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Population differences in cardiovascular reactivity to the cold pressor test

Duncan MT, Husain R, Chen HM, Horvath SM

Am J Hum Biol, 1995;7(3):329-337.
PMID: 28557027 DOI: 10.1002/ajhb.1310070309

The interaction of race and climatic adaptation on patterns of cardiovascular reactivity among young adult males was examined. Malay and Chinese subjects living in a tropical climate in the Orient and Caucasians living in a sub-tropical climate in North America were investigated. The cold pressor test with hand immersion in cold water was used as the stressor. Systolic and diastolic blood pressures, cardiac frequency, cardiac output, and stroke volume were measured. The results provided limited evidence for absence of differences in cardiac reactivity among racial groups and for greater vascular reactivity in the Caucasians. Cold immersion also elicited differential responses which could be partially attributed to differences in acclimatizations status. © 1995 Wiley-Liss, Inc.

Matched MeSH terms: Systole
Blood pressure variability in patients with diabetes mellitus

Mokhtar RH, Ayob A, Mohd Noor N

Asian Cardiovasc Thorac Ann, 2010 Aug;18(4):344-8.
PMID: 20719784 DOI: 10.1177/0218492310375723

Reduced arterial compliance in patients with diabetes mellitus has been shown in several studies, but it has not been significantly associated with either atherosclerosis or vessel wall thickness. Blood pressure variability is still poorly explored in diabetic patients. The aim of this study was to compare blood pressure variability and arterial compliance in patients with type 2 diabetes mellitus and controls matched for sex, age, and weight. Arterial compliance was measured and noninvasive 24-h ambulatory blood pressure monitoring was performed in 18 diabetic patients and 18 controls. There was significantly higher 24-h systolic blood pressure variability (17.7 +/- 6.8 vs. 14.6 +/- 2.6 mm Hg), diastolic blood pressure variability (15.6 +/- 7.1 vs. 11.4 +/- 3.1 mm Hg), and mean arterial blood pressure variability (14.8 +/- 7.0 vs. 11.1 +/- 2.9) in diabetic patients. Systolic, diastolic, and mean arterial blood pressure variability was significantly higher during daytime but not night time in diabetic patients compared to controls. Diabetic patients also had significantly reduced small artery compliance, but no differences in large artery compliance, cardiac output, or systemic vascular resistance. The findings suggest that hyperglycemia may affect the compliance of the vascular system, resulting in high blood pressure fluctuations.

Matched MeSH terms: Systole
Prospective study to determine the effect of intermittent pneumatic foot and calf compression on popliteal artery peak systolic blood flow

Mokhtar S, Azizi ZA, Govindarajanthran N

Asian J Surg, 2008 Jul;31(3):124-9.
PMID: 18658010

OBJECTIVE: This study investigated the effects of posture and also intermittent foot and calf compression on peak systolic flow of the popliteal artery in a normal population.
METHODS: This was a prospective study carried out in normal subjects at the Vascular Laboratory, Department of Surgery, Hospital Kuala Lumpur, from March 2006 to September 2006. The study compared the popliteal artery blood flow during change of posture from the horizontal (supine) to the sitting position and the effect of intermittent pneumatic compression (IPC) of the foot and calf on popliteal artery blood flow immediately and 10 minutes after cessation of compression.
RESULTS: A total of 15 subjects involving 30 limbs were examined in this study. On comparing flows between the horizontal and sitting position, there was a mean reduction in blood flow of 23% (p < 0.005). Immediately after compression of the foot and calf, there was an increase in blood flow of between 4% and 35% with a mean of 15% (p < 0.05). Peak systolic flows at 10 minutes postcompression were 536 +/- 95 mL/min, which was still significantly higher than precompression measurements.
CONCLUSION: There is a significant reduction in popliteal artery blood flow on changing from the supine to the sitting position. Popliteal artery blood flow is higher than baseline after 15 minutes of intermittent pneumatic foot and calf compression. The increase in popliteal artery blood flow is still present 10 minutes after cessation of IPC.

Matched MeSH terms: Systole
Fulltext Association of physical activity with blood pressure and blood glucose among Malaysian adults: a population-based study

Teh CH, Chan YY, Lim KH, Kee CC, Lim KK, Yeo PS, et al.

