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PubMed1994

Should magnesium therapy be considered for the treatment of coronary heart disease? II. Epidemiological evidence in outpatients with and without coronary heart disease.

In an epidemiological and follow-up survey on 712 patients, 52 subjects with proven ischaemic heart disease were matched with and compared to 52 coronary-prone subjects with similar major cardiovascular risk factors (high-risk controls, HR) as well as to 52 patients at low cardiovascular risk (low-risk controls, LR). HR and LR patients were all free of overt ischaemic heart disease. Both the average daily dietary magnesium intake and the 24 h renal magnesium output were slightly higher in HR as compared to LR and ischaemic heart disease patients. No difference could be observed between the three groups with respect to serum magnesium levels, whereas erythrocyte magnesium levels were lower in ischaemic heart disease patients than in LR (P = 0.089) and to HR (P = 0.042). Ischaemic heart disease patients below 60 years had significantly lower erythrocyte magnesium levels than older (> 60 years) ischaemic heart disease patients. Lower erythrocyte magnesium levels in ischaemic heart disease patients were also associated with an increased incidence of cardiac events in the follow-up period and with a more unfavourable outcome. A pilot phase 6 month open trial of oral magnesium supplementation in nine ischaemic heart disease patients with low erythrocyte magnesium levels led to significant increases of erythrocyte magnesium in these patients, and to an impressive decrease of anginal attacks and nitrate consumption, as well as to a lesser degree of ST segment depression on surface ECG obtained at exercise testing in seven patients.

Cohort Studies↗
PubMed1994

Physical activity, hypertension and risk of heart attack in men without evidence of ischaemic heart disease.

The role of hypertension in the increased rate of heart attack reported in vigorously active subjects was examined in a large prospective study of 7735 middle-aged men drawn from general practices in 24 British towns (The British Regional Heart Study). Analyses were restricted to 5694 men with no evidence of pre-existing ischaemic heart disease or stroke at screening, in whom there were 311 major ischaemic heart disease events after 9.5 years follow-up. Risk of major ischaemic heart disease events decreased significantly with increasing physical activity to levels of moderate/moderately vigorous activity, with a 50% reduction in risk compared with inactive men after adjustment for age, body mass index, smoking, heavy drinking, social class and blood cholesterol. However, at the highest level of physical activity (vigorous group) risk of major ischaemic heart disease events was increased above that seen in the moderate/moderately vigorous group (rr = 1.68, P = 0.05). When separated into normotensives (n = 3888) and hypertensives (n = 1806; SBP > or = 160 mmHg or DBP > or = 90 mmHg or on regular antihypertensive treatment), the increased risk of major ischaemic heart disease events in the vigorous group was only evident in hypertensive men. They showed more than a twofold increase in risk compared with the moderate and moderately vigorous group (rr = 2.7, P < 0.05). In normotensive men, risk was significantly lowered in those engaged in moderate activity with no further decline in rate of heart attack at increasing levels of physical activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Studies on function of vegetative nervous system in cardiopathic patients with heart-qi deficiency syndromes and heart-yin deficiency syndromes].

To explore the changes of the function of vegetative nervous system in the patients with the syndromes of Heart-Qi Deficiency (HQD) and Heart-Yin Deficiency (HYD), 53 cases of heart diseases were divided into HQD and HYD, the duration between heart beats, differences of blood pressure in the lying and standing position, and urine-catecholamine/24 hrs was determined separately, and compared with control group. The results showed that the duration between heart beats and heart rate in the lying position in those patients of HQD didn't manifest significant difference with control group. But in 78.9% of patients, the differences of heart rate in expiration/inspiration, surpassed 15 beats per minute, and the proportion of 30/15 was less than 1.03. Compared with control group, the difference was significant (P < 0.01). Meantime, the differences of heart rate of lying/standing position was less than 15 beats per minute, and the difference of blood pressure had an increasing tend in 47.4% of the cases. Those patients of HYD didn't show any difference in the above indexes. Urine-catecholamine/24 hrs in both of the two groups surpassed that of control group (P < 0.01). In short, this study showed that syndromes of HQD and HYD both displayed disturbed function of the vegetative nervous system, and their types and severities were correlated with the difference of Syndromes.

