BACKGROUND: Previous research has shown that the ventilatory threshold (VT) correlates highly with onset of lactate accumulation and maximal steady-state exercise (MSS) level. Also, studies have shown the VT is useful in prescribing exercise for cardiac patients in that it gives an exercise intensity at which the patient is metabolically stable. METHODS: The purpose of this study was to determine if a MSS response could be achieved at an exercise intensity corresponding to the VT for patients with CAD. A group of 31 patients with CAD performed a maximal effort treadmill exercise test in which respiratory gas exchange was measured. The VT was determined using the V-slope method of computer regression analysis of the plot of carbon dioxide production versus oxygen consumption. Subjects then performed a constant load treadmill test a speed and grade that corresponded to the VT. Heart rate (HR), systolic blood pressure (SBP), and rating of perceived exertion (RPE) evaluated for steady-state responses. If subjects showed a steady-state response in two of these three parameters they were scored as having achieved a maximal steady-state (MSS+) response; those not meeting this standard were scored as failing to achieve maximal steady-state (MSS-) response. Subjects were analyzed as an entire group (N=31), as well as analyzed in subsets according to history of myocardial infarction (MI+, N=20; MI-, N=11) and administration of beta-blocker medications (BB+, N=16; BB-, N=15). RESULTS: Overall, subjects demonstrated significantly more MSS+ responses than MSS- responses (80% Vs 20%, P<0.05). Analysis of the subgroup data showed that it was the patient s with a history of MI (MI+ =85%, P<0.05) and those not receiving beta-blocker medications (BB- = 93%, P<0.05) who had significantly greater proportions of subject achieving MSS+ responses in the fixed load exercise condition. Conversely patient in the MI- (73 %, P < 0.05) and BB (69% P < 0.05) groups showed no significant differences in the number of MSS+ and MSS- responses. CONCLUSIONS: The VT, as measured during ramp exercise testing on the treadmill, provided a basis for establishing a maximal steady-state load in terms of cardiovascular and perceptual variables for 80% of the patients in the CAD study group. The measurements of HR, SBP, and RPE are easily obtained in a clinical setting and thus enable the VT to be used in bringing about a more efficacious exercise prescription. The validity of this method may be questioned, however, for patient with out a history of MI and for those receiving beta-blocker medications. / Master of Science

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20283号 / 医博第4242号 / 新制||医||1021(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 湊谷 謙司, 教授 福原 俊一, 教授 横出 正之 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21666号 / 医博第4472号 / 新制||医||1035(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 松田 文彦, 教授 佐藤 俊哉, 教授 Shohab YOUSSEFIAN / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Medicine. Johannesburg, October 2017. / Background: Positron Emission Tomography (PET) is an imaging modality that guides the revascularization management of patients with left ventricular systolic dysfunction secondary to coronary artery disease. Segments of the myocardium demonstrating reduced perfusion and increased or preserved 18FFluorodeoxyglucose (18F-FDG) uptake are considered to be viable and thus suitable for revascularization. The aim of our study was to determine the prevalence of myocardial viability as determined by FDG-PET in our local cohort and to compare our prevalence of myocardial viability to data published elsewhere. Methods: We retrospectively reviewed 240 consecutive 99mTc-sestamibi myocardial perfusion Gated Single Photon Emission Tomography (SPECT) and 18FFDG PET reports of patients referred for evaluation of myocardial viability between January 2009 and June 2015. Results: 236 patients met the inclusion criteria. There were 194 (82.2%) males. The mean age was 59.1 (SD 11.0) years. A total of 4012 segments of the left ventricle were analyzed on the gated SPECT and reduced perfusion was noted in 1862 (46.4%) segments. Perfusion-metabolism mismatch (viable myocardium) was observed in 586 (31.5%) out of 1862 perfusion defects. The prevalence of myocardial viability in the study population was 61.4%. On the multivariate logistic regression model, aspirin intake [OR:0.37; CI:0.16-0.83; p=0.016] and hypertension [OR:0.26; CI:0.12-0.58; p=0.001] were associated with the presence of viable myocardium. Smoking was associated with the likelihood of having non-viable myocardium [OR:2.31; CI:1.01-5.29; p=0.048] Conclusion: The prevalence of myocardial viability as detected by 18F FDG PET in our local cohort is similar to prevalence rates reported in the developed world. / LG2018

