Nocturnal ventricular arrhythmias are associated with the severity of cardiovascular autonomic neuropathy in type 2 diabetes

BACKGROUND

Cardiovascular autonomic neuropathy (CAN) is a risk factor for arrhythmias and adverse cardiovascular events, but the relationship between CAN severity and nocturnal arrhythmias needs to be clarified. This study evaluated the association between nocturnal arrhythmias and CAN severity in patients with type 2 diabetes (T2D).

METHODS

In all, 219 T2D patients were recruited from January 2017 to May 2018. Subjects were classified into no CAN (NCAN), early CAN (ECAN), definite CAN (DCAN), or advanced CAN (ACAN) based on cardiovascular autonomic reflex tests (CARTs). A 24-hour electrocardiogram was recorded and daytime (0700-2300 hours) and night-time (2300-0700 hours) heartbeats were analyzed separately.

RESULTS

After adjusting for age, the incidence of ventricular arrhythmias increased with CAN severity at night-time (18.6%, 29.9%, 36.2%, and 60.0% in the NCAN, ECAN, DCAN, and ACAN groups, respectively; P_trend  = 0.034). Patients with nocturnal ventricular arrhythmias (NVAs) had higher CART scores (2.0 ± 1.0 vs 1.5 ± 0.9; P < 0.001) and lower heart rate variability (HRV) during deep breathing (9.5 ± 5.7 vs 11.6 ± 6.6 b. p. m; P = 0.021), HRV during the Valsalva maneuver (1.2 ± 0.1 vs 1.2 ± 0.2; P = 0.006), and postural blood pressure change (-8.8 ± 15.5 vs -4.1 ± 11.2 mmHg; P = 0.023). Multivariate regression analysis revealed that CAN stage (odds ratio 1.765; 95% confidence interval 1.184-2.632; P = 0.005) was independently associated with NVAs.

CONCLUSIONS

In T2D, CAN stage was independently associated with the presence of NVAs. Early detection, diagnosis, and treatment of CAN may help predict and prevent adverse cardiovascular events and cardiovascular mortality in diabetes.

Association between left ventricular diastolic function and right ventricular function and morphology in asymptomatic aortic stenosis

Background

Aortic stenosis (AS) is a progressive disease in which left ventricular (LV) diastolic dysfunction is common. However, the association between diastolic dysfunction and right ventricular (RV) loading conditions and function has not been investigated in asymptomatic AS patients.

Methods and findings

A total of 41 patients underwent right heart catheterization and simultaneous echocardiography at rest and during maximal supine exercise, stratified according to resting diastolic function. Cardiac chamber size and morphology was assessed using cardiac magnetic resonance imaging (cMRI). RV stroke work index, pulmonary artery (PA) compliance, PA elastance, PA pulsatility index, and right atrial pressure (RAP) were calculated at rest and maximal exercise. Ten patients (24%) had normal LV filling pattern, 20 patients (49%) had grade 1, and 11 patients (27%) had grade 2 diastolic dysfunction. Compared to patients with normal diastolic filling pattern, patients with diastolic dysfunction had lower RV end-diastolic volume (66 ± 11 ml/m² vs. 79 ± 15 ml/m², p = 0.02) and end-systolic volume (25 ± 7 ml/m² vs. 32 ± 9 ml/m², p = 0.04). An increase in mean RAP to ≥15 mmHg following exercise was not seen in patients with normal LV filling, compared to 4 patients (20%) with mild and 7 patients (63%) with moderate diastolic dysfunction (p = 0.003). PA pressure and PA elastance was increased in grade 2 diastolic dysfunction and correlated with RV volume and maximal oxygen consumption (r = -0.71, p < 0.001).

Conclusions

Moderate diastolic dysfunction is associated with increased RV afterload (elastance), which is compensated at rest, but is associated with increased RAP and inversely related to maximal oxygen consumption during maximal exercise.

