Hyper-homocysteinemia Inducing Hyperuricemia: What are the Mechanisms?

Hyperuricemia is related to metabolic syndrome, and is defined as an over-production or under-excretion of uric acid (UA), with increased UA serum concentration. Among other causes, Hyper-homocysteinemia (H-Hcy) can be responsible for hyperuricemia. The mechanisms underlying the association between these two conditions are unclear, but increased UA serum levels can be a consequence of renovascular atherosclerosis, with reduced UA excretion. An alternative hypothesis is the over-production of UA from adenosine (originating from S-adenosyl-homocysteine). Genetic polymorphism (C677T) of methylenetetrahydrofolate reductase (MTHFR) may contribute. A possible mechanism is purines biosyinthesis originating from this gene variant. However, the results obtained from several studies and meta-analyses of the relationship between H-Hcy and hyperuricemia are ambivalent, and broader research is needed.

Left Atrial Volume Index as Indicator of Left Ventricular Diastolic Dysfunction: Comparation between Left Atrial Volume Index and Tissue Myocardial Performance Index

BACKGROUND: To point out a possible correlation between left atrial volume index (LAVI) and left ventricular (LV) diastolic time interval to better define LV diastolic dysfunction, this study was performed. METHODS: In 62 hypertensive-hypertrophic patients without LV systolic dysfunction, LV volumes, myocardial mass index, ejection fraction% (EF%) and LAVI were measured by two-dimensional echocardiography. Instead, tissue Doppler echocardiography (TDE) was used to measure myocardial performance index (MPI) and its systo-diastolic time intervals, such as: iso-volumetric contraction time (IVCT); iso-volumetric relaxation time (IVRT); ejection time. LAVI, TDE-MPI and time intervals where also measured in 15 healthy controls, to obtain the reference values. RESULTS: Results shown a significant increase of LV volumes in hypertensives in comparison to the control group (p < 0.05). LV mass index also augmented (p < 0.001). Instead, EF% not significantly changed in hypertrophic patients in comparison with healthy controls. LAVI raised in hypertensives wih left ventricular hypertrophy, whereas IVCT resulted within the normal limits. On the contrary, IVRT significantly raised. Accordingly, MPI resulted higher in controls. CONCLUSION: LAVI, MPI and its time intervals appear as reliable tools to non-invasively individualize LV diastolic dysfunction in systemic hypertension, in absence of mitral valve disease.

Left Atrial Volume Index as Indicator of Left Ventricular Diastolic Dysfunction: Comparation between Left Atrial Volume Index and Tissue Myocardial Performance Index

BACKGROUND: To point out a possible correlation between left atrial volume index (LAVI) and left ventricular (LV) diastolic time interval to better define LV diastolic dysfunction, this study was performed. METHODS: In 62 hypertensive-hypertrophic patients without LV systolic dysfunction, LV volumes, myocardial mass index, ejection fraction% (EF%) and LAVI were measured by two-dimensional echocardiography. Instead, tissue Doppler echocardiography (TDE) was used to measure myocardial performance index (MPI) and its systo-diastolic time intervals, such as: iso-volumetric contraction time (IVCT); iso-volumetric relaxation time (IVRT); ejection time. LAVI, TDE-MPI and time intervals where also measured in 15 healthy controls, to obtain the reference values. RESULTS: Results shown a significant increase of LV volumes in hypertensives in comparison to the control group (p < 0.05). LV mass index also augmented (p < 0.001). Instead, EF% not significantly changed in hypertrophic patients in comparison with healthy controls. LAVI raised in hypertensives wih left ventricular hypertrophy, whereas IVCT resulted within the normal limits. On the contrary, IVRT significantly raised. Accordingly, MPI resulted higher in controls. CONCLUSION: LAVI, MPI and its time intervals appear as reliable tools to non-invasively individualize LV diastolic dysfunction in systemic hypertension, in absence of mitral valve disease.

