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Kamran H, Salciccioli L, Gusenburg J, Kazmi H, Ko EH, Qureshi G, Lazar JM. The effects of passive leg raising on arterial wave reflection in healthy adults. Blood Press Monit 2010; 14:202-7. [PMID: 19938336 DOI: 10.1097/mbp.0b013e32833128d4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Passive leg raising (PLR) produces hemodynamic and physiological changes related to centralizing blood volume and baroreceptor activation. METHODS/RESULTS To evaluate the effects of PLR on central hemodynamics, we prospectively studied 50 healthy participants (80% male, age 37 +/- 12 years). Central aortic blood pressures (CA-BPs) and reflected wave properties were evaluated using applanation tonometry at baseline and upon 1 min of PLR. Heart rate (HR) was unchanged. Brachial artery (BA)-systolic BP, BA-diastolic BP, and BA-pulse pressure (PP) all decreased from baseline to PLR. Changes in BA-PP were significantly greater than changes in CA-PP. Reflected wave augmentation pressure (P(s)-P(i)), HR corrected augmentation index (AIx@75), and augmentation index decreased significantly [(P(s)-P(i)): 5 +/- 6 vs. 4 +/-5, P < 0.001; AIx@75%: 10 +/- 13 vs. 7 +/- 12, P = 0.004; AI%: 14 +/- 12 vs. 12 +/- 12, P = 0.014, respectively]. HR corrected ejection duration (ED(c)), round trip travel time (deltat(p)), and reflected wave systolic duration (deltat(r)) all increased upon PLR [ED(c): 433 +/- 15 vs. 444 +/- 17, P < 0.001; deltat(p): 149 +/- 18 vs. 156 +/- 20, P = 0.003; deltat(r): 174 +/- 33 vs. 179 +/- 32, P = 0.046, respectively]. Indices of left ventricular (LV) workload including wasted LV energy and tension-time index decreased upon PLR. CONCLUSION PLR decreases the amplitude and delays the onset of the reflected aortic pressure wave. This decreases wasted LV pressure energy and workload.
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Affiliation(s)
- Haroon Kamran
- Division of Cardiovascular Medicine, State University of New York Downstate Medical Center, Brooklyn, New York 11203-2098, USA
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2
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Fisman EZ, Embon P, Pines A, Tenenbaum A, Drory Y, Shapira I, Motro M. Comparison of left ventricular function using isometric exercise Doppler echocardiography in competitive runners and weightlifters versus sedentary individuals. Am J Cardiol 1997; 79:355-9. [PMID: 9036758 DOI: 10.1016/s0002-9149(96)00761-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
It is unclear whether cardiovascular responses to heavy isometric exercise are changed by intensive training. We evaluated the effects of this type of exercise on left ventricular (LV) function in athletes engaged in static and dynamic sport, compared with sedentary persons, and looked for peculiarities in static athletes' responses that might reflect adaptive mechanisms to their specific activity. The study population comprised 45 men (age 24 +/- 5 years): 29 dynamic and 16 static athletes (runners and weightlifters, respectively). The control group consisted of 20 age and gender-matched healthy sedentary persons. All performed 50% of maximal voluntary contraction on a whole-body isometric exercise device for 2 minutes. Echocardiographic calculations were determined at rest and exercise. Upon exercise, stroke volume, cardiac output, end-diastolic volume, and ejection fraction increased significantly in athletes, while end-systolic volume and systemic vascular resistance decreased. In sedentary persons, stroke volume and resistance remained unchanged, cardiac output and LV volumes increased, and ejection fraction decreased from 67 +/- 5% to 60 +/- 5% (p <0.01 compared with rest; p <0.0001 compared with athletes). Whereas peak flow velocity decreased from 103 +/- 10 to 81 +/- 6 cm/s in sedentary persons, it increased from 112 +/- 9 to 126 +/- 8 cm/s in the static group and from 120 +/-3 to 126 +/- 9 cm/s in the dynamic athletes (p <0.0001 compared with the sedentary group). Mean acceleration decreased in the sedentary group, remained unchanged among the dynamic athletes, and increased among the static athletes. We conclude that cardiovascular responses to heavy isometric exercise are modified by intensive training. Athletes, taken as a group, react differently and adapt better than sedentary individuals. Moreover, among them, those involved in static sport show an improved cardiovascular adaptation to this type of exercise.