Effects of AT1 receptor antagonism on interstitial and ultrastructural remodeling of heart in response to a hypercaloric diet

Palatable hypercaloric feeding has been associated with angiotensin-II type 1 receptor (AT1R) stimulation and cardiac remodeling. This study analyzed whether AT1R antagonism attenuates cardiac remodeling in rats subjected to a palatable hypercaloric diet. Male Wistar-Kyoto rats were subjected to a commercial standard rat chow (CD) or a palatable hypercaloric diet (HD) for 35 weeks and then allocated into four groups: CD, CL, HD, and HL; L groups received losartan in drinking water (30 mg/kg/day) for 5 weeks. Body weight, adiposity, and glycemia were evaluated. The cardiovascular study included echocardiography, and myocardial morphometric and ultrastructural evaluation. Myocardial collagen isoforms Type I and III were analyzed by Western blot. Both HD and HL had higher adiposity than their respective controls. Cardiomyocyte cross-sectional-area (CD 285 ± 49; HD 344 ± 91; CL 327 ± 49; HL 303 ± 49 μm2 ) and interstitial collagen fractional area were significantly higher in HD than CD and unchanged by losartan. HD showed marked ultrastructural alterations such as myofilament loss, and severe mitochondrial swelling. CL presented higher Type I collagen expression when compared to CD and HL groups. The ultrastructural changes and type I collagen expression were attenuated by losartan in HL. Losartan attenuates systolic dysfunction and ultrastructural abnormalities without changing myocardial interstitial remodeling in rats subjected to a palatable hypercaloric diet.

Sildenafil ameliorates right ventricular early molecular derangement during left ventricular pressure overload

Right ventricular (RV) dysfunction following left ventricular (LV) failure is associated with poor prognosis. RV remodeling is thought initiated by the increase in the afterload of RV due to secondary pulmonary hypertension (PH) to impaired LV function; however, RV molecular changes might occur in earlier stages of the disease. cGMP (cyclic guanosine monophosphate)-phosphodiesterase 5 (PDE5) inhibitors, widely used to treat PH through their pulmonary vasorelaxation properties, have shown direct cardiac benefits, but their impacts on the RV in LV diseases are not fully determined. Here we show that RV molecular alterations occur early in the absence of RV hemodynamic changes during LV pressure-overload and are ameliorated by PDE5 inhibition. Two-day moderate LV pressure-overload (transverse aortic constriction) neither altered RV pressure/ function nor RV weight in mice, while it induced only mild LV hypertrophy. Importantly, pathological molecular features were already induced in the RV free wall myocardium, including up-regulation of gene markers for hypertrophy and inflammation, and activation of extracellular signal-regulated kinase (ERK) and calcineurin. Concomitant PDE5 inhibition (sildenafil) prevented induction of such pathological genes and activation of ERK and calcineurin in the RV as well as in the LV. Importantly, dexamethasone also prevented these RV molecular changes, similarly to sildenafil treatment. These results suggest the contributory role of inflammation to the early pathological interventricular interaction between RV and LV. The current study provides the first evidence for the novel early molecular cross-talk between RV and LV, preceding RV hemodynamic changes in LV disease, and supports the therapeutic strategy of enhancing cGMP signaling pathway to treat heart diseases.

N-Acetylcysteine Prevents Low T3 Syndrome and Attenuates Cardiac Dysfunction in a Male Rat Model of Myocardial Infarction

Nonthyroidal illness syndrome (NTIS) affects patients with myocardial infarction (MI). Oxidative stress has been implicated as a causative factor of NTIS, and reversed via N-acetylcysteine (NAC). Male Wistar rats submitted to left anterior coronary artery occlusion received NAC or placebo. Decreases in triiodothyronine (T3) levels were noted in MI-placebo at 10 and 28 days post-MI, but not in MI-NAC. Groups exhibited similar infarct areas whereas MI-NAC exhibited higher ejection fraction than did MI-placebo. Left ventricular systolic and diastolic diameters were also preserved in MI-NAC, but not in MI-placebo. Ejection fraction was positively correlated with T3 levels. Oxidative balance was deranged only in MI-placebo animals. Increased type 3 iodothyronine deiodinase expression was detected in the cardiomyocytes of MI-placebo compared with normal heart tissue. NAC was shown to diminish type 3 iodothyronine deiodinase expression and activity in MI-NAC. These results show that restoring redox balance by NAC treatment prevents NTIS- related thyroid hormone derangement and preserves heart function in rats subjected to MI.

