deterioro de la musculatura respiratoria en ancianas institucionalizadas con limitación funcional

Introduction

In elderly seniors (>80 years), respiratory function may be compromised when, in addition to the presence of comorbidity and loss of mobility, there is also reduced respiratory muscle (RM) strength. The literature has shown that RM training could be an effective method to improve RM function and prevent clinical deterioration, particularly in population with RM weakness.The main purpose of this paper was to assess the effectiveness of RM training on the respiratory muscle strength and endurance of institutionalized elderly women with functional impairment.

Method

Fifty-four residents (mean=85 years, SD=6.7) were randomly assigned to either a control (n=27) or training (n=27) group. A supervised training program was developed with Threshold^®IMT, five times per week for 6-weeks. The main variables of the intervention were: maximum inspiratory pressure (PI_max), maximum expiratory pressure (PE_max) and maximal voluntary ventilation (MVV), all of which were measured at weeks 0, 4, 7 and 10.

Results

Statistical analysis revealed no significant differences in PI_max (F_3,114=1.04, p=0.368, R²=0.027), PE_max (F_3,114=1.86, p=0.14, R²=0.047) and MVV (F_3,114=1.74, p=0.162, R²=0.044) between the two groups after the intervention. However, the workload significantly improved with the training sessions (F_5,100=72.031, p<0.001, R²=0.791).

Conclusion

In a 6-week interval-based training program, the threshold loading device does not significantly improve parameters related to RM strength and endurance of the study population.     

Increased mortality after transcatheter aortic valve implantation (TAVI) in patients with severe aortic stenosis and low ejection fraction: A meta-analysis of 6898 patients

Background

There is conflicting evidence regarding the safety and efficacy of transcatheter aortic valve implantation (TAVI) procedures in patients with severe aortic stenosis and low left ventricular ejection fraction (EF). The primary aim of this study was to determine the impact of TAVI on short- and long-term mortality in patients with low EF (EF < 50%); the secondary aim was to analyze the impact of TAVI procedure on EF recovery in the same setting of patients.

Methods and results

Twenty-six studies enrolling 6898 patients with severe aortic stenosis undergoing TAVI procedure were included in the meta-analysis and analyzed for 30-day, 6-month and 1-year all-cause and cardiovascular mortality; a further meta-analysis was also performed in patients with low EF to assess EF changes post TAVI.In low EF patients, both all-cause and cardiovascular short- and long-term mortality were significantly higher when compared to patients with normal EF (30-day-all-cause mortality: 0.13; 95% confidence interval [CI]: 0.01 to 0.25, I² = 49.65, Q = 21.85; 1-year-all-cause mortality: 0.25; 95% [CI]: 0.16 to 0.34, I² = 25.57, Q = 16.12; 30-day-cardiovascular mortality: 0.03; 95% [CI]: − 0.31 to 0.36, I² = 66.84, Q = 6.03; 1-year-cardiovascular mortality: 0.29; 95% [CI]: 0.12 to 0.45, I² = 0.00, Q = 1.88). Nevertheless, in low EF patients TAVI was associated with a significant recovery of EF, which started at discharge and proceeded up to 1-year-follow-up.

Conclusions

Patients with low EF severe aortic stenosis have higher mortality following TAVI compared to normal EF patients, despite a significant and sustained improvement in EF.     

Predictors of right ventricle dysfunction after anterior myocardial infarction

Background

Regardless significant therapeutic advances, mortality and morbidity after myocardial infarction (MI) are still high. For a long time, the importance of right ventricle (RV) function has been neglected. Recently, RV dysfunction has also been associated with poor outcomes in the setting of heart failure. The shape, location, and contraction conditions make the RV chamber assessment technically challenging.

Methods

Our study identified clinical characteristics and left ventricle (LV) echocardiographic data performed 3-5 days after MI that could be associated with RV dysfunction (RV fractional area change [FAC] < 35%) 6 months after MI.

Results

The RV dysfunction group consisted of 11 patients (RV FAC 29.4% ± 5.2) and the no RV dysfunction group of 71 patients (RV FAC 43.7% ± 5.1); (P < 0.001). Both groups presented the same baseline clinical characteristics. Left atrium (LA), interventricular septum (IVS), and left ventricular posterior wall (LVPW) were larger in RV dysfunction than in no RV dysfunction. Conversely, E wave deceleration time (EDT) was lower in RV dysfunction when compared with no RV dysfunction. Left atrium_adj (adjusted by gender, age, infarct size, and body mass index) (odds ratio [OR], 1.22; confidence interval [CI], 1.016-1.47; P = 0.032), interventricular septum_adj (OR, 1.49; CI, 1.01-2.23; P = 0.044), and E wave deceleration time_adj (OR, 0.98; CI, 0.97-0.98; P = 0.029) assessed soon after MI predicted RV failure after 6-months.

