Influence of heart rate on systolic time intervals: Effects of atrial pacing versus dynamic exercise

The effects of atrial pacing and dynamic exercise in the supine position on systolic time intervals (STI) were compared in 10 normals. In another group of 13 normals, the effect of exercise alone on STI was tested. A linear shortening of electromechanical systole (QS₂) and left ventricular ejection time (LVET) with increasing heart rate was demonstrated with right atrial pacing and dynamic exercise in the frequency range between 60 and 140 beats/min. However, the shortening of LVET was significantly less (p<0.01) with exercise compared to pacing. This is explained by an increase in left ventricular stroke volume with exercise. The pre-ejection period (PEP) was significantly (p<0.001) shortened with exercise, but there was no change with atrial pacing. Thus, changes in heart rate (HR) alone, without changes in the dynamic state of the heart, did not influence PEP. It is suggested that PEP at rest should not be corrected for heart rate. The supine exercise regression equations for correction of heart rate for LVET and PEP differ from both the resting and the upright exercise regression equations. With exercise a frequency correction of STI using regression equations should be abandoned. Instead, uncorrected STI at standard heart rates (e.g., 100, 110, and 130 beats/min) should be taken for comparison. Heart rate standardization should be employed using the formula     

Reference intervals of aortic pulse wave velocity assessed with an oscillometric device in healthy children and adolescents from Argentina

Age-related reference intervals (RIs) of aortic pulse wave velocity (Ao-PWV) obtained from a large healthy population are lacking in South America. The aims of this study were to determine Ao-PWV RIs in a cohort of healthy children and adolescents from Argentina and to generate year-to-year percentile curves.

Ao-PWV was measured in 1000 healthy subjects non-exposed to traditional cardiovascular risk factors (Age: 10–22 y. o., 56% males). First, we evaluated if RIs for males and females were necessaries (correlation and covariate analysis). Second, mean (M) and standard deviation (SD) age-related equations were obtained for cf-PWV, using parametric regression methods based on fractional polynomials. Third, age-specific (year to year) percentiles curves (for all, males and females children and adolescents) were generated using the standard normal distribution. They were, age-specific 1st, 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, 97.5th and 99th percentile curves and values.

After covariate analysis (i.e., adjusting by age, jugulum-symphysis distance, body weight and height), specific RIs for males and females of children and adolescents were evidenced as necessaries. The equations were

For all subjects:

Ao-PWV_Mean = 4.98 + 12.86x10^?5 Age³.

Ao-PWV_SD = 0.47 + 21.00x10^?6Age³.

For girls:

Ao-PWV_Mean = 5.07 + 10.23x10^?5Age³.

Ao-PWV_SD = 0.50 + 10.00x10^?6Age³.

For boys:

Ao-PWV_Mean = 4.87 + 15.81x10^?5Age³.

Ao-PWV_SD = 0.46 + 22.34x10^?6Age³.

Our study provides the largest database to-date concerning Ao-PWV in healthy children and adolescents in Argentina. Age-related equations (M and SD values) for Ao-PWV are reported by the first time. Specific RIs and percentiles of Ao-PWV are now available according to age and sex for an Argentinian population.     

Mortality outcomes based on ED qSOFA score and HIV status in a developing low income country

Objective

To evaluate the utility of the quick Sepsis-related Organ Failure Assessment (qSOFA) score to predict risks for emergency department (ED) and hospital mortality among patients in a sub-Saharan Africa (SSA) setting.

Determinants of Intima-Media Thickness in the Young: The ALSPAC Study

ObjectivesThis study characterized the determinants of carotid intima-media thickness (cIMT) in a large (n > 4,000) longitudinal cohort of healthy young people age 9 to 21 years.BackgroundGreater cIMT is commonly used in the young as a marker of subclinical atherosclerosis, but its evolution at this age is still poorly understood.MethodsAssociations between cardiovascular risk factors and cIMT were investigated in both longitudinal (ages 9 to 17 years) and cross-sectional (ages 17 and 21 years) analyses, with the latter also related to other measures of carotid structure and stress. Additional use of ultra-high frequency ultrasound in the radial artery at age 21 years allowed investigation of the distinct layers (i.e., intima or media) that may underlie observed differences.ResultsFat-free mass (FFM) and systolic blood pressure were the only modifiable risk factors positively associated with cIMT (e.g., mean difference in cIMT per 1-SD increase in FFM at age 17: 0.007 mm: 95% confidence interval [CI]: 0.004 to 0.010; p < 0.001), whereas fat mass was negatively associated with cIMT (difference: ?0.0032; 95% CI: 0.004 to ?0.001; p = 0.001). Similar results were obtained when investigating cumulative exposure to these factors throughout adolescence. An increase in cIMT maintained circumferential wall stress in the face of increased mean arterial pressure when increases in body mass were attributable to increased FFM, but not fat mass. Risk factor?associated differences in the radial artery occurred in the media alone, and there was little evidence of a relationship between intimal thickness and any risk factor.ConclusionsSubtle changes in cIMT in the young may predominantly involve the media and represent physiological adaptations as opposed to subclinical atherosclerosis. Other vascular measures may be more appropriate for the identification of arterial disease before adulthood.     

