Variability of Near-Fainting Responses in Healthy 6–16-Year-old Subjects

1. Fainting is a common phenomenon in young subjects, but the final events before the actual faint are not well known. The aim of the present study was to study the inter-individual variability of haemodynamic events associated with near-fainting in children and teenagers. 2. Sixty-eight healthy subjects (aged 6–16 years) performed a 70° tilt-up test with intravascular instrumentation for 5 min. Responses in 29 near-fainting subjects were analysed and compared with 39 non-fainting subjects. Arterial pressure was measured by Finapres. Left ventricular stroke volume was computed from the pressure pulsation waveform. 3. Inability to maintain vasomotor tone was the mechanism underlying near-fainting in the vast majority of near-fainting subjects. The three classical haemodynamic responses (vasovagal, vasodepressor and vagal) could be recognized, but large individual differences were found. After tilt back, blood pressure in near-fainters showed a mirror response to the stage before tilt-back; blood pressure gradually increased and was normal at 1 min after tilt-back. 4. The variability in haemodynamic responses on approach of an orthostatic faint is wide in the young.

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Joint Modelling Of Individual Trajectories, Within-Individual Variability And A Later Outcome: Systolic Blood Pressure Through Childhood And Left Ventricular Mass In Early Adulthood

American Journal of Epidemiology ◽

10.1093/aje/kwaa224 ◽

2020 ◽

Author(s):

Richard M A Parker ◽

George Leckie ◽

Harvey Goldstein ◽

Laura D Howe ◽

Jon Heron ◽

...

Keyword(s):

Blood Pressure ◽

Left Ventricular Mass ◽

Random Effect ◽

Early Adulthood ◽

Credible Interval ◽

Left Ventricular ◽

Individual Variability ◽

Joint Modelling ◽

Ventricular Mass ◽

Modelling Approach

Abstract Within-individual variability of repeatedly-measured exposures may predict later outcomes: e.g. blood pressure (BP) variability (BPV) is an independent cardiovascular risk factor above and beyond mean BP. Since two-stage methods, known to introduce bias, are typically used to investigate such associations, we introduce a joint modelling approach, examining associations of mean BP and BPV across childhood to left ventricular mass (indexed to height; LVMI) in early adulthood with data (collected 1990-2011) from the UK’s Avon Longitudinal Study of Parents and Children cohort. Using multilevel models, we allow BPV to vary between individuals (a “random effect”) as well as to depend on covariates (allowing for heteroscedasticity). We further distinguish within-clinic variability (“measurement error”) from visit-to-visit BPV. BPV was predicted to be greater at older ages, at higher bodyweights, and in females, and was positively correlated with mean BP. BPV had a weak positive association with LVMI (10% increase in within-individual BP variance was predicted to increase LVMI by 0.21% (95% credible interval: -0.23%, 0.69%)), but this association became negative (-0.78%, 95% credible interval: -2.54%, 0.22%)) once the effect of mean BP on LVMI was adjusted for. This joint modelling approach offers a flexible method of relating repeatedly-measured exposures to later outcomes.

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Supernormal Left Ventricular Performance in Young Subjects with Mild Hypertension: An Alerting Response to the Echocardiographic Procedure?

Clinical Science ◽

10.1042/cs0910275 ◽

1996 ◽

Vol 91 (3) ◽

pp. 275-281 ◽

Cited By ~ 1

Author(s):

Paolo Palatini ◽

Pieralberto Visentin ◽

Gianluigi Nicolosi ◽

Vincenzo Mione ◽

Paolo Stritoni ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Systolic Blood Pressure ◽

Systolic Function ◽

Blood Pressure Monitoring ◽

Left Ventricular Systolic Function ◽

Left Ventricular ◽

Ventricular Performance ◽

Young Subjects ◽

Mild Hypertensive

1. To assess the clinical significance of supernormal left ventricular systolic function in the initial phase of hypertension, 635 never-treated 18–45-year-old borderline to mild hypertensive subjects (477 males, 158 females) were studied. All subjects underwent echocardiography, 24 h ambulatory blood pressure monitoring and 24 h urine collection for catecholamine dosage. 2. Subjects whose left ventricular shortening-stress relationship was above the 95% confidence intervals of 50 normotensive subjects of similar age and sex distribution were defined as having supernormal function. 3. Age, duration of hypertension and left ventricular mass were similar in the hypertensive subjects with normal (85%) and supernormal (15%) ejective performance. Subjects with supernormal function showed higher office systolic blood pressure (P < 0001), office heart rate (P = 0.03) and cardiac index (P < 0001). Conversely, 24 h systolic blood pressure, 24 h heart rate and 24 h catecholamine output did not differ according to left ventricular function. 4. In conclusion, the greater white-coat effect and the normal baseline sympathetic tone exhibited by the patients with increased performance suggest that supernormal left ventricular pump function is only a marker of the alerting reaction elicited by the echocardiographic examination.

