Validation of a Doppler technique for beat-to-beat measurement of cardiac output

Mehta, N.; Iyawe, V. I.; Cummin, A.R.C.; Bayley, S.; Saunders, K.B.; Bennett, E. D.

doi:10.1042/cs0690377

Cited by 40 publications

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“…The flow velocity integral is a validated index of stroke volume [19, 20]. Absolute values of stroke volume and cardiac output have been obtained by measurement of the Doppler-derived flow velocity integral and echocardiographic aortic orifice area [21, 22, 23]. In our study, resting stroke volume was 28% lower in the transplanted patients, corresponding well with previous studies [2, 10, 11].…”

Section: Discussionsupporting

confidence: 78%

Attenuated Responses of Doppler-Derived Hemodynamic Parameters during Supine Bicycle Exercise in Heart Transplant Recipients

Auerbach¹,

Tenenbaum²,

Motro³

et al. 1999

Cardiology

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The aim of this study was to characterize Doppler-derived hemodynamic parameters in heart transplant recipients at rest and during symptom-limited supine bicycle exercise. Eighteen sedentary patients aged 54.0 ± 2 years, 1.6 ± 1.0 years following cardiac transplantation, and 18 sedentary healthy volunteers aged 51.8 ± 4 years were investigated. Basic hemodynamic parameters and Doppler-derived parameters were recorded at rest and at peak dynamic exercise. Resting heart rate, blood pressure and rate-pressure product were higher in the transplanted patients (p < 0.001). However, in comparison with the resting state, the increase in these parameters at exercise was lower in heart transplant recipients. In the healthy, dynamic exercise induced an increase in peak flow velocity, mean acceleration, flow velocity integral, stroke volume, cardiac output and cardiac index (p < 0.001 for all) while systemic vascular resistance, ejection time and acceleration time decreased (p < 0.001 for all). The following parameters increased in the transplanted patients at dynamic exercise: peak flow velocity, cardiac output and cardiac index (p < 0.001), mean acceleration (p < 0.01) and flow velocity integral (p < 0.05). Ejection time decreased (p < 0.05) and acceleration time and systemic vascular resistance remained unchanged. In conclusion, at rest peak flow velocity, mean acceleration, flow velocity integral and stroke volume are lower in the transplanted than in the healthy controls, while cardiac output, cardiac index and systemic vascular resistance are equal. Our study demonstrates attenuated responses of basic hemodynamic parameters and Doppler-derived cardiovascular indices at symptom-limited supine bicycle exercise in heart transplant recipients compared to healthy volunteers.

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Section: Discussionsupporting

confidence: 78%

Attenuated Responses of Doppler-Derived Hemodynamic Parameters during Supine Bicycle Exercise in Heart Transplant Recipients

Auerbach¹,

Tenenbaum²,

Motro³

et al. 1999

Cardiology

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“…We have developed the non-invasive pulsed Doppler technique to measure aortic flow beat-to-beat (Darsee, Walter & Nutter, 1980;Loeppky, Greene, Hoekenga, Caprihan & Luft, 1981; Alverson, Eldridge, Dillon, Yabek & Berman, 1982; Mehta, Iyawe, Cummin, Bayley, Saunders & Bennett, 1985). We report here measurements of ventilation and cardiac output during the first 20 s of exercise in normal man, the first time these transient changes have been simultaneously measured in this phase.…”

Section: Introductionmentioning

confidence: 99%

Ventilation and cardiac output during the onset of exercise, and during voluntary hyperventilation, in humans.

