Systematic correlation of cardiac chamber size and ventricular performance determined with echocardiography and alterations in heart rate in normal persons

DeMaria, Anthony N.; Neumann, Alexander; Schubart, Peter; Lee, Garrett; Mason, Dean T.

doi:10.1016/0002-9149(79)90036-5

Cited by 152 publications

(56 citation statements)

References 19 publications

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“…3) was of a similar magnitude to results obtained when preload was kept constant in conscious adult dogs (2,19). Although most studies have demonstrated a 2-4 mmHg decrease of left ventricular end diastolic pressure during pacing-induced tachycardia (2,9,19,21,28) there was no change in the study by Graber and associates (18) or in our study except at the most rapid heart rate in the newborn lambs (Table 2). It is possible that the unusual activation sequence initiated by left atrial pacing may have influenced the results in the newborns by producing shunting through the foramen ovale.…”

Section: Discussionsupporting

confidence: 85%

“…The left column was recorded during the control period when the heart rate was 150 bpm and the right column was recorded during a period of pacing induced tachycardia when the heart rate was 270 bpm. either a decreased or constant preload and an increased or constant afterload we used the directly measured maximal positive dP/dt and dV/dt to estimate the contractile function of the left ventricle during the study (2,9,18,19,21,27). A decrease in preload (Table 2) would be expected to minimize the magnitude of an increase in dP/dt and have no significant effect on dV/dt whereas an increase in afterload would minimize the magnitude of an increase in dV/ dt and have no significant effect on dP/dt (30,38).…”

Section: Discussionmentioning

confidence: 99%

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The Effect of Atrial Pacing-Induced Tachycardia on Left Ventricular Contractile Function in Conscious Newborn and Adult Sheep

Fisher¹,

Gross²

1983

Pediatr Res

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SummaryIn order to determine if an increase in heart rate is associated with an increase of left ventricular contractile function during the neonatal period we recorded phasic and mean aortic blood pressure. left atrial mean or left ventricular end diastolic Dressure. phasic left ventricular blood pressure, aortic blood flow velocity and the instantaneous first derivatives of left ventricular blood pressure (dP/dt) and aortic blood flow velocity (dV/dt) during pacing-induced tachycardia in conscious newborn and adult sheep. There was a significant positive linear correlation between heart rate and both indices of contractility (dP/dt and dV/dt) in both age groups. Left ventricular end diastolic pressure was unchanged except for a decrease at the most rapid heart rate in the newborns. There was no change in aortic mean blood pressure during the study. Our data demonstrate that an increase of heart rate is associated with an increase of left ventricular contractile function in conscious neonatal and adult sheep. Investigations of the effects of potential inotropic agents on left ventricular contractile performance in newborns and adults must evaluate the independent effect of any simultaneously occurring increase in heart rate.The positive inotropic effect of an increase of contraction frequency was originally demonstrated in vitro by Bowditch (5). Multiple recent investigations in vitro have demonstrated that atrial pacing-induced tachycardia is associated with a small but significant increase in left ventricular contractile function in conscious adult humans and dogs (9, 17-19, 28, 33). Although there is some information available concerning the effect of a heart rate increase on left ventricular contractility in the unanesthetized lamb fetus (1, 23) and in neonatal cat and lamb heart muscle in vitro (1,8), to our knowledge there is no such information available in conscious neonates of any species. Therefore, we studied the effect of a pacing-induced heart rate increase on left ventricular contractile function in conscious newborn lambs. As species variability has been reported in adults (25) we also performed a pacing study in conscious adult sheep. MATERIALS AND METHODSSurgical technique. We operated on 1 1 Western newborn lambs 1-25 (9 + 2, mean + S.E.) days after birth and on 8 nulliparous female adult sheep. The lambs weighed 6.5 f 0.6 g. We anesthetized the animals with 1-2% fluothane (Halothane), intubated the trachea, and ventilated the lungs with an animal ventilator (Methomatic, Pittman-Moore). We performed a thoracotomy in the left fourth intercostal space and inserted polyvinyl catheters (inside diameter, 0.10 cm; outside diameter, 0.15 cm) into the ascending aorta via the left internal thoracic artery and into the left atrium through a purse-string suture in the atrial appendage. The catheters were closed after they were filled with heparin. We sutured a pair of stainless steel pacing wires (#A5633 hookup wire, Cooner Wire Co., Chatsworth, CA) to the left atrial epicardium. Through a separate incis...