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Abstract 12605: Defining the Reference Range for Left Ventricular Strain by Echocardiography in Healthy Subjects: A Novel Meta-analysis Strategy

Circulation ◽

10.1161/circ.142.suppl_3.12605 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Tom Kai Ming Wang ◽

Milind Y Desai ◽

Patrick H Collier ◽

Richard A Grimm ◽

Brian Griffin ◽

...

Keyword(s):

Blood Pressure ◽

Confidence Intervals ◽

Healthy Subjects ◽

Meta Analysis ◽

Left Ventricular ◽

Reference Ranges ◽

Global Strain ◽

Echocardiographic Parameters ◽

The Mean ◽

2D And 3D

Background: Left ventricular global longitudinal strain (LVGLS), circumferential strain (LVGCS) and radial strain (LVGRS) are established echocardiographic parameters of systolic function with wide clinical applicability and prognostic implications. Despite this, the reference ranges of left ventricular (LV) strain, particularly the lower limit of normal (LLN), are not well established. This meta-analysis aims to determine the mean and LLN of two- (2D) and three-dimensional (3D) LV strain in healthy subjects and factors that may influence strain measurements. Methods: We searched Pubmed, Embase and Cochrane databases until 30 November 2019 for studies reporting left ventricular (LV) global strain in at least 50 healthy subjects. We pooled the mean and LLN of 2D and 3D LV strain using random-effects models, and performed subgroup and meta-regression analysis for 2D-LVGLS. Results: Forty-four studies were eligible totaling 8747 subjects. The pooled means and LLNs (95% confidence intervals) were -20.0% (-20.6%, -19.5%) and -15.6% (-16.2%, -15.0%) respectively for 2D-LVGLS; -22.1% (-23.7%, -20.5%) and -15.7% (-17.3%, -14.1%) respectively for 2D-LVGCS; and 48.0% (43.8%, 52.1%) and 23.2% (20.9%, 25.5%) respectively for 2D-LVGRS; all listed in Table 1. Significant heterogeneity was observed for almost all pooled LV strain analyses. The only factors associated with significant differences in both pooled mean and LLN of 2D-LVGLS were systolic blood pressure and vendor software. Conclusion: Pooled means and LLNs of 2D- and 3D- LV global strain parameters in healthy subjects were reported. Based on the pooled LLNs and their confidence intervals, the thresholds for abnormal, borderline and normal LV strains can be defined. Systolic blood pressure and vendor software were the most important parameters influencing 2D-LVGLS mean and LLN. Our novel methodology can also be applied to the meta-analysis of other echocardiographic parameters to define reference ranges.

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Genetics of cardiomyopathies: left ventricular non-compaction

ESC CardioMed ◽

10.1093/med/9780198784906.003.0156_update_001 ◽

2018 ◽

pp. 697-699

Author(s):

Eloisa Arbustini ◽

Alessandro Di Toro ◽

Lorenzo Giuliani ◽

Nupoor Narula ◽

Valentina Favalli

Keyword(s):

Congenital Heart Disease ◽

Heart Disease ◽

Healthy Subjects ◽

Congenital Heart ◽

Left Ventricular ◽

Individual Variability ◽

Left Ventricular Dilation ◽

Normal Left Ventricular ◽

And Function ◽

Ventricular Trabeculae

Left ventricular non-compaction (LVNC) describes a ventricular wall anatomy, characterized by prominent left ventricular trabeculae, a thin compacted layer, and deep intertrabecular recesses. Individual variability is extreme. The trabecular configuration represents a type of individual dynamic ‘cardioprinting’. On its own, the diagnosis of LVNC does not coincide with that of a ‘cardiomyopathy’ because it can be observed in healthy subjects with normal left ventricular size and function, and it can be acquired and reversible. Rarely, LVNC is intrinsically part of a cardiomyopathy: the paradigmatic examples are infantile tafazzinopathies. The prevalence of LVNC in healthy athletes, its possible reversibility, and increasing diagnosis in healthy subjects suggest cautious use of the term LVNC cardiomyopathy, which describes the morphology, but not the functional profile of the cardiomyopathy or the associated congenital disease. Therefore, when associated with left ventricular dilation and dysfunction, hypertrophy, or congenital heart disease, the leading diagnosis is cardiomyopathy or congenital heart disease followed by the addition of the descriptor LVNC.

