Frequency spectral analysis of cardiac wall motion as calculated from the recorded video kymogram are demonstrated. Characteristic harmonics following the fundamental frequency of the cardiac rate have been demonstrated to have an alternating sequential energy distribution as measured from the free margin of the left ventricle of humans. The characteristic patterns occur in approximately 80% of the 50 patients evaluated. The correlation of these harmonics with physiologic events is not yet complete. Amplitude frequency spectral analysis offers an objective method for analysis of cardiac kymography not otherwise possible.

Adult↗

PubMedDate not supplied

Velocity of left ventricular wall motion determined by fluoroscopic videodensitometry. A noninvasive method for evaluating myocardial contractile state.

Videodensitometry of the margins of the fluoroscopic image of the left ventricle (LV) was used to evaluate LV wall motion and differentiation of the wall motion signal reflected velocity of LV contraction (dV/dt) during various inotropic interventions in six anesthetized dogs. During these interventions heart rate, afterload and preload were maintained constant. Alterations in dV/dt were similar to changes in simultaneously measured LV peak dP/dt and the quotient of dP/dt and developed LV pressure, two widely accepted parameters of LV contractile state. Wide variations in preload and afterload caused no significant changes in dV/dt. Thus, the current study indicates that fluoroscopic videodensitometry provides a specific and reliable noninvasive method for evaluating LV contractile state.

Absorptiometry, Photon↗

PubMedDate not supplied

Arterial blood flow measurement: assessment of velocity estimation methods.

Three methods are presented which provide statistically acceptable estimates of mean transit time of opacified blood during angiography. While the methods vary in precision, the selection of the method appropriate for any particular experimental model depends on the degree of precision required to demonstrate the effect under investigation. As the day follows the night, the cost of equipment increases with increasing precision and the inexpensive method may provide sufficient accuracy for most clinical situations.

Angiography↗

PubMedDate not supplied

Television fluorodensitometry. Technical considerations and some clinical applications.

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Animals↗