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Affiliation(s)
- E Z Fisman
- Cardiac Rehabilitation Institute, Chaim Sheba Medical Center, Tel-Hashomer, Israel
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3
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Carstensen S, Ali SM, Stensgaard-Hansen FV, Toft J, Haunsø S, Kelbaek H, Saunamäki K. Dobutamine-atropine stress echocardiography in asymptomatic healthy individuals. The relativity of stress-induced hyperkinesia. Circulation 1995; 92:3453-63. [PMID: 8521567 DOI: 10.1161/01.cir.92.12.3453] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Interpretation of dobutamine-atropine stress echocardiography (DASE) is based on the assumption that the normal response to dobutamine-atropine infusion is characterized by increased systolic thickening and motion of the left ventricular (LV) walls, whereas a reduction or no change is considered indicative of coronary artery disease. The aim of this study was to quantitatively assess changes in LV dimension and wall motion patterns during DASE in a healthy population. METHODS AND RESULTS Forty-two asymptomatic voluntary subjects (22 men) with a mean age of 59 years (range, 31 to 79 years) and a likelihood of < 5% for coronary artery disease underwent DASE with digital recording of two-dimensional and M-mode echocardiography at baseline and low-dose and peak infusion rates. Mean end-diastolic and end-systolic LV diameters and areas decreased and wall thicknesses increased progressively throughout the test. Wall motion and thickening increased from baseline to low-dose infusion in nearly all subjects. However, from low-dose to peak infusion, the mean absolute wall motion and relative wall thickening decreased by 13.1% (95% CI, 2.7 to 23.5) and 21.4% (95% CI, 6.4 to 36.4) regardless of age, sex, or use of atropine. Changes in fractional shortening and absolute wall thickening varied considerably, with a decrease observed in 15 and 13 individuals (36% and 31%), respectively. CONCLUSIONS In healthy subjects, measures of wall motion and wall thickening increased from baseline to low-dose infusion but decreased from low-dose to peak infusion. These findings call for revision of the assumptions on which the common analysis of DASE is based.
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Affiliation(s)
- S Carstensen
- Department of Medicine, Rigshospitalet, University of Copenhagen, Denmark
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4
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Percy RF, Conetta DA. Comparison of velocity and volumetric indexes of left ventricular filling during increased heart rate with exercise and amyl nitrite. J Am Soc Echocardiogr 1994; 7:388-93. [PMID: 7917347 DOI: 10.1016/s0894-7317(14)80197-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Physiologic variables, such as heart rate, affect the noninvasive indexes of left ventricular filling, complicating the interpretation of these indexes for clinical assessment of diastolic function. We compared the effect in normal subjects of increased heart rate provoked by both exercise and amyl nitrite on noninvasive velocity and volumetric indexes of left ventricular filling. Velocity indexes were affected in a different pattern with exercise compared with amyl nitrite because peak E wave velocity and relative atrial contribution to filling increased with exercise. In contrast, the volumetric index of rapid left ventricular filling increased similarly with both mechanisms. These findings demonstrate the importance of recognizing the different effects on indexes of left ventricular filling when heart rate is increased by different methods.