BMC Public Health, 2015;15:1205.
PMID: 26630916 DOI: 10.1186/s12889-015-2528-1

The health-enhancing benefits of physical activity (PA) on hypertension and diabetes have been well documented for decades. This study aimed to determine the association of PA with systolic and diastolic blood pressure as well as blood glucose in the Malaysian adult population.

Matched MeSH terms: Systole
Fulltext Leptin increases blood pressure and markers of endothelial activation during pregnancy in rats

Ibrahim HS, Omar E, Froemming GR, Singh HJ

Biomed Res Int, 2013;2013:298401.
PMID: 24167814 DOI: 10.1155/2013/298401

Raised leptin levels have been reported in the placentae and serum of women with elevated blood pressure and proteinuria during pregnancy. The role of leptin in this however remains unknown. This study investigates the effect of leptin administration on systolic blood pressure (SBP) and proteinuria and serum markers of endothelial activation during pregnancy in Sprague Dawley rats. From day 1 of pregnancy, 24 rats were randomised into those given either saline (group 1) or leptin at 60 or 120 μ g/kg/body weight/day (groups 2 and 3 resp.). SBP was measured every 5 days and 24-h urinary protein was measured at days 0 and 20 of pregnancy. Animals were euthanised on day 20 of pregnancy, and serum was collected for estimation of E-selectin and ICAM-1. Compared to group 1, SBP during the latter part of the pregnancy was significantly higher in the leptin-treated group (P < 0.01). Urinary protein excretion, serum E-selectin, and ICAM-1 were significantly higher in leptin-treated rats (P < 0.05). It seems that leptin administration to normotensive Sprague Dawley rats during pregnancy significantly increases SBP, urinary protein excretion, and markers of endothelial activation. However, further studies are required to examine the underlying mechanism responsible for this and its relevance to preeclampsia in humans.

Matched MeSH terms: Systole/drug effects
MiD49 and MiD51: New mediators of mitochondrial fission and novel targets for cardioprotection

Samangouei P, Crespo-Avilan GE, Cabrera-Fuentes H, Hernández-Reséndiz S, Ismail NI, Katwadi KB, et al.

Cond Med, 2018 Aug;1(5):239-246.
PMID: 30338314

Acute myocardial infarction (AMI) and the heart failure (HF) that often follows are among the leading causes of death and disability worldwide. As such novel therapies are needed to reduce myocardial infarct (MI) size, and preserve left ventricular (LV) systolic function in order to reduce the propensity for HF following AMI. Mitochondria are dynamic organelles that can undergo morphological changes by two opposing processes, mitochondrial fusion and fission. Changes in mitochondrial morphology and turnover are a vital part of maintaining mitochondrial health, DNA stability, energy production, calcium homeostasis, cellular division, and differentiation, and disturbances in the balance of fusion and fission can predispose to mitochondrial dysfunction and cell death. Changes in mitochondrial morphology are governed by mitochondrial fusion proteins (Mfn1, Mfn2 and OPA1) and mitochondrial fission proteins (Drp1, hFis1, and Mff). Recent experimental data suggest that mitochondria undergo fission during acute ischemia/reperfusion injury (IRI), generating fragmented dysfunctional mitochondrial and predisposing to cell death. We and others have shown that genetic and pharmacological inhibition of the mitochondrial fission protein Drp1 can protect cardiomyocytes from acute IRI and reduce MI size. Novel components of the mitochondrial fission machinery, mitochondrial dynamics proteins of 49 kDa (MiD49) and mitochondrial dynamics proteins of 51 kDa (MiD51), have been recently described, which have been shown to mediating mitochondrial fission by targeting Drp1 to the mitochondrial surface. In this review article, we provide an overview of MiD49 and MiD51, and highlight their potential as novel therapeutic targets for treating cardiovascular diseases such as AMI, anthracycline cardiomyopathy, and pulmonary arterial hypertension.

Matched MeSH terms: Systole
Systolic hypertension and duration of diabetes mellitus are important determinants of retinopathy and microalbuminuria in young diabetics

Wan Nazaimoon WM, Letchuman R, Noraini N, Ropilah AR, Zainal M, Ismail IS, et al.

