P3488Mechanistic insight on the cardioprotective effect of levosimendan against doxorubicin induced cardiomyopathy: Pivotal role of PKA signaling

Background

Levosimendan (LEVO) an inodilator indicated for the treatment of heart failure exerts multifaceted cardioprotective effects. Case-studies indicate protection against doxorubicin (DXR)-induced cardiotoxicity, but this effect remains elusive. We have previously shown that LEVO exerts cardioprotection against DXR-induced cardiomyopathy in a rat in vivo model, in a PKA/PKG-dependent manner.

Purpose

We sought to elucidate the mechanism of LEVO's induced cardioprotection and clarify the contribution of PKG and PKA pathways converging onto phospholamban (PLN).

Methods

As previously observed, LEVO at a dose of 24μg/kg protects against DXR cardiotoxicity, with protein kinase B (Akt)/ endothelial nitric oxide synthase (eNOS) and protein kinase A and G (PKA/PKG) pathways emerging as the main contributors to cardioprotection. Moreover, phospholamban seems to be the end-target of the signaling cascade. To verify the contribution of phospholamban, phospholamban deficient mice (PLN−/−) were assigned to PLN−/−/DXR (18mg/kg) and PLN−/−/DXR+LEVO (acute) (LEVO bolus, 24 μg/kg) groups for 14 days. Echocardiographic analysis was conducted in all groups and protocols. Furthermore, in order to solidify the mechanism of LEVO-mediated cardioprotection, primary adult ventricular murine cardiomyocytes (AVMCs) were isolated and treated with doxorubicin or/and LEVO as well with L-NAME, DT-2 and H-89 (eNOS, PKG and PKA inhibitors, respectively) and cardiomyocyte-toxicity was assessed.

Results

In the transgenic PLN−/− mice, LEVO did not exert cardioprotection, whilst the co-administration of doxorubicin and levosimendan led to an impaired Left ventricular function [FS (%): PLN−/−/Control: 39.01±0.42 vs PLN−/−/DXR: 38.12±0.51 in (NS); PLN−/−/DXR+LEVO: 35.38±0.86 (**p<0.01 vs PLN−/−/Control, *p<0.05 vs PLN−/−/DXR]. The latter data suggest that phospholamban is crucial for LEVO's cardioprotective effect. Finally, by investigating the contribution of different molecular pathways -shown to be induced by LEVO in vivo- on the AVMCs, we found that only PKA inhibition by H-89, abrogated LEVO-mediated cytoprotection, indicating that the effect is cAMP-PKA dependent.

Conclusions

Single-dose LEVO prevented DXR cardiotoxicity through a cAMP-PKA-phospholamban pathway, highlighting the role of inotropy in DXR cardiotoxicity. These preclinical data can stand as promising grounds for further clinical investigations.

P3552Estimating left ventricular myocardial deformation during cardiopulmonary exercise testing in patients with dilated cardiomyopathy and reduced ejection fraction

Background

Cardiopulmonary exercise testing (CPET) has been recognized as a valuable tool regarding the integrated estimation of exercise ability in patients with several cardiopulmonary diseases, dilated cardiomyopathy (DCM) included. Left ventricular (LV) abnormal myocardial deformation might be studied by newer echocardiography techniques. Aim of this study is to explore differences of LV myocardial deformation in DCM patients during a CPET session.

Methods

Forty-four DCM patients (mean age 53±13 years, 34 men) with an ejection fraction <50% (mean EF = 33±10%) and no history of previous pulmonary disease were subjected to maximum CPET. Simultaneously, we estimated LV myocardial deformation using speckle tracking imaging and we measured global longitudinal strain (GLS), longitudinal strain rate both at systole (GLSrS) and diastole (GLSrE) at baseline and at peak exercise. The difference between GLS at baseline-GLS at peak exercise was defined as GLS difference.

Results

All patients finished uneventfully CPET (peakVO2 = 20±7 ml/min/kg) and improved GLS at peak exercise (GLS difference = 1.5±2). We found that at peak exercise, systolic blood pressure (SBP) was increased (119±14 vs. 159±23 mmHg, p<0.001) while GLS (−12.5±4 vs. −14±5, p<0.001), GLSrS (−0.7±0.2 and −1.0±0.4, p<0.001) and GLSrE (0.7±0.4 and 1.0±0.6, p=0.001) were improved. A positive correlation between peakVO2 and GLS difference was found, independent of peak SBP (β=0.38, p=0.01).

Relationship between GLS dif and CPET

Conclusions

Patients with dilated cardiomyopathy and ejection fraction <50% present an increased exercise ability when they manage to improve LV GLS during maximum exercise. Consequently, LV GLS improvement during exercise characterizes beside patient's exercise ability the severity of heart failure as well.

Thyroid hormone receptor alpha1 downregulation in postischemic heart failure progression: the potential role of tissue hypothyroidism

Thyroid hormone (TH) signaling is altered in response to various stresses including myocardial ischemia. The present study investigated potential implication of TH signaling in the pathophysiology of postischemic remodeling. Acute myocardial infarction was induced in rats by coronary artery ligation (AMI). After 34 weeks, 6 animals were on congestive heart failure (CHF) as indicated by measurements in lung and right ventricular weight. 7 animals were in compensated state (Non-CHF) and 8 sham-operated animals (SHAM) served as controls. Progression to congestive heart failure was characterized by marked decrease in EF% and all other functional echocardiographic parameters. Furthermore, beta-MHC expression was significantly increased in CHF. A distinct pattern of thyroid hormone receptor (TR) expression was observed in the course of postischemic remodeling; TR alpha 1 was upregulated and TR beta 1 was downregulated in Non-CHF, and TR alpha 1 expression was markedly decreased during the transition from Non-CHF to CHF resulting in tissue hypothyroidism. Circulating T3 and T4 remained unchanged. This response was associated with marked decrease in mTOR activation. A potential link between mTOR and TR alpha 1 expression was shown in a neonatal cardiomyocytes model of PE (phenylephrine)-induced pathological growth. Phenylephrine increased the expression of TR alpha 1 in nucleus and this response was abrogated in the case of mTOR inhibition by rapamycin. In conclusion, progression to congestive heart failure after myocardial infarction is associated with suppressed expression of TR alpha 1 and results in tissue hypothyroidism. This process may, at least in part, be mTOR dependent.

Thyroid hormone modulates the responsiveness of rat aorta to alpha1-adrenergic stimulation: an effect due to increased activation of beta2-adrenergic signaling

AIM

The ability of the thyroid hormone to increase cardiac output and to lower systemic vascular resistance may provide a novel treatment for cardiovascular diseases. Therefore, understanding the mechanisms of thyroid hormone action on the heart and peripheral vasculature could be of clinical importance. We previously found that thyroid hormone modulates the alpha1-adrenergic effect on vascular reactivity of rat aortas. In the present study we further investigated possible mechanisms of this response.

METHODS

Hyperthyroidism was induced on Wistar-Kyoto male rats with L-Thyroxine, (THYR) treatment for two weeks, N.=18 while untreated rats used as controls (NORM), N.=16. The thoracic aorta was dissected and cut into rings that were suspended in an isolated organ bath with Krebs-Henseleit buffer. Maximal tension, Tmax, in g was measured in response to Potassium Chloride (KCl) and Phenylephrine (PE) in rings in the presence of Ritodrine, a beta-2 agonist (NORM-RITO, N:=8, THYR-RITO, N.=9), or in the absence of Ritodrine (THYR, N.=9, NORM, N.=8).

