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At least 1,693 records · Page 94Linked to original sources
PubMed1991

[Cardiac function after radical correction of tetralogy of Fallot in infants].

A total of 20 patients (mean age 8.9 months) were examined after total correction of Fallot's tetralogy, 9 of them underwent transannular plasty and 11, separate right ventricular outflow tract plasty. Two-dimensional and Doppler echocardiographies were used to measure cardiac index, end-diastolic and end-systolic volumes, ejection fraction of the left and right ventricles, regurgitation fraction on the pulmonary and tricuspid valves, right ventricular-pulmonary artery pressure gradient. The study of the immediate postoperative period indicated that the pattern of its course was affected by the type of right ventricular outflow tract plasty, however, its function (ejection fraction) remained diminished in the periods up to 12 months of the operation. Pulmonary valve regurgitation was found to be one of the factors contributing to its diminution.

Hemodynamics↗
PubMed2004

C34T AMP deaminase 1 gene mutation protects cardiac function in donors.

Dysfunction of the donor heart is an important clinical problem that could be affected by genetic factors. We tested the hypothesis that possession of the C34T nonsense mutation in AMPD1 gene, which is known to improve survival in chronic heart failure, protects against cardiac dysfunction in donors. Genetic analysis for C34T mutation was performed by single-stranded conformational polymorphism (SSCP) in 22 donor hearts used for transplantation, 10 unused donor hearts with acute heart failure (HF), 37 patients with chronic HF, and 207 healthy controls. We found a significantly higher frequency of the mutation among donors with healthy hearts used for transplantation (31.8%) as compared to control population (13.5%, P < 0.001) and a lower frequency in dysfunctional donor hearts (5.0% P = 0.025); the frequency of the C34T mutation in patients with chronic heart failure (14.8%) was not different from that of a control population. The presence of the C34T mutation in AMPD1 gene appears to be protective against acute heart failure in cardiac donors.

AMP Deaminase↗
PubMed2000

Autonomic regulation of cardiac function during sleep in patients with irritable bowel syndrome.

OBJECTIVE: Several studies have provided evidence of abnormal autonomic activity in irritable bowel syndrome (IBS), suggesting that abnormal central nervous system-autonomic nervous system arousal mechanisms may be part of its pathophysiology. The goal was to investigate cardiac sympatho-vagal balance during waking and the different stages of sleep using heart rate variability analysis in IBS patients compared to healthy controls. METHODS: A total of 15 IBS patients (13 female, two male, mean age 34.9 +/- 2.1 yr) and 15 controls (13 female, two male, mean age 36.2 +/- 2.3 yr) were studied during 1 h of pre-sleep quiet waking and during seven-hours of sleep. Polysomnography was used for the determination of state of consciousness. Electrocardiography provided the beat-to-beat intervals, which were then subjected to spectral analysis for determination of the percentage of energy in the low and high frequency bands, respectively. The low frequency/high frequency band ratio was also calculated. For each subject, heart rate variability analysis was performed using 15-min segments of waking, non-rapid eye movement sleep, and rapid eye movement sleep. RESULTS: The low frequency band power was significantly greater in IBS patients during waking. No group differences were found in high frequency band power during any state. The low frequency to high frequency band ratio was significantly greater in IBS patients during rapid eye movement sleep. CONCLUSIONS: IBS patients have greater sympathetic activity during waking and greater overall sympathetic dominance during rapid eye movement sleep. These results support the presence of autonomic abnormalities in patients with IBS. The possibility is discussed that sympathetic dominance during rapid eye movement sleep may play a role in sensitizing the gut to waking stimulation.

Adult↗
PubMed2002

[Cardiac function involving the T-type Ca2+ channel].

Functional involvement of the T-type calcium channel in the heart excitation at the pathophysiological conditions has been elucidated. The T-type channel is classified as the low voltage-activated channel (LVA) solely in the voltage activated calcium channel. In 1998, Perez-Reyes and coworkers cloned the first LVA alpha(1) subunit, which was named as alpha(1G) or Ca(V)3.1. In the cardiac muscle, alpha(1G) and the other clone alpha(1H) are dominantly expressed in the sinoatrial node, atrioventricular node and other signal conduction tissues. Abnormal activity of T channels has been suggested in the following cardiovascular diseases: hypertension, cardiac hypertrophy, cardiac infarction. The cloning of the T-type calcium channel allows us to understand the function of the channel in detail and options for therapeutics in the T-type channel-related diseases.