A newly discovered activity in human serum protects porcine aortic endothelial cells in culture from injury by very low density lipoproteins (VLDL). This factor, toxicity-preventing activity (TxPA), was measured in 29 relatively young men (43 ± 8 years) who had undergone coronary angiography. The level of TxPA was found to be significantly reduced (P < 0.001) in men who demonstrated more than 15% narrowing of their coronary arteries. Men (n = 18) who had 15% or less narrowing were found to have 104 ± 48 units of TxPA while men (n = 11) with coronary artery disease had 48 ± 24 units of TxPA. A value derived from the product of TxPA and the high density lipoprotein cholesterol (HDL-C) level divided by the non-HDL-C (total cholesterol-HDL-C) accurately separated 97% of the men into 2 groups. TxPA thus appears to be a new protective factor in coronary artery disease, which, when combined with total cholesterol and high density lipoprotein cholesterol values, provides an accurate classification of established coronary artery disease in these subjects.

No description available.

<p>Background: Genome wide association studies (GWAS) performed in Caucasian populations have identified several single nucleotide polymorphisms (SNPs) associated with coronary artery disease (CAD), although their cumulative impact in other ethnicities is unknown. Using a genetic risk score (GRS), we examined the impact of CAD related SNPs on myocardial infarction (MI) in a multi-ethnic population.</p> <p>Methods: We included 4083 MI cases and 4473 controls from the INTERHEART case: control study, stratified by six ethnic groups: European, South Asian, other Asian, Arab, Latin American, and African. We created a GRS comprised of 25 SNPS, and tested its association with MI in individual ethnicities using logistic regression, and across ethnic groups through meta-analyses. Results were adjusted for age, sex, and modifiable risk factors.</p> <p>Results: The GRS was significantly associated with MI in Europeans (odds ratio [OR] = 1.08, 95% confidence interval [CI] 1.04-1.12 per risk allele), South Asians (OR = 1.09, 95% CI 1.05-1.14), other Asians (OR = 1.09, 95% CI 1.04-1.15), and Arabs (OR = 1.07, 95% CI 1.03-1.12). In Latin Americans and Africans the GRS was not significant. Meta-analysis of ethnic groups demonstrated a 1.06 (95% CI 1.03-1.09) increase in the odds of MI with the GRS per risk allele. Significant heterogeneity was observed, which was reduced by exclusion of Latin Americans (I2=63% to 0%). Above clinical risk factors, the GRS modestly increased population attributable risk (PAR) (0.92 to 0.94), concordance statistic (0.73 to 0.74), net reclassification improvement (0.14), and integrated discriminatory improvement (0.007).</p> <p>Conclusions:<strong> </strong>The GRS was associated with a significant increase in the odds of MI in multiple ethnic groups. Improvements in PAR, discrimination and reclassification were modest above clinical factors.</p> / Master of Science (MSc)

The physiological and psychosocial benefits of sustained exercise adherence among individuals with coronary artery disease (CAD) have been well-documented (e.g., Blumenthal et al., 1997; Rozanski et al., 1999; Wenger et al., 1995). Despite these known benefits, approximately 80% of patients who enter the maintenance phase of cardiac rehabilitation drop out after one year (Balady et al., 1994; Hedback, Perk, Wodlin, 1993 ). Among this 80%, less than 25% continue to exercise at levels that will maintain or improve cardiorespiratory fitness (Daltroy, 1985; Radtke, 1989). Self-efficacy has been identified as a significant predictor of adherence to exercise beyond the initial 6 months of participation. In addition to self-efficacy, outcome satisfaction has been suggested as a potentially significant predictor of adherence to exercise beyond the initiation phase (i.e., beyond the first 6 months). Unfortunately, most research examining these predictors of adherence has been conducted among asymptomatic populations. Thus, little is known about the predictive utility of self-efficacy and outcome satisfaction in relation to sustained exercise adherence among the CAD population. The purpose of the present study was to examine self-efficacy (Bandura, 1986) and outcome satisfaction (Rothman, 2000) in the prediction of adherence to maintenance cardiac rehabilitation in 101 men (M age= 68.15 ± 8.03) with coronary artery disease (CAD). A series of three hierarchical multiple regression analyses were conducted to predict onsite, offsite and total adherence to the maintenance cardiac rehabilitation exercise prescription. Interestingly, Exercise Beliefs (i.e., days of aerobic exercise per week believed necessary to maintain cardiovascular health), one of the study covariates, emerged as an important predictor of both offsite and total exercise adherence and explained a significant amount of variance in these variables (R2 = .25 [offsite], .23 [total],ps < .01). As predicted, self-regulatory efficacy was a significant predictor and explained a significant amount of variance in onsite exercise adherence (R2 = .17 [scheduling],p < .001). Task self-efficacy was not a significant predictor and did not account for a significant amount of variance in onsite exercise adherence. Also as predicted, task self-efficacy was a significant predictor and explained a significant amount of variance in offsite exercise adherence (R2= .10,p < .05). Self-regulatory efficacy was not a significant predictor and did not account for a significant amount of variance in offsite exercise adherence. In addition, consistent with hypothesis, both task self-efficacy and self-regulatory efficacy were significant predictors of total exercise adherence and explained a significant amount of the variance in this variable (R2 = .12 [task], .07 [scheduling],ps < .05). Contrary to hypothesis, outcome satisfaction did not explain a significant amount of variance in exercise adherence (onsite, offsite, and total) beyond that explained by self-efficacy (task and self-regulatory) alone. Taken together, this research has enhanced our knowledge of the psychosocial predictors of adherence to the maintenance cardiac rehabilitation exercise prescription among men with CAD. These findings also have important implications for health care professionals working in the area of cardiac rehabilitation. Specifically, it is up to health care professionals to ensure that patient beliefs regarding the maintenance cardiac rehabilitation exercise prescription are accurate, and that patients are efficacious in their ability to engage in the elemental physical aspects of exercise and to effectively schedule exercise into their daily lives. / Thesis / Master of Science (MS)