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Myocardial oxygen consumption and coronary blood flow in hypothermia

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1959.196.4.719 ◽

1959 ◽

Vol 196 (4) ◽

pp. 719-725 ◽

Cited By ~ 19

Author(s):

A. Gerola ◽

H. Feinberg ◽

L. N. Katz

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Oxygen Consumption ◽

Coronary Flow ◽

Myocardial Oxygen Consumption ◽

Control Period ◽

Mechanical Efficiency ◽

Individual Variability ◽

Large Individual ◽

Oxygen Requirement

Effects of hypothermia (at 32° and 27°C) were determined in the open-chest anesthetized dog prepared for measurement of total coronary flow and myocardial oxygen consumption. When hypothermia was induced at any fixed cardiac output, cardiac oxygen consumption and heart rate declined while blood pressure remained constant. Cardiac external mechanical efficiency increased at the same time. Hypothermia did not alter the relationship between the myocardial oxygen requirement and the total cardiac effort as indicated by the product of blood pressure times heart rate. Without regard to the large individual variability, the coronary venous O2 rose; thus the general trend during the induction of hypothermia was a decline in the coronary A-V oxygen difference, the percentage O2 extracted by the heart and the ratio: cardiac O2 consumption/O2 availability. The coronary venous O2 content and the coronary A-V O2 difference remained fairly constant as the cardiac effort and its oxygen requirement varied during hypothermia, just as in the control period. Thus coronary flow was the only means of adjusting to the altered cardiac oxygen need in both periods.

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Genetics of cardiomyopathies: left ventricular non-compaction

ESC CardioMed ◽

10.1093/med/9780198784906.003.0156 ◽

2018 ◽

pp. 697-699

Author(s):

Eloisa Arbustini ◽

Alessandro Di Toro ◽

Lorenzo Giuliani ◽

Nupoor Narula ◽

Valentina Favalli

Keyword(s):

Congenital Heart Disease ◽

Heart Disease ◽

Healthy Subjects ◽

Congenital Heart ◽

Left Ventricular ◽

Individual Variability ◽

Left Ventricular Dilation ◽

Normal Left Ventricular ◽

And Function ◽

Ventricular Trabeculae

Left ventricular non-compaction (LVNC) describes a ventricular wall anatomy characterized by prominent left ventricular trabeculae, a thin compacted layer, and deep intertrabecular recesses. Individual variability is extreme. The trabecular configuration represents a type of individual ‘cardioprinting’. By itself, the diagnosis of LVNC does not coincide with that of a ‘cardiomyopathy’ because it can be observed in healthy subjects with normal left ventricular size and function, and it can be acquired and reversible. Rarely, LVNC is intrinsically part of a cardiomyopathy: the paradigmatic examples are infantile tafazzinopathies. The prevalence of LVNC in healthy athletes, its possible reversibility, and increasing diagnosis in healthy subjects suggests cautious use of the term ‘LVNC cardiomyopathy’, which describes the morphology, but not the morpho-functional profile of the cardiomyopathy or the associated congenital disease. Therefore, when associated with left ventricular dilation and dysfunction, hypertrophy, or congenital heart disease, the leading diagnosis is the cardiomyopathy or the congenital heart disease followed by the addition of the descriptor LVNC.

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Parameters of Vascular Tone Regulation and Gene Polymorphism Associated With Cardiovascular Risk in Young Subjects

10.21203/rs.3.rs-916152/v1 ◽

2021 ◽

Author(s):

Anastasiya Elkina ◽

Natalya Akimova ◽

Yury Shvarts ◽

Ivan Sokolov

Keyword(s):

