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Results for “Cardiac function”

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At least 1,603 records · Page 89Linked to original sources
PubMed2005

Beneficial effects of biatrial pacing on cardiac function in patients with bradycardia -- tachycardia syndrome.

BACKGROUND: Biatrial (BiA) pacing prevents atrial fibrillation. By an unknown mechanism. The purpose of this study was to use Doppler echocardiography to evaluate the hemodynamic effects during BiA pacing. METHODS AND RESULTS: The subjects were 7 patients with bradycardia - tachycardia syndrome with an implanted pacemaker. Atrial pacing sites were the right atrial appendage (RAA) and coronary sinus. P wave duration during BiA pacing (123 +/-16 ms) was significantly shorter than during either RAA pacing (167+/-19 ms, p<0.05) or sinus rhythm (148+/-12 ms, p<0.05). Doppler echocardiography revealed a greater cardiac output during BiA pacing than during RAA pacing (4.1+/-1.1 vs 3.5+/-0.7 L/min, p=0.042). The Doppler waveform of transmitral flow indicated that the left ventricular contraction interrupted the atrial filling wave during RAA pacing. The interval between the end of the atrial filling wave of transmitral flow and the mitral valvular closing sound was significantly increased by BiA pacing compared with RAA pacing (56+/-65 vs 40+/-57 ms, p=0.047). CONCLUSION: Cardiac hemodynamics were improved by BiA pacing and reduction of left atrial load may be one of the mechanisms.

Aged↗
PubMed2004

Comparison of the effects of tibolone and estrogen replacement therapy on echocardiographic basic cardiac functions in post-menopausal women: a randomized placebo controlled study.

OBJECTIVES: This study is designed to investigate and compare the effects of synthetic steroid tibolone and HRT on systolic and diastolic heart functions in post-menopausal women. METHODS: This prospective, randomized placebo controlled double blind study was conducted in a university clinic. Fifty-eight non-smoking, otherwise healthy post-menopausal women who did not receive any kind of HRT at least for 3 years within the onset of menopause were included in the study. The patients were randomly allocated to either 2.5 mg per day tibolone (OD, n = 18), daily combined 0.625 mg of conjugated estrogens 2.5 mg-1 of medroxy progesterone acetate pill (EP, n = 20) or a vitamin pill (n= 20) in a double blinded fashion. Their basic systolic and diastolic functions were investigated with HP Sonos-1000 echocardiography using standard positions and windows before and 6 months after the initiation of HRT. RESULTS: Mean age, weight, length of post-menopausal period, heart rate, systolic and diastolic pressures were similar between the groups. At the initiation of the study all groups had similar echocardiographic measurements. However, at the end of 6 months, left ventricular end-systolic and -diastolic volumes were decreased significantly compared to pretreatment and placebo in both EP and OD treated groups. (55.5 +/- 18.4 and 53.7 +/- 19.1.8 ml; 109.9 +/-19.9 and 110.7 +/- 20.8 ml versus 74.5 +/- 14.9 and 142.7 +/- 19.1 ml, respectively; P < 0.05). Improvement in diastolic functions was significant in EP/OD groups compared to pre-treatment period and the placebo groups (E/A 1.34 +/- 0.1 and 1.38 +/- 0.1 versus 1.18 +/-.09, deceleration time 204 +/- 11.1 and 202.8 +/- 27.1 ms versus 237.6 +/- 26.9 ms, respectively). Besides increase in left ventricular mass adjusted for height, decrease in left ventricular relative wall thickness, and systemic vascular resistance were significant in EP and OD treated groups than placebo and the pre-treatment measurements. Although improved in both OD and EP groups, the changes in systolic and diastolic functions were significantly higher in the OD treated group. Based on our preliminary results, we may conclude that both EP and OD regimens may improve cardiac performance and age related dysfunctions. CONCLUSION: The present results may further support that both OD and EP exert many direct effects on cardiovascular system other than metabolic changes regarding lipoproteins. The greater improvement in the OD group may be explained by its weak androgenic activity which is consistent with the in vitro data that androgens are potent relaxing agents on coronary arteries and restores cardiac myosin isoenzyme and ATPase patterns which mandates further clinical studies.

