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Left ventricle systolic volume in vasovagal syncope patients

100%

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.

Haemodynamic responses to the dynamic exercise in subjects exposed to different gravitational conditions

84%

Puchalska L., Belkania G. S.

Journal of Physiology and Pharmacology. Supplement

2006

tom 57

nr 11

103-113

Different types of adaptation of the cardiovascular system to the gravitational forces (hypokinetic and hyperkinetic) have been described in the healthy and the sick subjects under resting conditions. The aim of the present study was to elucidate whether haemodynamic responses to the dynamic exercise performed under various gravitational conditions are determined by the type of adaptation of the cardiovascular system to the gravitational forces at rest. The study was performed on 249 healthy men, 20-60 years old. To assess the type of regulation of the cardiovascular system arterial blood pressure (MABP), heart rate (HR), stroke volume (SV), cardiac output (CO), and systolic function (SF) of the heart were determined in each subject at rest in the upright (orthostatic state) and in the supine position. Subsequently, the subjects were performing exercise on a cycloergometer in the sitting and the supine position. Four gradually increasing workloads were applied. Measurements of HR, MABP, SV, CO, and SF were repeated at the end of each workload. SV, CO and SF were determined by means of rheography. The results revealed that in the individuals showing at rest the hypokinetic type of orthostatic cardiovascular adaptation the augmentation of CO during exercise in the sitting position was caused by significant increases of HR and SV. In contrast, the subjects with the hyperkinetic type of orthostatic adaptation the increase in CO during exercise in the sitting position was much smaller and resulted predominantly from acceleration of HR. It is concluded that the cardiovascular adaptation to the dynamic exercise depends not only on the position of the body in which the exercise is performed but it is also determined by the type of adaptation of the cardiovascular system to the gravitational forces at rest. In the sitting position the pumping capacity of the heart is significantly greater in the hypokinetic than in the hyperkinetic type of the cardiovascular regulation; this relationship being reversed during exercise in the horizontal position.

Ograniczanie wyników

1 Folia Morphologica

1 Journal of Physiology and Pharmacology. Supplement

1 Belkania G. S.

1 Byrdziak P.

1 Gawrysiak M.

1 Kozlowski D.

1 Krupa W.

1 Kubica J.

1 Piwko G.

1 Puchalska L.

1 Swiatecka G.

1 2006

1 2003

Wyniki wyszukiwania

Left ventricle systolic volume in vasovagal syncope patients

Haemodynamic responses to the dynamic exercise in subjects exposed to different gravitational conditions