The impact of antiviral therapy for HCV on kidney disease: a systematic review and meta-analysis

BackgroundControversy persists about the role of hepatitis C as a risk factor for developing kidney disease in the general population. Some authors have evaluated the effect of antiviral therapy for HCV on the risk of kidney disease.Study Aims and DesignA systematic review of the published medical literature was performed to assess whether antiviral therapy for HCV has an independent impact on kidney survival in the adult general population. A random effects model was used to generate an overall estimate of the risk of kidney disease after anti-HCV therapy across the published studies. Meta-regression and stratified analysis were also carried out.ResultsFifteen studies were eligible (n = 356, 285 patients) and separate meta-analyses were conducted according to the outcome. Pooling studies based on viral responses (n = 7; 34,763 individual patients) demonstrated a relationship between sustained viral response and lower frequency of kidney disease; the overall estimate for adjusted risk of kidney disease was 2.50 (95% CI, 1.41; 4.41) (p = 0.0016) and between-study heterogeneity was found (p-value by Q test = 0.004). Aggregation of studies comparing treated vs untreated cohorts (n = 8, n = 333,312 patients) revealed an association between anti-HCV therapy and lower risk of kidney disease. The overall estimate for adjusted risk of kidney disease across the eight studies was 0.39 (95% CI, 0.25; 0.612) (p = 0.0001). Meta-regression showed that the effectiveness of antiviral therapy in reducing the frequency of kidney disease diminishes as cirrhosis (p = 0.02) and HBV infection (p = 0.0001) increase among HCV-infected individuals.ConclusionsAntiviral therapy for HCV lowers the risk of kidney disease among HCV-infected individuals. Studies to understand the mechanisms underlying this association are ongoing.     

Association of IL-8 gene polymorphisms with non small cell lung cancer in Tunisia: A case control study

Interleukin 8 (IL-8), is a proinflammatory chemokine, has been reported to have angiogenic activity and to be responsible for tumor-associated angiogenesis in several cancers. In this study, we aimed to study the (IL-8) gene polymorphism in relation with risk development of non small cell lung cancer in Tunisian patient. Two single nucleotide polymorphisms (−251T/A [rs4073], +781C/T [rs2227306]) of the IL-8 gene were screened in 170 patients with NSCLC and 225 healthy controls by PCR–RFLP.     

Acute effects of alcohol, beta blockade, and their combination on left ventricular function and hemodynamics in normal man

Twenty-three healthy males, aged 23 to 62 years, were examinedby M-mode echocardiography and systolic time intervals for 3h after (1) ethanol 1 g/kg by mouth taken over 60 minutes; (2)atenolol 100 mg by mouth; (3) ethanol (1 g/kg) + atenolol (100mg). The peak mean blood ethanol (± s.e.) was 112 ±4mg/100 ml in test 1 and 104 ± 7 mg/100 ml in test 3.During increasing blood ethanol, heart rate (HR), systolic bloodpressure (BP), cardiac output (CO) and echocardiographic indicesof left ventricular (LV) function were significantly augmented,while total peripheral resistance (TPR) decreased. During decliningblood ethanol, systolic BP, L V end-diastolic and end-systolicdiameters, stroke volume (SV) and circumferential wall stresswere significantly reduced; echocardiographic indices of LVfunction were unaltered, but the pre-ejection period/LV ejectiontime ratio was increased, Atenolol decreased llR, systolic BP,SV, CO, and all estimates of LV function, but increased TPR.Ethanol + atenolol tended to cause smaller depressions in theindices of LV function than did atenolol alone, in spite ofsimilar plasma atenolol concentrations (n = 6). It is concludedthat ingestion of modest doses of ethanol evokes vasodilationand enhances LV function during increasing blood ethanol, andreduces LV preload and afterload during decreasing blood ethanolwithout impairing contractility. Social drinking and beta blockadeseem not to have any harmful acute combined effects on the heartand circulation, at least in normal subjects.     

