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Biomedical subjects

J Takkunen

Publications and source records attributed to J Takkunen.

At least 19 recordsLinked to original sources
PubMed1991

Changes in myocardial energy metabolism in elective coronary angioplasty.

STUDY OBJECTIVE: The aim was to investigate the effect of coronary angioplasty on myocardial energy metabolism, and to assure the safety of the procedure in patients with coronary heart disease. DESIGN: Before angioplasty a catheter was introduced into the coronary sinus. Blood samples were taken simultaneously from femoral artery and coronary sinus before balloon inflation, upon balloon deflation, and two minutes later, and arteriovenous differences in myocardial substrates, pH, PCO2, oxygen saturation, and adenosine catabolites were determined. PATIENTS: 14 patients with angiographically documented coronary artery disease with lesions in the left coronary artery suitable for elective coronary angioplasty were included in the study. RESULTS: During balloon inflation the positive femoroarterial-coronary sinus difference of lactate turned negative, from 0.21(SEM 0.05) mM to -0.10(0.11)mM, p less than 0.02. At the same time pH and PCO2 differences increased: from 0.04(0.00) U to 0.07(0.01) U, p less than 0.01, and from -1.15(0.10) kPa to -1.41(0.10) kPa, p less than 0.01, respectively. The changes were, however, transient and the arteriovenous differences in these metabolic variables rapidly returned towards preinflation levels after balloon deflation. The femoroarterial-coronary sinus concentration differences in glucose and free fatty acids became positive in coronary angioplasty. The energy state remained good during the procedure as assessed from the negligible net efflux of adenosine and its degradation products. CONCLUSIONS: Elective coronary angioplasty can be performed without any persistent derangements in myocardial metabolism, and may in fact lead to improvement of utilisation of some myocardial substrates. Lactate appears to be a more sensitive indicator of short term ischaemia than adenosine degradation products.

Adenosine↗
PubMed1990

Isometric exercise testing and echocardiography at rest in aortic valve incompetence.

Thirty patients with aortic valve incompetence and 21 control subjects were examined by M-mode echocardiography at rest and radionuclide ventriculography during submaximal handgrip exercise. The patients had greater left ventricular dimensions and end-systolic wall stress values but peak systolic wall stress values did not differ. During exercise the controls' ejection fraction increased by 3 +/- 4%, 95% confidence interval (CI) from +1% to +5%, while the aortic incompetence patients showed no change -1% +/- 5%, CI from -3 to +1%. The 15 symptomatic aortic incompetence patients had a different ejection fraction response from the controls (-2 +/- 4%, p less than 0.01), CI from 4% to +1%, but the 15 asymptomatic patients had not (0 +/- 6%, not significant, CI from -3% to +3%). Three symptomatic and two asymptomatic patients with a decrease in ejection fraction below 5% during handgrip were not identified by left ventricular size and function of systolic loading conditions at rest. Neither echocardiographic or radionuclide parameters of left ventricular size and function at rest correlated with the individual ejection fraction changes during handgrip. Thus, in aortic valve incompetence, the radionuclide angiography assessed functional response to handgrip cannot be predicted by left ventricular size and function or systolic loading conditions at rest.

Adult↗
PubMed1989

Left ventricular dimensions during isometric exercise in aortic valve incompetence assessed by M-mode echocardiography and gated equilibrium radionuclide angiography.

We compared M-mode echocardiographic and gated equilibrium radionuclide angiography assessment of the left ventricular (LV) dimensions at rest and during isometric exercise in 18 patients with chronic aortic valve incompetence. The two methods showed a satisfactory correlation when comparing LV size at rest and during exercise (LV end-diastolic dimension in echocardiography vs LV end-diastolic volume in radionuclide angiography, r = 0.80, P less than 0.01 at rest and r = 0.81, P less than 0.01 at rest and r = 0.75; P less than 0.01 during exercise), but fractional shortening in echocardiography and ejection fraction in radionuclide angiography did not correlate (r = 0.27, not significant (NS) at rest and r = 0.34, NS during exercise). Thus echocardiography and radionuclide angiography describe LV dimensions at rest and during handgrip exercise in a similar fashion, documenting the concordance of these noninvasive methods to describe LV size in aortic incompetence at rest and during exercise.

Adult↗
PubMed1987

Impaired left ventricular diastolic function in athletes after utterly strenuous prolonged exercise.