Adult↗
PubMed1992

The use of technetium-99m hexamethylpropylene amine oxime labelled white blood cells to detect subclinical inflammation of the heart after cardiopulmonary bypass in children with congenital heart disease.

Ten children (6 boys and 4 girls, aged 1-9 years old) underwent operations with a cardiopulmonary bypass, and the technetium-99m hexamethylpropylene amine oxine (99mTc-HMPAO) labelled white blood cell (WBC) heart scans were used to detect postoperative leukocyte infiltration in the hearts. The results showed that 80% (8/10) of the cases had subclinical inflammation in the hearts (grading of WBC scans > or = score 2), and a positive correlation (R = 0.77) was noted between the severity of the inflammation (grading of the WBC scans) and the duration of the cardiopulmonary bypass in the operations. Another control group (9 boys and 2 girls, aged 2-13 years old) underwent operations without a cardiopulmonary bypass, and subclinical inflammation of hearts was demonstrated in only 1 case (9%) by the 99mTc-HMPAO labelled WBC scans (grading of WBC scans < score 2) after the operations. There was a significant difference (P < 0.001, by a Wilcoxon rank sum test) based upon the severity of the ischaemic heart damage in the two groups. In our preliminary conclusions, the 99mTc-HMPAO labelled WBC heart scans may provide non-invasive and directly discernible evidence of subclinical inflammation in the heart due to a transient ischaemic state during a cardiopulmonary bypass, even if the clinical symptoms and signs of carditis are not apparent.

Cardiopulmonary Bypass↗
PubMed2003

Closing behavior of the mechanical heart valve in a total artificial heart.

Recently, cavitation on the surface of mechanical heart valves has been studied as a cause of fractures occurring in implanted mechanical heart valves. The cause of cavitation in mechanical heart valve was investigated in both 25-mm Björk-Shiley and 25-mm Medtronic Hall valves. The closing events of these valves in the mitral position were simulated in an electrohydraulic total artificial heart with a stroke volume of 85 ml. The tests were conducted under physiologic pressures at heart rates of 60, 70, 80, and 90 beats/min with cardiac outputs of 4.5, 5.5, 6.4, and 7.5 l/min, respectively. The disk closing behavior was measured by a laser displacement sensor. The closing behaviors were investigated under various atrial and aortic pressures. In both valves, the duration of closing decreased with an increase in the cardiac output. The greater the amount of atrial pressure, the shorter the closing duration of both valves. The maximum closing velocity of the Medtronic Hall monostrut valve ranged from 0.8 to 0.9 m/s, and that of the Björk-Shiley monostrut valve ranged from 0.73 to 0.78 m/s. In both valves, the maximum closing velocities were less than the reported cavitation thresholds. This suggests that there should be no possibility of occurrence of cavitation in an electrohydraulic total artificial heart with mechanical heart valve.

Biomechanical Phenomena↗
PubMed1988

Abnormal coronary hemodynamics and myocardial energetics in patients with chronic heart failure caused by ischemic heart disease and dilated cardiomyopathy.

Coronary sinus blood flow, transmyocardial oxygen extraction, myocardial oxygen consumption, and transmyocardial lactate extraction were determined, along with systemic hemodynamics, in 34 patients with chronic stable angina without heart failure (group 1), in 66 patients with heart failure associated with coronary artery disease (group 2), and in 28 patients with heart failure caused by dilated cardiomyopathy without coronary artery disease (group 3). Compared with group 1 patients, in patients with heart failure in groups 2 and 3, resting coronary sinus blood flow was 30% and 24% higher, respectively (p less than 0.05), myocardial oxygen consumption was 25% higher (p less than 0.01), and coronary sinus oxygen content was 33% lower (p less than 0.01). The rate-pressure product was not different between the three groups. In eight patients with heart failure (five in group 2 and three in group 3), myocardial lactate production was observed without angina. Thus in patients with chronic heart failure resulting from either chronic coronary artery disease or dilated cardiomyopathy, resting coronary blood flow and myocardial oxygen consumption tend to increase probably because of an increase in myocardial oxygen requirements. Silent myocardial ischemia may also occur in both the presence and absence of coronary artery disease in patients with chronic heart failure. The abnormal coronary hemodynamics and myocardial metabolic function may play a role in causing progressive deterioration in cardiac function in dilated cardiomyopathy.