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Section: Discussionsupporting

confidence: 85%

Section: Discussionmentioning

confidence: 99%

The Effect of Atrial Pacing-Induced Tachycardia on Left Ventricular Contractile Function in Conscious Newborn and Adult Sheep

Fisher¹,

Gross²

1983

Pediatr Res

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“…The increase in fractional shortening and ejection fraction thus indicates a rise in myocardial contractility. Maximal velocity of circumferential fibre shortening increased by 6% (P < 0.05 in a single paired Student's t-test) in contrast to the expected 6% decrease with heart rate reduction of 12 beats min-' (DeMaria et al, 1979).…”

Section: Effects Of Digoxin During Handgrip With Autonomic Blockadementioning

confidence: 65%

“…The effect of heart rate on ejection fraction and fractional shortening is small or negligible. (Hirschleifer et al, 1975;DeMaria et al, 1979;Ricci et al, 1979;Erbel et al, 1984). Velocity of circumferential fibre shortening is also heart rate-dependent (DeMaria et al, .1979).…”

Section: Physiological and Methodological Aspectsmentioning

confidence: 99%

“…Ejection fraction and fractional shortening increased in the present study without any changes in loading conditions. Fractional shortening has been shown to be independent of heart rate (DeMaria et al, 1979). Ejection fraction does not depend on heart rate until a rise of 30 beats min-' in pulse frequency (Ricci et al, 1979) or then it decreases by only 1% of the left ventricular volume with each 10 beats min-' rise in heart rate (Erbel et al, 1984).…”

Section: Effect Of Digoxin At Restmentioning

confidence: 99%

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Effect of digoxin on the heart in normal subjects: influence of isometric exercise and autonomic blockade: a noninvasive study.

Partanen

Heikkilä

Pellinen

et al. 1988

Brit J Clinical Pharma

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1 Eight healthy subjects were studied before digoxin and after successive therapy periods of 1 week 0.125, 0.25 and 0.50 mg of digoxin. The mean serum concentrations (± s. d.) were 0.4 ± 0.2, 0.6 ± 0.3 and 1.4 ± 0.5 nmol I-1, respectively. The effects of digitalis were studied by echocardiography and systolic time intervals at rest and after 3 min handgrip exercise. Effects of simultaneous autonomic blockade induced by atropine and propranolol were also examined. 2 Digoxin in increasing doses slowed the heart rate at rest; with the daily dose of 0.50 mg from 63 ± 10 to 53 ± 6 beats min-', and fractional shortening rose from 28 ± 6 to 33 ± 3% (P < 0.05 for both). Preload, afterload and cardiac output did not change. The electromechanic systolic time index (QS2I) decreased (P < 0.001) and the observed alteration of QS2I was dose-related.3 The influence of digoxin was similar during isometric exercise, except for unchanged fractional shortening. 4 During autonomic blockade digoxin slowed the intrinsic heart rate from 93 ± 6 to 86 ± 6 beats min-' (0.25 mg) and to 83 ± 6 beats min-' (0.50 mg) (P < 0.01 for both). QS2I was shortened (P < 0.01). Echocardiographically determined ejection phase indices remained unchanged. 5 When handgrip stress was induced during autonomic blockade, digoxin evoked a clearcut increase in contractile function, resembling the effects of digoxin alone at rest. Thus, fractional shortening increased by 14% and QS21 decreased by 16 ms (P < 0.01 for both). 6 We conclude that digoxin increases the contractility in normal heart without changes in loading conditions. The rise in inotropy at rest is obvious from both fractional shortening by echo and systolic time intervals. The same takes place during handgrip with autonomic blockade, when the heart lacks sympathetic support. The influence of long-term digoxin on heart rate is partly direct without autonomic mediation. The effect of digoxin is dosedependent.Keywords digoxin isometric exercise autonomic blockade left ventricular contractility echocardiography systolic time intervals

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Asymptomatic Degenerative Mitral Regurgitation

et al. 2020

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Systematic correlation of cardiac chamber size and ventricular performance determined with echocardiography and alterations in heart rate in normal persons

Cited by 152 publications

References 19 publications

The Effect of Atrial Pacing-Induced Tachycardia on Left Ventricular Contractile Function in Conscious Newborn and Adult Sheep

The Effect of Atrial Pacing-Induced Tachycardia on Left Ventricular Contractile Function in Conscious Newborn and Adult Sheep

Effect of digoxin on the heart in normal subjects: influence of isometric exercise and autonomic blockade: a noninvasive study.

Asymptomatic Degenerative Mitral Regurgitation

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