Digitized M mode echocardiography was used to evaluate the effect of a competitive 24-h run on the left ventricular diastolic function in 12 well-trained marathon runners who completed 146-227 km during the race. Mitral valve opening was delayed, early diastolic filling was decreased and prolonged, and posterior wall thinning was reduced, particularly among those athletes completing close to 200 km or more. Since the alterations were in part the opposite in those running 160 km or less, only the reductions in the peak rate of dimension increase (P less than 0.05) and posterior wall thinning (P less than 0.01) were significant in the group as a whole. The delay in mitral valve opening (r = 0.76), the decrease in the peak rate of dimension increase (r = -0.68), and the prolongation of the early diastolic filling period (r = 0.60) were correlated with the distance completed. The reductions in left ventricular end-diastolic dimension and fractional shortening were not in proportion to the distance run, however (r = 0.23 and 0.46, respectively). Measurements made on six athletes 2-3 days after the race showed reversal of the indices of left ventricular diastolic function. Extremely exhaustive prolonged exercise thus appears to result in a marked reversible impairment in left ventricular relaxation and filling. Since the effect of these abnormalities in cardiac filling during exercise is probably more important due to the shorter diastole, the prevention of hypohydration, which could otherwise further compromise left ventricular filling, becomes crucial.

Adult↗
PubMed1987

Comparison of echocardiographic and radionuclide methods with contrast angiography assessment of left ventricular function--response to isometric exercise in subjects without definite heart disease.

In order to study the validity of non-invasive assessment of left ventricular response to isometric exercise, 21 subjects with chest pain, but without any cardiac abnormalities performed an isometric handgrip test during cardiac catheterization, M-mode echocardiography and radionuclide angiography. Fourteen of the subjects were suitable for comparison of all the three methods. In response to handgrip exercise the ejection fraction (EF) remained unchanged in contrast angiography (68 +/- 9% at rest; 68 +/- 9% during exercise) and echocardiography (74 +/- 4% at rest; 74 +/- 5% during exercise), but showed a small increase on radionuclide angiography (from 57 +/- 5% to 60 +/- 7% (p less than 0.01). Individual changes in ejection fraction during the handgrip exercise had a reasonable correlation between contrast angiography and radionuclide angiography (r = 0.63, p less than 0.01). In order to validate the reproducibility of M-mode echocardiography and radionuclide angiography, the haemodynamic and left ventricular responses during two consecutive handgrip tests were compared in eight subjects. No significant differences were seen in the haemodynamic responses or between the changes in ejection fraction or fractional shortening in the two tests. Thus, in subjects without heart disease the non-invasively determined results of the left ventricular response to the handgrip exercise were similar to those obtained invasively and could be reliably reproduced.

Cardiac Catheterization↗
PubMed1985

Determination of the anaerobic threshold in the evaluation of functional status before and following valve replacement for aortic regurgitation.

The effect of aortic valve replacement on exercise capacity was evaluated in 28 patients with aortic regurgitation using repeat determinations of peak oxygen uptake (VO2) and the anaerobic threshold (AT), based on a nonlinear increase in the plot of pulmonary ventilation versus VO2. Although the AT was on average 68% of peak VO2 before and 1 year after surgery, the test-to-test correlation coefficient was 0.92 for the AT but only 0.68 for peak VO2 postoperatively. 11 patients (39%) improved in AT, usually within the first 6 months. The preoperative echocardiographic left ventricular end-diastolic dimension and its postoperative change correlated with that in the AT (r = 0.64 and -0.60, p less than 0.001) but not with that in peak VO2. The patients likely to improve had a lower AT (p less than 0.05) preoperatively, however. Thus repeat determinations of AT using respiratory measurements give additional data on changes in functional status. Sequential exercise testing does not require the patient to be exercised much past his AT.

Adult↗
PubMed1984

Impaired left ventricular filling in young female diabetics. An echocardiographic study.

To assess left ventricular (LV) function in diabetes mellitus, M-mode echocardiograms were recorded in 36 insulin-treated diabetic women, mean age 25 +/- 6 (SD) years, and 13 healthy women of the same age. Echocardiographic tracings of the septum and LV posterior wall were digitized and continuous plots were made of LV dimension and its rate of change. The pattern of LV filling was abnormal in 19 diabetics, when the mean value +/- 2 SD in the healthy women was taken as the normal range of the indices. The most common abnormality was a prolonged rapid filling period. The LV systolic function was normal in all diabetics. Diabetics with severe microvascular complications had thicker LV walls (p less than 0.05) and smaller LV end-diastolic diameters and stroke volumes (p less than 0.01) than the healthy women. The electrocardiographic voltage was lower in the diabetic group (p less than 0.05). These studies suggest that minor abnormalities in LV function reflecting stiffness of the myocardium are common in young female diabetics, a patient group with a relatively low prevalence of coronary artery disease.