English Abstract↗
PubMed1995

Effects of type 1 diabetes mellitus on cardiac function: a study of monozygotic twins.

OBJECTIVE: To investigate left ventricular size and function in type 1 diabetes and their relation with diabetes duration, glycaemic control, autonomic dysfunction, and complications of diabetes. DESIGN: Cross sectional study using a pulsed wave Doppler echocardiogram to assess left ventricular dimensions, wall thickness, and transmitral blood flow velocity signals. PATIENTS: 40 monozygotic twin pairs (23 male, mean age 26 years) discordant for type 1 diabetes and 40 non-diabetic singleton controls with no clinical evidence of cardiac ischaemia. RESULTS: For all Doppler echocardiographic measurements there were strong correlations between monozygotic twins but not between twins and control subjects. Left ventricular dimensions, wall thickness and systolic function, peak E velocity, and the velocity integrals of early left ventricular filling were similar in all three groups. Peak A velocity and the velocity integrals of late ventricular filling (mean (SD)) were greater in diabetic twins (45 (12) v 38 (8) cm/s, P = 0.002; and 32 (11) v 26 (6), P = 0.0002). Diabetic twins had lower E/A ratio (1.59 (0.39) v 1.83 (0.39), P < 0.001), greater atrial filling fraction to total diastolic filling (28 (6) v 25 (5)%, P = 0.002), and prolonged isovolumic relaxation time (72 (12) v 63 (9) ms, P < 0.001). The differences in Doppler findings between diabetic and non-diabetic twins were related to disease duration whereas the prolongation of the isovolumic relaxation time was related to cardiac autonomic dysfunction. CONCLUSIONS: These results show that twins with type 1 diabetes have left ventricular diastolic dysfunction related to diabetes duration and cardiac autonomic dysfunction but not to glycaemic control or microvascular complications. In addition, genetic factors contribute to left ventricular dimension and function.

Adolescent↗
PubMed2006

Effect of passive cardiac containment on ventricular synchrony and cardiac function in awake dogs.

OBJECTIVE: Passive restraint of the left ventricle (LV) has been shown to have beneficial effects on acute hemodynamics and reverse remodeling in both animal and human models. The goals of this study were to test whether a left ventricular support device (LVSD) improves LV synchrony and/or affects cardiac performance. METHODS: Ten dogs were chronically instrumented to measure hemodynamics and LV volume (sonomicrometry). Congestive heart failure (CHF) was induced by repeated intracoronary microembolization via a chronically implanted coronary catheter. The LVSD was implanted after establishment of CHF in five animals, and five animals were observed as controls. All animals were then observed for 8 weeks. A mathematical model to measure LV synchrony was used to evaluate LV motion over time. RESULTS: Mean arterial pressure and LV pressures was significantly increased after LVSD therapy, and LV pressure-volume relationships were shifted leftwards, although no change was seen in ejection fraction, end-systolic elastance, or LV dP/dt versus control. There was no significant change in diastolic function in LVSD animals compared with control animals. End-diastolic volumes were reduced by 15% after 8 weeks with LVSD treatment, versus an increase of 8% in control animals (p<0.05). Synchrony was significantly improved with LVSD therapy compared with control (9% vs 76% of baseline) in 1 of 11 ventricular dimension axes (Anterior-Apex). CONCLUSIONS: LVSD therapy provided only minimal improvement in ventricular synchrony and partially improved hemodynamics. Further study into mechanisms of benefit are warranted.

Animals↗
PubMed1999

Evaluation of cardiac functions in patients with thalassemia major.

It is known that a blood transfusion is necessary for survival in patients with thalassemia, but it may cause myocardial dysfunction due to myocardial siderosis as in other organs. The aim of this study was to evaluate myocardial perfusion by means of stress thallium scanning (MPS) and left ventricular functions by rest radionuclide ventriculography (RNV). Twenty-one patients at ages 9-16 (mean 12.1 +/- 3.2) who have been diagnosed with thalassemia for 4-15 years (mean 12.7 +/- 4.8) were included in the study. They had blood transfusions 78-318 times (mean 162.1 +/- 71). MPS and RNV was performed within two days after the any transfusion. MPS showed ischemia in 3 patients and normal perfusion in 18 patients. RNV revealed normal systolic parameters (wall motion, EF, PER, TPE) but diminished diastolic parameters (TPF, PFR) compared with normal values (p < 0.05). We conclude that ischemia or fixed defects may be seen in stress MPS as a result of cardiac involvement in patients with thalassemia. But, RNV is an important and preferable test for the early detection of subclinic cardiomyopathy. RNV may therefore show diastolic abnormalities before the systolic abnormalities show up.

