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Relationships Between Systolic Time Intervals and Heart Rate During Initial Response to Orthostatic Manoeuvre in Men of Different Age

100%

Cybulski G. , Niewiadomski W. , Strasz A. , Laskowska D. , Gąsiorowska A.

tom 21

57-64

An analysis of transient changes in physiological parameters in response to the standardized tests could be used to evaluate the efficiency of the regulatory processes. Relationships between systolic time intervals and heart rate following the action of standing up from the supine position were investigated in 41 healthy men, aged 20 to 59 years, classified into three groups: (22 to 26 yrs, n=14), (33 to 49, yrs, n=13) and (51 to 59 yrs, n=14). The protocol consisted of the following sequence: laying down (20 minutes) - standing up (8 minutes). Ejection time, pre-ejection period, electromechanical systole, heart rate and the length of R-R intervals were continuously calculated using automatized impedance cardiography and electrocardiogram. The ratio of ejection time to pre-ejection period in young men was significantly higher in comparison with the other groups. The ratio of ejection time to the length of R-R interval increased with age in supine position and after standing up when R-R interval was maximal. It was suggested that changes of ejection time to pre-ejection period during the orthostatic manoeuvre are rather the result of balance between heart rate and hemodynamic factors, than solely related to heart rate.

Left ventricle systolic volume in vasovagal syncope patients

86%

Kozlowski D. , Byrdziak P. , Krupa W. , Gawrysiak M. , Piwko G. , Kubica J. , Swiatecka G.

Folia Morphologica

2003

tom 62

nr 3

175-178

One of the hypotheses put forward concerning the mechanism of vasovagal syncope is that the vagal afferent fibres are activated during vigorous contractions against a partly empty left ventricle. The aim of the study was to confirm this hypothesis by using 2D echocardiography during a head-up tilt test. The study was carried out on 39 patients (17 male, 22 female, age range 21–64 years), all with a history of recurrent syncope. The patients were examined using a 2D echo to measure the end-diastolic and end-systolic volume before the head-up tilt test after the Westminster protocol (45min/60 grade) and every five minutes after tilting. T patients during head-up tilt test had a positive response and 32 proved negative. A reduction of both the end-diastolic and end-systolic volumes of the left ventricle was noticed. There was no significant difference in the degree of ejection fraction reduction. The difference in ejection fraction reduction between the two groups was similarly non-significant. It was also noticed that the patients with a positive response had more vigorous contractions than those with a negative test. The decision was therefore taken to use a different parameter for the left ventricle contraction, namely the LV posterior wall slope. As this parameter is partly dependent on time, its use in confirming the extremely vigorous nature of the contractions was considered appropriate. Only 6 patients were tested using this parameter. A tendency towards greater left ventricle posterior wall slope values, both before and during tilting was noticed in the group of patients with vasovagal reaction. Our data shows that vigorous contraction is probably less responsible for vasovagal syncope release than left ventricle volume reduction.