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Biomedical subjects

H Huikuri

Publications and source records attributed to H Huikuri.

31 records · Page 2Linked 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↗
PubMed1989

Theophylline and salbutamol in combination in patients with obstructive pulmonary disease and concurrent heart disease: effect on cardiac arrhythmias.

We compared the frequency and severity of cardiac arrhythmias during combined oral theophylline and inhaled salbutamol vs. salbutamol therapy alone in 18 patients with moderate to severe chronic obstructive pulmonary disease who had concurrent cardiac disease. Seventeen patients showed at least one supraventricular premature complex (SVPC) on the 24-h ECG recording when receiving salbutamol alone: eight patients had isolated SVPCs, less than 10/h; five patients had greater than or equal to 10 SVPCs/h; eight patients showed runs of supraventricular tachycardia or paroxysmal atrial fibrillation. Seventeen patients also had at least one ventricular premature complex: seven patients had less than 10 isolated PVCs/h, five patients greater than or equal to 10 PVCs/h; eight patients had paired or multifocal PVCs and one patient a run of ventricular tachycardia. The addition of oral theophylline at an average dose of 600 mg in the evening (blood concentrations showed a mean maximum of 13.4 +/- 4.0 (SD) and minimum of 5.5 +/- 2.9 mg/l) had no influence on the frequency or severity of either ventricular or supraventricular arrhythmias. Thus, cardiac arrhythmias are very common in patients with chronic obstructive pulmonary disease and concomitant heart disease, but oral theophylline added to a regimen of salbutamol does not seem to affect the occurrence or severity of arrhythmias.

Aged↗
PubMed1989

Reversal of proarrhythmic effects of flecainide acetate and encainide hydrochloride by propranolol.

The use of membrane-active antiarrhythmic agents may be complicated by aggravation of existing arrhythmias or development of new drug-induced arrhythmias. Four patients, referred because of out-of-hospital cardiac arrest or symptomatic sustained ventricular tachycardia, were receiving class IC antiarrhythmic agents in an attempt to prevent inducibility of sustained ventricular tachycardia. New or worsening spontaneous arrhythmias developed while they were on flecainide acetate (n = 3) or encainide hydrochloride (n = 1) therapy. Spontaneous runs of rapid nonsustained and sustained ventricular tachycardia developed in two. Increased frequency of premature ventricular contractions and repetitive forms of ventricular ectopic activity developed in one, despite the fact that inducibility of sustained ventricular tachycardia had been prevented. Salvos and nonsustained ventricular tachycardia developed in the fourth patient. Propranolol had failed to prevent inducibility of sustained ventricular tachycardia during previous programmed stimulation studies in three of the four patients, but it reproducibly suppressed drug-induced arrhythmias that appeared only after administration of the IC agents in each patient. Suppression of the proarrhythmic effects by beta-adrenergic blockade suggests a possible interaction of these drugs with autonomic function in the genesis of the observed proarrhythmic effects. Direct pharmacologic control of proarrhythmic drug effects has not previously been reported.

Aged↗
PubMed1988

Cellular electrophysiological changes during ischemia in isolated, coronary-perfused cat ventricle with healed myocardial infarction.

Cellular electrophysiological consequences of acute ischemia superimposed on healed myocardial infarction were studied in isolated, coronary-perfused cat left ventricles 2-4 months after ligation of multiple distal tributaries of the left anterior descending and circumflex coronary arteries. Oxygenated Tyrode's solution was perfused through the left anterior descending and circumflex coronary arteries, and the preparations were superfused with Tyrode's solution gassed with 95% N2-5% CO2. Transmembrane action potentials were recorded from the endocardial cells in normal and infarcted zones. There were no significant differences in measured action potential variables and refractory periods between cells in the normal and infarcted zones before acute ischemia. When coronary perfusion was discontinued ("ischemia"), resting potential, action potential amplitude, and action potential duration were reduced, and the refractory period was shortened progressively in cells of the normal zone. However, the action potential changes were less prominent, and the refractory period was unchanged in cells in the infarcted zone. As a result, there were significant differences in resting membrane potential, action potential amplitude, action potential duration, and refractory period between cells in the normal and infarcted zones at 10 minutes of ischemia. These differences became larger as the ischemic period was prolonged. Spontaneous rapid ventricular activity was observed during the last 20-30 minutes of ischemia in four of eight preparations with healed myocardial infarction, whereas no spontaneous rapid ventricular activity was recorded in any of six normal heart preparations. Our data suggest that superimposition of acute ischemia on healed myocardial infarction produces electrophysiological inhomogeneities that may enhance arrhythmogenesis.