Diabetes Res Clin Pract, 1999 Dec;46(3):213-21.
PMID: 10624787 DOI: 10.1016/s0168-8227(99)00095-9

This cross-sectional study looked at the prevalence of microalbuminuria and retinopathy in a cohort of 926 young, Type 1 and Type 2 diabetes mellitus (DM) patients, and determined the factors which were associated with these microvascular complications. The prevalence of microalbuminuria, defined as the albumin:creatinine ratio > or = 2.5 (for males) or > or = 3.5 mg/mmol (for females), was 13.4% in Type 1 DM, 69.5% in insulin-requiring Type 2 DM and 16% in Type 2 DM treated only with oral hypoglycemic agents. Compared to those with normal renal functions, these patients were older (P < or = 0.01), had significantly elevated blood pressures (P < 0.01 or P = 0.0001), and in the case of Type 1 DM, with a higher body mass index (P = 0.0001) and waist-hip ratio (P < 0.01). The prevalence of diabetic retinopathy in Type 1 DM was found to increase with the duration of diabetes, from 1.4% in the newly-onset (< 5 years), to 9.9% in those with 5-10 years disease, to 35% among patients with more than 10 years of diabetes (P < 0.0001). In this study, it was also observed that 10% of the Type 2 DM patients already had retinopathy within 5 years of diagnosis, and the prevalence increased significantly to 42.9% (P < 0.0001) among patients who had been diabetics for more than 10 years. Stepwise multiple regression analysis showed that besides the disease duration, systolic blood pressure was the most common and significant determinant for both microalbuminuria and retinopathy in both types of DM, thus implying that in order to reduce the risk of microvascular complications in diabetes mellitus, systolic and not just the diastolic blood pressure, should be effectively controlled.

Matched MeSH terms: Systole
Fulltext The Role of Speckle Tracking Echocardiography in the Evaluation of Common Inherited Cardiomyopathies in Children and Adolescents: A Systematic Review

Dorobantu DM, Wadey CA, Amir NH, Stuart AG, Williams CA, Pieles GE

Diagnostics (Basel), 2021 Apr 01;11(4).
PMID: 33915862 DOI: 10.3390/diagnostics11040635

Speckle tracking echocardiography (STE) has gained importance in the evaluation of adult inherited cardiomyopathies, but its utility in children is not well characterized. We conducted a systematic review to evaluate the role of STE in pediatric inherited cardiomyopathies. PubMed, EMBASE, Web of Science, Scopus, CENTRAL and CINAHL databases were searched up to May 2020, for terms related to inherited cardiomyopathies and STE. Included were dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), left ventricular non-compaction (LVNC) and arrhythmogenic cardiomyopathy (ACM). A total of 14 cohorts were identified, of which six were in DCM, four in HCM, three in LVNC and one in ACM. The most commonly reported STE measurements were left ventricular longitudinal strain (Sl), circumferential strain (Sc), radial strain (Sr) and rotation/torsion/twist. Sl, Sc and were abnormal in all DCM and LVNC cohorts, but not in all HCM. Apical rotation and twist/torsion were increased in HCM, and decreased in LVNC. Abnormal STE parameters were reported even in cohorts with normal non-STE systolic/diastolic measurements. STE in childhood cardiomyopathies can detect early changes which may not be associated with changes in cardiac function detectable by non-STE methods. Longitudinal and circumferential strain should be introduced in the cardiomyopathy echocardiography protocol, reflecting current practice in adults.

Matched MeSH terms: Systole
Fulltext Intraclass correlation in practice: assessment of reliability of manual blood pressure measurement among assessors in a clinical trial

Wan Nor Arifin, Wan Arfah Nadiah, Muhammad Irfan, Chen, Xin Wee, Nani Draman, Nyi, Nyi Naing