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Affiliation(s)
- R F Percy
- Division of Cardiology, University of Florida College of Medicine, University of Florida Health Science Center-Jacksonville 32209
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5
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Beker B, Vered Z, Bloom NV, Ohad D, Battler A, Di Segni E. Decreased thickening of normal myocardium with transient increased wall thickness during stress echocardiography with atrial pacing. J Am Soc Echocardiogr 1994; 7:381-7. [PMID: 7917346 DOI: 10.1016/s0894-7317(14)80196-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Stress echocardiography is used increasingly in the evaluation of coronary artery disease. The echocardiographic evaluation of ischemia is based on stress-induced changes in wall motion and wall thickening of the ischemic segments. Studies have demonstrated that left ventricular volumetric changes may induce changes in wall thickness. The aim of the study was to evaluate whether significant changes in ventricular volume, wall thickness, and wall thickening occur during stress echocardiography with atrial pacing. Seven German Landrace female pigs were studied 4 weeks after the induction of a small myocardial infarction. Echocardiographic measurements were conducted in noninfarcted segments on the short-axis view at baseline and during atrial pacing at 120, 150, and 180 beats/min. End-diastolic circumferential area decreased from 12.3 +/- 2.0 cm2 at baseline to 8.9 +/- 1.9 cm2 at 180 beats/min of atrial pacing (p < 0.01). Mean wall thickness (interventricular septal plus posterior wall thickness divided by 2) increased markedly and progressively from 6.7 +/- 0.6 mm at baseline to 9.8 +/- 1.0 mm at 180 beats/min (p < 0.01). The increase in wall thickness correlated inversely with end-diastolic area (r = -0.57; p < 0.01). Percent systolic thickening decreased from 38.9 +/- 12.0 at baseline to 14.9 +/- 7.4 at 180 beats/min of atrial pacing (p < 0.01). The decrease in percent wall thickening correlated with the increase in wall thickness (r = -0.71; p < 0.01). In conclusion, this study shows that a marked increase in wall thickness (pseudohypertrophy) and decrease in percent systolic thickening are observed during rapid atrial pacing in normal myocardium and do not indicate stress-induced left ventricular dysfunction.
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Affiliation(s)
- B Beker
- Neufeld Cardiac Research Institute, Sackler School of Medicine, Tel Aviv University, Tel Hashomer, Israel
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6
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Surdacki A, Bednarek J, Radziszewski W, Szczepkowski J, Dubiel JS, Ruskoaho H, Sedziwy L, Wieczorek E. Plasma ANP and cyclic GMP levels versus left ventricular performance at different AV delays in AV sequential pacing. Pacing Clin Electrophysiol 1994; 17:627-36. [PMID: 7516546 DOI: 10.1111/j.1540-8159.1994.tb02399.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Eleven resting patients with an implanted DDD pacemaker were studied. After 30 minutes of AV sequential pacing at a rate of 80 beats/min with three consecutive atrioventricular delays (AVDs; 100, 150, and 200 msec) peripheral venous blood was drawn for further analyses by specific radioimmunoassays of atrial natriuretic peptide (ANP) and the ANP second messenger, cyclic guanosine monophosphate (cGMP). Relative changes in left ventricular (LV) stroke volume following alterations of AVD were assessed by means of pulsed-Doppler echocardiography through measurement of LV outflow time-velocity integrals (TVI). The optimal AVD (oAVD) was defined in individual patients as that which was associated with the greatest TVI and with improvement over both other AVDs of more than 4%. The oAVD was found in nine patients. For these nine patients no significant differences in either plasma ANP or cGMP between various AVDs were observed. However, we found such differences with respect to values measured at oAVD; both ANP and cGMP levels were lowest at oAVD. Pooling together the data obtained in 11 patients at three AVDs, a positive correlation between ANP and cGMP levels was found (r = 0.7, P < 0.0001, n = 33). Moreover, changes of plasma ANP and cGMP induced by every AVD increment of 50 msec were also correlated (r = 0.6, P < 0.01, n = 22). It is concluded that in AV sequential pacing at rest plasma ANP reaches minimal levels at the AVD, which provides the best LV performance. Although levels of cGMP changed in parallel with those of ANP, low relative values of cGMP differences may limit the usefulness of cGMP assays in optimization of the AVD.