Cummin¹,

Iyawe²,

Mehta³

et al. 1986

The Journal of Physiology

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SUMMARY1. Three normal subjects performed rest-exercise transitions on a cycle ergometer, from rest to unloaded pedalling (0 W), 50, 100 and 150 W. Each experiment was performed in triplicate, with randomized work load order, in two sessions. Ventilation was obtained breath-to-breath by integration of a pneumotachygraph signal, and cardiac output beat-to-beat by a new development of the Doppler technique. Results were bin-averaged in 4 s bins over the first 20 s, and compared to resting values.2. Both ventilation and cardiac output increased significantly in the first 2 s. This initial rise in ventilation was due entirely to an increase in rate, the subsequent rise mainly to increase in tidal volume. Cardiac output increased predominantly through change in rate with smaller increases in stroke volume.3. A striking feature was a tendency for ventilation and cardiac output responses to be biphasic with an initial rise followed by a slight fall at the 14 s mark, and a subsequent rise, at all work loads. Overall correlation between ventilation and cardiac output was therefore high (r = 0 92).4. Six normal subjects hyperventilated for 45 s voluntarily, (a) at rate 24/min and normal tidal volume; (b) at normal rate and tidal volume of 1-5 1; (c) at rate 24/min and tidal volume of 1-5 1. Cardiac output, averaged over 10-45 s, rose by 0 4, 0 5, and 1-0 1 min-respectively, with falls in end-tidal PCO, of 4, 6, and 8 mmHg.5. Six normal subjects hyperventilated for 60 s with rate 24/min and tidal volume of 1-4 1, and end-tidal Pco, maintained at 38 + 2 mmHg. Cardiac output, averaged from 10-60 s, rose by 1-0 I min'.6. With increased rate and tidal volume, whether isocapnic or hypocapnic, cardiac output responses showed an overshoot with a peak value at about 30 s.7. The hypothesis of 'cardiodynamic hyperpnoea' considers a possible effect of increasing cardiac output on ventilation. The effects of ventilation on cardiac output must also be considered. We propose an extended hypothesis involving stable positive feed-back.

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“…The Doppler ultrasound technique has made it possible to record stroke volume (SV) directly, non-invasively and on a beat-to-beat basis (Loeppky, Greene, Hoekenga, Caprihan & Luft, 1981; Ihlen, Amlie, Dale, Forfang, Nitter-Hauge, Otterstad, Simonsen & Myhre, 1984; Mehta, Iyawe, Cummin, Bayley, Saunders & Bennett, 1985; Innes, Mills, Noble, Murphy, Pugh, Shore & Guz, 1987), and the technique has been applied also to the dynamic phase at the onset of exercise (Loeppky et al 1981; Cummin, Iyawe, Mehta & Saunders, 1986;Adams, Guz, Innes & Murphy, 1987). However, technical problems have apparently hitherto prevented a full exploitation of the potential time resolution of the method.…”

Section: Introductionmentioning

confidence: 99%

Dynamics and dimensions of cardiac output changes in humans at the onset and at the end of moderate rhythmic exercise.

Eriksen

Waaler

Walløe

et al. 1990

The Journal of Physiology

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SUMMARY1. An improved Doppler ultrasound technique was used to measure stroke volume (SV) and cardiac output (CO) on a beat-to-beat basis in a group of supine humans before, during and after periods of standardized, rhythmic exercise, involving the quadriceps muscle groups on both sides. The development of CO on such bouts of exercise was compared to Doppler ultrasound records of the simultaneous femoral arterial flow (FF) response.2. Records of CO at rest revealed spontaneous fluctuations around a mean level, with differences between the minimal and maximal values of the order of 11 min'. The mean CO level at rest again varied considerably from one day to another and from test run to test run.3. Upon start of exercise an immediate and rapid increase in heart rate (HR) and CO took place. The entire increase, the size of which varied appreciably from test run to test run, was completed within 10-15 s. No or only minor changes were seen in the mean SV level during the exercise periods.4. The time course of the increase in FF was indistinguishable from that of the increase in CO, which occurred without any detectable delay relative to the changes in FF. These closely parallel developments indicate a tight regulatory coupling between the two types of flow changes.5. In the majority of tests the total and two-sided increase in FF seen in the steady-state situation in the last part of an exercise period was significantly larger than the recorded increase in CO. This discrepancy implies that some redistribution of flow from tissues other than the working muscles might take place, even at this moderate level of work.

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Validation of a Doppler technique for beat-to-beat measurement of cardiac output

Cited by 40 publications

References 0 publications

Attenuated Responses of Doppler-Derived Hemodynamic Parameters during Supine Bicycle Exercise in Heart Transplant Recipients

Attenuated Responses of Doppler-Derived Hemodynamic Parameters during Supine Bicycle Exercise in Heart Transplant Recipients

Ventilation and cardiac output during the onset of exercise, and during voluntary hyperventilation, in humans.

Dynamics and dimensions of cardiac output changes in humans at the onset and at the end of moderate rhythmic exercise.

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