Androgen Antagonists↗
PubMedDate not supplied

Cardiac function assessed by gated heart pool studies in an alcohol clinic population: a preliminary study.

The nuclear gated heart pool scan was used to assess the left ventricular ejection fraction (LVEF) in 19 patients attending the Drug and Alcohol Unit for treatment of their alcoholism. Eighteen of the patients were asymptomatic and had no signs of cardiac impairment. In 14 subjects (13 asymptomatic), the LVEF was subnormal. Repeat studies were performed in 10 of the subjects following a period of 4-9 months of reduced intake of alcohol or abstinence. The LVEF improved in four subjects, remained unchanged in four, and actually decreased in two others despite a reduction in reported alcohol intake.

Adult↗
PubMed1980

Regional myocardial blood flow and cardiac function in a naturally occurring congestive cardiomyopathy of turkeys.

Round heart disease, a presumed viral myocarditis of turkeys, provides a unique opportunity for the study of congestive cardiomyopathy. Regional myocardial blood flow and cardiac output measurements were made in nine, 19 to 34 day old anaesthetised birds using 141Ce labelled microspheres (15 micron diameter). Atrial, right ventricular and weighted-average left ventricular myocardial blood flow values were similar in control (n = 5) and round heart disease (n = 4) turkeys. The left ventricular subendocardial/subepicardial blood flow ratio of 0.89 +/- 0.02 (mean +/- SE) in round heart disease birds was, however, reduced compared with the value of 1.19 +/- 0.09 in the control birds (P < 0.05). Round heart disease turkeys also had lower systemic pressures and lower cardiac outputs when compared with control birds. M-mode echocardiograms were obtained in 42 unanaesthetised 17 to 37 day old turkeys, 34 control and eight with round heart disease. Echocardiographic evidence of left ventricular dysfunction characterised by left atrial and left ventricular dilation and a markedly reduced left ventricular shortening fraction was found in round heart disease turkeys. Paradoxical motion of the interventricular septum was present in two of eight round heart disease turkeys but in none of the control turkeys. The interventricular septum/left ventricular posterior wall ratio in control and round heart turkeys were similar. Although the body weight of control and round heart disease turkeys were similar, and the diastolic thickness of the left ventricular wall were not substantially different, the ventricular weight/body weight ratio in round heart disease turkeys was increased approximately 52%. The increased ventricular weight was not due to myocardial oedema, as myocardial water content was similar in control and round heart disease turkeys. The features which characterise round heart disease in turkeys: left atrial and left ventricular dilatation, reduced left ventricular shortening fraction, systemic hypotension, low cardiac output, relative subendocardial underperfusion, and an increase in ventricular mass, make it a useful model for congestive cardiomyopathy.

Animals↗
PubMed1978

Cardiac function in the normal newborn: additional information by computer analysis of the M-mode echocardiogram.

Computer analysis of the M-mode echocardiogram in 50 normal newborns provided measurements of wall thicknesses and chamber size and, in addition, assessment of right and left ventricular wall, septal, and cavity dynamics throughout the cardiac cycle. Data obtained with this new technique indicated that (1) right and left ventricular cavity functions are similar in the normal newborn, (2) right and left ventricular cavity filling and emptying vary directly with peak rates of septal and ventricular wall thinning and thickening, respectively, and (3) there is a close time relationship among maximum left atrial dimension, minimum left ventricular dimension, and mitral valve opening. This analysis, which is the first complete analysis of the echocardiogram in the newborn, provides a normal range of septal and ventricular wall dynamics as well as right and left ventricular and left atrial function and has clinical implications in that it may allow early recognition of both congenital and perinatal myocardial disease.

Atrial Function↗
PubMed2005

Activated nuclear transcription factor kappaB in patients with myocarditis and dilated cardiomyopathy--relation to inflammation and cardiac function.

