Effect of changes in aortic pressure and in coronary arterial pressure on left ventricular geometry and function Anrep vs. gardenhose effect

Schipke, J. D.; Stocks, Ian; Sunderdiek, Ulrich; Arnold, G.

doi:10.1007/bf00788879

Cited by 16 publications

(7 citation statements)

References 46 publications

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“…According to present knowledge, other factors that may alter the dP/dt values after increasing AP are shortening deactivation (21)(22)(23)(24), the Anrep effect (15,18,19) and variations in coronary flow (25) or coronary perfusion pressure (26). Previous studies from our laboratory have shown that large increases of developed force (27) and coronary perfusion (28) do affect left ventricular performance in the intact canine left ventricle.…”

Section: Discussionmentioning

confidence: 86%

“…At present, two known factors are suggested as potentially affecting the rate of myocardial force generation when afterload changes: the Anrep effect (15,(18)(19)(20) and the shortening deactivation (21)(22)(23). Until (20) convincingly demonstrated the occurrence of the Anrep effect in muscle strips specially instrumented in order to obtain "physiological" contraction.…”

Section: Discussionmentioning

confidence: 99%

“…Concerning the influence of afterload on dP/dt, the available data (1)(2)(3)5,(7)(8)(9)(10)(11)(12)(13)(14)(15) point to a very controversial situation. From a linear point of view, it would be natural to expect that the maximal dP/dt value is not changed by the aortic diastolic pressure rise since its maximum positive value occurs before aor-tic valve opening takes place (6,8,16).…”

Section: Introductionmentioning

confidence: 99%

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The rate of force generation by the myocardium is not influenced by afterload

Fioretto¹,

Okoshi

et al. 1997

Braz J Med Biol Res

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The influence of afterload on the rate of force generation by the myocardium was investigated using two types of preparations: the in situ dog heart (dP/dt) and isolated papillary muscle of rats (dT/dt). Thirteen anesthetized, mechanically ventilated and thoracotomized dogs were submitted to pharmacological autonomic blockade (3.0 mg/ kg oxprenolol plus 0.5 mg/kg atropine). A reservoir connected to the left atrium permitted the control of left ventricular end-diastolic pressure (LVEDP). A mechanical constriction of the descending thoracic aorta allowed to increase the systolic pressure in two steps of 20 mmHg (conditions H 1 and H 2 ) above control values (condition C). After arterial pressure elevations (systolic pressure C: 119 ± 8.1; H 1 : 142 ± 7.9; H 2 : 166 ± 7.7 mmHg; P<0.01), there were no significant differences in heart rate (C: 125 ± 13.9; H 1 : 125 ± 13.5; H 2 : 123 ± 14.1 bpm; P>0.05) or LVEDP (C: 6.2 ± 2.48; H 1 : 6.3 ± 2.43; H 2 : 6.1 ± 2.51 mmHg; P>0.05). The values of dP/dt did not change after each elevation of arterial pressure (C: 3,068 ± 1,057; H 1 : 3,112 ± 996; H 2 : 3,086 ± 980 mmHg/s; P>0.05). In isolated rat papillary muscle, an afterload corresponding to 50% and 75% of the maximal developed tension did not alter the values of the maximum rate of tension development (100%: 78 ± 13; 75%: 80 ± 13; 50%: 79 ± 11 g mm -2 s -1 , P>0.05). The results show that the rise in afterload per se does not cause changes in dP/dt or dT/dt.

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Section: Discussionmentioning

confidence: 86%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The rate of force generation by the myocardium is not influenced by afterload

Fioretto¹,

Okoshi

et al. 1997

Braz J Med Biol Res

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“…The increase of the aortic pressure could affect the values of dP/dt, inducing variations in the afterload 8,23 , in the perfusion pressure and in the coronary flow [24][25][26][27] . A series of publications 3,7,8,23 report that the maximal values of dP/dt are directly proportional to the levels of BP; others 9,28,29 , however, suggest that the aortic pressure has no influence on the dP/dt.…”

Section: Discussionmentioning

confidence: 99%

Influence of the elevation of the left ventricular diastolic pressure on the values of the first temporal derivative of the ventricular pressure (dP/dt)

Okoshi¹,

Fioretto²,

Bonatto³

et al. 1999

Arq. Bras. Cardiol.