RESULTS

With KCL, Tmax was not different between the THYR, NORM, NORM-RITO, and THYR-RITO groups. With PE, there was a difference in Tmax between NORM-RITO and NORM, 0.66 (0.056) g vs 1.00 (0.066) g, P<0.05 and THYR and NORM, 0.75 (0.055) g vs 1.00 (0.066) g, P<0.05. No significant difference was observed between THYR-RITO AND THYR. Furthermore, Relax % was not significantly different between the NORM and the THYR, NORM-RITO, and THYR-RITO groups, 64.5%(3.7) vs 67.3%(6.7), 73.5% (4.3) and 81.8 %(4.7), P>0.05.

CONCLUSIONS

PE induced vasoconstriction in isolated rat aortic rings was reduced after both ritodrine and thyroxine treatment. However, co-administration of thyroid hormone and ritodrine did not result in a synergistic reduction of PE induced vasoconstriction. Thus, thyroxine may modulate the alpha1-adrenergic vascular responsiveness by enhancing beta2-adrenergic stimulation.

Detection of coronary artery lesions and myocardial necrosis by magnetic resonance in systemic necrotizing vasculitides

OBJECTIVE

Myocardium and coronary arteries can occasionally be affected in patients with systemic necrotizing vasculitides; however, such involvement has not been systematically assessed using cardiovascular magnetic resonance imaging (MRI).

METHODS

Magnetic resonance angiography and contrast-enhanced MRI were applied for the assessment of coronary arteries (the left anterior descending [LAD], left circumflex [LCx], and right coronary artery [RCA]) and myocardium, respectively, in 39 patients with vasculitis who were asymptomatic for cardiac disease (16 with microscopic polyangiitis [MPA], 11 with Wegener's granulomatosis [WG], 9 with Churg-Strauss syndrome [CSS], and 3 with polyarteritis nodosa [PAN]). Data were compared with age-matched disease-control patients with rheumatoid arthritis (n = 20) or systemic lupus erythematosus (n = 13), and with healthy control individuals with normal coronaries (n = 40).

RESULTS

Patients with MPA, WG, and PAN (but not with CSS) were found to display significantly increased maximal diameters of coronary arteries compared with healthy controls (for MPA and WG; P < 0.001 for LAD and RCA, and P < 0.01 for LCx) and with both disease-control groups (for only MPA; P < 0.01 for LAD and RCA, and P < 0.05 for LCx). Fusiform coronary aneurysms were detected in patients with MPA (4/16) and PAN (2/3), whereas coronary ectasias were evident in patients with MPA (14/16) and WG (2/11). The presence of myocardial necrosis (by assessment of late gadolinium-enhanced images) was identified only in patients with MPA (2/16) and CSS (3/8 studied).

CONCLUSION

Cardiovascular MRI assessment of patients with systemic vasculitis revealed coronary ectatic disease in the majority of patients with MPA and PAN, as well as in several patients with WG. Myocardial necrosis can be detected in MPA and CSS.

Thyroid hormone at supra-physiological dose optimizes cardiac geometry and improves cardiac function in rats with old myocardial infarction

Thyroid hormone (TH) is critical in cardiac cell differentiation (regulating contractile proteins and cell geometry) and this effect could be potentially exploited therapeutically in reversing the process of de-differentiation which underlies postischemic cardiac remodeling. Acute myocardial infarction was induced in male Wistar rats by ligating left coronary artery (AMI, n=8), while sham operated animals served as control (SHAM, n=8). 13 weeks after AMI, TH was administered in a group of animals for 4 weeks (AMI-THYR, n=9). TH significantly increased beta-MHC and decreased alpha-MHC expression in the myocardium. This response was accompanied by changes in cardiac geometry: sphericity index, (SI, long to short axis ratio) was found to be 1.95 (SEM, 0.02) in SHAM, 1.51(0.03) in AMI and 1.64(0.03) in AMI-THYR, p<0.05. As a consequence, cardiac function was significantly improved: left ventricular ejection fraction (EF%) was 74.5% (SEM, 2.8) in SHAM vs 29.5% (2.1) in AMI, and 40.0% in AMI-THYR, p<0.05. Furthermore, +dp/dt and -dp/dt were 4250 (127) and 2278 (55) in SHAM vs 2737(233) and 1508 (95) in AMI vs 3866 (310) and 2137(111) in AMI -THYR, respectively, p<0.05. TH treatment partially reverses cardiac dysfunction in rats with old myocardial infarction by favorably changing cardiac chamber geometry and expression of myosin isoforms. Thyroid hormone, unlike current treatments, appears to be a paradigm of therapeutic intervention which aims at restoring cardiac geometry and may prove new effective treatment for heart failure.

The value of anginal pain in exercise testing after myocardial infarction

The result of treadmill exercise tests were studied in 158 patients (pts) who were exercised submaximally 1 to 3 month after an acute transmural myocardial infarction. A 4 minute test had initially been performed prior to their discharge, 14 to 20 days after the acute event. Eight pts had and inferior and 65 an anterior infarction; 13 could not be reliable classified and were not further included. In the inferior infarction group, 10/80 had a positive test characterized by ST changes (9 pts), and aniginal pain (4 pts.). In the anterior infarction group, 11/65 had a positive test: ST-changes could be reliable assessed in only 2, while 9 had anginal pain; one had ventridular tachycardia. Fourteen pts underwent coronary arteriography; all showed severe triple vessel disease, and in 8 myocardial revascularization was performed. In pts with a previous anterior myocardial infarction, anginal pain can be a very helpful finding, since ST changes are usually hard to interpret.

Abnormal signal-averaged electrocardiograms in patients with incomplete right bundle-branch block

BACKGROUND AND HYPOTHESIS

A hypothesis was formulated that regional delayed activation of the right ventricle, as seen in incomplete right bundle-branch (IRBBB) aberrancy, may simulate late potential activity and may be responsible for abnormal signal-averaged electrocardiograms (SAECGs). No previous studies have specifically addressed this issue in this particular group of patients (with IRBBB). Therefore, the aim of the present study was to investigate the incidence of abnormal SAECGs in patients with IRBBB. If this were confirmed, our purpose would further be to investigate ways of reducing the false positive results.

METHODS

The study group included 53 patients (28 men and 25 women), aged 53 +/- 13 years, with no history of previous myocardial infarction or ventricular tachycardia and who had an electrocardiogram (ECG) showing IRBBB. An SAECG was also performed in a control group of 19 age-matched individuals with a normal ECG. Time domain analysis was performed using a band pass filter of 40-250 Hz. The following parameters were considered normal: filtered QRS duration (QRSD) < 114 ms, root mean square of the voltage of the last 40 ms of the QRS complex (RMS) > 20 microV, and the duration of the low amplitude signal (< 40 microV) at the terminal portion of the QRS (LAS) < 38 ms. An SAECG was considered abnormal if any two of these criteria were abnormal.

RESULTS

The mean values of the SAECG parameters were: QRSD 101 +/- 11 ms, RMS 32 +/- 20 microV, LAS 32 +/- 12 ms, and noise 0.29 +/- 0.13 microV. Abnormal SAECGs with at least two criteria satisfied were present in 16 of 53 (30%) patients compared with 0 (0%) of 19 individuals in the control group (p = 0.02). Abnormal values included the combination of RMS and LAS in 12 patients and all three parameters in 4 patients. However, if the definition of late potentials were limited to the combination of abnormal QRSD and either RMS or LAS values, the incidence of false positive results (4 patients) (7.5%) would be significantly decreased (p = 0.007). At 21 months of follow-up, no arrhythmic events occurred.