Conclusions

LV diastolic dysfunction, resulting from anterior MI and assessed 3-5 days after the event, may play an important role in predicting RV dysfunction 6 months later.     

Seated and semi-recumbent positioning of the ventilated intensive care patient – Effect on gas exchange,respiratory mechanics and hemodynamics

Objectives

To compare the effect of semi-recumbent and sitting positions on gas exchange, respiratory mechanics and hemodynamics in patients weaning from mechanical ventilation.

Background

Upright positions are encouraged during rehabilitation of the critically ill but there effects have not been well described.

Methods

A prospective, randomized, cross-over trial was conducted. Subjects were passively mobilized from supine into a seated position (out of bed) and from supine to a semi-recumbent position (>45° backrest elevation in bed). Arterial blood gas (PaO₂/FiO₂, PaO₂, SaO₂, PaCO₂ and A–a gradient), respiratory mechanics (V_E,V_T, RR, C_dyn, RR/V_T) and hemodynamic measurements (HR, MABP) were collected in supine and at 5 min and 30 min after re-positioning.

Results

Thirty-four intubated and ventilated subjects were enrolled. The angle of backrest inclination in sitting (67 ± 5°) was greater than gained with semi-recumbent positioning (50 ± 5°, p < 0.001). There were no clinically important changes in arterial blood gas, respiratory mechanic or hemodynamic values due to either position.

Conclusions

Neither position resulted in significant changes in respiratory and hemodynamic parameters. Both positions can be applied safely in patients being weaned from ventilation.     

Non-invasive assessment of pulse wave velocity in mice by means of ultrasound images

Objective

Pulse wave velocity (PWV) is considered as a surrogate marker of arterial stiffness and could be useful for characterizing cardiovascular disease progression even in mouse models. Aim of this study was to develop an image process algorithm for assessing arterial PWV in mice using ultrasound images only and test it on the evaluation of age-associated differences in abdominal aorta PWV.

Methods

Ultrasound scans were obtained from ten adult (mean age: 5.5 months) and nine old (mean age: 15.5 months) wild type male mice (strain C57BL6) under gaseous anesthesia. For each mouse, instantaneous values of diameter and flow velocity were obtained from abdominal aorta B-mode and PW-Doppler, respectively. Single-beat mean diameter and velocity were calculated providing the velocity-diameter (lnD-V) loop. PWV values for both the early systolic phase (aaPWV) and the late systolic one (aaPWV_ls) were obtained from the slope of the corresponding linear parts of the loop. Relative distension (relD) was calculated from the mean diameter signal.

Results

aaPWV values for adult mice (1.91 ± 0.44 m/s) were significantly lower (p < 0.01) than those obtained for older ones (2.71 ± 0.63 m/s) and the same result was found for aaPWV_ls (2.68 ± 0.68 vs 3.67 ± 0.95 m/s; p < 0.05). relD measurements were significantly higher (p < 0.01) in adult (22.7% ± 5.2%) compared with older animal evaluations (15.8% ± 3.9%).

Conclusions

The proposed system discriminates well between age groups and supplies a non-invasive evaluation of anatomical and functional parameters of the mouse abdominal aorta. Since it provides a non-invasive PWV assessment from ultrasound (US) images only, it may offer a simple and useful system for evaluation of local vascular stiffness at other arterial site in the mouse, such as the carotid artery.     