Adolescent↗
PubMed1984

One turn more: threshold superiority of 3-turn versus 2-turn screw-in myocardial electrodes.

Epicardial electrodes are an alternative for patients in whom the transvenous approach presents technical difficulties. We have had clinical experience with two types of myocardial sutureless electrodes inserted in the anterior left ventricular wall: the 3-turn screw-in electrode (Medtronic 6917) was used in 209 patients from 1974 to 1977 and the 2-turn screw-in lead (Medtronic 6917 A) was used in 61 patients from 1978 to 1981. The initial threshold was equal and acceptable with both types of electrodes. During a follow-up period (up to 48 months), critical elevation of the pacing threshold resulting in exit block was found in 12% (25) of the patients with the 3-turn screw-in electrode and in 20% (12) of the patients with the 2-turn electrode (p less than 0.05). Elevation of the pacing threshold developed fairly early, usually within 6 months, with the 2-turn screw-in electrode, but much later, within 2-4 years, with the 3-turn electrode. During a longer follow-up time of up to 96 months the frequency of exit block increased up to 16% with the 3-turn electrode. Our results indicate that late critical elevation of the pacing threshold is surprisingly frequent with screw-in electrodes inserted into the left ventricular myocardium, and it is especially common with the 2-turn screw-in electrode.

Adolescent↗
PubMed1984

Systolic time intervals and the QT-QS2 interval in young female diabetics.

To detect subclinical cardiomyopathy in diabetic patients without evidence of coronary artery disease, systolic time intervals were measured in 51 insulin-treated young female diabetics (mean age 27 years and mean duration of diabetes 12 years) and in 15 healthy women of the same age. The ratio of the pre-ejection period to the left ventricular ejection time (PEP/LVET) was used as an index of left ventricular performance. The PEP/LVET ratio was normal in all diabetics and did not differ statistically from that in the control group. The electrical (QT) and electromechanical (QS2) systole were measured from the same high velocity recordings. The QT-QS2 interval (mean +/- SD) was shorter in the diabetic group (-16 +/- 22 ms vs. -33 +/- 9 ms, p less than 0.01). Ten diabetics but none of the healthy women, had the QT interval longer than the QS2. This was a result of both shortening of the QS2 and prolongation of the QT. In conclusion, our results suggest normal myocardial contractility in these young female diabetics. The significance and mechanism of the shortened QT-QS2 interval in the diabetics need further investigation.

Adolescent↗
PubMed1983

Functional evaluation after aortic valve replacement.

Preoperative and sequential postoperative bicycle exercise tests were compared with clinical and catheterization data in assessment of the functional outcome of uncomplicated aortic valve replacement (AVR) in 33 patients. The operation was done because of aortic stenosis (AS) in 14 patients and aortic regurgitation (AR) in 19. Both groups of patients showed improved NYHA functional class and peak achieved workload after AVR, but the results in these respects did not correlate. Nor did the regression in left ventricular (LV) hypertrophy and dilatation after AVR that was seen in both patient groups correlate with the changes measured in exercise tolerance. Preoperative exercise capacity was not predictive of the postoperative performance. In the AR patients, however, preoperative ability to raise the systolic blood pressure during exercise appeared to predict which patients were likely to show enhanced resting LV systolic pump function after AVR. It is concluded that objective tests of exercise tolerance alone permit reliable evaluation of the functional outcome of uncomplicated AVR. Indices of resting LV performance, though helpful in observation of the changes resulting from removal of the untoward LV burden after AVR, are likely to be less useful for evaluating changes in the LV exercise reserve. The response of the systolic blood pressure to exercise may be an additional predictive factor for postoperative resting LV performance in patients with AR.

Adult↗
PubMed1982

Effects of renal transplantation on left ventricular size and function.