CONCLUSIONS

Delayed terminal conduction observed in IRBBB may cause a high incidence of false positive late potentials on SAECGs. Based on this study, we propose that this can be largely remedied if the optimal criteria for the presence of late potentials in patients with IRBBB always include the combination of QRSD and either RMS or LAS.

Lipoprotein(a) is related to the extent of lesions in the coronary vasculature and to unstable coronary syndromes

BACKGROUND

Lp(a) is a highly atherogenic particle with a prothrombotic effect. Until now its relation to the extent and severity of the atheromatic lesions had not been established by standard procedures.

HYPOTHESIS

This study examined the correlation of Lp(a) to the extent and severity of coronary artery disease (CAD) and its relation to unstable clinical events (not including sudden death).

METHODS

In 202 patients undergoing coronary angiography, plasma lipids were measured with the usual procedures and Lp(a) with the enzyme-linked immunosorbent assay. The extent of CAD was expressed in the number of diseased vessels and its severity in terms of the severity coefficient and the obstruction coefficient.

RESULTS

A very strong relationship between LP(a) and the number of diseased vessels (p = 0.0007) signifying diffuse atherosclerosis, but no relation with the severity of the lesions. was found. However, it was the only lipid that correlated significantly with the number of totally occluded vessels (p = 0.0003). The thrombogenic ability of Lp(a) was manifested by increased incidence of myocardial infarction and unstable angina episodes in patients with elevated Lp(a) (p = 0.0157).

CONCLUSION

Elevated Lp(a) predisposes to the extent of CAD and total occlusions but not to the severity of lesions. Patients with increased Lp(a) levels and unstable angina are at increased danger of suffering myocardial infarction. Thus, Lp(a) may predispose to plaque destabilization and thrombosis of noncritical lesions.

Thyroid hormone receptor alpha 1: a switch to cardiac cell "metamorphosis"?

Thyroid hormone receptor alpha1 (TRalpha1) is predominantly expressed in the myocardium but its biological function under physiological or pathological conditions remains largely unknown. The present study investigated possible interactions between alpha1 adrenergic and thyroid hormone signaling at the level of TRalpha1, potential underlying mechanisms and physiological consequences, as well as the role of TRalpha1 in cell differentiation. This may be of physiological relevance since both thyroid hormone and adrenergic signalling are implicated in the pathophysiology of cardiac remodelling. Neonatal cardiomyocytes obtained from newborn rats (2-3 days) were exposed to phenylephrine (PE, an alpha1 adrenergic agonist) for 5 days, in the absence or excess of T3 in the culture medium. PE, in the absence of T3, resulted in 5.0 fold increase in TRalpha1 expression in nucleus and 2.0 fold decrease in TRalpha1 expression in cytosol, P<0.05. As a result, a fetal pattern of myosin isoform expression with marked expression of beta-MHC was observed in PE treated vs the untreated cells, P<0.05. PD98059 (an ERK signalling inhibitor) abrogated this response. In the presence of T3 in the culture medium, TRalpha1 expression was increased 1.6 fold in nucleus and 2.0 fold in cytosol in PE-T3 vs PE treated cells, P<0.05, and the fetal pattern of myosin isoform expression was prevented. Parallel studies with H9c2 myoblasts showed that reduction of T3 binding to TRalpha1 receptor delayed cardiac myoblasts differentiation without affecting proliferation. In conclusion, in neonatal cardiomyocytes, nuclear TRalpha1 is overexpressed after prolonged activation of the alpha1- adrenergic signalling by PE. This response seems to be an ERK kinase dependent process. Over-expression of TRalpha1 may lead to fetal cardiac phenotype in the absence of thyroid hormone availability. Furthermore, TRalpha1 seems to be critical in cardiac myoblast differentiation.

Ischemic preconditioning fails to confer additional protection against ischemia-reperfusion injury in the hypothyroid rat heart

There is accumulating evidence showing that ischemic preconditioning (PC) may lose its cardioprotective effect in the diseased states. The present study investigated whether PC can be effective in hypothyroidism, a clinical condition which is common and often accompanies cardiac diseases such as heart failure and myocardial infarction. Hypothyroidism was induced in rats by 3-week administration of 6n-propyl-2-thiouracil in water (0.05 %). Normal and hypothyroid hearts (HYPO) were perfused in Langendorff mode and subjected to 20 min of zero-flow global ischemia and 45 min of reperfusion. A preconditioning protocol (PC) was also applied prior to ischemia. HYPO hearts had significantly improved post-ischemic recovery of left ventricular developed pressure, end-diastolic pressure and reduced lactate dehydrogenase release. Furthermore, phospho-JNK and p38 MAPK levels after ischemia and reperfusion were 4.0 and 3.0 fold lower in HYPO as compared to normal hearts (P<0.05). A different response to PC was observed in normal than in HYPO hearts. PC improved the post-ischemic recovery of function and reduced the extent of injury in normal hearts but had no additional effect on the hypothyroid hearts. This response, in the preconditioned normal hearts, resulted in 2.5 and 1.8 fold smaller expression of the phospho-JNK and phospho-p38 MAPK levels at the end of reperfusion, as compared to non-PC hearts (P<0.05), while in HYPO hearts, no additional reduction in the phosphorylation of these kinases was observed after PC. Hypothyroid hearts appear to be tolerant to ischemia-reperfusion injury. This response may be, at least in part, due to the down-regulation of ischemia-reperfusion induced activation of JNKs and p38 MAPK kinases. PC is not associated with further reduction in the activation of these kinases in the hypothyroid hearts and fails to confer added protection in those hearts.

No incremental clinical information of NT Pro BNP at peak exercise over resting levels in patients with impaired left ventricular function

There is an increasing tension to use NT Pro BNP blood levels at peak exercise testing. Their possible superiority over resting levels in congestive heart failure or factors associated with their increase have not been adequately studied. We studied 65 patients, 51 males and 14 females with impaired left ventricular function. Mean left ventricular ejection fraction (LVEF) was 35+/-9%. Our findings suggest that in patients with heart failure NT Pro BNP plasma levels at peak exercise do not provide incremental clinical information over resting levels. Baseline NT Pro BNP alone can provide sufficient clinical information.

[Prognostic value of ventricular longitudinal systolic velocities and maximal oxygen consumption in patients with dilated cardiomyopathy]

OBJECTIVE

To compare the prognostic value of regional longitudinal ventricular systolic velocities with that of maximal oxygen consumption (VO(2max)) in patients with dilated cardiomyopathy (DCM).

METHODS

VO(2max) derived from cardiopulmonary exercise tests and regional longitudinal ventricular systolic velocities obtained from tissue Doppler imaging were compared in 18 DCM patients with cardiac events (death, cardiac transplantation, hospitalization, group A) and 24 patients without cardiac events (group B). Peak velocities during isovolumic contraction (is) and ejection (ez) were interrogated at the mitral or tricuspid annulus (site 1), at the mid parts of the walls (site 3, at the level of papillary muscle), and at the midpoints (site 2) between sites 1 and 3 of interventricular septum (S), lateral wall of LV (L) and of RV (R) in apical 4 chambers view.

RESULTS

R1is, R2is, R2ez, R3is, S1is, S1ez, S2ez, L1is, L1ez and L2ez of group A were significantly lower than those in group B (all P < 0.05). Independent of VO(2max), high sensitivity and specificity were shown for R3ez, S1ez, L1ez, L1is, L2is and L3is in predicting cardiac events of DCM patients.