Blood Pressure ◽

Cardiovascular Risk ◽

Healthy Subjects ◽

Vascular Tone ◽

Prognostic Significance ◽

Vascular Pathology ◽

Exclusion Criteria ◽

Polymorphic Variants ◽

Standing Test ◽

Young Subjects

Abstract Introduction. Dysregulation of vascular tone (VT) is one of the cardiovascular risk factors that significantly worsens the quality of life, and can be a predictor for persistent hypertension (HTN). The identification of preclinical stages of vascular pathology is the most promising for prevention of hypertension. Therefore, it is important to investigate the polymorphism of genes which end products are involved in the regulation of blood pressure (BP) and predispose to VT dysregulation.Objective. To investigate the clinical and prognostic significance of the AGT and AGTR1 polymorphic variants associated with increased cardiovascular risk in young and relatively healthy subjects and patients with HTN. Materials and methods. The study involved 90 young healthy subjects and 62 patients with hypertension. The exclusion criteria for young subjects were as follows: organic cardiovascular and central nervous system disorders and smoking. The exclusion criteria for patients with HTN were identical. Additionally, the patients with uncontrolled HTN were not included. The VT regulation was assessed by the active standing test in which the changes in blood pressure (BP) and heart rate (HR) were measured. The polymorphism was identified using DNA pyrosequencing.Results. The relationship between BP and HR and the AGTR1 A1666C A>C and AGT M268T T>C variants was established. Both in young subjects and hypertensive patients was found that the C allele of the AGTR1 A1666C A>C variant was associated with lower HR in supine compared with subjects without this allele. The risk allele C of the M268T T>C polymorphism was associated with lower sBP and dBP during the 1st minute of upright posture. The identified features can probably be explained by the vascular tone increased at baseline in the presence of these polymorphic variants which was manifested by smaller changes in BP and HR during the active standing test compared to subjects without these allelic variants. The C allele of the AGTR1 A1666C A>C variant was associated with earlier onset of HTN.Conclusion. The identification of the AGTR1 A1666C A>C and AGT M268T T>C variants can be informative for clarifying the risk of HTN when the young subjects are examined, as well as the probability of early onset of hypertension.

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Non-invasive assessment of left ventricular myocardial work in healthy subjects with echocardiography

Medical alphabet ◽

10.33667/2078-5631-2020-14-45-52 ◽

2020 ◽

Vol 1 (14) ◽

pp. 45-52

Author(s):

M. N. Alekhin ◽

S. I. Ivanov ◽

A. I. Stepanova

Keyword(s):

Blood Pressure ◽

Healthy Subjects ◽

Global Longitudinal Strain ◽

Negative Relationship ◽

Left Ventricular ◽

Healthy Individuals ◽

Men And Women ◽

Mean Values ◽

Non Invasive ◽

Constructive Work

Purpose: to evaluate the left ventricular (LV) echocardiographic indices of myocardial work using the LV pressure-strain loops method in healthy individuals.Material and methods. The study included 50 healthy subjects (28 men, mean age: 44 ± 14 years). The inclusion criteria were the absence of any cardiovascular diseases and diabetes mellitus. After calculating global longitudinal strain (GLS) from speckle-tracking Echo and inserting values of brachial artery cuff blood pressure (BP), the vendor-specific module constructed non-invasive LV pressure-strain loops. The following parameters were calculated: global myocardial work index (GWI), global constructive work (GCW), global wasted work (GWW), global work efficiency (GWE).Results. The lowest values of GWI in men and women were 1382 mmHg% and 1821 mmHg%, the highest values were 2875 mmHg% and 2589 mmHg%, mean values were 2056 ± 326 mmHg% and 2109 ± 200 mmHg%, respectively. Mean values of GCW were 2292 ± 329 mmHg% in men and 2304 ± 211 mmHg% in women. The median and the highest value of GWW were 66 mmHg% and 313 mmHg% in men and 79,5 mmHg% and 172 mmHg% in women, respectively. The lowest value of GWE were 89% in men and 91% in women. GWI was significantly and naturally correlated only with systolic BP (r = 0,30, р = 0,03) and GLS (r = -0,72, р < 0,001). GCW was significantly correlated with systolic BP (r = 0,36, р = 0,01) and GLS (r = -0,72, р < 0,001) too, however, the negative relationship with the age of the patients was found (r = -0,27, р = 0,04). LV myocardial work indices did not significantly differ between men and women. Coefficients of variation for GWI, GCW and GWE did not exceed 10%, which is typical for good reproducible indices.Conclusion. The study presents values of the echocardiographic LV myocardial work indices, obtained with help of the LV pressure-strain loops method in healthy individuals. The natural correlation of LV myocardial work indices with strain and blood pressure was demonstrated, as well as a dependence on the age of the subjects and good reproducibility.