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Affiliation(s)
- A Surdacki
- Department of Cardiology, Jagiellonian University, Cracow, Poland
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7
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Sheppard RC, Ren JF, Ross J, McAllister M, Chandrasekaran K, Kutalek SP. Doppler echocardiographic assessment of the hemodynamic benefits of rate adaptive AV delay during exercise in paced patients with complete heart block. Pacing Clin Electrophysiol 1993; 16:2157-67. [PMID: 7505929 DOI: 10.1111/j.1540-8159.1993.tb01021.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
To determine if rate adaptation of the atrioventricular (AV) delay (i.e., linearly decreasing the AV interval for increasing sinus rate) improves exercise left ventricular systolic hemodynamics, we performed paired maximal semi-upright bicycle exercise tests (EXTs) on 14 chronotropically competent patients with dual chamber pacemakers. Nine patients with complete AV block (CAVB) and total ventricular pacing dependence during exercise comprised the experimental group. Pacemakers in these patients were programmed randomly to rate adaptive AV delay (AVDR) for one EXT and fixed AV delay (AVDF) for the other EXT. AVDF was 156 msec; AVDR decreased linearly from 156-63 msec from rates of 78-142 beats/min. The other five patients had intact AV conduction and comprised the control group who were exercised in identical fashion while their pacemakers were inhibited throughout exercise to assure reproducibility of hemodynamic measurements between EXTs. Cardiac hemodynamics were calculated using measured Doppler echocardiographic systolic aortic valve flows recorded suprasternally with an independent 2-MHz Doppler transducer during a graded ramp exercise protocol. For analysis, exercise was divided into four phases to compare Doppler measurements at submaximal and maximal levels of exercise: rest, early exercise (1st stage), late exercise (stage preceding peak), and peak. Patients achieved statistically similar heart rates between EXTs at each phase of exercise. Although at lower levels of exercise cardiac hemodynamics did not differ, experimental patients (with CAVB) showed a statistically significant benefit to cardiac output at peak exercise with heart rates of 129 +/- 13 beats/min (AVDR: 9.4 +/- 2.8 L/min; AVDF: 8.2 +/- 2.6 L/min, P = 0.002), stroke volume (AVDR: 74.1 +/- 25.6 mL; AVDF: 64.3 +/- 24.4 mL, P = 0.0003), and aortic ejection time (AVDR: 253.3 +/- 35.7 msec; AVDF: 226.7 +/- 35.0 msec, P = 0.002). Duration of exercise, peak rate pressure product, peak aortic flow velocities, and acceleration times did not differ. In contrast, control group patients (intact AV conduction throughout exercise) showed no statistical differences between any hemodynamic parameters measured at any phase of exercise from the first to second exercise test. These data demonstrate that systolic cardiac hemodynamics measured echocardiographically at the high heart rates achieved with peak exercise are improved with AVDR compared to AVDF in chronotropically competent patients with complete AV block. This is due primarily to improved stroke volume and a longer systolic ejection time with AV delay rate adaptation.
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Affiliation(s)
- R C Sheppard
- Department of Clinical Cardiac Electrophysiology and Cardiac Ultrasound, Likoff Cardiovascular Institute, Hahnemann University, Philadelphia, Pennsylvania
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8
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Norgård G, Johannessen KA. Variability of digitized left ventricular M-mode echocardiography: a study in healthy subjects and patients with repaired tetralogy of Fallot. CLINICAL PHYSIOLOGY (OXFORD, ENGLAND) 1993; 13:373-83. [PMID: 8370237 DOI: 10.1111/j.1475-097x.1993.tb00337.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
To assess possible factors affecting the variability of digitized left ventricular M-mode echocardiograms, the influence of respiration and the variability due to different beats and observers were analysed in 11 healthy subjects and 11 patients with repaired tetralogy of Fallot. Left ventricular end-diastolic dimension (LVEDD) decreased from end-expiration to end-inspiration in the healthy subjects, but not in the patients. The maximal rate of dimension change decreased in both healthy subjects and patients from end-expiration to end-inspiration. The beat-to-beat variability assessed by the coefficient of variation (CV,%) between measurements of one cardiac cycle was twice the CV for three cycles, whereas the CV for three and five cardiac cycles was not different. The CV for intraobserver variability was less than 5.0% for dimensions and less than 13.0% for the rates of dimension change, whereas the interobserver variability had CV of 17.1% for rates of dimension changes. The influence of respiration and different observers on the variability of LV end-systolic dimension and shortening fraction was larger in the patients than in the healthy subjects. Thus, to obtain optimal technique for analysis of digitized LV M-mode echocardiograms in serial patient studies, the number of observers should be kept at a minimum and at least 3 beats at end-expiration should be used.
