Systolic Phases of the Cardiac Cycle in Children

Abstract

The duration of the systolic phases of the cardiac cycle in 390 normal children was determined from high-speed simultaneous recordings of the electrocardiogram, phonocardiogram, apexcardiogram, and carotid pulse. Data were obtained on children 1 mo to 13 years of age and analyzed to define the independent effects of aging and heart rate on the systolic intervals. Electromechanical systole (Q-II) was found to prolong with increasing age in children with the same heart rate. Pre-ejection period was also prolonged in older children and occupied an increased percentage of total systole. The interval from onset of contraction to first sound varied inversely with heart rate and was independent of age. Electromechanical delay and isometric contraction time were directly related to age and independent of rate. Ejection time varied directly with age and inversely with heart rate but occupied a smaller percentage of systole in older children. Alterations in systolic phase duration occurring with maturation reflect the normal functional adaptation of the developing heart. Measurement of these phases can provide useful information relative to cardiac function in children.

Naturally Occurring Shear Waves in Healthy Volunteers and Hypertrophic Cardiomyopathy Patients

“…The LV isovolumetric periods are very short (30À100 ms). However, several mechanical, electrical and hemodynamic events take place during this time (Goetz et al 2005;Golde and Burstin 1970;Konofagou and Provost 2012;Costet et al 2014). In patients with normal atrio-ventricular and intraventricular conduction, the first component of the two heart sounds is the valvular component: mitral (for the first heart sound) and aortic (for the second heart sound), respectively (Leatham 1954), and thus synchronous with the onset of the fast shear waves generated by the closure of the same valves (Remme 2008).…”

“…The three cycles were freely selected by each observer from the 10 available cycles per subject per exam as the heartbeats where the best visualization of the shear waves could be obtained. The very short isovolumic times are complex to analyze (Goetz et al 2005;Golde and Burstin 1970). In order to identify the exact times of valve closure and discriminate shear waves from other events, the acquisitions included a synchronous PCG signal, by using a Fukuda Denshi MA-300 HDS(V) PCG microphone.…”

Die Bestimmung der systolischen Zeitintervalle bei herzgesunden und mit Adriamycin behandelten Kindern

“…ICT entspricht demnach der Druckanstiegszeit des linken Ventrikels = DAZ nach Holldack (16). (18) in die Klinik, und in den letzten Jahren erneut auch von Weissler (26,27), ist sie von verschiedenen Autoren mehrfach überprüft worden (15,23,24…”

Accuracy of subject-specific prediction of end-systolic time in MRI across a range of RR intervals

“…It cannot cope with physiological differences among subjects due for example to pathological conditions, diurnal variation in the systolic intervals [6], pressure changes [7] or medication that alter systolic or diastolic times [8]. More so, it is known that equations from females and males differ slightly [9,10] and that the left ventricular ejection duration increases independently from heart rate from infancy to puberty [11,12] and is prolonged in the elderly [10,13]. These inter-individual differences should be taken into account.…”