Adult↗
PubMed1992

Clinical, hemodynamic and sympathetic neural correlates of heart rate variability in congestive heart failure.

Heart rate (HR) variability has long been recognized as a sign of cardiac health. In the presence of heart disease, HR variability decreases, an observation that has been associated with poor prognosis in a number of recent studies. HR variability is particularly altered in congestive heart failure (CHF), a condition associated with a number of typical functional hemodynamic and neurohumoral alterations. The relation of measurements of HR variability to these abnormalities in patients with heart failure has not been carefully examined. Twenty-three patients (19 men, 4 women, mean age 49 years) with New York Heart Association class II to IV CHF were studied prospectively without cardiac medications; radionuclide ventriculography, right-sided heart catheterization, peroneal microneurography, plasma norepinephrine and 24- to 48-hour ambulatory electrocardiography were performed. Average RR interval and its standard deviation, and HR power spectrum (0 to 0.5, 0.05 to 0.15 and 0.2 to 0.5 Hz) were derived from the ambulatory electrocardiographic recordings and compared with left ventricular ejection fraction, thermodilution cardiac output, pulmonary arterial wedge pressure, New York Heart Association class, age, muscle sympathetic nerve activity (peroneal nerve) and norepinephrine level by linear regression. None of the measures of HR variability were significantly related to age, left ventricular ejection fraction, cardiac output or functional classification, whereas the 0.05 to 0.15 and 0.20 to 0.50 Hz components were weakly but significantly related to cardiac output (r = 0.49 and 0.42, p = 0.02 and 0.045, respectively). In contrast, a generally stronger and negative relation was demonstrated between spectral and nonspectral measurements of HR variability, and indicators of sympathoexcitation, muscle sympathetic nerve activity and plasma norepinephrine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Pediatric heart transplantation for congenital heart disease and cardiomyopathy.

Orthotopic heart transplantation has become an accepted therapy for adult patients with end-stage heart disease. In newborns and infants, this procedure is still controversial because of the unknown long-term results and the lack of donor organs. Since March 1988, we have performed orthotopic heart transplantation in 11 infants and children with hypoplastic left heart syndrome (n = 6), cardiomyopathy (n = 4), or congenital endocardial fibroelastosis (n = 1). The smallest infant was 3 days old and weighed 2,650 g. Four of 15 potential donors had to be refused for various medical reasons, and 4 were transferred to our hospital for organ retrieval. Seven hearts were procured remotely. We accepted weight mismatches up to 105% between donor and recipient. There were three perioperative deaths, two in patients 5 and 17 days old with hypoplastic left heart syndrome and 1 in a 2-year-old patient with a dilated cardiomyopathy. All 3 patients had drug-resistant right heart failure. A 2-year-old girl with a dilated cardiomyopathy died 2 months after transplantation owing to severe pulmonary embolism originating from the superior vena cava. The remaining 7 patients are alive and well between 1 month and 31 months after transplantation. Angiographic follow-up has not revealed signs of graft atherosclerosis at 2 years.

Cardiomyopathy, Dilated↗
PubMed1992

Day vs night ECG and heart rate variability patterns in patients without obvious heart disease.

The day vs night values of variables that may be related to the autonomic nervous system were compared in 50 individuals without obvious heart disease. Using ambulatory electrocardiographic monitoring and heart rate variability analysis, it was found that in contrast to daytime, nocturnal heart rate and total heart rate variability were reduced and low (0-0.05 Hz) and high (0.2-0.35 Hz) frequency power of nocturnal heart rate variability were increased, whereas mid-frequency (0.05-0.2 Hz) power was reduced. In addition, nocturnal episodes of trapezoidal-shaped waveforms of heart rate increase were present primarily at night and ST was elevated to a greater extent at night. Many of these factors were related to age and tentatively, despite the small sample size, reflect an age-related diminished autonomic nervous system response. These results serve to establish a circadian basis for comparison when evaluating disease states such as ischemic heart disease and its prognosis.