CONCLUSION

LV and RV systolic velocities could independently predict cardiac events in DCM patients.

Pharmacological inhibition of TRalpha1 receptor potentiates the thyroxine effect on body weight reduction in rats: potential therapeutic implications in controlling body weight

It has been previously reported that thyroid hormone receptor alpha1 (TRalpha1) is involved in the regulation of food intake and heart rhythm. Herein, we show that pharmacological inhibition of TRalpha1 by dronedarone, an amiodarone like compound (shown to antagonize thyroid hormone binding to TRalpha1), prevented the thyroid hormone induced increase in food intake and heart rate acceleration in rats. This resulted in a marked reduction in body weight. It is likely that thyroid analogs may prove potential therapeutic agents for controlling body weight.

Cardiac repair--fact or fancy?

Patients with ischemic cardiomyopathy have a poor prognosis despite all pharmacological, interventional and surgical treatment modalities currently applied. Heart transplantation remains the ideal treatment for this group of patients but the scarcity of donors hinders its widespread application. The autologous transplantation of stem cells (SCs) for cardiac repair is emerging as a new therapy for patients with myocardial dysfunction early after an acute infarction or ischemic cardiomyopathy. The rationale of this novel method is the enhancement of the repair mechanisms achieved by tissue-specific and circulating stem/progenitor cells. SCs assist naturally occurring myocardial repair by contributing to increased myocardial perfusion and contractile performance especially in the setting of acute myocardial infarction (AMI), but also in patients with chronic ischemic heart failure and advanced, diffuse coronary artery disease. The exact mechanism of their action has not been fully elucidated. Few studies continue to suggest a formation of few new contractile tissue. The majority if investigators believe that these cells do not persist long in the myocardium but that they secrete vascular growth and other cardioprotective factors.

Intermittent acute aortic valve regurgitation: a case report of a prosthetic valve dysfunction

Complications of any mechanical prosthesis include thrombus or pannus formation. In our case report we demonstrate that prosthetic aortic valve regurgitation due to pannus formation may be intermittent and non-cyclic in pattern and therefore not obvious at the time of original clinical examination. Under these conditions and as transesophageal echocardiography cannot be repeated promptly, transthoracic 2-D and Doppler echocardiography should be available at any time when symptoms occur and present the method of choice for acute patient evaluation. Thrombolysis seems to be the first treatment of choice in case of thrombus formation and re-do surgery in case of pannus formation.

Long-term oral bosentan treatment in patients with pulmonary arterial hypertension related to congenital heart disease: a 2-year study

OBJECTIVE

To evaluate the long-term clinical and exercise effect of chronic oral administration of the non-selective endothelin receptor antagonist bosentan in patients with pulmonary arterial hypertension (PAH) related to congenital heart disease (CHD).

DESIGN

Extension of a preceding prospective non-randomised open clinical study on bosentan treatment in PAH related to CHD.

SETTING

A tertiary referral centre for cardiology.

PATIENTS

19 of the original 21 patients of mean (standard deviation (SD)) age 22 (3) years (13 with Eisenmenger syndrome) in World Health Organization (WHO) class II-IV and having a mean (SD) oxygen saturation of 87 (2) %.

INTERVENTION

Patients received bosentan treatment for 2.4 (0.1) years and underwent clinical and exercise evaluation at baseline, 16 weeks and 2 years of treatment, with haemodynamic assessment at baseline and 16 weeks.

RESULTS

All patients remained stable with sustained subjective clinical and WHO class improvement (p<0.01) at 16 weeks and 2 years of treatment without significant side effects or changes in oxygen saturation. After the initial 16-week improvement (p<0.05) in peak oxygen consumption and exercise duration at treadmill test, and walking distance and Borg dyspnoea index at 6-min walk test, all exercise parameters appeared to return to their baseline values at 2 years of follow-up.

CONCLUSIONS

Long-term bosentan treatment in patients with PAH related to CHD is safe and induces clinical stability and improvement, but the objective exercise values appear to slowly return to baseline. Larger studies on long-term endothelin receptor antagonism including quality of life assessment are needed to evaluate the therapeutic role of bosentan in this population.

Spatial QRS-T angle: association with diabetes and left ventricular performance

The spatial QRS-T angle obtained by vectorcardiography is a combined measurement of the electrical activity of the heart and predicts cardiovascular morbidity and mortality. Disturbances in repolarization and depolarization are common in diabetes. No data, however, exist on the effect of diabetes on QRS-T angle. In this study we examined differences in QRS-T angle between type 2 diabetic and non-diabetic subjects; in addition, the potential relationship between QRS-T angle and left ventricular performance as well as glycaemic control were also examined. A total of 74 subjects with type 2 diabetes and 74 non-diabetic individuals, matched for age and sex with the diabetic subjects were examined. All subjects were free of clinically apparent macrovascular complications. Spatial vectorcardiogaphic descriptors of ventricular depolarization and repolarization were reconstructed from the 12-electrocardiographic leads using a computer-based electrocardiogram. Left ventricular mass and performance were measured using M-mode and Doppler echocardiography. QRS-T angle values were higher (by almost 2-fold) in the diabetic in comparison with the non-diabetic subjects (P < 0.001). After multivariate adjustment, QRS-T angle was independently associated with age (P = 0.01), HbA(1c) (P = 0.003), and low-density lipoprotein cholesterol levels (P = 0.04) in the non-diabetic, and with HbA(1c) (P = 0.03) as well as Tei index (P = 0.003) in the diabetic subjects. The spatial QRS-T angle is high in subjects with type 2 diabetes and is associated with glycaemic control and left ventricular performance. The prognostic importance of the higher spQRS-T angle values in subjects with diabetes remains to be evaluated in prospective studies.

Differential pulse pressure response to various antihypertensive drug families

Pulse pressure (PP) is emerging as a major pressure predictor of cardiac disease. The study comprised 10 185 untreated patients with essential hypertension. A total of 5395 men and 4790 women 56+/-13 years old, with uncomplicated essential hypertension, after a 15-day washout period and after 6 months of antihypertensive monotherapy were included. All patients included in the final cohort were responders and had normalized their blood pressure. PP was decreased least with diuretics (-5 mm Hg) and most with angiotensin II receptor blockers (ARBs) and calcium antagonists (-15 mm Hg), followed by angiotensin-converting enzyme inhibitors (ACEI) (-12 mm Hg) alpha- and beta-blockers (-10 and -9 mm Hg), differentiating among antihypertensive classes (P<0.001). The magnitude of PP fall was related to the degree of left ventricular (LV) mass reduction (P<0.001), seen best with ARBs (r=0.42) and least with ACEIs (r=0.18). Of the antihypertensive medications used in everyday practice, PP decrease may be achieved best with ARBs and calcium antagonists, whereas diuretics confer poor response. PP was decreased least with diuretics (-5 mm Hg) and most with ARBs and calcium channel blockers (-15 mm Hg), followed by ACEI (-12 mm Hg) alpha- and beta-blockers (-10 and -9 mm Hg), differentiating among antihypertensive classes (P<0.001). Of the antihypertensive medications used in everyday practice, PP decrease may be achieved best with ARBs and calcium antagonists.