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Purpose -To assess the effects of the elevation of the left ventricular end-diastolic pressure (LVEDP) on the value of the 1 st temporal derivative of the ventricular pressure (dP/dt). Methods (128±18.3mmHg and 150±21.5mmHg), diastolic blood pressure (98±16.9mmHg and 115±19.8mmHg), LVEDP (5.5±2.49 and 9.3±3.60mmHg), and dP/dt (4,855 ± 1,082 mmHg/s and 5,149±1,242mmHg/s) The rate of change in pressure with time (dP/dt), usually known as the 1 st temporal derivative of ventricular pressure, is one of the parameters employed for the assessment of the left ventricular function.In the 60's and 70's, the maximal values of dP/dt (dP/ dtmax) were largely employed to assess the inotropic capacity of the heart 1-4 . From the studies conducted at that time, it was suggested that dP/dt did not reliably reflect the inotropic state. The concept that finally prevailed was that dP/dtmax had limited practical applications as an indicator of the inotropic capacity 5 . The major limitation 6,7 was the lack of specificity of this parameter, since other factors, in addition to myocardial inotropic capacity, interfered with the maximal value of dP/dt. The factors capable of interfering with the values of the dP/dtmax include: the afterload 7,8 , the preload 9,10 and the presence of myocardial hypertrophy 2,11 . The correct interpretation of the relationship between the degree of myocardial stretching (preload) and dP/dt is particularly complex. According to the most traditional version of the concepts related to ventricular function, the inotropic capacity of the heart and the variation of the performance of the heart as a result of change in the muscular length during rest (Frank-Starling mechanism) were considered independent myocardial characteristics. Yet, the influence of the Frank-Starling mechanism on dP/dtmax would not be related to changes in the inotropic capacity of the heart. For this reason, variations in the ventricular volume occurring during the evaluation of dP/dt max would preclude an exact definition of the inotropic state.Advances in the knowledge of the physiological basis of myocardial contraction make this traditional view questionable, currently allowing alternative explanations. More recent information 12-17 about the subcellular adjustments involved in the relationship between the ventricular stretching during rest and the mechanical performance of the ventricles indicate that myocardial stretching interferes with the degree of activation of the contractile phenomenon, i.e., with myocardial contractility. The identification of

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“…Reduced afterload immediately increases the beat volume, thus reducing residual volume and end-diastolic pressure. Homeometric autoregulation (Anrep effect) counteracts, re-adjusting the end-diastolic pressure within a series of beats [19,21,31]. Such adjustment settles during the mounted guinea pig hearts adapt to the artificial circulation.…”

Section: Heterometric Autoregulative Component (Frank-starling)mentioning

confidence: 99%

Autocorrelation Patterns in the Left-Ventricular Pressure Course of Isolated Working Hearts at Sinus Rhythm

Langer¹

2016

ICFJ

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<pre class="western">Background Observations of short term uniformity or microrhythmical undulation in ventricular pressure courses at sinus rhythm are lacking but necessary to describe cardiac status. The present investigation aims for (a) detecting repetitive similarity patterns in ventricular pressure at isolated sinus rhythm, (b) tagging hemodynamic parameters which contribute most to dissimilarity, and (c) for a stochastical characterisation of the random component in mutual similarity. Methods Left-ventricular pressure curves from isolated working small animal hearts, at sinus rhythm and electrical stimulation, are analysed by autocorrelation. Results Ventricular pressure courses consistently reach their peak coefficient of autocorrelation either at one-beat lag (monorhythm) or at two-beat lag (duorhythm). Replacing sinus rhythm with strictly even electrical right-atrial stimulation provokes more duorhythms to occur (Langer paradox). Duorhythms become scarcer at hypothermia and high cardiac output. Repetition of very similarly shaped beats accords with an exponential law. Variability of twelve hemodynamic parameters, regarding microrhythm, is given as a Table. Conclusions (a) Incidence of alternating patterns (duorhythms) suggests the presence of effective heterometric autoregulation (Frank-Starling law). Consequently, a pacing test may assess contractile reserve in certain conditions. Higher multi-beat patterns occur by chance at isolated sinus rhythm. (b) Interbeat variability of relevant hemodynamic parameters complies with the initial conclusion. Statistical pooling of data from consecutive beats seems permissible; pooling alterant beats separately will do better. (c) Random fluctuation is a constituent part of medium-term ventricular pressure course. Mutually very similar beats occur stochastically by a Poisson process with fade-out. Deviations accord with the presence of mono- or duorhythms.</pre>

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Effect of changes in aortic pressure and in coronary arterial pressure on left ventricular geometry and function Anrep vs. gardenhose effect

Cited by 16 publications

References 46 publications

The rate of force generation by the myocardium is not influenced by afterload

The rate of force generation by the myocardium is not influenced by afterload

Influence of the elevation of the left ventricular diastolic pressure on the values of the first temporal derivative of the ventricular pressure (dP/dt)

Autocorrelation Patterns in the Left-Ventricular Pressure Course of Isolated Working Hearts at Sinus Rhythm

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