Thirteen patients with chronic renal failure and uraemia were investigated by echocardiography preoperatively before and after haemodialysis and again after a successful renal transplantation to evaluate the cardiac changes caused by renal transplantation. After renal transplantation, the left ventricular end-diastolic and end-systolic diameters, as well as the cardiac index, decreased, probably because of the decreased left ventricular filling pressure. The left ventricular wall thickness and mass decreased, apparently as a result of the decrease of the left ventricular preload and also of the decrease of the afterload, because the systolic blood pressure decreased. The left atrial diameter decreased in response to the decreased left ventricular preload and wall hypertrophy. The changes in the indices of left ventricular function as a result of haemodialysis appeared to predict the changes seen after renal transplantation. Renal transplantation appears to have a tendency to result in normal left ventricular and left atrial volumes, as well as to lessen left ventricular hypertrophy, without significantly improving left ventricular function.

Adult↗
PubMed1981

Effect of open heart surgery on intellectual performance.

The interrelationship between postoperative psychosis, neurologic symptoms, and changes in tests of cognitive performance have been studied in a series of 60 cardiac valvular patients who underwent open heart surgery. The effects of preoperative psychological, psychiatric, and cardiologic factors on postoperative cognitive changes were analyzed. The investigation period was from five months before up to five months after the operation. There was a general trend towards improvement in intellectual performances. The psychotic group, however, still showed a persisting impairment in some visual and psychomotor tests several months after the surgery. The group with neurologic symptoms showed impairment in one visual test. Of the preoperative variables, mitral valve disease, a high level of hypochondriasis and anxiety, and poor performance in some visual and psychomotor tests predicted postoperative intellectual impairment. The results suggest two types of cerebral complications of open heart surgery. Postoperative psychosis reflects diffuse brain dysfunction manifesting itself in psychological tests long after the clinical symptoms have resolved. The presence of neurologic symptoms refers to a focal or lateralized injury. Both the neurologic and neuropsychologic findings indicate that the right hemisphere may be prone to dysfunction than the left hemisphere.

Cardiac Surgical Procedures↗
PubMed1980

The oxygen uptake - work-output relationship of runners during graded cycling exercise: sprinters vs. endurance runners.

In order to study oxygen consumption (VO2) for a given work load at the exhaustive level of a graded cycling exercise in well-trained runners, a progressive cycle ergometer exercise test was performed on 9 sprinters and 12 endurance runners, all in good national standing; 12 sedentary men served as control subjects. The relationship between VO2 and work-output appeared to be linear in most of the subjects, but a plateau phenomenon was observed in two sprinters and two endurance runners. An upwards curvilinear increase in VO2 was noticed during the last two minutes of exercise in four endurance runners, but not in any of the sprinters. The four endurance runners with this unexpected increase in VO2 had a significantly higher (p < .01) "peak VO2" (mean = 75.3 ml.kg.-1.min.-1) than the rest of the endurance runners (mean = 55.1), and a significantly higher (p < .001) peak VO2 than the sprinters (mean = 46.0). It is concluded that the plateau phenomenon appears in runners during graded cycle ergometry, though rather seldom. It is less clear if the endurance runners showing the upwards curvilinear increase in VO2 possess a better aerobic performance capacity towards the end of progressive exercise. Nevertheless, the linear relationship between VO2 and work load does not appear to be the only one observed in runners during graded exercise.

Adult↗
PubMed1980

Left ventricular function after dynamic and static exercise in ischaemic heart disease.

The effects of dynamic and static exercise on left ventricular function in ischaemic heart disease were studied in 20 patients with angiographically documented coronary artery disease. Radiocardiography was used to determine left ventricular volumes at rest and during exercise tests. Dynamic exercise increased cardiac output significantly (p less than 0.001) in the 10 patients with one-vessel coronary artery disease, whereas end-diastolic and end-systolic volume and ejection fraction did not change from the resting values. In contrast, in the 10 patients with multiple coronary vessel disease significant increases in end-diastolic (p less than 0.05) and end-systolic volumes (p less than 0.001) were observed during dynamic exercise. Cardiac output increased by only 21% (p less than 0.05) while a decrease in ejection fraction (p less than 0.005) reflected pump dysfunction in these patients. Static exercise did not change cardiac output or end-diastolic volume significantly. The end-systolic volumes increased in both patient groups, more so in the patients with multi-vessel coronary involvement (p less than 0.005 and p less than 0.01, respectively). These data revealed a different left ventricular volume response to dynamic exercise in the patients with one-vessel coronary artery disease compared with those with multi-coronary involvement. The afterload stress taking place during the static exercise, on the other hand, evoked left ventricular dysfunction very sensitively and similarly, irrespective of the extent of coronary artery stenoses.

Adult↗