Measurement of internal left ventricular diameter by a tracking sonomicrometer

Stinson, Edward B.; Rahmoeller, Glenn A.; Tecklenberg, Paul L.

doi:10.1093/cvr/8.2.283

Cited by 17 publications

(2 citation statements)

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“…This placement was chosen because the majority of muscle fibers in the mid-myocardium are oriented in the circumferential direction (Streeter et al, 1966(Streeter et al, , 1969, and these fibers have been used previously to represent myocardial fiber length (Weber et al, 1976). In seven animals, an additional pair of ultrasonic crystals (4-6 mm in diameter) was implanted on the left ventricular endocardium midway between apex and base by a modification of the technique described by Stinson et al (1974). The rationale here was that shortening of this internal minor axis diameter accounts for the majority of stroke volume during ejection (Rankin et al, 1976).…”

Section: Preparation and Data Acquisitionmentioning

confidence: 99%

Regional end-systolic pressure-length relationships using a volume-loading technique in the intact pig heart.

Miller¹,

Liedtke²,

Nellis³

1984

Circulation Research

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SUMMARY. The purpose of this study was to characterize left ventricular systolic elastances as derived from pressure-segment length and pressure-diameter relationships, and to compare the resulting regional and global elastances to known changes in inotropy. Left ventricular pressuresegment length and pressure-diameter were varied in a series of consecutive beats by means of a volume-loading technique, and both regional and global relationships at 20-msec intervals throughout systole were found to be nonlinear and to exhibit hysteresis. In eight animals, regional hysteresis was present after vagotomy, propranolol (1.0 mg/kg), and atropine (0.1 mg/kg), and was present no matter whether hearts were loaded by volume (45-60 ml/sec) or by pressure (partial aortic occlusion) over a similar range of left ventricular systolic pressures. Elastance was linearly approximated by the slope of the major axis of the hysteresis loops. In each instance, elastance increased to a maximum and then decreased, thus defining end-systole. In seven animals, maximum elastance-length and -diameter were compared before and after treatments with dobutamine (5-13 Mg/kg per min) and propranolol (6-51 Mg/kg per min), or after induction of global ischemia. Dobutamine increased maximum elastance-diameter by 37% (P < 0.01) and maximum elastance-length by 159% (P < 0.05). Propranolol decreased maximum elastancediameter by 27% (P < 0.05) and maximum elastance-length by 6% (P = NS). Global ischemia (50% reduction in coronary flow) did not significantly change either maximum elastance-diameter or -length. However, with ischemia, the diameter intercept of maximum elastance-diameter increased by 24% (P < 0.025), and the time to maximum elastance-length decreased by 33% (P < 0.01). Comparing all interventions, the percent changes in maximum elastance-length and -diameter related directly but with a low correlation coefficient (r = 0.49). These differences in regional and global elastance suggest a complex relationship between regional and global myocardial mechanics, and may not necessarily reflect specific changes in contractility. (Circ Res 55: 326-335, 1984)

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Section: Preparation and Data Acquisitionmentioning

confidence: 99%

Regional end-systolic pressure-length relationships using a volume-loading technique in the intact pig heart.

Miller¹,

Liedtke²,

Nellis³

1984

Circulation Research

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“…Piezoelectric crystals (ultrasonic dimension system Mod 401 Schuessler and Coll.) were secured on the endocardium of the anterior and posterior walls, close to the septum, to record LV diameter changes continuously [5].…”

Section: Animal Preparationmentioning

confidence: 99%

Myocardial, coronary, and peripheral effects of xamoterol (ICI 118,587) in open-chest pigs

Galiè

Metalli

Zannoli

et al. 1989

Cardiovasc Drug Ther

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The hemodynamic and coronary effects of increasing doses of xamoterol, a beta-adrenoceptor partial agonist, were assessed in an anesthetized pig preparation in which cardiovascular reflexes were abolished and sympathetic tone was modified by infusion of noradrenaline (NA). Xamoterol, in basal conditions, increased heart rate (HR) from 104 +/- 12 to 120 +/- 13 beats/min (p less than .001); systolic, diastolic, and mean blood pressure, respectively, from 77 +/- 8 to 103 +/- 17 mmHg (p less than .01), from 48 +/- 7 to 70 +/- 12 mmHg (p less than .01), and from 58 +/- 7 to 84 +/- 14 mmHg (p less than .01); left ventricular dP/dT max from 2098 +/- 564 to 4205 +/- 937 mmHg/sec (p less than .001); and systemic vascular resistance (SVR) from 1745 +/- 564 to 2270 +/- 739 dynes sec cm-5 (p less than .01). The increase in HR and dP/dT max brought about by xamoterol was about 37% and 56%, respectively, of the maximum increase produced by NA. At the highest level of sympathetic tone, xamoterol reduced HR from 148 +/- 11 to 122 +/- 11 beats/min (p less than .001) and no significant change was observed in dP/dT max. The increase in blood pressure and SVR induced by xamoterol was maintained at each level of sympathetic tone. On the contrary, SVR did not change after NA, as expected, since receptors were fully blocked. For a given inotropic effect, xamoterol and NA produced a similar increase in coronary blood flow and myocardial O2 consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

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Methods in Cardiovascular Safety Pharmacology

Guth

2006

Drug Discovery and Evaluation

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Measurement of internal left ventricular diameter by a tracking sonomicrometer

Cited by 17 publications

References 0 publications

Regional end-systolic pressure-length relationships using a volume-loading technique in the intact pig heart.

Regional end-systolic pressure-length relationships using a volume-loading technique in the intact pig heart.

Myocardial, coronary, and peripheral effects of xamoterol (ICI 118,587) in open-chest pigs

Methods in Cardiovascular Safety Pharmacology

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