Fragmented QRS (fQRS) is a marker of conduction block due to myocardial scar that presents in electrocardiography (ECG) as an additional one or more R wave (R') or notching in the S wave nadir in contiguous leads. However, fQRS description on premature ventricular contractions (PVCs) has not been previously described. We describe a case of a 67-year-old male with a past medical history of prediabetes, hypertension and coronary artery disease who presented after an ophthalmic procedure with asymptomatic PVCs and episodes of bigeminy. Initial ECG showed an isolated fQRS in V2. However, during PVCs significant extrasystoles fragmentation was seen in other coronary territories. Upon reviewing his most recent cardiac catheterization, it showed a 40% ostial and 70% distal left anterior descending stenosis with a mid-segment patent stent, 95% first diagonal stenosis and totally occluded proximal right coronary artery. Identification of diffuse fQRS known to be associated with myocardial scar, sustained arrhythmic events and sudden cardiac death, particularly when seen in the inferior leads, became extremely relevant in our patient. We noted that ejection fraction reduction from 52% to 34% on his last coronary intervention was crucial to decide if an implantable cardioverter-defibrillator would be needed. PVC fragmentation might be a new ECG marker that could uncover both scar and arrhythmia potential in patients at risk of adverse cardiac events.

Background and objectives: Coronary artery disease (CAD) is the leading cause of death among women both nationally and internationally. Despite increased knowledge regarding CAD in women, early diagnosis remains a difficult clinical task. A correlation between peripheral arterial disease (PAD) and CAD has been noted in previous research; however, these studies were either retrospective or did not focus on women. This research investigates the correlation of ankle brachial index (ABI), measurements used to diagnose PAD, and presence of CAD in women, in an effort to determine the predictive value of ABI specifically in women. Subjects and methods: A prospective correlation design was used to study women (n = 30) who were undergoing a diagnostic cardiac catheterization. Ankle brachial index readings were obtained prior to the catheterization procedure. Catheterization findings were grouped according to absence of CAD or presence of 1-vessel or multivessel CAD and coupled with each woman's ABI and recorded cardiovascular risk factors. Results: Peripheral arterial disease (based on ABI of <0.90 mm Hg) was found in 13.3% of the women. A significant correlation was found between ABI of less than 0.90 mm Hg and increasing age (t = -2.30, P =.029). Coronary artery disease was found in 82.1% of the women; more than half (57.1%) had multivessel disease. Absence of CAD was noted in 17.9%. Women with CAD were older than women without CAD (F = 3.86, P =.035). No significant differences were found between presence or absence of PAD based on ABI and diagnosis of no coronary disease or 1-vessel or multivessel coronary disease. Conclusions: This study failed to show the expected correlation between ABI of less than 0.90 mm Hg and CAD, but did show a significant correlation of age with presence of both PAD and CAD. Further research that focuses specifically on women is needed and should include a larger sample, additional unique cardiovascular risk factors, and innovative diagnostic tests to determine presence of CAD in women early in the disease process.