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Role of Adrenergic Overactivity and Pressure Overload in the Pathogenesis of Left Ventricular Hypertrophy in Borderline and Sustained Essential Hypertension in Man

Clinical Science ◽

10.1042/cs063379s ◽

1982 ◽

Vol 63 (s8) ◽

pp. 379s-381s ◽

Cited By ~ 2

Author(s):

Luigi Corea ◽

Maurizio Bentivoglio ◽

Paolo Verdecchia ◽

Mario Motolese

Keyword(s):

Blood Pressure ◽

Left Ventricular Hypertrophy ◽

Plasma Renin Activity ◽

Healthy Subjects ◽

Ventricular Hypertrophy ◽

Plasma Renin ◽

Posterior Wall ◽

Left Ventricular ◽

Hypertensive Patients ◽

Borderline Hypertension

1. In 16 borderline and 18 sustained hypertensive patients, interventricular septal thicknesses (by echocardiography) were greater than those found in 18 healthy subjects. Values in borderline and sustained hypertensives did not differ significantly. 2. In healthy subjects and borderline hypertensive patients, posterior wall thicknesses were normal, whereas they were greater in sustained hypertensive patients than in the former two groups. 3. In borderline hypertension, interventricular septal thickness was positively correlated with resting supine (r = 0.89, P < 0.001) as well as upright (r = 0.60, P < 0.01) plasma noradrenaline, but not with adrenaline, plasma renin activity and mean blood pressure. 4. In sustained hypertension, posterior wall thickness was positively correlated with mean blood pressure (r = 0.85, P < 0.001), but not with noradrenaline, adrenaline and plasma renin activity. 5. In human hypertension, left ventricular hypertrophy seems to involve only the interventricular septum in the borderline stage, extending to the posterior wall in the sustained stage. Adrenergic overactivity could play an important role in development of interventricular septal hypertrophy in borderline hypertension, whereas pressor factors could be mainly involved in the development of posterior wall hypertrophy in sustained hypertension.

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Cyclooxygenase inhibition augments central blood pressure and aortic wave reflection in aging humans

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00032.2012 ◽

2012 ◽

Vol 302 (12) ◽

pp. H2629-H2634 ◽

Cited By ~ 8

Author(s):

Jill N. Barnes ◽

Darren P. Casey ◽

Casey N. Hines ◽

Wayne T. Nicholson ◽

Michael J. Joyner

Keyword(s):

Blood Pressure ◽

Arterial Pressure ◽

Wave Reflection ◽

Diastolic Pressure ◽

Augmentation Index ◽

Left Ventricular ◽

Central Blood Pressure ◽

Cox Inhibitor ◽

Older Subjects ◽

Young Subjects

The augmentation index and central blood pressure increase with normal aging. Recently, cyclooxygenase (COX) inhibitors, commonly used for the treatment of pain, have been associated with transient increases in the risk of cardiovascular events. We examined the effects of the COX inhibitor indomethacin (Indo) on central arterial hemodynamics and wave reflection characteristics in young and old healthy adults. High-fidelity radial arterial pressure waveforms were measured noninvasively by applanation tonometry before (control) and after Indo treatment in young (25 ± 5 yr, 7 men and 6 women) and old (64 ± 6 yr, 5 men and 6 women) subjects. Aortic systolic (control: 115 ± 3 mmHg vs. Indo: 125 ± 5 mmHg, P < 0.05) and diastolic (control: 74 ± 2 mmHg vs. Indo: 79 ± 3 mmHg, P < 0.05) pressures were elevated after Indo treatment in older subjects, whereas only diastolic pressure was elevated in young subjects (control: 71 ± 2 mmHg vs. Indo: 76 ± 1 mmHg, P < 0.05). Mean arterial pressure increased in both young and old adults after Indo treatment ( P < 0.05). The aortic augmentation index and augmented pressure were elevated after Indo treatment in older subjects (control: 30 ± 5% vs. Indo 36 ± 6% and control 12 ± 1 mmHg vs. Indo: 18 ± 2 mmHg, respectively, P < 0.05), whereas pulse pressure amplification decreased (change: 8 ± 3%, P < 0.05). In addition, older subjects had a 61 ± 11% increase in wasted left ventricular energy after Indo treatment ( P < 0.05). In contrast, young subjects showed no significant changes in any of the variables of interest. Taken together, these results demonstrate that COX inhibition with Indo unfavorably increases central wave reflection and augments aortic pressure in old but not young subjects. Our results suggest that aging individuals have a limited ability to compensate for the acute hemodynamic changes caused by systemic COX inhibition.

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