P252
Peculiarities of left ventricular remodeling in subjects with masking arterial hypertension
I Osipova1, O Antropova1, A Zalzman2, N Lobanova2, K Golovina1
1
Altay State Medical University, Barnaul, Russian Federation,2Departmental Clinical Hospital, Barnaul, Russian Federation
Topic: Early detection of asymptomatic disease
the purpose of the study was to estimate target-organs condition in patients with masking (isolated ambulatory) hypertension having operator professions. 329 males were included in the study. According to blood pressure monitoring during working and rest hours the subjects were distributed into 2 groups. 197 patients with masking arterial hypertension at working place formed the 1st group, 132 males with low-stress work and essential hypertension formed the second group. All subjects were performed echocardiography, duplex scanning of brachiocephal arteries. In comparison with 2nd group subjects, 1st group subjects had lower early diastolic filling rate (peak E) over 9.5% (p=0,001) and higher late diastolic filling rate (peak A) over 19.1% (p=0,001), less ratio E/A over 33.3% (p=0,001). Type I diastolic dysfunction was revealed in 147 (74.6%) and 79 (59.8%) subjects of the 1st and 2nd groups correspondingly, that is over 14.8% (X2=8.0, p=0,005) more frequent in males with masking arterial hypertension. Left ventricular (LV) hypertrophy was revealed in 75 (38.1%) and 37 (28.1%) subjects of 1 and 2 group correspondingly, thus its frequency was comparable. In 1st group subjects normal LV geometry was detected in 72 (36.5%) subjects, concentric remodeling in 50 (25.4%) subjects, concentric LV hypertrophy – 48 (24.4%) subjects, eccentric LV hypertrophy was detected in 27 (13.7%) subjects. In 2nd group subjects normal LV geometry was detected in 59 (44.7%) subjects, concentric remodeling in 36 (27.3%) subjects, concentric LV hypertrophy – 16 (12.1%) subjects, eccentric LV hypertrophy was detected in 12.3% subjects (X2=7.9; p=0.05). Consequently, in comparison with patients with essential hypertension the patients with masking arterial hypertension have more frequent LV diastolic dysfunction, comparable frequency of LV hypertrophy but its more adverse concentric type.
P253
Preventing arrhythmic accidents under chronic stress in mid-aged: QT variability points to the hot spot
R M Negoescu
Institute of Public Health Bucharest, Bucharest, Romania
Topic: Psychosocial factors and stress
Background: Exacerbation of sympathetic drive to ventricles (SDV) is suspected to entail arrhythmic incidents or even sudden cardiac death innon-cardiac subjects under chronic psychosocial stress (PSS). the advent of efficient algorithms for software measurements of beat by beat QT interval in high resolution (1–2 ms) ECG facsimiles put forward a SDV-indexing value of QT spectral low frequency power (LF: 0.04–0.15 Hz), this study try to calibrate using the exercise known to elicit a clear-cut higher SDV.
Methods: 15 healthy mid-aged subjects (ss), averaging 47.8 years, were monitored during 10 minute relaxed rest in sitting, a 10–15 minutes (min) semi-structured stress interview (S. Wolf) on lasting life worries, and finally a 3–8 min sub-maximal bicycle exercise followed by recovery in situ. RR and QT time series were derived from a pre-cordial ECG lead, re-sampled at 500 ms, then the most stationary 3 min epochs in cardiotachogram at visual inspection were Fourier-transformed to sum the LF power.
Results: In terms of QT-LF, SDV induced by evoking life-trauma during a stress interview is statistically indiscernible from that elicited by a sub-maximal exercise sustainable no more than a few minutes (Table 1). RR-LF, the alternative index of sympathetic drive to the heart, does not show a comparable ventricular specificity. Suggestion arises that in mid-aged healthy adults chronic PSS may put the myocardium under a lasting, supernormal SDV known to jeopardize electrical stability of the heart. So that, depending on heart pre-clinical condition or undermined heredity – e.g. through Brugada's “canalopathies” – PSS may ultimately elicit arrhythmic accidents.
Conclusion: QT-LF holds promise for indexation of sympathetic drive to ventricles under mental or physical stress in clinical and subclinical settings and for preventing arrhythmic accidents.
Signs ≪ or ≫ show significant difference versus superior or inferior average respectively cf. bilateral Wilcoxon, P>0.01; other adjacent differences are not significant.