Action Potentials↗
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

Disopyramide pharmacokinetics in patients with acute myocardial infarction.

To study the effects of acute myocardial infarction on the pharmacokinetics of disopyramide a single oral dose of disopyramide base (200 mg) was administered to 6 patients with myocardial infarction both in the acute (Study I) and recovery (Study II) phases. An intravenous tracer dose of 14C-disopyramide (2.5 micrograms/0.3 mg) was given simultaneously with the oral dose. On the basis of the intravenous tracer data, the volume of distribution, binding to plasma proteins, total plasma clearance, renal clearance and elimination half-life of disopyramide and mono-N-dealkyl disopyramide were the same in Studies I and II. The peak serum concentrations of disopyramide after oral dosing in Studies I and II were 2.6 +/- 1.2 (SEM) and 6.4 +/- 1.9 microgram/ml, respectively (p less than 0.05), the peak times 3.29 +/- 1.22 and 1.21 +/- 0.39 h (N.S.) and the AUCINF 38.0 +/- 7.7 and 60.7 +/- 9.9 micrograms . h . ml-1 (p less than 0.05). The recovery of disopyramide in urine over 3 days averaged 46% and 47% of dose, and that of mono-N-dealkyl disopyramide 22% and 16% of the dose, respectively. Thus, the gastrointestinal absorption of disopyramide was disturbed, resulting in low plasma concentrations after oral dosing, whereas the elimination of disopyramide was unaltered in the acute phase of myocardial infarction.

Administration, Oral↗
PubMed1984

Antihypertensive effect of prizidilol.

The antihypertensive effect of a new compound, prizidilol hydrochloride (SKF 92657), with both vasodilator and non-selective beta-adrenoceptor antagonist properties was assessed in a series of 17 outpatients 2 of whom were subsequently withdrawn. After a placebo period the systolic supine blood pressure decreased from 154 (SD 3) mmHg to 143 (SD 4) mmHg (p less than 0.05) and the diastolic supine blood pressure from 102 (SD 2) mmHg to 94 (2) mmHg (p less than 0.02) during 12 weeks treatment. Standing blood blood pressure decreased by 14/9 mmHg (p less than 0.05 and p less than 0.02) during treatment. The dose of prizidilol was increased by 100 mg biweekly, the mean dose being 466 mg at the end of the study. No significant side-effects were noted and the laboratory tests disclosed no significant biochemical or immunological changes during the study.

Adult↗
PubMed1983

Clonidine twice daily in hypertension. Effects of two dosage regimens on blood pressure, side-effects and plasma clonidine concentrations.

The effects of two b.i.d. dosing schedules of clonidine on blood pressure, side-effects and plasma concentration of clonidine were studied in a randomized cross-over study. The blood pressures of 10 hypertensive inpatients on diuretic treatment were recorded every 3-4 hours throughout the study. A twice-daily regimen with 0.075 mg clonidine administered at 8 a.m. and 0.15 mg at 10 p.m. resulted in a wider fluctuation of blood pressure than the same doses given at 8 a.m. and 4 p.m. The most conspicuous finding was the significant rise (p less than 0.001) of diastolic blood pressure at 8 p.m., when clonidine was given at 8 a.m. and 10 p.m. The overall mean values of supine systolic and diastolic blood pressures were normotensive and did not differ from each other in the two dosing schedules. There were no obvious differences in subjective side-effects between the two regimens. Predose clonidine concentrations varied interindividually between 0.15 and 1.12 ng/ml, but the fluctuation in one and the same subject was small and related to dose and its timing. Thus, twice-daily dosing of clonidine seems to result in a satisfactory blood pressure reduction. Fluctuation of blood pressure is greater when the evening dose is given at 10 p.m.

Adult↗