Iloprost for prevention of contrast-mediated nephropathy in high-risk patients undergoing a coronary procedure. Results of a randomized pilot study

OBJECTIVE

The prevention of contrast-mediated nephropathy (CMN), which accounts for considerable morbidity and mortality, remains a vexing problem. Contrast induced renal vasoconstriction is believed to play a pivotal role in the CMN mechanism. The aim of this pilot study was to examine the safety and efficacy of two doses of the prostacyclin analogue iloprost in preventing CMN in high-risk patients undergoing a coronary procedure.

METHODS

Forty-five patients undergoing coronary angiography and/or intervention who had a serum creatinine concentration >or=1.4 mg/dL were randomized to receive iloprost at 1 or 2 ng/kg/min or placebo, beginning 30-90 minutes before and terminating 4 hours after the procedure. CMN was defined by an absolute increase of serum creatinine >or=0.5 mg/dL or a relative increase of >or=25% measured 2 to 5 days after the procedure. Study drug infusion was discontinued in 2 patients in the low-dose iloprost group due to flush/nausea and in 5 patients in the high-dose group due to severe hypotension.

RESULTS

The mean creatinine concentration change in the placebo group (0.02 mg/dL) was unfavorable compared to that in the low-dose iloprost group (-0.11 mg/dL; p=0.08) and high-dose iloprost group (-0.23 mg/dL; p=0.048). The difference between the absolute changes in creatinine clearance was favorable compared to placebo for both the low (mean difference 6.1 mL/min, 95%CI -0.5 to 12.8 mL/min, p=0.07) and the high-dose iloprost group (11.8 mL/min, 95%CI 4.7 to 18.8 mL/min, p=0.002). Three cases of CMN were recorded; all in the placebo group (p=0.032).

CONCLUSIONS

The results of this pilot study suggest that prophylactic administration of iloprost may effectively prevent CMN, but higher dosages are connected with substantial tolerability issues.

Decreased vascular reactivity to alpha1 adrenergic stimulation in the presence of hypothyroid state: a part of an adaptive response?

AIM

A hypothyroid state frequently accompanies cardiac illnesses but its physiological significance for the cardiovascular hemodynamics remains largely unknown. Therefore, the present study investigated possible physiological consequences on vascular function in an experimental model of low thyroid hormone state.

METHODS

Hypothyroidism was induced in rats by the administration of 6-n-propyl-2-thiouracil in drinking water (final concentration of 0.05%) for 3 weeks, HYPO rats, and untreated rats served as controls (Control). Isolated aortic rings with or without endothelium (E+, E-) were contracted with KCl (10 to 60 mM) and phenylephrine (PE) (10(-10) to 10(-5) M). Maximal tension (Tmax) in g and EC(50) in response to PE and KCl were measured.

RESULTS

Tmax was significantly lower while EC(50) was significantly higher in response to PE in HYPO(E+) than in Control(E+). Upon endothelium removal, Tmax was not significantly different between the groups but EC(50) was still significantly higher in HYPO(E-) than in Control(E-). EC(50) in response to KCl was significantly higher in HYPO with or without endothelium and no difference was found in Tmax.

CONCLUSIONS

Hypothyroid aortic rings respond less to a1 adrenergic stimulation probably due to the endothelium modulatory effect as well as to intrinsic smooth muscle defect. This seems to be of important clinical relevance.

Hyperthyroid hearts display a phenotype of cardioprotection against ischemic stress: a possible involvement of heat shock protein 70

Hyperthyroid hearts are shown to display a phenotype of cardioprotection against ischemic stress, but the underlying signaling mechanisms remain largely unknown. The present study investigated the possible relation of HSP70 to the thyroid hormone induced cardioprotection. HSP70 is a redox-regulated molecular chaperone, and enhances cell survival under stress. Thyroxin (25 microg/100 g body weight) was administered to Wistar male rats for four days (THYR-4d) and two weeks (THYR-14d), respectively, while untreated animals served as controls (CON-4d, CON-14d). Isolated hearts from control and thyroxin treated rats were subjected to 20 min zero-flow ischemia followed by 45 min of reperfusion (I/R). The amount of HSP70 in the myocardium for THYR-14d was 1.85 times the levels of CON-14d (p < 0.05). The levels of HSP70 expression were no different between THYR-4d and CON-4d, p > 0.05. This was only accompanied by an increase in MDA levels (used as an index of oxidative stress) in THYR-14d compared to untreated hearts. These changes corresponded to a differential response of the heart to I/R; post-ischemic recovery of function was significantly increased in THYR-14d compared to CON-14d, and was no different between the THYR-4d and CON-4d hearts. In conclusion, long-term thyroxin administration results in increased tolerance of the myocardium to I/R and enhances the expression of HSP70 which may, at least in part, account for this response.

Tangier Disease Four Decades of Research: A Reflection of the Importance of HDL

Reduced circulating levels of high density lipoprotein cholesterol (HDL-C) are a frequent lipoprotein disorder in coronary heart disease patients and can be caused by either genetic and/or environmental factors (sedentary lifestyle, diabetes mellitus, smoking, obesity or a diet enriched in carbohydrates). Extremely low serum HDL-C levels occur in patients with Tangier disease (TD), which is caused by mutations in the adenosine triphosphate (ATP)-binding cassette transporter A1 (ABCA1). Clinical manifestations are related to the storage of cholesteryl esters in reticuloendothelial tissues and to peripheral neuropathy. This review focuses on the genetic and lipid abnormalities of TD, the consequence of these on clinical outcome and the possible treatment options. These abnormalities reflect the importance of HDL in the pathogenesis of vascular disease.

Thyroid hormone receptors alpha1 and beta1 are downregulated in the post-infarcted rat heart: consequences on the response to ischaemia-reperfusion

There is accumulating evidence that thyroid hormone metabolism is altered after myocardial infarction (AMI) but its physiological relevance remains largely unknown. The present study investigated the possible role of thyroid hormone signaling in the response of the post-infarcted heart to ischaemia-reperfusion. Wistar rats were subjected to left coronary artery ligation (AMI), or sham operation (SHAM). After 8 weeks, hearts from AMI and SHAM rats were perfused in Langendorff mode and subjected to 20 min of zero-flow global ischaemia (I) and 45 min of reperfusion (R); AMI(I/R), n = 7 and SHAM(I/R), n = 7. Basal left ventricular pressure (LVDP), +dp/dt, and -dp/dt were significantly reduced. Left ventricular weight of the viable myocardium was increased by 14% in the AMI as compared to SHAM hearts, P < 0.05. T(3) and T(4) plasma levels in nM were 1.83 (0.08) and 53.3 (2.9) for SHAM and 1.76 (0.06) and 59.4 (5.2) for AMI rats, respectively, P > 0.05. TRalpha1 and TRbeta1 expression levels were 1.3- and 1.8-fold less in AMI than in SHAM hearts, P < 0.05. Furthermore, SERCA and NHE1 expression levels were 2.1- and 1.8-fold less in AMI than in SHAM, P < 0.05. PKCepsilon was 1.35-fold more in AMI compared to SHAM, P < 0.05. Myocardial glycogen content (in micromol/g) was 7.8 (1.2) in AMI as compared to 4.4 (0.5) for SHAM hearts, P < 0.05. After I/R, left ventricular end-diastolic pressure at 45 min of R (LVEDP45 in mmHg) was 20.3 (3.2) for AMI(I/R) vs 50.6 (4.8) mmHg for SHAM(I/R), P < 0.05. LDH release per gram of tissue was 251 (103) for AMI(I/R) and 762 (74) for SHAM(I/R), P < 0.05. In conclusion, TRalpha1 and TRbeta1 are downregulated after myocardial infarction and this was associated with altered expression of thyroid hormone responsive genes and increased tolerance of the post-infarcted heart to ischaemia-reperfusion injury.