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Affiliation(s)
- G Norgård
- Department of Clinical Physiology, Haukeland Hospital, Bergen, Norway
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9
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Left ventricular filling measured by Doppler echocardiography during dynamic exercise in patients with myocardial infarction. Heart Vessels 1993. [DOI: 10.1007/bf02630562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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10
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Nakamura N, Nonogi H, Miyazaki S, Nakanishi N, Yoshioka K, Haze K, Hiramori K. Left ventricular filling measured by Doppler echocar diography during dynamic exercise in patients with myocardial infarction. Heart Vessels 1993. [DOI: 10.1007/bf01744471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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11
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MacFarlane N, Northridge DB, Wright AR, Grant S, Dargie HJ. A comparative study of left ventricular structure and function in elite athletes. Br J Sports Med 1991; 25:45-8. [PMID: 1833026 PMCID: PMC1478796 DOI: 10.1136/bjsm.25.1.45] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Adaptations to left ventricular (LV) structure and function appear to be dependent on the type, intensity and duration of exercise training. We therefore studied two clearly defined groups of elite athletes, by M-mode and Doppler echocardiography, with a group of inactive individuals as controls. All groups were age matched. Group 1 comprised ten elite endurance athletes with maximal oxygen consumption (VO2 max) of 74.7 +/- 1.43 (mean +/- SEM). Group 2 consisted of ten elite weightlifters with VO2 max 45.3 +/- 2.00. Group 3 comprised of ten inactive individuals with VO2 max 44.5 +/- 2.13. Left ventricular end diastolic dimension was significantly higher in group 1 (5.72 +/- 0.07) than in groups 2 or 3 (5.29 +/- 0.09 and 5.19 +/- 0.09 respectively, p less than 0.001). Left ventricular mass index was significantly higher in groups 1 and 2 (156.4 +/- 5.97 and 138.6 +/- 7.27 respectively) than in group 3 (104.1 +/- 3.16 p less than 0.001). Percentage fractional shortening was used as an index of systolic function and no significant difference was found between groups. Doppler E:A ratio was taken as an index of diastolic function and was found to be significantly elevated in group 1 at rest (3.37 +/- 0.24) compared with 2.38 +/- 0.16 and 1.99 +/- 0.10 in groups 2 and 3 respectively (p less than 0.003). On exercise, the E:A ratio in group 1 was significantly higher than in group 3 (1.95 +/- 0.14 and 1.23 +/- 0.05 respectively p less than 0.001), and tended to be higher than group 2 (1.68 +/- 0.15 p = ns). These data show that both modes of intense training produce left ventricular hypertrophy. Diastolic function is not impaired in the athletes and may be augmented in the endurance athletes.