Education in Medicine Journal, 2011;3(2):44-52.
MyJurnal

To ensure the reliability of manual blood pressure (BP) readings in a clinical trial, sources of error due to measurement must be reduced as much as possible. Apart from following standard procedure for BP measurement and ensuring good equipments, the measurement errors that come from the assessors themselves should be assessed. Objective: To demonstrate the use of two-way random effects, interactions absent, absolute agreement (Type A), single measures (Type 1) intraclass correlation coefficient (ICC) in the assessment of reliability of manual BP readings among assessors involved in a clinical trial using manual BP measurement, by using an interrater reliability study conducted by the authors as an example study. Methods: The steps involved in obtaining ICC in the study were discussed. Sample size given the number of assessors in the study was calculated. BP was measured using regularly maintained mercury sphygnomanometers, following recommendations by Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) for BP measurement in office setting. The outcomes were systolic and diastolic BP readings. A type of ICC, two-way random effects, interactions absent, absolute agreement (Type A), single measures (Type 1) ICC was chosen for the analysis and specifically discussed. Pre-requisite assumptions for ICC were meticulously checked and described. The interrater reliability for systolic and diastolic BP readings as expressed by ICC (single measure) were presented with confidence interval (CI). The ICCs obtained in the example study were discussed and concluded. The flaws of the study were also criticised. Results: The interrater reliability for systolic and diastolic BP measurements as expressed by ICC (single measure) were 0.87 (95% confidence interval [CI] 0.722, 0.956) and 0.77 (95% CI 0.560, 0.918) respectively. Conclusion: We demonstrated the steps required to obtain ICC. Since the use of manual BP measurement using mercury sphygmomanometer is still considered as gold standard of BP measurement, it is important that studies in which the BP outcome is measured using such method conduct interrater reliability studies properly.

Matched MeSH terms: Systole
Fulltext Piper sarmentosum Leaves Aqueous Extract Attenuates Vascular Endothelial Dysfunction in Spontaneously Hypertensive Rats

Hashim Fauzy F, Mohd Zainudin M, Ismawi HR, Elshami TFT

Evid Based Complement Alternat Med, 2019;2019:7198592.
PMID: 31485247 DOI: 10.1155/2019/7198592

Piper sarmentosum is a tropical plant in Southeast Asia known for its traditional use in curing various ailments including hypertension. Previous research works have provided evidence for the herb's antihypertensive property. However, the exact mechanisms involved are still in question. The present study investigated the effects of Piper sarmentosum leaves aqueous extract (PSAE) treatment on vascular endothelin system in spontaneously hypertensive rats (SHRs). Four groups of SHRs were treated for 28 consecutive days, with negative and positive control groups receiving distilled water and 3 mg/kg perindopril, respectively. Another two groups are the treatment groups, which received PSAE and combination of 1.5 mg/kg perindopril and PSAE. Weekly measurements of blood pressure showed that PSAE significantly reduced the systolic, diastolic, and mean arterial pressures (P < 0.05) of the rats. PSAE also increased mesenteric artery nitric oxide (NO) level (P < 0.05) and reduced endothelin-1 (ET-1) level (P < 0.05) in the treatment groups. Our results demonstrate that oral administration of PSAE reduced blood pressure in SHRs by reducing the ET-1 level while increasing NO production.

Matched MeSH terms: Systole
Baska mask versus endotracheal tube in laparoscopic cholecystectomy surgery: a prospective randomized trial

Ng CC, Sybil Shah MHB, Chaw SH, Mansor MB, Tan WK, Koong JK, et al.

Expert Rev Med Devices, 2021 Feb;18(2):203-210.
PMID: 33322949 DOI: 10.1080/17434440.2021.1865796

Background: Supraglottic airway devices have increasingly been used as the airway technique of choice in laparoscopic surgeries. This study compared the efficacy and safety of the Baska Mask with endotracheal tube (ETT) in patients undergoing elective laparoscopic cholecystectomy.Research design and methods: This single-center, prospective, randomized controlled trial recruited 60 patients aged 18-75 years with American Society of Anesthesiologists' classifications I to III. The time taken to achieve effective airway, number of attempts, ease of insertion, ventilation parameters, hemodynamics data, and pharyngolaryngeal complications were recorded.Results: The time taken to achieve effective airway was shorter for the Baska group (26.6 ± 4.7 vs. 47.2 ± 11.8 s; p

Matched MeSH terms: Systole
Fulltext Glycaemic Control, Lipid Profile, Blood Pressure and Body Weight Status Among Diabetics in Rural Malaysia

Hazizi, A.S., Zaitun, Y., Kandiah, M., Chan, S.P.