Carcinoid Heart Disease: A Rare Cause of Right Ventricular Dysfunction Evaluation by Transthoracic 2D, Doppler and 3-D Echocardiography

Carcinoid heart disease is a rare cause of heart failure with or without right valvular heart impairments. In this study, we showed a case of carcinoid tumour with hepatic metastases inducing carcinoid heart disease. Neuroendocrine heart involvement happens for severe tricuspid valve insufficiency and plaques on right ventricular (RV) walls produced by a release of serotonin (5-HT). A patient affected by primitive ileal tumour with 5-HT-secernent hepatic metastases inducing tricuspid insufficiency is showed. Transthoracic 2-D echocardiography showed tricuspid valve regurgitation and both right atrium, RV-walls plaques and RV dilation. Continue-wave Doppler showed a characteristic "dagger shaped" spectrum of tricuspid systolic flow. RV function was evaluated with 3-D transthoracic echocardiography. In particular, RV volumes, RV ejection fraction and stroke volume were defined by this technique. 2, 3-D echocardiography and Doppler method are useful techniques to show heart valves' derangements and RV function to non-invasively detect RV impairments in carcinoid heart disease.

Natriuretic peptide system and cardiovascular disease

The mammalian Natriuretic Peptide [NP] system consists of neuro-hormones, such as atrial natriuretic peptide [ANP], brain natriuretic peptide [BMP], c-type natriuretic peptide [CNP], and the N-Terminal fragment of BMP [NT-pro-BNP]. In response to some cardiovascular derangement the heart [acting as an endocrine organ], brain and other structures secretes natriuretic peptides in an attempt to restore normal circulatory conditions. Their actions are modulated through membrane-bound guanylyl cyclased [GC] receptors. They induce diuresis, natriuresis and vasodilation in the presence of congestive heart failure. These neuro-hormones also play a role in the suppression of neointimal formation after vascular injury. In addition, they act as antifibrotic and antihypertrophic agents preventing cardiac remodeling after myocardial infarction. Further, NP have diagnostic and prognostic role in heart failure, vasoconstriction, left ventricular late remodeling after Ml and others. At present, some drugs such as Nesiritide, NEP inhibitors and vasopeptidase inhibitors were synthetized from NP, to antagonize these cardiovascular derengements. In future, it will be possibile to elaborate some drugs similar to petidase inhibitors and some CNP-like drugs able to reduce many symptoms of cardiovascular derangements without significant side effects

Echocardiographic evaluation of ejection fraction: 3DE versus 2DE and M-mode

Using echocardiography, left ventricular function was evaluated in accordance with the diverse ultrasound methods. M-Mode and two-dimensional methods have some limitations due to the geometric assumptions to calculate the different parameters, which may cause important errors. 3-D imaging can be used for direct calculation of intracavitary volumes and global/regional ejection fraction. In the present review, the first and second scanner's generation of 3D echocardiography are illustrated. The image acquisition and reconstruction were exposed and the advantages and limitations of this technique are also reported. "Live" 3D echocardiography, which directly and more rapidly provides a free quantification of global and regional LV function, appears to be superior to other versions of real-time 3D imaging. Finally, rapid three-dimensional echocardiography allows the immediate collection of data within a few seconds, making this technique feasible in most clinical scenarios

Left ventricular function in the successive phases of systemic hypertension evaluated with pulsed Doppler echocardiography

Systolic and diastolic function is impaired in patients with hypertensive heart disease. Systolic hypertension induces a succession of LV hemodynamic changes and can be regarded as a spectrum from maladaptive hypertophy to heart failure. The left ventricular hemdynamic changes that occur can be measured non-invasively by Doppler echocardiography. The aim of the study was to hemodynamically characterize the different phases of left ventricular [LV] function in patients affected by systemic hypertension [SH]. 95 normotensive healthy controls [group I] and 94 hypertensives [group II] were enrolled. Hypertensive patients were divided in two sub-groups according to echocardiographic signs of left ventricular hypertrophy [LVH]. Other echocardiographic parameters measured using tissue Doppler were Isovolumic Relaxation Time [IRT], isovolumic contraction time [ICT], and systolic motion [Sm]. Myocardial Performance Index [MPI] using Tissue Doppler Echocardiography [TDE] was defined in both the control group and the two hypertensive subgroups. Ejection fraction [EF] was also calculated in all participants. An increased MPI derived from the rise of isovolumetric relaxation time [IRT] was found in hypertensives without LVH [sub-group II-a], whereas isovolumetric contraction time [ICT] and Systolic motion [Sm] were unchanged. Hypertensive patients with LVH demonstrated more prominent increase of MPI, increase in IRT-prolongation, ICT-increase and Sm-decrease. The results obtained indicate impaired relaxation in sub-group II-a. On the contrary, a systolo-diastolic LV dysfunction was found in sub-group II-b. E.F decreased in this same sub-group of hypertensives in comparison with controls and sub-group II-a, as a sign of maladaptive LVH evolving towards heart failure. Doppler echocardiography appears able to distinguish the different forms and degrees of LV dysfunction in SH in relation to the different phases of the hypertensive disease process