Adolescent↗
PubMed2003

Improved functional cardiac MR imaging using the intravascular contrast agent CLARISCAN.

PURPOSE: Using segmented k-space turbo gradient echo MR techniques (TGE) contrast between blood and myocardium is often reduced in long axis views due to reduced in plane spin-refreshment, particularly in patients with low ejection fraction. The application of an intravascular contrast agent (CA) may improve endocardial border delineation. MATERIALS AND METHODS: In 15 patients cardiac cine loops in two long axis and two short axis views were acquired during breath hold using a TGE sequence without and with increasing doses of CA (0.75, 2.0, 5.0 mg Fe/kg). Two independent observers evaluated left ventricular function (LVEF, modified Simpson's rule) and assigned a visual score (range: 0 = 'not visualized' to 6 = 'excellent visualization') for endocardial border delineation. Signal- and contrast-to-noise ratios (SNR; CNR) were determined. RESULTS: Endocardial border delineation score for TGE was 1.7 +/- 0.6 and 3.9 +/- 0.6**, 4.4 +/- 0.5**, 4.6 +/- 0.4** for 0.75, 2.0, 5.0 mg Fe/kg of CA, respectively (**p < 0.01 vs. TGE). SNR of blood increased significantly with any dose of CA with a mild drop of myocardial SNR resulting in a significant increase of CNR blood/myocardium. The maximum effect with 2.0 mg Fe/kg was a >2-fold CNR increase. Inter- and intraobserver variability assessed according to the method of Bland-Altmann was reduced at 2.0 mg Fe/kg for determination of LVEF and reached statistical significance for LVEF <50%. CONCLUSION: Intravascular CA increased CNR between blood and myocardium by a factor >2 and significantly improved the determination of cardiac volumes. The benefit in accuracy was most for patients with left ventricular ejection fraction <50%.

Aged↗
PubMed2001

Effects of a new cardiomyoplasty technique on cardiac function.

OBJECTIVE: The current cardiomyoplasty technique was modified to maintain the resting tension of the latissimus dorsi muscle and to prevent lateral movement of the heart during muscle stimulation. The aim of this study is to compare the short term hemodynamic effects of the new cardiomyoplasty wrap (W1) with those of the clinically applied cardiomyoplasty wrap (W2). Preliminary indications of the long-term hemodynamic effects of W1 are presented. METHODS: In three acute experiments in sheep mean central venous pressure (MCVP), mean arterial pressure (MAP), mean cardiac output (MCOP), mean left ventricular systolic pressure (MLVSP), and mean left ventricular diastolic pressure (MLVDP) were measured for 30s before and five minutes after applying each procedure with and without stimulation of the muscle graft. The same parameters were also recorded 5min after removing each muscle wrap. Hemodynamic changes associated with unstimulated muscle wraps were compared to the baseline data. Hemodynamic effects of muscle stimulation were determined by comparing the assisted to the preceding unassisted cardiac cycle. The long-term effects of W1 on the hemodynamics of another three sheep were studied at 6-12months after the operation. The viability of the muscles used in the chronic experiments were evaluated by morphometric analysis. RESULTS: Unstimulated W2 significantly increased mean central venous pressure and reduced mean cardiac output. It also increased mean left ventricular diastolic pressure and reduced peak negative dP/dt. Unstimulated W1 had no deleterious effect on mean central venous pressure, mean left ventricular diastolic pressure or peak -dP/dt, but it also reduced mean cardiac output and increased mean left atrial pressure (MLAP). Synchronised muscle stimulation, in both techniques, augmented the mean arterial pressure, mean cardiac output and mean left ventricular systolic pressure. In W2, however, myostimulation was also associated with a significant increase of the mean left ventricular diastolic pressure. In two long-term experiments significant hemodynamic assistance was observed at 6months and at 1yr after W1. In those sheep 68% of the cross-sectional area of the muscle was well preserved. CONCLUSIONS: Unstimulated cardiomyoplasty wraps acutely impair left ventricular function in sheep. The new technique, however, may offer significant long-term hemodynamic assistance and adequate preservation of the structural and functional integrity of the muscle flap for up to 1yr.

Animals↗