International Medical Journal Malaysia, 2009;8(2):21-28.
MyJurnal

Introduction: Diabetes is associated with a high risk of cardiovascular disease. The management of blood glucose, dyslipidaemia and other modifiable risk factor, is a key element in the multifactorial approach to prevent complications of type 2 diabetes. Materials and Methods: A cross sectional study was conducted to determine the level of glycaemic control, lipid profile, blood pressure and body weight status among type 2 diabetics in rural Malaysia. A total of 237 diabetic subjects participated in this study. Physical examination was carried out, including measurements of height, weight, waist and hip circumferences, and systolic and diastolic blood pressure. Fasting venous blood samples were collected to determine the glucose level and lipid profile. Results: About 70% of the subjects had a high body mass index (BMI), equal to or above 25 kg/m2. More than 60% of the subjects had systolic blood pressure >= 140 mmHg and/or diastolic >=90 mmHg. Mean fasting blood glucose was 9.84±4.54 mmol/L. Mean total cholesterol was 5.18±1.35 mmol/L. High density lipoprotein cholesterol (HDLC) and triglyceride (TG) and glucose levels were higher in male than in female, but not statistically significant (p>0.05). However, low density lipoprotein cholesterol (LDLC) was higher in females than males (p

Matched MeSH terms: Systole
Fulltext Uncomplicated hyperemesis gravidarum does not alter the course of cardiovascular changes during pregnancy

Sheila Rani Kovil George, Sivalingam Nalliah

International e-Journal of Science, Medicine & Education, 2014;8(1):34-43.
MyJurnal

The purpose of this prospective longitudinal study was to investigate the maternal cardiac haemodynamic and structural changes that occur
in pregnancies with uncomplicated hyperemesis gravidarum in a selected Malaysian population. Nine women underwent serial echocardiography beginning at 12 weeks of gestation and throughout pregnancy at monthly intervals. Their echocardiograms were repeated at 6 and 12 weeks following delivery to reflect the pre-pregnancy haemodynamic state. Cardiac output was measured by continuous wave Doppler at the aortic valve. Interventricular septum thickness was determined by M- mode echocardiography and ventricular diastolic function by assessing flow at the mitral valve with Doppler recording. Cardiac output showed an increase of 32.9% at 36 weeks and maintained till 40 weeks of gestation. Heart rate increased from 79 ± 6 to 96 ± 8 beats/min at 36 weeks. Stroke volume increased by 16.4 % at 40 weeks of gestation when compared to the baseline
value. Systolic and diastolic blood pressure did not appreciably change but showed a lower reading during the mid-trimester period. Early inflow velocity of left ventricle did not show a rise while peak atrial velocity showed an increasing trend; thus the ratio of early inflow to peak atrial transport showed a declining trend from early pregnancy to term. End diastolic dimension of left ventricle and interventricular septum thickness showed an increased value at term. Uncomplicated hyperemesis gravidarum did not alter the haemodynamic changes throughout pregnancy and concur with established data for normal pregnancy.

Matched MeSH terms: Systole
The role of infarct transmural extent in infarct extension: A computational study

Leong CN, Lim E, Andriyana A, Al Abed A, Lovell NH, Hayward C, et al.

Int J Numer Method Biomed Eng, 2017 Feb;33(2).
PMID: 27043925 DOI: 10.1002/cnm.2794

Infarct extension, a process involving progressive extension of the infarct zone (IZ) into the normally perfused border zone (BZ), leads to continuous degradation of the myocardial function and adverse remodelling. Despite carrying a high risk of mortality, detailed understanding of the mechanisms leading to BZ hypoxia and infarct extension remains unexplored. In the present study, we developed a 3D truncated ellipsoidal left ventricular model incorporating realistic electromechanical properties and fibre orientation to examine the mechanical interaction among the remote, infarct and BZs in the presence of varying infarct transmural extent (TME). Localized highly abnormal systolic fibre stress was observed at the BZ, owing to the simultaneous presence of moderately increased stiffness and fibre strain at this region, caused by the mechanical tethering effect imposed by the overstretched IZ. Our simulations also demonstrated the greatest tethering effect and stress in BZ regions with fibre direction tangential to the BZ-remote zone boundary. This can be explained by the lower stiffness in the cross-fibre direction, which gave rise to a greater stretching of the IZ in this direction. The average fibre strain of the IZ, as well as the maximum stress in the sub-endocardial layer, increased steeply from 10% to 50% infarct TME, and slower thereafter. Based on our stress-strain loop analysis, we found impairment in the myocardial energy efficiency and elevated energy expenditure with increasing infarct TME, which we believe to place the BZ at further risk of hypoxia. Copyright © 2016 John Wiley & Sons, Ltd.