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Affiliation(s)
- N MacFarlane
- Cardiac Research Department, Western Infirmary, Glasgow, UK
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12
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Abstract
To assess left ventricular structure and function at rest and during exercise in endurance athletes, 10 elite marathon runners, aged 28 to 37 years, and 10 matched nonathletes were studied by echocardiography and supine bicycle ergometry. Each athlete's best marathon time was less than 2 h 16 min. Echocardiography was performed at rest, at a 60 W work load and at an individually adjusted work load, at which heart rate was 110 beats/min (physical working capacity 110 [PWC110]). Oxygen uptake at PWC110 averaged (+/- SD) 1.14 +/- 0.2 liters/min in the nonathletes and 2.0 +/- 0.2 liters/min in the runners (p less than 0.001). The left ventricular internal diameter at end-diastole was similar at the three activity levels in the control subjects but increased significantly from rest to exercise in the runners (p less than 0.001). Left ventricular systolic meridional wall stress remained unchanged during exercise in the nonathletes but was significantly higher at PWC110 in the athletes (p less than 0.05). Both the systolic peak velocity of posterior wall endocardial displacement and fractional shortening of the left ventricular internal diameter increased with exercise; at PWC110 the endocardial peak velocity was higher in the runners than in the control subjects (p less than 0.01). The endocardial peak velocity during relaxation was comparable in athletes and control subjects at rest, increased similarly at a 60 W work load, but was higher in the runners at PWC110 (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R Fagard
- Department of Pathophysiology, Faculty of Medicine, University of Leuven, Belgium
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13
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Mehta N, Boyle G, Bennett D, Gilmour S, Noble MI, Mills CM, Pugh S. Hemodynamic response to treadmill exercise in normal volunteers: an assessment by Doppler ultrasonic measurement of ascending aortic blood velocity and acceleration. Am Heart J 1988; 116:1298-307. [PMID: 3055908 DOI: 10.1016/0002-8703(88)90455-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Accurate assessment of ascending aortic blood velocity indices and reproducibility of a Doppler ultrasonic system during exercise were determined; the Doppler technique was then used to assess the effects of age, sex, and beta blockade on exercise hemodynamics. Doppler-determined velocity correlated well with an invasive electromagnetic system. Reproducibility of Doppler variables during three exercise tests was high (coefficient of variation less than 10%) and did not deteriorate appreciably with exercise. Peak velocity (PV) and maximum acceleration (MA) were inversely related to age, the relationship being more significant during exercise, whereas the systolic velocity integral showed no such relationship either at rest or during exercise. Doppler variables showed no difference between sexes, except at high levels of exercise. Beta blockade markedly attenuated the exercise response as shown by significant decreases in both MA and PV during exercise. The Doppler velocity data presented in this study provide a reference against which previously documented changes in exercising ischemic patients can be better related.
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Affiliation(s)
- N Mehta
- Department of Medicine 1, St. George's Hospital Medical School, Midhurst, Sussex, England
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14
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Nonogi H, Hess OM, Ritter M, Krayenbuehl HP. Diastolic properties of the normal left ventricle during supine exercise. Heart 1988; 60:30-8. [PMID: 3408616 PMCID: PMC1216511 DOI: 10.1136/hrt.60.1.30] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Diastolic function in response to dynamic exercise was studied by biplane left ventriculography and by measuring left ventricular pressure with a high fidelity micromanometer tipped catheter at rest and during supine bicycle exercise in nine normal subjects. During exercise there was a fall in end systolic volume, in the time constant of left ventricular isovolumic pressure decay, and in the lowest diastolic pressure. Stroke volume, peak filling rate, mean passive filling rate, and the volume at the lowest diastolic pressure increased. There was an increase in the number of time constants that had elapsed before the lowest diastolic pressure was reached and the slope of the pressure-volume curves during passive filling (delta P/delta V) increased without changes in end diastolic pressure and volume. These results show that during exercise elastic recoil is enhanced and left ventricular relaxation is faster and more complete. Both phenomena reduce the lowest diastolic filling pressure. The observed increase in chamber stiffness from rest to exercise is probably related to increased resistance of the left ventricular wall caused by higher passive filling rates. The enhanced early diastolic pressure decay during exercise allows stroke volume to increase despite an increase in diastolic viscoelastic resistance and chamber stiffness.
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Affiliation(s)
- H Nonogi
- Medical Policlinic, Cardiology, University Hospital, Zurich, Switzerland
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