Serial assessment of left ventricular diastolic function after Fontan procedure

OBJECTIVE—To assess longitudinal changes in systemic ventricular diastolic function late after the Fontan procedure.
DESIGN AND PATIENTS—Prospective study of 13 patients at 2.8 (2.0) years (early) and again at 11.4 (2.0) years (late) after the Fontan procedure by Doppler echocardiography with simultaneous ECG, phonocardiogram, and respirometer.
SETTING—Tertiary paediatric cardiac centre.
RESULTS—The isovolumic relaxation time (IVRT) was significantly longer, and E wave deceleration time, E and A wave velocities, and E:A velocity ratio were reduced compared to normal both early and late after the procedure. The mean (SD) z score of IVRT decreased significantly from +2.50 (1.00) to +1.24 (0.80) (p = 0.002), and the z score of the E wave deceleration time decreased from −1.69 (1.31) to −2.40 (1.47) (p = 0.03) during follow up. The A wave deceleration time also tended to decrease (early 80 (12) ms v late 73 (11) ms, p = 0.13) with increased follow up. There were no changes of the E and A wave velocities and E:A velocity ratio. The E wave velocity was inversely related to IVRT both early (r = −0.82, p = 0.001) and late (r = −0.59, p = 0.034) after the operation. The prevalence of diastolic flow during isovolumic relaxation decreased from 85% (11/13) to 38% (5/13) (p = 0.04), while that of mid diastolic flow increased from 23% (3/13) to 77% (10/13) (p = 0.02) between the two assessments.
CONCLUSIONS—Left ventricular diastolic function remains highly abnormal late after the Fontan procedure. The longitudinal changes demonstrated on follow up are compatible with reduction of left ventricular compliance in addition to persisting abnormalities of relaxation.


Keywords: diastolic function; Fontan procedure     

Medición del patrón ventilatorio mediante tomografía por impedancia eléctrica en pacientes con EPOC

Background and Objective

The measurement of breathing pattern in patients with chronic obstructive pulmonary disease (COPD) by electrical impedance tomography (EIT) requires the use of a mathematical calibration model incorporating not only anthropometric characteristics (previously evaluated in healthy individuals) but probably functional alterations associated with COPD as well. The aim of this study was to analyze the association between EIT measurements and spirometry parameters, static lung volumes, and carbon monoxide diffusing capacity (DLCO) in a group of male patients to develop a calibration equation for converting EIT signals into volume signals.

Materials and Methods

We measured forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), FEV₁/FVC, residual volume, total lung capacity, DLCO, carbon monoxide transfer coefficient (KCO) and standard anthropometric parameters in 28 patients with a FEV₁/FVC ratio of <70%. We then compared tidal volume measurements from a previously validated EIT unit and a standard pneumotachometer.

Results

The mean (SD) lung function results were FVC, 72 (16%); FEV₁, 43% (14%); FEV₁/FVC, 42% (9%); residual volume, 161% (44%); total lung capacity, 112% (17%); DLCO, 58% (17%); and KCO, 75% (25%). Mean (SD) tidal volumes measured by the pneumotachometer and the EIT unit were 0.697 (0.181) L and 0.515 (0.223) L, respectively (P<.001). Significant associations were found between EIT measurements and CO transfer parameters. The mathematical model developed to adjust for the differences between the 2 measurements (R²=0.568; P<.001) was compensation factor=1.81?− 0.82?× height (m)?−0.004×KCO (%).

Conclusions

The measurement of breathing pattern by EIT in patients with COPD requires the use of a previously calculated calibration equation that incorporates not only individual anthropometric characteristics but gas exchange parameters as well.     

Los contaminantes atmosféricos urbanos son factores de riesgo significativos para el asma y la neumonía en niños: influencia del lugar de medición de los contaminantes

Background

Air pollution is associated with a substantial burden on human health; however, the most important pollutants may vary with location. Proper monitoring is necessary to determine the effect of these pollutants on respiratory health.

Objectives

This study was designed to evaluate the role of outdoor, indoor and personal exposure to combustion-related pollutants NO₂ and O₃ on respiratory health of children in a non-affluent urban area of São Paulo, Brazil.

Methods

Levels of NO₂ and O₃ were continuously measured in outdoor and indoor air, as well as personal exposure, for 30 days using passive measurement monitors. Respiratory health was assessed with a Brazilian version of the ISAAC questionnaire.

Results

Complete data were available from 64 children, aged 6-10 years. Respiratory morbidity was high, with 43 (67.2%) reporting having had wheezing at any time, 27 (42.2%) wheezing in the last month, 17 (26.6%) asthma at any time and 21 (32.8%) pneumonia at any time. Correlations between levels of NO₂ and O₃ measured in the three locations evaluated were poor. Levels of NO₂ in indoor air and personal exposure to O₃ were independently associated with asthma (both cases P = .02), pneumonia (O₃, P = .02) and wheezing at any time (both cases P < .01). No associations were seen between outdoor NO₂ and O₃ and respiratory health.

Conclusions

Exposure to higher levels of NO₂ and O₃ was associated with increased risk for asthma and pneumonia in children. Nonetheless, the place where the pollutants are measured influences the results. The measurements taken in indoor and personal exposure were the most accurate.