Aging and the cardiac collagen matrix: Novel mediators of fibrotic remodelling

Cardiovascular disease is a leading cause of death worldwide and there is a pressing need for new therapeutic strategies to treat such conditions. The risk of developing cardiovascular disease increases dramatically with age, yet the majority of experimental research is executed using young animals. The cardiac extracellular matrix (ECM), consisting predominantly of fibrillar collagen, preserves myocardial integrity, provides a means of force transmission and supports myocyte geometry. Disruptions to the finely balanced control of collagen synthesis, post-synthetic deposition, post-translational modification and degradation may have detrimental effects on myocardial functionality. It is now well established that the aged heart is characterized by fibrotic remodelling, but the mechanisms responsible for this are incompletely understood. Furthermore, studies using aged animal models suggest that interstitial remodelling with disease may be age-dependent. Thus with the identification of new therapeutic strategies targeting fibrotic remodelling, it may be necessary to consider age-dependent mechanisms. In this review, we discuss remodelling of the cardiac collagen matrix as a function of age, whilst highlighting potential novel mediators of age-dependent fibrotic pathways.

Cardiac myxoma originating from areas of ventricular akinesia

We present a case of large pedunculated myxoma (61×39 mm) in the left ventricular cavity with anterior-septal and anterior free wall akinesia. Angiographic study showed normal coronary arteries, but the clinical signs strongly suggested a previous myocardial infarction. We cannot exclude the possibility that the ventricular akinesia results from embolization of tumor fragments. For a time, cardiac myxomas were believed to arise from mural thrombi. In this case the presence of blood stasis or low-velocity blood flow related to wall motion abnormalities may have played a role in improving tumor growth.

Novel role for vinculin in ventricular myocyte mechanics and dysfunction

Vinculin (Vcl) plays a key structural role in ventricular myocytes that, when disrupted, can lead to contractile dysfunction and dilated cardiomyopathy. To investigate the role of Vcl in myocyte and myocardial function, cardiomyocyte-specific Vcl knockout mice (cVclKO) and littermate control wild-type mice were studied with transmission electron microscopy (TEM) and in vivo magnetic resonance imaging (MRI) tagging before the onset of global ventricular dysfunction. MRI revealed significantly decreased systolic strains transverse to the myofiber axis in vivo, but no changes along the muscle fibers or in fiber tension in papillary muscles from heterozygous global Vcl null mice. Myofilament lattice spacing from TEM was significantly greater in cVclKO versus wild-type hearts fixed in the unloaded state. AFM in Vcl heterozygous null mouse myocytes showed a significant decrease in membrane cortical stiffness. A multiscale computational model of ventricular mechanics incorporating cross-bridge geometry and lattice mechanics showed that increased transverse systolic stiffness due to increased lattice spacing may explain the systolic wall strains associated with Vcl deficiency, before the onset of ventricular dysfunction. Loss of cardiac myocyte Vcl may decrease systolic transverse strains in vivo by decreasing membrane cortical tension, which decreases transverse compression of the lattice thereby increasing interfilament spacing and stress transverse to the myofibers.

Quantification of diffuse myocardial fibrosis and its association with myocardial dysfunction in congenital heart disease

BACKGROUND

the etiology of ventricular dysfunction in adult congenital heart disease (ACHD) is not well understood. Diffuse fibrosis is a likely common final pathway and is quantifiable using MRI.