Matched MeSH terms: Systole
The role of end-diastolic myocardial fibre stretch on infarct extension

Leong CN, Dokos S, Andriyana A, Liew YM, Chan BT, Abdul Aziz YF, et al.

Int J Numer Method Biomed Eng, 2020 01;36(1):e3291.
PMID: 31799767 DOI: 10.1002/cnm.3291

Myocardial infarct extension, a process involving the enlargement of infarct and border zone, leads to progressive degeneration of left ventricular (LV) function and eventually gives rise to heart failure. Despite carrying a high risk, the causation of infarct extension is still a subject of much speculation. In this study, patient-specific LV models were developed to investigate the correlation between infarct extension and impaired regional mechanics. Subsequently, sensitivity analysis was performed to examine the causal factors responsible for the impaired regional mechanics observed in regions surrounding the infarct and border zone. From our simulations, fibre strain, fibre stress and fibre stress-strain loop (FSSL) were the key biomechanical variables affected in these regions. Among these variables, only FSSL was correlated with infarct extension, as reflected in its work density dissipation (WDD) index value, with high WDD indices recorded at regions with infarct extension. Impaired FSSL is caused by inadequate contraction force generation during the isovolumic contraction and ejection phases. Our further analysis revealed that the inadequacy in contraction force generation is not necessarily due to impaired myocardial intrinsic contractility, but at least in part, due to inadequate muscle fibre stretch at end-diastole, which depresses the ability of myocardium to generate adequate contraction force in the subsequent systole (according to the Frank-Starling law). Moreover, an excessively stiff infarct may cause its neighbouring myocardium to be understretched at end-diastole, subsequently depressing the systolic contractile force of the neighbouring myocardium, which was found to be correlated with infarct extension.

Matched MeSH terms: Systole/physiology
Impact of myocardial infarction on intraventricular vortex and flow energetics assessed using computational simulations

Chan BT, Ahmad Bakir A, Al Abed A, Dokos S, Leong CN, Ooi EH, et al.

Int J Numer Method Biomed Eng, 2019 06;35(6):e3204.
PMID: 30912313 DOI: 10.1002/cnm.3204

Flow energetics have been proposed as early indicators of progressive left ventricular (LV) functional impairment in patients with myocardial infarction (MI), but its correlation with individual MI parameters has not been fully explored. Using electro-fluid-structure interaction LV models, this study investigated the correlation between four MI parameters: infarct size, infarct multiplicity, regional enhancement of contractility at the viable myocardium area (RECVM), and LV mechanical dyssynchrony (LVMD) with intraventricular vortex and flow energetics. In LV with small infarcts, our results showed that infarct appearance amplified the energy dissipation index (DI), where substantial viscous energy loss was observed in areas with high flow velocity and near the infarct-vortex interface. The LV with small multiple infarcts and RECVM showed remarkable DI increment during systole and diastole. In correlation analysis, the systolic kinetic energy fluctuation index (E') was positively related to ejection fraction (EF) (R2 = 0.982) but negatively correlated with diastolic E' (R2 = 0.970). Diastolic E' was inversely correlated with vortex kinetic energy (R2 = 0.960) and vortex depth (R2 = 0.876). We showed an excessive systolic DI could differentiate infarcted LV with normal EF from healthy LV. Strong flow acceleration, LVMD, and vortex-infarct interactions were predominant factors that induced excessive DI in infarcted LVs. Instead of causing undesired flow turbulence, high systolic E' suggested the existence of energetic flow acceleration, while high diastolic E' implied an inefficient diastolic filling. Thus, systolic E' is not a suitable early indicator for progressive LV dysfunction in MI patients, while diastolic E' may be a useful index to indicate diastolic impairment in these patients.

Matched MeSH terms: Systole
The role of regional myocardial topography post-myocardial infarction on infarct extension

Leong CO, Leong CN, Liew YM, Al Abed A, Aziz YFA, Chee KH, et al.