Blockade of angiotensin II type 1 receptor diminishes cardiac hypertrophy, but does not abolish thyroxin-induced preconditioning

Growth and stress seem to share common intracellular pathways and activation of growth signaling can increase resistance to stress. Thyroid hormone induces cardiac hypertrophy and preconditions the myocardium against ischemia reperfusion injury. The present study investigated whether this response is mediated by renin-angiotensin system (RAS). RAS is shown to be activated in hyperthyroidism and is involved in the development of cardiac hypertrophy. Male Wistar rats were treated with L-thyroxin (25 microg/100 g, sc, od) for fourteen days, while normal rats served as controls. In addition, irbesartan (150 mg/kg po), a potent blocker of angiotensin II type 1 receptor (AT1), was given with L-thyroxin for fourteen days. Isolated hearts were perfused in Langendorff mode; after stabilization, they were subjected to 20 min zero-flow global ischemia and 45 min of reperfusion. Thyroxin induced cardiac hypertrophy, which was diminished with irbesartan administration. Post-ischemic recovery of function was increased in thyroxin-treated hearts as compared to controls while ischemic contracture was accelerated and intensified. Irbesartan did not abolish this response. In conclusion, blockade of angiotensin II type 1 receptor with irbesartan preserves thyroxin-induced cardioprotection while diminishing cardiac hypertrophy. It is likely that thyroxin-induced cardioprotection is due to a direct effect of thyroid hormone.

Effect of the oral endothelin antagonist bosentan on the clinical, exercise, and haemodynamic status of patients with pulmonary arterial hypertension related to congenital heart disease

OBJECTIVE

To evaluate the clinical, exercise, and haemodynamic effects of chronic oral administration of the non-selective endothelin receptor antagonist bosentan on patients with pulmonary arterial hypertension (PAH) related to congenital heart disease (CHD).

DESIGN

Prospective non-randomised open clinical study.

SETTING

Cardiology tertiary referral centre.

PATIENTS

21 patients with a mean (SEM) age of 22 (3) years with chronic PAH related to CHD (15 with Eisenmenger's syndrome). Patients were in World Health Organization (WHO) class II to IV with oxygen saturation 87 (2)%.

INTERVENTION

Patients underwent clinical, exercise, and haemodynamic evaluations at baseline and after 16 weeks of treatment.

RESULTS

Bosentan improved (p < 0.01) WHO class, peak oxygen consumption from 16.8 (1.4) to 18.3 (1.4) ml/kg/min, exercise duration from 9.0 (0.8) to 10.7 (0.6) minutes during the treadmill test, walking distance from 416 (23) to 459 (22) m, and Borg dyspnoea index from 2.8 (0.2) to 2.0 (0.1) during the six minute walk test. Bosentan treatment improved (p < 0.05) mean pulmonary artery pressure from 87 (4) to 81 (4) mm Hg, pulmonary blood flow index from 3.2 (0.4) to 3.7 (0.5) l/min/m2, pulmonary to systemic blood flow ratio from 1.2 (0.2) to 1.4 (0.2), and pulmonary vascular resistance index from 2232 (283) to 1768 (248) dyn.s.cm(-5). Two patients died, presumably of arrhythmic causes, who were in WHO class IV at baseline and who had improved during treatment.

CONCLUSIONS

Bosentan induces short and mid term clinical, exercise, and haemodynamic improvements in patients with PAH related to CHD. Larger studies with long term endothelin receptor antagonism are needed to assess the safety and possible treatment role of bosentan in this population.

Heterozygote men with familial hypercholesterolaemia may have an abnormal triglyceride response post-prandially. Evidence for another predictor of vascular risk in familial hypercholesterolaemia

Familial hypercholesterolaemia (FH) is associated with premature coronary heart disease (CHD). Post-prandial hypertriglyceridaemia has also been associated with cardiovascular disease. Thus, an abnormal post-prandial triglyceride (TG) clearance may contribute to the heterogeneity in the risk of CHD in heterozygous (h) FH. Therefore, we investigated the response of TG levels to a fatty meal in men with hFH. We studied 26 Greek men divided into two groups: the hFH group of 14 men, mean age 39 (SD = 11) years and the control group of 12 healthy men, mean age 43 (50:5) years. An increased TG response to the fatty meal was defined as a post-prandial TG concentration (at 4, 6 or 8 h) greater than the highest TG concentration in any hour in any control individual. All hFH patients had normal baseline fasting TG levels. However, seven hFH men showed an abnormal TG response after the fatty meal; these patients had higher baseline fasting TG levels than others [1.5 (0.2) vs. 1.0 (0.4) mmol/l, p = 0.005]. The hFH men constituted a heterogeneous group regarding their TG response to the fatty meal compared with healthy men because 50% with higher, but nevertheless 'normal' basal TG levels, had an abnormal post-prandial TG response. The reduced activity of low-density lipoprotein receptors in hFH together with other defects in TG handling may explain the abnormal rise of TG levels post-prandially.

The effect of nicotinic acid and alcohol co-administration in Wistar rats

The effects of co-administration of nicotinic acid (NA) and alcohol (Alc) on liver function in male Wistar rats were evaluated. The rats were randomized into five groups: (i) Olive oil (Oil), (ii) Alc+Oil, (iii) NA+Oil, (iv) NA+Alc+Oil, and (v) Controls (fed only normal rat chow). Alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AP), total cholesterol and triglycerides (TG) were measured. Liver histopathology was also assessed. The Alc+Oil group had higher TG levels compared with the NA+Alc+Oil group and all other groups, as well. NA+Oil group had higher levels of AP compared with Alc+Oil and Oil groups. The NA+Oil group had higher ALT levels compared with the Oil group. The Oil group had lower ALT levels compared with the control group. The Alc+Oil group had higher AST levels compared with the NA+Alc+Oil group, as well as with all other groups. Liver histopathology was within the normal range. A moderate amount of Alc daily together with NA is safe in rats. The NA and Alc co-administration reduces the TG and AST levels in rats, compared with the administration of Alc alone.

Radiation dose measurements to the interventional cardiologist using an electronic personal dosemeter

The aim of this study was to investigate the use of an electronic personal dosemeter (EPD) worn by a senior cardiologist in an Interventional Cardiology (IC) Laboratory of a busy cardiac centre and how the results could help in the evaluation of radiation protection equipment used. Patient samples consist of 28 patients (10 coronary angiographies (CAs) and 18 percutaneous transluminal coronary angioplasties (PTCAs)). Patient dose was measured with a dose-area product (DAP) meter. Cardiologist radiation dose value written on the EPD as well as the protective equipment used was collected. Between patient and cardiologist dose, a significant correlation was found in CA and a moderate correlation in PTCA. Mean cardiologist effective dose E per procedure was found to be 0.2 microSv in CA and 0.3 microSv in PTCA. EPD proved to be an easy, direct and straightforward way to measure the radiation dose that the cardiologist receives in an IC laboratory.

Educational level and risk profile of cardiac patients in the EUROASPIRE II substudy

STUDY OBJECTIVE

To ascertain, whether, conventional risk factors and readiness of coronary patients to modify their behaviour and to comply with recommended medication were associated with education in patients with established coronary heart disease.