METHODS AND RESULTS

patients with ACHD (n=50) were studied with cardiac MRI to quantify systemic ventricular volume and function and diffuse fibrosis. The fibrosis index for a single midventricular plane of the systemic ventricle was quantified by measuring T1 values for blood pool and myocardium before and after administration of gadolinium (0.15 mmol/kg) and then adjusted for hematocrit. Results were compared to healthy volunteers (normal controls, n=14) and patients with acquired heart failure (positive controls, n=4). Patients studied (age, 37±12 years; female sex, 40%) included 11 with a systemic right ventricle (RV), 17 with tetralogy of Fallot, 10 with cyanosis, and 12 with other lesions. The fibrosis index was significantly elevated in patients with ACHD compared to normal controls (31.9±4.9% versus 24.8±2.0%; P=0.001). Values were highest in patients with a systemic RV (35.0±5.8%; P<0.001) and those who were cyanotic (33.7±5.6%; P<0.001). The fibrosis index correlated with end-diastolic volume index (r=0.60; P<0.001) and ventricular ejection fraction (r=-0.53; P<0.001) but not with age or oxygen saturation in patients who were cyanotic. Late gadolinium enhancement did not account for the differences seen.

CONCLUSIONS

patients with ACHD have evidence of diffuse, extracellular matrix remodeling similar to patients with acquired heart failure. The fibrosis index may facilitate studies on the mechanisms and treatment of myocardial fibrosis and heart failure in these patients.

Vulnerable windows define susceptibility to alternans and spatial discordance

Electrophysiological alternans is a beat-to-beat alternation of the action potential duration and/or Ca(2+) transient amplitude and is linked to ventricular arrhythmias. We investigated the significance of various rate parameters under different experimental conditions with respect to alternans incidence and the propensity for spiral wave formation. Voltage and Ca(2+) were optically mapped in monolayers of neonatal rat ventricular myocytes. Alternans did not occur at physiological temperature, but its incidence increased significantly at lowered temperatures. Pacing cycle length for spatially concordant alternans onset (PCL(C)), PCL for spatially discordant alternans onset (PCL(D)), and minimum cycle length for loss of 1:1 or 2:2 capture (MCL) also significantly increased with lower temperature but in a way such that the differences between PCL(C) and MCL and between PCL(D) and MCL widened. These results provided the rationale to identify the former difference as the alternans vulnerable window (AVW; in ms) and the latter difference as the discordant alternans vulnerable window (AVW(D); in ms). Computational simulations showed that interventions that widen AVW, including altered Ca(2+) cycling and enhanced K(+) currents, also promote alternans, regardless of whether PCL(C) or MCL increased or decreased. The simulation results were confirmed experimentally by addition of the ATP-sensitive K(+) channel agonist pinacidil. Mathematical analysis provided a theoretical basis linking the size of AVW to the incidence of alternans. Finally, experiments showed that the size of AVW(D) is related to the incidence of spatially discordant alternans and, additionally, to the incidence of spiral wave formation. In conclusion, vulnerable windows can be defined that are strongly correlated with alternans incidence, spatial discordance, and spiral wave formation.

[Usefulness of left atrial diametres and volumes for the evaluation of left ventricular diastolic function]

INTRODUCTION

The diastolic function of the left ventricle is a main point of the physiological adaptations of the cardiovascular system to the various situations.

AIM OF THE STUDY

Evaluation of left atrium diameter change during diastole and left atrial volume and their possible correlation with different left ventricular diastolic filling pattern.

MATERIAL AND METHODS

Ninety patients with echocardiographically determined diastolic dysfunction and eighty healthy volunteers were included in the study. We measured left atrium emptying fraction (LAEF), defined as ratio of end-diastolic left atrial diameter to end-systolic diameter and left atrial volume. Mitral flow pulsed wave velocities were recorded. E, A, E/A, deceleration time of early diastolic filling, isovolumetric relaxation time were measured. Pulmonary vein S, D and atrial reversal velocities and tissue Doppler imaging of E' and A' mitral anular velocities were obtained.

RESULTS

LAEF was found 0.6 +/- 0.4 (mean SE) in the control group, 0.81 +/- 0.04 in pseudonormal pattern (P < 0.05, control vs pseudonormal group), 0.89 +/- 0.01 in the greater A wave than E wave (P < 0.001, control vs restrictive pattern group), and 0.78 +/- 0.2 in the A > E group (P < 0.05, control vs A > E pattern group).

CONCLUSIONS

LAEF and atrial volume are a new and practical methods for the differentiation of the normal-pseudonormal mitral flow pattern, in particular in setting without new ultrasound technologies.