Int J Numer Method Biomed Eng, 2021 08;37(8):e3501.
PMID: 34057819 DOI: 10.1002/cnm.3501

Infarct extension involves necrosis of healthy myocardium in the border zone (BZ), progressively enlarging the infarct zone (IZ) and recruiting the remote zone (RZ) into the BZ, eventually leading to heart failure. The mechanisms underlying infarct extension remain unclear, but myocyte stretching has been suggested as the most likely cause. Using human patient-specific left-ventricular (LV) numerical simulations established from cardiac magnetic resonance imaging (MRI) of myocardial infarction (MI) patients, the correlation between infarct extension and regional mechanics abnormality was investigated by analysing the fibre stress-strain loops (FSSLs). FSSL abnormality was characterised using the directional regional external work (DREW) index, which measures FSSL area and loop direction. Sensitivity studies were also performed to investigate the effect of infarct stiffness on regional myocardial mechanics and potential for infarct extension. We found that infarct extension was correlated to severely abnormal FSSL in the form of counter-clockwise loop at the RZ close to the infarct, as indicated by negative DREW values. In regions demonstrating negative DREW values, we observed substantial fibre stretching in the isovolumic relaxation (IVR) phase accompanied by a reduced rate of systolic shortening. Such stretching in IVR phase in part of the RZ was due to its inability to withstand the high LV pressure that was still present and possibly caused by regional myocardial stiffness inhomogeneity. Further analysis revealed that the occurrence of severely abnormal FSSL due to IVR fibre stretching near the RZ-BZ boundary was due to a large amount of surrounding infarcted tissue, or an excessively stiff IZ.

Matched MeSH terms: Systole
Global Burden of Hypertension and Systolic Blood Pressure of at Least 110 to 115 mm Hg, 1990-2015

Forouzanfar MH, Liu P, Roth GA, Ng M, Biryukov S, Marczak L, et al.

JAMA, 2017 01 10;317(2):165-182.
PMID: 28097354 DOI: 10.1001/jama.2016.19043

Importance: Elevated systolic blood (SBP) pressure is a leading global health risk. Quantifying the levels of SBP is important to guide prevention policies and interventions.
Objective: To estimate the association between SBP of at least 110 to 115 mm Hg and SBP of 140 mm Hg or higher and the burden of different causes of death and disability by age and sex for 195 countries and territories, 1990-2015.
Design: A comparative risk assessment of health loss related to SBP. Estimated distribution of SBP was based on 844 studies from 154 countries (published 1980-2015) of 8.69 million participants. Spatiotemporal Gaussian process regression was used to generate estimates of mean SBP and adjusted variance for each age, sex, country, and year. Diseases with sufficient evidence for a causal relationship with high SBP (eg, ischemic heart disease, ischemic stroke, and hemorrhagic stroke) were included in the primary analysis.
Main Outcomes and Measures: Mean SBP level, cause-specific deaths, and health burden related to SBP (≥110-115 mm Hg and also ≥140 mm Hg) by age, sex, country, and year.
Results: Between 1990-2015, the rate of SBP of at least 110 to 115 mm Hg increased from 73 119 (95% uncertainty interval [UI], 67 949-78 241) to 81 373 (95% UI, 76 814-85 770) per 100 000, and SBP of 140 mm Hg or higher increased from 17 307 (95% UI, 17 117-17 492) to 20 526 (95% UI, 20 283-20 746) per 100 000. The estimated annual death rate per 100 000 associated with SBP of at least 110 to 115 mm Hg increased from 135.6 (95% UI, 122.4-148.1) to 145.2 (95% UI 130.3-159.9) and the rate for SBP of 140 mm Hg or higher increased from 97.9 (95% UI, 87.5-108.1) to 106.3 (95% UI, 94.6-118.1). For loss of DALYs associated with systolic blood pressure of 140 mm Hg or higher, the loss increased from 95.9 million (95% uncertainty interval [UI], 87.0-104.9 million) to 143.0 million (95% UI, 130.2-157.0 million) [corrected], and for SBP of 140 mm Hg or higher, the loss increased from 5.2 million (95% UI, 4.6-5.7 million) to 7.8 million (95% UI, 7.0-8.7 million). The largest numbers of SBP-related deaths were caused by ischemic heart disease (4.9 million [95% UI, 4.0-5.7 million]; 54.5%), hemorrhagic stroke (2.0 million [95% UI, 1.6-2.3 million]; 58.3%), and ischemic stroke (1.5 million [95% UI, 1.2-1.8 million]; 50.0%). In 2015, China, India, Russia, Indonesia, and the United States accounted for more than half of the global DALYs related to SBP of at least 110 to 115 mm Hg.
Conclusions and Relevance: In international surveys, although there is uncertainty in some estimates, the rate of elevated SBP (≥110-115 and ≥140 mm Hg) increased substantially between 1990 and 2015, and DALYs and deaths associated with elevated SBP also increased. Projections based on this sample suggest that in 2015, an estimated 3.5 billion adults had SBP of at least 110 to 115 mm Hg and 874 million adults had SBP of 140 mm Hg or higher.