Myocardial performance index evaluated with tissue doppler echocardiography at early, intermediate and late phase of acute myocardial infarction

In this study, ejection fraction% [EF%] and myocardial performance index [MPI] were recorded in 67 survivors at early, intermediate and late phase of acute myocardial infarction [AMI] .EF% was echocardiographically obtained by the Simpson's method; MPI was calculated using Tissue Doppler Echocardiography [IDE] derived from isovolumetric contraction time [ICT]; isovolumetric relaxation time [IRT] and ejection time [ET]. Results were compared with those obtained in 70 controls matched for age and sex.At hospital discharge [early evaluation], EF% was < 50% with significant increase in MPI in respect to the healthy controls [increase in ICT, significant reduction in ET and IRT was unchanged]. Six months later [intermediate evaluation], EF% still resulted in < 50%, MPI was slightly reduced with further increase in ICT and IRT in comparison to the early evaluation, and slight reduction in ET Finally, one year later [late evaluation], in spite of increase in EF>50%, MPI was still increased, with slight rise in ICT, almost normalization in ET, but more evident increase in IRT. The outcomes of MPI demonstrate that in post-AMI patients, late prevalent diastolic ventricular dysfunction occurs following an early systolic dysfunction. In this study, EF% appears to be less sensitive than MPI in defining late post-AMI left ventricular dysfunction. Finally,TDE seems to be more sensitive than conventional Doppler method in measuring MPI

Post-necrotic left ventricular dysfunction in Diabetes Mellitus: effects of trimetazidine

The Index of Myocardial Performance [IMP] in 149 non-diabetic [group I] and 151 diabetic [group II] subjects who were treated for acute myocardial infarction was evaluated using two-dimensional Doppler echocardiography. Isovolumetric Contraction Time [ICT], Isovolumetric Relaxation Time [IRT] and Ejection Time [ET] were also measured. All patients in both groups received conventional, anti-ischaemic therapy [nitrates, ACE-inhibitors, and antiplatelet drug]. In addition, 74 patients in group II [subgroup IIa] received an oral dose of 20 mg of trimetazidine, three times daily. The remaining 77 diabetics in group II were treated with conventional drugs alone [subgroup IIb]. All diabetic patients [group II] also received an anti-diabetic [oral drug or insulin] treatment to keep their diabetes under control. Twelve months after the experiment, IMP was significantly [p<0.001] higher in diabetic patients [0.55 +/- 0.05] compared to non-diabetic controls [0.49 +/- 0.04]. IRT was similar in both groups [81 +/- 15 ms vs 83 +/- 12 ms] and ET [275 +/- 27 ms vs 295 +/- 29 ms] was decreased in diabetics compared to the control group. The one-year follow-up showed a significant decrease in IMP in patients treated with trimetazidine [subgroup IIa] compared to those treated with conventional drugs [subgroup IIb alone]. IRT values were lower in sub-group IIa compared to that of subgroup IIb. ICT returned towards the normal limits in both subgroups. Finally, ET decreased in subgroup IIa but increased in subgroup IIb compared to values obtained at the onset of treatment. In conclusion, trimetazidine when added to the conventional, anti-ischaemic therapy, seems to induce a more evident attenuation of post-AMI left ventricular dysfunction compared to those not given the drug