DESIGN AND METHODS

EUROASPIRE II was a cross sectional survey undertaken in 1999-2000 in 15 European countries to ascertain how effectively recommendations on coronary preventions are being followed in clinical practice. Consecutive patients, men and women </=71 years who had been hospitalised for acute coronary syndrome or revascularisation procedures, were identified retrospectively. Data were collected through a review of medical records, interview, and examination at least six months after hospitalisation. The education reached was ascertained at the interview.

MAIN RESULTS

A total of 5556 patients (1319 women) were evaluated. Significantly more patients with ischaemia had only primary education, in contrast with the remaining diagnostic groups. Body mass index and glucose were negatively associated with educational level, while HDL-cholesterol was positively associated. Men with highest education had significantly lower systolic blood pressure and total cholesterol. The prevalence of current smoking decreased significantly from primary to secondary and high education only in men. Both men and women with primary educational level were more often treated with antidiabetics, and antihypertensives, but less often with lipid lowering drugs. The effectiveness of treatment was virtually the same in all education groups.

CONCLUSIONS

Patients with higher education had lower global coronary risk, than those with lower education. This should be considered in clinical practice. Particular strategies for risk communication and counselling are needed for those with lower education status.

Postprandial hypertriglyceridaemia in patients with Tangier disease

BACKGROUND

Tangier disease (TD) is the phenotypic expression of rare familial syndromes with mutations in the ABCA1 transporter. TD results in extremely low high density lipoprotein (HDL) cholesterol and reduced low density lipoprotein cholesterol, with normal or mildly increased fasting triglyceride (TG) concentrations. Although there is a close relation between HDL cholesterol values and atherogenesis, the risk of coronary artery disease is variable in TD. Raised fasting or postprandial TG values frequently accompany low HDL cholesterol and can add to the risk of a vascular event.

AIMS

To investigate the postprandial TG response in TD.

PATIENTS AND METHODS

Five patients (three homozygotes (HTD) and two heterozygotes (hTD)) from one family were studied. One was defined by DNA analysis as homozygous for a new mutation (C2033A) resulting in truncation of the ABCA1 protein. Their TG concentrations were measured before and four, six, and eight hours after a standardised fat load and compared with a control group.

RESULTS

Two patients with HTD had high fasting TG concentrations. The third patient with HTD, the two with hTD, and the control group had TG concentrations within the reference range. The patients with HTD had increased postprandial peak TG values when compared with those with hTD and controls.

CONCLUSION

Patients with HTD, with or without fasting hypertriglyceridaemia, may have an increased TG response to a fatty meal. The small number of patients does not allow definitive conclusions to be made. However, postprandial hypertriglyceridaemia could be a reason why some patients with TD develop premature atherosclerosis.

Acute endothelin A receptor antagonism improves pulmonary and systemic haemodynamics in patients with pulmonary arterial hypertension that is primary or autoimmune and related to congenital heart disease

OBJECTIVE

To evaluate the acute haemodynamic effect of BQ-123, a selective endothelin A receptor antagonist, in severe chronic pulmonary arterial hypertension (PAH) of primary or autoimmune origin or related to congenital heart disease.

DESIGN

Prospective open clinical study.

SETTING

Cardiology tertiary referral centre.

PATIENTS

26 patients with chronic PAH were studied, with mean (SEM) age 29 (3) years (range 4-71 years), mean pulmonary artery pressure 68 (4) mm Hg, and pulmonary vascular resistance index 1694 (170) dyne x s x cm(-5). Patients were divided in three groups according to PAH aetiology: primary or autoimmune PAH (n = 12), and PAH associated with congenital heart defects with (n = 6) or without (n = 8) complete mixing.

INTERVENTION

BQ-123 200 nmol/min was infused for 60 minutes in the right atrium with sequential haemodynamic measurements at 30 minute intervals.

RESULTS

BQ-123 improved mean pulmonary artery pressure from 68 (4) to 64 (4) mm Hg (p < 0.05), pulmonary vascular resistance index from 1694 (170) to 1378 (145) dyne x s x cm(-5) (p < 0.001), pulmonary cardiac index from 3.0 (0.2) to 3.4 (0.3) l/min/m2 (p < 0.001), and effective cardiac index from 2.5 (0.2) to 2.7 (0.2) l/min/m2 (p < 0.01). Haemodynamic response was similar in all groups except for systemic cardiac index where a different (p = 0.0001, F = 5.53) response was observed; systemic cardiac index increased from 2.7 (0.2) to 2.9 (0.2) l/min/m2 (p < 0.001) when patients with complete mixing were excluded, in whom systemic cardiac index tended to decrease from 3.4 (1.0) to 3.0 (0.6) l/min/m2 (p = 0.06).

CONCLUSIONS

Acute endothelin A receptor antagonism induces substantial haemodynamic improvement in severe chronic PAH of primary or autoimmune origin or related to congenital heart disease.

Increased distance between mitral valve coaptation point and mitral annular plane: significance and correlations in patients with heart failure

OBJECTIVE

To measure the distance between the mitral leaflet coaptation point and the mitral annulus (CPMA) and assess the relation of this index to structural and functional characteristics of the failing left ventricle.

DESIGN

Echocardiographic indices and CPMA were measured at baseline and again during dobutamine infusion and leg lifting. Left ventricular diastolic and systolic dimensions, left ventricular ejection fraction (LVEF) by Simpson's rule, mitral annulus dimension, and E point septal separation were correlated with CPMA.

SETTING

Tertiary referral centre.

PATIENTS

The total study population of 129 patients included 94 with LVEF < 35% and 35 with LVEF 35%-45%; 76 had coronary artery disease and 53 had dilated cardiomyopathy.

INTERVENTIONS

A dobutamine infusion was given in 18 patients and preload increase by leg lifting in 28.

MAIN OUTCOME MEASURES

Correlations between CPMA and contractility indices at baseline and during interventions.

RESULTS

CPMA was correlated with left ventricular diastolic dimension (r = 0.52), left ventricular systolic dimension (r = 0.53), LVEF (r = -0.44), fractional shortening (r = -0.42), E point septal separation (r = 0.48), and mitral annulus dimension (r = 0.44) (all p < 0.001). Dobutamine decreased CPMA from (mean (SD)) 12.04 (3.64) mm to 8.92 (2.56) mm and increased LVEF from 27 (6.2)% at baseline to 33.4 (6.9)% at 10 microg/kg/min (both p < 0.001). These changes were strongly related (r = 0.68, p < 0.007). After leg lifting, CPMA decreased from 13 (4) mm at baseline to 10 (3) mm (p < 0.001), and LVEF increased from 32 (11)% at baseline to 39 (11)% (p < 0.001). Fractional shortening and left ventricular diastolic dimension also increased (p < 0.001) and mitral annulus dimension and E point septal separation decreased (p < 0.002), but left ventricular systolic dimension did not change.

CONCLUSIONS

The mechanism displacing the mitral coaptation point towards the left ventricular apex is multifactorial. The correlations between CPMA difference (before versus after interventions) and ejection fraction difference (before versus after interventions) shows that this index depends mainly on left ventricular function.