Matched MeSH terms: Systole
Fulltext Prevalence of prehypertension and its associated factors among adults visiting outpatient clinic in Northeast Malaysia

Rafan SN, Zakaria R, Ismail SB, Muhamad R

J Taibah Univ Med Sci, 2018 Oct;13(5):459-464.
PMID: 31435362 DOI: 10.1016/j.jtumed.2018.06.005

Objectives: Prehypertension refers to a systolic blood pressure of 120-139 mmHg systolic or a diastolic blood pressure of 80-89 mmHg. Estimation of the prevalence of prehypertension in the population and identification of cardiovascular associated factors are important to reduce progression to hypertension. This study aimed to determine the prevalence of prehypertension and its associated factors among Malaysian adults.
Methods: In 2015, a cross-sectional study was conducted among adults visiting an outpatient clinic in Northeast Malaysia. Face-to-face interviews were conducted using Malay and English versions of the Malaysia Non-Communicable Disease surveillance questionnaire. This instrument captured information about sociodemographic, lifestyle status, and anthropometric data. Blood pressure was measured three times with a sphygmomanometer, the first measurement value was discarded, and an average of blood pressure from the second two readings was recorded for further data analysis. Logistic regression was performed to analyse factors associated with prehypertension.
Result: A total 151 adults participated in the study, and the prevalence of prehypertension was 37.1% (95% confidence interval [CI]: 29.29, 44.69). Factors associated with prehypertension in this study were age (adjusted odds ratio [aOR] = 1.06 95% CI: 1.02, 1.11; p = 0.007), male sex (aOR = 4.44 95% CI: 1.58, 12.44; p = 0.005), and abnormal waist circumference (aOR = 31.65 95% CI: 11.25, 89.02; p

Matched MeSH terms: Systole
Effects of sevoflurane increments on left ventricular systolic long-axis performance during sevoflurane-remifentanil anesthesia for cardiovascular surgery

Kwon WK, Sung TY, Yu GY, Sidik H, Kang WS, Lee Y, et al.

J Anesth, 2016 Apr;30(2):223-31.
PMID: 26577248 DOI: 10.1007/s00540-015-2094-9

BACKGROUND: The direct impact of sevoflurane on intraoperative left ventricular (LV) systolic performance during cardiac surgery has not been fully elucidated. Peak systolic tissue Doppler velocities of the lateral mitral annulus (S') have been used to evaluate LV systolic long-axis performance. We hypothesized that incremental sevoflurane concentration (1.0-3.0 inspired-vol%) would dose-dependently reduce S' in patients undergoing cardiac surgery due to mitral or aortic insufficiency.
METHODS: In 20 patients undergoing cardiac surgery in sevoflurane-remifentanil anesthesia, we analyzed intraoperative S' values which were determined after 10 min exposure to sevoflurane at 1.0, 2.0, and 3.0 inspired-vol% (T1, T2, and T3, respectively) with a fixed remifentanil dose (1.0 μg/kg/min) using transesophageal echocardiography.
RESULTS: Linear mixed-effect modeling demonstrated dose-dependent declines in S' according to the end-tidal sevoflurane concentration increments (C(ET)-sevoflurane, p < 0.001): the mean value of S' reduction for each 1.0 vol%-increment of C(ET)-sevoflurane was 1.7 cm/s (95 % confidence interval 1.4-2.1 cm/s). Medians of S' at T1, T2, and T3 (9.6, 8.9, and 7.5 cm/s, respectively) also exhibited significant declines (by 6.6, 15.6, and 21.2 % for T1 vs. T2, T2 vs. T3, and T1 vs. T3, p < 0.001, =0.002, and <0.001 in Friedman pairwise comparisons, respectively).
CONCLUSIONS: Administering sevoflurane as a part of a sevoflurane-remifentanil anesthesia regimen appears to dose-dependently reduce S', indicating LV systolic performance, in patients undergoing cardiac surgery. Further studies may be required to evaluate the clinical implications of these findings.

Matched MeSH terms: Systole

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