Biomedical subjects

M Mäntysaari

Publications and source records attributed to M Mäntysaari.

40 records · Page 3Linked to original sources

PubMed1985

Rapid changes in rate-corrected and uncorrected systolic time intervals during cold pressor test.

The changes in heart rate and systolic time intervals were studied in a group of 10 young healthy male volunteers during immersion of their hand in ice water for 1 min. The heart rate and systolic time intervals were measured from electro-, phono-, and impedance cardiograms in the standard way. When the cold immersion was done in the supine position the left ventricular ejection time (LVET) and the electromechanic systole (Q-S2Tc) shortened, and when corrected for the heart rate the Q-S2Tc lengthened in the beginning of the immersion. In the head-up position the Q-S2T shortened in the beginning of the immersion while the rate-corrected systolic time intervals remained unchanged. Most of the changes in the systolic time intervals disappeared before the last quarter of the cold immersion. It was observed that during the cold immersion the linear regression coefficients between the heart rate and the Q-S2T in the supine position as well as between the heart rate and the LVET, Q-S2T and the PEP in the head-up position were greater than the regression coefficients used in the rate correction.

Adult↗

PubMed1984

Relationship between systolic time intervals and heart rate during four circulatory stress tests.

The linear regression equations between heart rate and systolic time intervals were calculated before and during a handgrip test, an orthostatic test, the Valsalva test and a cold pressor test. The subjects were 30 healthy men, average age 20 years. During the 1st min of orthostasis the regression line of the left ventricular ejection time (LVET) was significantly (P less than 0.05) steeper than at rest and that of the pre-ejection period (PEP) was significantly (P less than 0.01) less steep than at rest, and the regression between HR and the PEP/LVET ratio deviated significantly (P less than 0.001) from zero. During the Valsalva maneuver, the regression line of the LVET became significantly (P less than 0.001) steeper than at rest and the regression coefficient of the PEP changed from negative to positive, the difference being significant (P less than 0.001); the regression between HR and the PEP/LVET also deviated significantly (P less than 0.001) from zero. During the cold pressor test the regression line of the electromechanic systole (Q-S2 time) was significantly (P less than 0.01) less steep than at rest. It was concluded that the use of regression equations calculated for the systolic time intervals and heart rate at rest can lead to errors when applied to rate correction of systolic time intervals during an orthostatic, Valsalva, or a cold pressor test.

Adolescent↗

PubMed1984

Hemodynamic reactions to circulatory stress tests in patients with neurocirculatory dystonia.

The hemodynamic reactions of 30 patients with neurocirculatory dystonia (NCD, DaCosta's syndrome) were compared to those of 30 healthy controls during the isometric handgrip test, orthostatic test, Valsalva test and the cold pressor test. The effects of hyperventilation on the ability to hold the breath were studied in both groups using the hyperventilation test. The patients and controls were young men, who were doing their conscript service, and the average age was 20 years in both groups. The diagnosis of NCD was made using the criteria described by Friedman (1947). The patients had several symptoms related to the cardiorespiratory system, the intensity of which varied from time to time and were not closely related to physical effort. In order to exclude organic diseases that could have caused the symptoms the patients were required to have no history of chronic organic diseases. They were also required to have no infectious diseases nor to be convalescents when participating in this study and to have a normal ECG and a normal thorax x-ray. The controls were anamnestically free from chronic diseases. The changes in the blood pressure, heart rate, stroke volume, cardiac index, peripheral vascular resistance and the systolic time intervals during the four tests were measured noninvasively using sphygmomanometry, electro-, phono- and impedance cardiography. The ability to hold the breath after a deep inspiration was similar in the two groups. Immediately after hyperventilation the ability to hold the breath did not improve in the NCD group as much as in the control group. In the orthostatic test the rise in the mean blood pressure was only momentarily greater in the control group than in the NCD group, and the heart rate increased about equally in the two groups. The transthoracic impedance increased significantly more in the controls than in the patients in the head-up position. The alterations in the systolic time intervals immediately after the changes of posture were more rapid in the control group that in the NCD group. During the expiratory strain of the Valsalva maneuver the hemodynamic changes in the two groups did not clearly differ from each other, but after the end of the strain the blood pressure overshoot lasted longer in the NCD group than in the control group. During the cold immersion the stroke volume decreased significantly more in the NCD group than in the control group. The stroke work index increased significantly in the control group, but did not change in the NCD group during the immersion.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1984

Relationship between the changes in heart rate and cardiac output during the Valsalva maneuver.

Ten young (average age 20 years) healthy male volunteers performed the Valsalva maneuver (40 mmHg for 15 seconds) in the supine and the upright position. The heart rate (HR), stroke volume (SV) and the cardiac index (CI) were registered using ECG and impedance cardiography. During the expiratory strain of the Valsalva maneuver the HR increased about equally in the two positions while the decreases in the SV and the CI were in the supine position significantly greater than in the upright position. The CI decreased to equal levels in both positions after 15 seconds of strain. The rise in the HR due to the expiratory strain did not correlate significantly with the decrease in the CI in either position. The correlation between the HR rise and the SV decrease was almost significant (p less than 0.05) in the supine position and significant (p less than 0.01) in the upright position after 5 seconds of strain but not after 10 or 15 seconds. These observations suggest that the relationship between the rise in the HR and the decrease in the venous return does not remain constant during 15 seconds of expiratory strain. Perhaps the cardiopulmonary baroreceptor reflexes affect the HR after five seconds of strain more than they do after 10 or 15 seconds of strain.

Adult↗