Captopril adjuvant therapy to beta-blockers and nitrates improves post-myocardial infarction left ventricular performance

A growing body of data support the beneficial effects of angiotensin-convertingenzyme inhibitors in the prevention of cardiac enlargement andimprovement of left ventricular function in patients with acutemyocardial infarction. However, very little information existsabout the direct effect of increased afterload on cardiac performancein these patients and the possible favourable effects of angiotensin-convertingenzyme inhibitors as adjunctive treatment to thrombolysis, beta-blockersand nitrates. We have, therefore, studied the effects of captoprilas adjuvant therapy to thrombolysis, beta-blockers and nitrates(standard therapy) on left ventricular performance in 77 consecutivepatients with uncomplicated Q-wave acute myocardial infarction,by the measurement of the pre-ejection period/left ventricularejection time ratio before and after (0·25–0·50mg) phenylephrine administration on the 4th and 30th post-infarctiondays. Patients were randomized on day 4 either to continue standardtherapy alone (group 1, 35 patients) or to receive oral captopriltherapy (12·5 mg t.i.d.) in addition to standard therapy(group 2, 42 patients) in a double-blind parallel study. Among the patients of group 1 there was a significant deteriorationof left ventricular function after phenylephrine administration.This was shown by an increase of pre-ejection period/left ventricularejection time ratio only in the subset of patients with ejectionfraction <40%, as measured by contrast ventriculography,on both the 4th and 30th post-infarction days changing from0·435±0·070 to 0·528±0·101,P<0·01 and from 0·404±0·098 to0·515±0·092, P<0·02, respectively.In contrast there were no significant changes in patients withejection fraction 40%. Among patients of group 2, phenylephrineadministration induced a significant increase, only on the 4thday, in pre-ejection period/left ventricular ejection time ratioonly in the subset of patients with ejection fraction <40%changing from 0·410±0·107 to 0·535±0·102,P<0·01. In the remaining patients with ejection fraction>40% there were no significant changes on either the 4thor 30th post-infarction days. Furthermore, a significant improvementwas observed after phenylephrine administration in the pre-ejectionperiod/left ventricular ejection time ratio between the 4thand 30th post-infarction days, which changed from 0·535±0·102on day 4 to 0·368± 0·052 on day 30 (P<0·004).Also, a four-way ANOVA detected a significant reduction of heartrate in patients with ejection fraction <40< from day4 to day 30. The results indicate that: (1) the response of pre-ejectionperiod/left ventricular ejection time ratio after increasingafterload may be a useful non-invasive method for the detectionof left ventricular dysfunction in myocardial infarction patients;and (2) captopril adjuvant therapy as compared to thrombolysis,beta-blockers and nitrates alone, after phenylephrine administration,improves the left ventricular performance response in asymptomaticQ-wave post-infarction patients and beneficially affects heartrate. This effect is most pronounced in patients with ejectionfraction 40% whereas those with ejection fraction 40% do notobtain clear benefit.     

The combined association of depression and socioeconomic status with length of post-operative hospital stay following coronary artery bypass graft surgery: Data from a prospective cohort study

Objective

To understand the association between pre-operative depression symptoms, including cognitive and somatic symptom subtypes, and length of post-operative stay in patients undergoing coronary artery bypass graft (CABG) surgery, and the role of socioeconomic status (SES).

Methods

We measured depression symptoms using the Beck Depression Inventory (BDI) and household income in the month prior to surgery in 310 participants undergoing elective, first-time, CABG. Participants were followed-up post-operatively to assess the length of their hospital stay.

Results

We showed that greater pre-operative depression symptoms on the BDI were associated with a longer hospital stay (hazard ratio = 0.978, 95% CI 0.957–0.999, p = .043) even after controlling for covariates, with the effect being observed for cognitive symptoms of depression but not somatic symptoms. Lower SES augmented the negative effect of depression on length of stay.

Conclusions

Depression symptoms interact with socioeconomic position to affect recovery following cardiac surgery and further work is needed in order to understand the pathways of this association.     

Prognostic value of the Geneva prediction rule in patients with pulmonary embolism

Background

Assessment of pre-test probability of pulmonary embolism (PE) and prognostic stratification are two widely recommended steps in the management of patients with suspected PE. Some items of the Geneva prediction rule may have a prognostic value.We analyzed whether the initial probability assessed by the Geneva rule was associated with the outcome of patients with PE.

Methods

In a post-hoc analysis of a multicenter trial including 1,693 patients with suspected PE, the all-cause death or readmission rates during the 3-month follow-up of patients with confirmed PE were analyzed. PE probability group was prospectively assessed by the revised Geneva score (RGS). Similar analyses were made with the a posteriori-calculated simplified Geneva score (SGS).

Results

PE was confirmed in 357 patients and 21 (5.9%) died during the 3-month follow-up. The mortality rate differed significantly with the initial RGS group, as with the SGS group. For the RGS, the mortality increased from 0% (95% Confidence Interval: [0–5.4%]) in the low-probability group to 14.3% (95% CI: [6.3-28.2%]) in the high-probability group, and for the SGS, from 0% (95% CI: [0–5.4%] to 17.9% (95% CI: [7.4-36%]). Readmission occurred in 58 out of the 352 patients with complete information on readmission (16.5%). No significant change of readmission rate was found among the RGS or SGS groups.

Conclusions

Returning to the initial PE probability evaluation may help clinicians predict 3-month mortality in patients with confirmed PE.(ClinicalTrials.gov: NCT00117169)