Propylthiouracil-induced hypothyroidism is associated with increased tolerance of the isolated rat heart to ischaemia-reperfusion

The present study investigated the response of the hypothyroid heart to ischaemia-reperfusion. Hypothyroidism was induced in Wistar rats by oral administration of propylthiouracil (0.05%) for 3 weeks (HYPO rats), while normal animals (NORM) served as controls. Isolated hearts from NORM and HYPO animals were perfused in Langendorff mode and subjected to zero-flow global ischaemia followed by reperfusion (I/R). Post-ischaemic recovery of left ventricular developed pressure was expressed as % of the initial value (LVDP%). Basal expression of protein kinase C epsilon (PKCepsilon) and PKCdelta and phosphorylation of p46 and p54 c-jun NH(2)-terminal kinases (JNKs) in response to I/R were assessed by Western blotting. LVDP% was found to be significantly higher in HYPO hearts than in NORM. At baseline, PKCepsilon expression was 1.4-fold more in HYPO than in NORM hearts, P<0.05, while PKCdelta was not changed. Furthermore, basal phospho-p54 and -p46 JNK levels were 2.2- and 2.6-fold more in HYPO than in NORM hearts, P<0.05. In response to I/R, in NORM hearts, phospho-p54 and -p46 JNK levels were 5.5- and 6.0-fold more as compared with the baseline values, P<0.05, while they were not significantly altered in HYPO hearts. HYPO hearts seem to display a phenotype of cardioprotection against ischaemia-reperfusion and this is associated with basal PKCepsilon overexpression and attenuated JNK activation after I/R.

Prognostic significance of soluble interleukin-2 receptor levels in patients with dilated cardiomyopathy

BACKGROUND

Activation of T lymphocytes is thought to mediate myocardial dysfunction in dilated cardiomyopathy (CMP), probably through cytotoxic cytokines, but its value as a prognostic factor has not been evaluated.

METHODS

For 2 years we prospectively followed 76 patients (65 males, 11 females, age 49 +/- 7 years) with CMP and New York Heart Association(NYHA) Class II-III heart failure; left ventricular (LV) function was assessed echocardiographically. Thirty-three patients (28 males, five females, age 52 +/- 6 years) with ischaemic heart disease (IHD) and similar NYHA and LV function characteristics were used as controls. Serum sIL-2R levels, peripheral blood lymphocyte proliferation (basal, + concanavalin A) and HLA-DQB1 genotyping was carried out in all patients.

RESULTS

The CMP patients had increased sIL-2R levels (1259 +/- 130 pg mL-1) compared with the IHD patients (703 +/- 80 pg mL-1, P < 0.01, only 3 > 800 pg mL-1). In the CMP patients, there was a significant (r = +0.45, P= 0.04) correlation between sIL-2R and the LV end-diastolic diameter but not with the LV ejection fraction or NYHA Class. During the 24-month follow up, 17 of the CMP patients had an adverse clinical course (death, need for cardiac transplantation, or worsening heart failure). Of these, 14 (75%) had elevated (>or= 800 pg mL-1) sIL-2R levels (Group I) compared with only five (6%) with a stable clinical course (Group II). Neither [3H] thymidine incorporation into the peripheral blood lymphocytes nor the excess of HLA-DQB1-30 histidine homozygotes in the Group I patients (38% vs. 17%, P < 0.05) could predict the clinical outcome.

CONCLUSION

Increased sIL-2R levels in CMP patients are an independent predictor of a more aggressive clinical course.

Coronary flow: clinical considerations

In the measurement of coronary blood flow to determine the success of percutaneous coronary intervention, invasive techniques, coupled with plaque characterisation and other intracoronary imaging modalities, may prove invaluable.

Arrhythmia recurrences are rare when the site of radiofrequency ablation of the slow pathway is medial or anterior to the coronary sinus os

AIMS

The site of successful ablation of the slow atrioventricular (AV) nodal pathway may be located in the posteroseptal or midseptal area. We have previously shown that the site of successful radiofrequency (RF) ablation of the slow pathway, rather than residual slow pathway conduction correlates with AV nodal re-entrant tachycardia (AVNRT) recurrences, with more recurrences noted in inferoposterior (to the coronary sinus os) locations. Accordingly, we have since modified our approach, and in a consecutive series of 105 patients we have performed slow pathway RF ablation exclusively at medial or anterior locations, with the objective of prospectively examining the recurrence rate of AVNRT incurred with this approach.

METHODS AND RESULTS

The study included 40 men and 65 women, aged 42 +/- 18 years, having RF ablation for symptomatic AVNRT exclusively in anterior to the coronary sinus os locations. A combined anatomical and electrophysiological approach to slow pathway ablation was employed. This series of patients was compared with the previous series of 55 patients (historical group) with AVNRT undergoing RF ablation at both inferoposterior and anteromedial locations. The mean cycle length of the induced AVNRT was 329 +/- 48 ms. RF ablation was successful in all patients (100%). A mean of 7 +/- 6 lesions were applied. Persistent jump or echo beats were noted in 48 patients (46%). The procedure lasted for 2.1 +/- 1.0 h. Fluoroscopy time was 23 +/- 14 min. Procedures were complicated by heart block in two patients (1.9%). Over 26 +/- 19 months, there has been only one recurrence of AVNRT (1%). The historical group had similar age (37 +/- 18 years), gender (17 men/38 women), AVNRT cycle length (340 +/- 60 ms), number of RF lesions (9 +/- 6), or residual slow pathway conduction (42%), but longer fluoroscopy time (41 +/- 25 min) and procedure duration (4 +/- 1 h), and a significantly higher recurrence rate (seven patients/13%) (P=0.004) at a much shorter follow-up period of 12 +/- 8 months.

CONCLUSION

AVNRT recurrences are rare (1%) when slow pathway RF ablation is performed in medial or anterior locations at the tricuspid annulus, rather than in inferoposterior sites, whereby a higher (13%) recurrence rate has been previously noted.

Hyperprolactinaemia in patients with heart failure: clinical and immunogenetic correlations

BACKGROUND

Prolactin represents a stimulatory link between the neuroendocrine and immune systems, but its involvement in the neurohumoral adaptations to heart failure (HF) has not been explored.

METHODS

We prospectively studied 55 patients (45 males, 10 females, age 48 +/- 7 years) with NYHA Class II/III HF due either to dilated cardiomyopathy (CMP) (n = 33) or ischemic heart disease (IHD) (n = 22). Serum prolactin levels were determined by radioimmunoassay, soluble interleukin-2 receptor (sIL-2R) levels by enzyme-linked immunoassay and HLA-DQ genotyping with PCR. Left ventricular ejection fraction (LVEF) and end-diastolic diameter (LVEDd) were assessed echocardiographically.

RESULTS

Hyperprolactinaemia (17.3 +/- 4 ng mL-1 [Group I] vs. 4.64 +/- 2 ng mL-1 [Group II], P < 0.01) was found in 14 patients (8 with IHD, 6 with CMP). The distribution of HLA-DQB1 alleles was compared in the two groups and showed a significant increase in the frequency of *0301 (86% in Group I vs. 45% in Group II, P < 0.05). Histidine at position 30 of the HLA-DQB1 gene was found in 22% of Group II but in none of Group I patients. Furthermore, there was an inverse correlation between the presence of histidine at position 30 and the levels of serum prolactin. Both sIL-2R levels, a marker of T-cell activation, and concanavalin A-stimulated lymphocyte proliferation were lower in Group I patients (561 +/- 106 vs. 804 +/- 109 pg mL-1 and 20.8 +/- 4 vs. 37.3 +/- 5 cpmX103 [3H] thymidine, respectively). LVEF was significantly higher (32 +/- 5%) and LVEDd smaller (62.0 +/- 6 mm) in Group I compared to Group II (25 +/- 4% and 68.0 +/- 5 mm, respectively, P < 0.01) patients.

CONCLUSION

Hyperprolactinaemia presents in 25% of patients with HF and may reflect decreased activation of T-lymphocytes associated with relatively preserved LV systolic function which is under immune-genetic control at the HLA-DQ locus.