P254
Patients with atypical angina pectoris and equivocal stress test: risk stratification and efficient patient pre-selection before non-invasive coronary angiography
C Langer1, S Regenzuck1, F Van Buuren1, KP Mellwig1, C Beller1, M Vlachojannis1, A Fruend2, D Horstkotte1
1
Heart and Diabetes Center NRW, Ruhr-University of Bochum, Department of Cardiology, Bad Oeynhausen, Germany, 2Heart and Diabetes Center NRW, Ruhr-University of Bochum, Department of Physiotherapy, Bad Oeynhausen, Germany
Topic: Imaging in atherosclerosis
Purpose: Myocardial infarction and sudden cardiac death remain the first signs of coronary artery disease (CAD) in >40% of all patients with symptomatic CAD. Preventive medicine serves to identify patients with subclinical coronary artery disease and to differentiate relevant from low-grade CAD. this is reliably provided by multi-slice computed tomography (MSCT). However, while the strength of this method lies in the exclusion of CAD, the presence of CAD limits its diagnostic performance due to calcification-induced artefacts. With regard to frequently false indications of MSCT, we introduce an efficient way of patient pre-selection.
Methods: In 287 patients (pts; male 128, female 159; 61±7.3 years) with inconclusive findings including atypical angina pectoris (AAP) the PROCAM score (low PROCAM risk =9%, intermediate 10–19%, high =20%) and the Agatston score equivalent (ASE) were determined. the latter served for identification of individuals with advanced CAD (ASE =75th percentile (pctl)) based on an age-, sex- and population-specific data base (Heinz-Nixdorf-Recall database). Subsequently, MSCT based non-invasive coronary angiography (CA) was performed validated by invasive CA
Results: In this collective of patients (pts) with atypical angina pectoris and inconclusive findings CAD was found in 22.3% of the pts with a low PROCAM, 31% with an intermediate PROCAM and 43.9% with a high PROCAM score. Focusing on coronary calcium CAD was found in 63.6% of the pts with an ASE =75th pctl and 80.1% with an ASE =90th pctl. the prevalence of CAD in the entire study cohort as diagnosed by MSCT was 33.9% (94/287). this value could be cut down to 19.2% by excluding all patients with an intermediate and high PROCAM score and an ASE above the 75th pctl. (CAD prevalence of 66.1% (39/59) (p>0.05)). For CAD the combination of AAP, a PROCAM score =20% and an ASE =75th pctl resulted in a negative predictive value of 91.8%.
Conclusions: Pts with an ASE =75th pctl have a significantly increased pre-test probability for relevant coronary stenoses, while pts >75th pctl present a rather low pre-test probability. the above system identifies pts to be prevented from unnecessary non-invasive CA but be canalized to invasive CA for intervention. On the other hand it qualifies pts with suspected CAD but a rather low pre-test probability for MSCT providing a high diagnostic accuracy due to better image quality.
P256
Lack of effect of physical activity on vasoprotective proteins in venous tissue
VT Dao, M Floeren, M Oppermann, S Kumpf, T Suvorava, G Kojda
Heinrich-Heine University of Dusseldorf, Institute of Pharmacology and Clinical Pharmacology, Dusseldorf Germany
Topic: Exercise physiology, testing and training
Purpose: Many observations in animals and humans provide evidence for profound changes of arterial gene expression and protein activity induced by exercise, while little is known about its effect in the pulmonary circulation. Furthermore, increased expression and activity of endothelial nitric oxide synthase (eNOS) is considered a key event although our understanding of the signals initiating upregulation of arterial eNOS is still incomplete. We sought to investigate the importance of shear stress, pulsatile stretch and transmural pressure and compared the effects of two different training protocols on the expression of eNOS and extracellular superoxide dismutase (ecSOD) in aortic, heart and lung tissue.
Methods: Young male C57Bl/6 mice (three months) were randomized into three groups and singularized in a 350cm2 small cage for 6 weeks. Mice were trained for four weeks using two different exercise protocols, forced exercise training (5 days a week for 30min at 0.25m/s) and voluntary running.
Results: Both training protocols similarly increased significantly relative heart weight vs. body weight and resulted in a significant upregulation of aortic and myocardial eNOS (P>0.05, n=6). In striking contrast, eNOS expression in lung tissue remained unchanged (P>0.05, n=6) vs. sedentary controls. Similar results were obtained in pulmonary arteries. Furthermore both training protocols had no effect on eNOS mRNA expression level in lung tissue normalized to HPRT, compared to non exercised mice (one-way ANOVA, P>0.05; n=6). Likewise, exercise significantly upregulated ecSOD in the aorta and in left ventricular tissue (P>0.05, n=6) but remained unchanged in lung tissue (P>0.05, n=6). We observed a comparable increase of eNOS-Ser1177 phosphorylation in all tissues suggesting that exercise increased shear stress in the lung. In addition, 4 weeks of treatment with the NO-donor pentaerythrithyl tetranitrate (60 mg/kg BW/day) had no effect on eNOS expression (P>0.05, n=5) but more than doubled the expression of ecSOD in lung tissue (P>0.05, n=5) demonstrating that lung tissue is able to upregulate ecSOD upon stimulation with NO.