OBJECTIVES AND BACKGROUND: Myocarditis is caused by various agents and autoimmune processes. It is unknown whether viral genome persistence represents inactive remnants of previous infections or whether it is attributed to ongoing adverse processes. The latter also applies to the course of autoimmune myocarditis. One principal candidate for an adverse remodeling is nuclear factor-kappaB (NFkappaB). METHODS: A total of 93 patients with suspected myocarditis/cardiomyopathy was examined. Hemodynamics were assessed by echocardiography as well as right and left heart catheterization. Endomyocardial biopsies were taken from the left ventricle. Biopsies were examined by immunohistochemistry and PCR for viral genomes. Selective immunostaining of activated NFkappaB was performed. RESULTS: NFkappaB was increased in patients with myocarditis when compared with controls (11.1+/-7.1% vs. 5.0+/-5.3%, P<0.005) whereas dilated cardiomyopathy showed no significant increase. Patients with myocarditis and preserved left ventricular function exhibited increased activated NFkappaB when compared with reduced function (r2=0.72, P<0.001). In parallel, inverse correlation of NFkappaB and left ventricular enddiasstolic volume was found (r2=0.43, P<0.02). Increased activated NFkappaB was found in adenovirus persistence when compared with controls (P=0.001). Only a trend of increased NFkappaB activation was seen in cytomegalovirus persistence. Parvovirus B19 persistence did not affect NFkappaB activation. CONCLUSIONS: Increased activation of NFkappaB is related to inflammatory processes in myocarditis. Since activated NFkappaB correlates with left ventricular function, it could be assumed that NFkappaB activation occurs at early stages of inflammation. Potentially, NFkappaB could inhibit loss of cardiomyocytes by apoptosis and protect from cardiac dilation. Since NFkappaB is a crucial key transcription factor of inflammation, its prognostic and future therapeutic relevance should be addressed.

Adult↗
PubMed2005

Recombinant N-terminal fragments of chromogranin-A modulate cardiac function of the Langendorff-perfused rat heart.

In this study we tested the hypothesis that vasostatins could act as myocardial modulators in the mammalian heart. Using the Langendorff-perfused rat heart, the cardiac effects of the two recombinant human CGA N-terminal fragments STA-CGA1-78 and STA-CGA1-115, containing the vasostatin-1 (CGA 1-76) and vasostatin-2 (CGA 1-113) sequences, respectively, were evaluated at concentrations of 11 / 165 nM. Cardiac performance was evaluated by analyzing left ventricular pressure (LVP) and the rate pressure product (RPP: HR x LVP), used as indexes of contractile activity and cardiac work, respectively. Under basal conditions, STA-CGA1-78 at all concentrations tested elicited a dose-dependent negative inotropism (LVP variations ranging from -9.6% +/- 2 to -23% +/- 2.9) without affecting coronary pressure (CP). In contrast, STA-CGA1-115 increased CP at 110 and 165 nM without affecting inotropism. Both STA-CGA1-78 and STA-CGA1-115 counteracted the cardio-stimulatory effects of isoproterenol (ISO). The ISO-dependent positive chronotropism was unaffected by STA-CGA1-78, while being reduced by STA-CGA1-115. Both peptides abolished the ISO-induced positive inotropism without modifying either the beta-adrenergic-dependent coronary dilation or the ouabain-induced positive inotropism. The analysis of the percentage of variations of RPP in terms of EC50 values of ISO alone (-8.5 +/- 0.3; r2 = 0.88) and in presence of STA-CGA1-78 (11, or 33, or 65 nM: -7.7 +/- 0.15, r2 = 0.97; -7.7 +/- 0.15, r2 = 0.97; -7.8 +/- 0.78, r2 = 0.55, respectively) revealed a non-competitive type of antagonism of STA-CGA1-78. Taken together, these data suggest vasostatins as novel cardioregulatory peptides in mammals.

Adrenergic beta-Agonists↗