Adult↗
PubMed1986

The coronary arterioles in newborns, infants and children. A morphometric study of normal hearts and hearts with aortic atresia and complete transposition.

The state of development of the intramyocardial coronary arterioles in normal hearts and hearts with congenital malformations is unknown, although these vessels play an important role in regulating myocardial blood flow. To remedy the situation, we studied 64 normal hearts (ranging in age from 23 weeks gestational age to 75 years), 13 hearts with complete transposition (5 with intact ventricular septum and 8 with a defect) and 11 hearts with classical aortic atresia. The medial thickness of arterioles with an external diameter from 20 to 100 microns was measured. The number of arterioles was calculated per mm2; a distinction was made between vessels between 20 and 100 microns and those smaller than 20 microns. The results show that the arteriolar vascular bed is not yet full grown at term. Within the first year of life the medial smooth muscle mass increases, most likely due to growth and peripheral extension onto the smaller branches. In the hearts of patients with aortic atresia who lived for a week or less, the arteriolar media appeared to lag behind that in normal hearts. In those patients who survived into the second post-natal week, however, the arteriolar bed was almost as anticipated for normal. The normal values obtained in the latter group could be due to intrinsic differences, rather than expressing actual and rapid growth.

Age Factors↗
PubMed1995

Impact of atrioventricular delay on heart rate variability of paced patients with and without heart failure.

The aim of the study was to investigate whether the optimisation of atrioventricular (AV) delay in patients with complete AV block, with or without heart failure, paced under VDD mode, has an effect on heart rate variability and consequently on the autonomic nervous system in these patients. We studied 10 patients (Group I: 7 men, aged 68 +/- 9 years) with normal left ventricular function and 9 patients (Group II: 6 men, aged 70 +/- 6 years) with systolic left ventricular dysfunction (NYHA heart failure Class II or III). Each patient was paced for 24 h with the optimal and 24 h with the worst AV delay in random order and ambulatory electrocardiograms (ECGs) (Marquette) were recorded. Spectral heart rate variability was analysed for each 24-h period on a Holter analysis system (Marquette Series 8000). The optimal and worst AV delay were determined by echo-Doppler as those which produced the greatest and least cardiac output, respectively. For the patients in Group I, there was no difference between the two AV delays as regards indices of heart rate variability. In contrast, for Group II the total frequency (TF) was significantly higher and the low frequency (LF) and LF/high frequency (HF) ratio were significantly lower when the patients were paced with optimum AV delay. Furthermore, this AV delay resulted in significantly higher mean NN and SD. In conclusion, in patients with normal left ventricular function, changes in AV delay do not appear to affect the activity of the autonomic nervous system in the heart. In patients with mild to moderate heart failure, optimisation of the AV delay causes a significant drop in sympathetic nervous tone.

Aged↗
PubMed2006

Relation of heart rate turbulence to severity of heart failure.

The aim of this study was to evaluate the association between heart rate turbulence (HRT) parameters and clinical, biochemical, echocardiographic, and electrocardiographic measures of heart failure (HF) in a large, prospectively enrolled population of patients with HF to determine whether HRT could be considered a marker of HF advancement and progression, giving insight into hemodynamic changes as well as changes of the autonomic nervous system. In 487 patients with HF (mean age 63 years), the following tests were performed: 12-lead surface electrocardiography, echocardiography, chest x-rays, N-terminal-pro-brain natriuretic peptide levels, and 24-hour Holter monitoring for HRT and heart rate variability analyses. Most patients were in New York Heart Association class II (82%) and had a mean left ventricular (LV) ejection fraction of 37 +/- 14%. Both HRT parameters, but especially turbulence slope, were significantly correlated with clinical indexes of HF (the third heart sound, peripheral edemas, jugular distension, and pulmonary congestion). Patients in New York Heart Association class III had significantly lower turbulence slopes and greater turbulence onset values than those in class II. Significant correlations were found between HRT parameters and the LV ejection fraction as well as with LV diameters. HRT parameters were significantly correlated with N-terminal-pro-brain natriuretic peptide levels (r = -0.47, p <0.001 for turbulence slope). Multivariate analyses showed that abnormal HRT parameters were independent predictors of HF severity measured by New York Heart Association class III and a LV ejection fraction <40%. In conclusion, the findings indicate that in patients with HF, HRT reflects well the severity of HF and associated LV dysfunction, which were verified in this study by a series of established clinical, echocardiographic, and biochemical parameters.