Conclusion: Our data underscore the importance of physical forces as signals mediating exercise-induced upregulation of vasoprotective proteins. In addition, the development and progression of impaired pulmonary circulation, e.g. following chronic smoking, is unlikely prevented by exercise.
P257
Comparative study of autonomic adaptations promoted by aerobic and resistance training in ovariectomized rats
H C Hugo CelsoDutra De Souza, LR Silveira, GCSV Tezini, MCO Salgado
University of Sao Paulo, Ribeirao Preto, Brazil
Topic: Exercise physiology, testing and training
Purpose: We have compared the autonomic cardiovascular adaptations induced by aerobic and resistance training in ovariectomised rats using different approaches: 1) autonomic double blockade with methylatropine and atenolol; and 2) evaluation of the autonomic modulation of heart rate variability (HRV) and systolic arterial pressure (SAP) by means of autoregressive power spectral analysis.
Methods: Wistar rats were divided into two groups; SHAM rats (n=42); and OVARICTO-MIZED rats (n=42). Each group was divided into three sub-groups: sedentary group (n=14), aerobic exercise-trained rats (aerobic group; n=14), and resistance exercise-trained rats (resistance group; n=14). the trainings were conducted for 10 weeks. All animals were submitted to experimental procedure to record both heart rate (HR) and arterial pressure as well as to assess cardiovascular autonomic function.
Results: the autonomic double blockade with methylatropine and atenolol showed that only SHAM rats, aerobic (85 ± 3%) and resistance (84 ± 2%) groups had an increase in cardiac vagal tonus compared to SHAM sedentary (71 ± 4%) group. In turn, all trained rats, either SHAM or OVARIECTOMISED, had reduction in basal and intrinsic HR when compared to sedentary rats. On the other hand, the analysis of HRV showed that only aerobic physical training reduced low frequency oscillations (LF; 0.2–0,75 Hz) and increased high frequency oscillations (HF, 0.75–2.5 Hz) in SHAM rats. Similarly, OVARICTOMIZED rats also showed a reduction in LF oscillations only with physical aerobic exercise.
Conclusion: the aerobic exercise, as well as resistance training promoted similar improvements in the autonomic tonus. However, only aerobic physical training promoted an improvement in cardiac autonomic modulation in SHAM animals, characterised by increased influence of vagal autonomic component and decreased influence of sympathetic autonomic component. Our results also suggest that ovariectomy affects cardiac autonomic control and exercise-induced adaptations.
P258
T-wave alternans and heart arrhythmia in patients with early stages of heart failure with preserved left ventricular systolic function
N M NargisSeidova, DA Napalkov, VA Sulimov
I.M. Sechenov Moscow Medical Academy, Moscow, Russian Federation
Topic: Heart disease
Objective: To study the prevalence of T-wave alternans (TWA) in patients with early stages of heart failure (CHF) with preserved left ventricular (LV) systolic function.
Methods: 84 patients with CHF and ejection fraction (EF) of LV 45–55% were enrolled in the study, including 41 (48,8%) males and 43 (51,2%) females (mean age 66,1±9,3 years). According to classification of New York Heart Association (NYHA) 36 (42,8%) patients had CHF I class, 48 (57,2%) had CHF II class. In 46 patients (54,7 %) the cause of CHF was hypertension (HTN), 38 patients (45,3%) had comorbidity of HTN and coronary heart disease (CHD). 7,1% patients of CHD had angina and 36,9%- myocardial infarction in the past. 24-h Holter ECG monitoring with simultaneous analysis TWA was performed in all the enrolled patients.
Results: 68 (80%) patients had negative TWA test (I group); 11 patients (13%) – positive (II group) and in 5 cases (7%) test was uncertain. Patients in TWA+ group were significantly older (68±5,6 vs. 64±4,3 years; p=0,04), and more likely to have NYHA II class CHF (73%) and lower level of quality of life (20,9 vs.16,3 points; p>0,001). In the II group CHF more frequently resulted from comorbidity of HTN and CHD (up to 68% of cases) and patients had significantly lower left ventricular EF than patients with TWA- (45,2% vs. 50,7%; p>0,01) the correlation analysis of interrelations between TWAmax, TWA HR 100 and heart arrhythmia therefore moderate correlation communication between TWAmax, TWA HR 100 and single infranodal extrasystole, infranodal extrasystole high gradation, supraventricular extrasystole and reccurent ventricular tachycardia (r=0,57; p >0,05). In group TWA + TWAmax, TWA HRmax was positively correlated with single infranodal extrasystole, supraventricular extrasystole (r=0,77; p >0,05).
Conclusions: TWA, a promising marker of arrhythmia vulnerability, in patients with early stages of CHF and preserved LV systolic function is mostly detected in those with combined etiology (HTN and CHD) of CHF and in patients with lower left ventricular EF. this might be associated with early developed morphofunctional changes of myocardium in this group of patients.