Adolescent↗
PubMed2006

Heart-targeted overexpression of Nip3a in zebrafish embryos causes abnormal heart development and cardiac dysfunction.

We transiently expressed a proapoptotic protein, Nip3a, by a heart-specific BMP4 promoter in zebrafish embryos and generated two variants of embryos with abnormal heart phenotypes (A and B). Embryos with phenotype A heart defects showed hypoplastic or elongated ventricles, elongated or enlarged atriums with no normal cardiac looping resulting a significant longer SV-BA distance, and bradycardia at 48 h post-fertilization (hpf). Embryos with phenotype B heart defects showed an enlarged fluid-filled pericardium, severe hypoplasia, non-contracting ventricles, and elongated or enlarged slowly beating atriums with no normal looping. Histological sections further revealed the absence of a proper atrioventricular boundary and no endocardial cells lining this region in both 48- and 72-hpf Nip3a-overexpressing embryos, implicating defective endocardial cushion formation. These phenotypes are reminiscent of atrioventricular canal defects in humans. In addition, induced apoptotic myocardium cells were clustered in the presumptive atrioventricular boundary as well as in the adjacent ventricle and atrium of 48- and 72-hpf Nip3a-overexpressing embryos. Nip3a expression was readily detected in 80% epiboly BMP4-Nip3a-injected embryos, and defects in heart development were observed in both the linear heart tube and subsequent chamber formation stages. These results showed that myocyte apoptosis is a universal pathogenic factor for congenital heart failure using zebrafish as a model organism.

Animals↗
PubMed2005

Heart failure in the adult patient with congenital heart disease.

BACKGROUND: Adult survival is now the rule for most congenital heart defects. However, despite surgical "repair," heart failure remains a common long-term complication of congenital heart disease. Heart failure specialists are seeing an increasing number of patients with congenital defects as the underlying etiology of their heart failure. METHODS AND RESULTS: Familiarity with the anatomy, physiology, and long-term sequelae of surgical correction are essential for providing care to this complex group of patients. CONCLUSION: This review discusses the diagnosis, pathophysiology, and management of the adult congenital heart patient with concomitant heart failure.

Adult↗
PubMed2005

Phenotypic assessment of endothelial microparticles in patients with heart failure and after heart transplantation: switch from cell activation to apoptosis.

BACKGROUND: Endothelial microparticles (EMPs) are sub-microscopic membrane vesicles that are shed from the surface of endothelial cells during activation, injury and/or apoptosis. Endothelial cells release phenotypically and quantitatively distinct endothelial microparticles (EMPs) in activation and apoptosis. Therefore, the phenotypic assessment of EMPs can provide useful information reflecting the nature of endothelial injury. We tested the hypothesis that heart transplantation (HT) modifies the pattern of endothelial injury seen in patients with congestive heart failure (CHF). METHODS: Flow cytometry was used to measure EMPs identified by E-selectin (CD62) and platelet-endothelial cell adhesion molecule 1 (CD31) in 23 patients with advanced heart failure and in 23 HT recipients. A cohort of 23 healthy individuals served as controls. RESULTS: Heart failure patients were found to have significantly higher levels of EMP62E (577 counts/microl) than controls (192 counts/microl) and post-transplant patients (152 counts/microl) (p < 0.0001). Levels of endothelial microparticles expressing CD31 were significantly different among study groups (analysis of variance [ANOVA], p = 0.001). Heart failure patients had significantly higher levels (1,526 counts/microl) than controls (395 counts/microl) (p < 0.01). Levels of EMP31 remained elevated after heart transplant (935 counts/microl) (p = non-significant). The EMP62/EMP31 ratio, an index of activation (high ratio) or apoptosis (low ratio), was significantly different between the groups (ANOVA, p = 0.01). Post-transplant patients had significantly lower ratios (0.16) than CHF patients (0.38) and controls (0.49). CONCLUSIONS: Cardiac transplantation is associated with a different pattern of endothelial cell injury than that seen in heart failure. The phenotypic assessment of EMPs in post-transplant patients is consistent with increased apoptotic activity.

Adult↗
PubMed2006

Natural history of postoperative heart block in congenital heart disease: implications for pacing intervention.

After half a century of major progress in congenital heart disease management, atrioventricular conduction block continues to complicate 1-3% of surgical procedures. Unless treated with an implanted pacemaker, permanent postoperative heart block is associated with 28-100% mortality. Postoperative heart block often proves to be transient, typically resolving within 10 days of onset. The duration of postoperative heart block is widely used as a key determinant for permanent pacemaker implantation. Current professional pacemaker implantation guidelines are largely based on this criterion. However, available natural history data suggest that other factors, such as residual conduction system injury, likely play a role in increasingly recognized cases of very late postoperative mortality and morbidity in patients who have experienced transient postoperative heart block. As growing numbers of congenital heart disease patients survive into adulthood, and artificial pacemaking capabilities continue to improve, it might be necessary to reconsider and refine currently accepted pacing indications for postoperative heart block.

Cardiac Pacing, Artificial↗
PubMed2006

The pathology of the heart conduction system in congenital heart block.

The incidence of congenital complete heart block is estimated in 1 of 2500-20,000 births. Many cases are isolated (found in an otherwise normal heart) and the pathology of the heart conduction system is variable. We report a 51-year-old man with the diagnosis of complete heart block, with a permanent pacemaker. No family history of rhythm disturbances was available. The patient presented and endocarditis after replacement of the pacemaker battery. The prognosis was poor and the patient died three months later. Autopsy examination showed signs of shock, of septic origin. The heart was hypertrophic (450g) and the left ventricle thickened. Histopathological examination of the heart conduction system showed that the sinus and atrioventricular nodes were normal, but the His bundle was interrupted and replaced by fibrous tissue. No inflammatory signs were present. Loss of conducting fibres and their replacement by fibrous tissue is the most common pathological process in complete heart block. In this case His bundle was mostly affected, different to Lev's disease where the process is more distal (branching atrioventricular bundle) and to Lenegre's disease, which shows a diffuse damage in the conducting system.

Autopsy↗
PubMed1996

Effects of bisoprolol on heart rate variability in heart failure.

Analysis of heart rate variability (HRV) provides a non-invasive index of autonomic nervous system activity. HRV has been shown to be reduced in heart failure. Preliminary data indicate that beta blockers improve clinical status in patients with heart failure, but HRV improvement remains to be demonstrated. Fifty-four patients from the randomized double-blind, placebo-controlled Cardiac Insufficiency Bisoprolol Study were included in the HRV study. The bisoprolol daily dose was 5 mg once daily. We assessed HRV during 24-hour Holter recordings before randomization and after 2 months of treatment. HRV as measured in the time domain by root-mean-square successive differences (rMSSD), the percentage of adjacent RR differences >50 ms (pNN50), and the SD of RR intervals (SDNN), and in the frequency domain by high-frequency (0.16 to 0.40 Hz) and low-frequency (0.04 to 0.15 Hz) power. Most patients were in New York Heart Association functional class III. The mean left ventricular ejection fraction was 27 +/- 7%, and heart failure was idiopathic or ischemic. After 2 months, the patients receiving bisoprolol had a reduced mean heart rate compared with that in placebo patients (p=0.0004). Bisoprolol increased 24-hour rMSSD (p=0.04) and 24-hour pNN50 (p=0.04), daytime SDNN (p=0.05), and daytime high-frequency power (p=0.03) power. Bisoprolol induced a significant increase in HRV parameters related to parasympathetic activity in heart failure. Increased vagal tone may contribute to the protective effect of beta blockers and may have prognostic implications.

Adrenergic beta-Antagonists↗