IL-6 loss causes ventricular dysfunction, fibrosis, reduced capillary density, and dramatically alters the cell populations of the developing and adult heart

Interleukin-6 (IL-6) is a pleiotropic cytokine responsible for many different processes including the regulation of cell growth, apoptosis, differentiation, and survival in various cell types and organs, including the heart. Recent studies have indicated that IL-6 is a critical component in the cell-cell communication between myocytes and cardiac fibroblasts. In this study, we examined the effects of IL-6 deficiency on the cardiac cell populations, cardiac function, and interactions between the cells of the heart, specifically cardiac fibroblasts and myocytes. To examine the effects of IL-6 loss on cardiac function, we used the IL-6(-/-) mouse. IL-6 deficiency caused severe cardiac dilatation, increased accumulation of interstitial collagen, and altered expression of the adhesion protein periostin. In addition, flow cytometric analyses demonstrated dramatic alterations in the cardiac cell populations of IL-6(-/-) mice compared with wild-type littermates. We observed a marked increase in the cardiac fibroblast population in IL-6(-/-) mice, whereas a concomitant decrease was observed in the other cardiac cell populations examined. Moreover, we observed increased cell proliferation and apoptosis in the developing IL-6(-/-) heart. Additionally, we observed a significant decrease in the capillary density of IL-6(-/-) hearts. To elucidate the role of IL-6 in the interactions between cardiac fibroblasts and myocytes, we performed in vitro studies and demonstrated that IL-6 deficiency attenuated the activation of the STAT3 pathway and VEGF production. Taken together, these data demonstrate that a loss of IL-6 causes cardiac dysfunction by shifting the cardiac cell populations, altering the extracellular matrix, and disrupting critical cell-cell interactions.

[Idiopathic and secondary pulmonary hypertension]

In the available literature, there are single papers on the association of the values of external respiratory function and the EchoCG sings of pulmonary hypertension with the morphological parameters of pulmonary arterial branches in idiopathic pulmonary hypertension (IPH) and secondary pulmonary hypertension (SPH). The present investigation comprised a comprehensive study of life-time functional changes in the cardiopulmonary system and postmortem morphometric changes in the heart and pulmonary vessels in idiopathic pulmonary fibrosis (IPF)-induced SPH and IPH. The investigation has indicated that PPH and SPH are characterized by the same-type rearrangement of pulmonary arterial branches as intimal hyperplasia and medial hypertrophy; however, IPH, as compared with SPH, induces a more significant cor pulmonale. The magnitude of right and left ventricular dysfunction corresponds to the degree of pulmonary hypertension (PH) and cor pulmonale. In IPF, the decreases in tidal volumes and pulmonary diffusion capacity favor PH progression.

Active bacterial myocarditis: a case report and review of the literature

Bacterial myocarditis (BM) is an uncommon cause of infectious myocarditis. BM is usually seen in the context of overwhelming sepsis or as part of a specific bacterial syndrome. The definitive diagnosis of bacterial myocarditis requires biopsy or morphologically proven active myocarditis with evidence of bacterial invasion or positive tissue cultures. The management of bacterial myocarditis consists of aggressive and early antibiotic or anti-toxin treatment, appropriate hemodynamic support, and treatment of arrhythmias or mechanical complications. We present a case of acute Listeria monocytogenes myocarditis in an immunocompetent patient and highlight the challenges in the diagnosis and treatment of bacterial myocarditis.

Distinct cardiodynamic and molecular characteristics during early and late stages of sepsis-induced myocardial dysfunction

We hypothesized that progressive decline in myocardial performance would correlate with upregulation of markers for apoptotic mechanisms following increased duration of polymicrobial sepsis in the rat. Male Sprague-Dawley rats (350-400 g) were randomized into sham, 1-, 3- and 7-day sepsis groups. Each septic rat received 200 mg/kg cecal inoculum intraperitoneally (i.p). The post-mortem analysis showed a severely inflamed peritoneum with the presence of pus in all septic animals that was directly proportional to the duration of sepsis. We observed 10, 33 and 42% mortality in the 1-, 3- and 7-day sepsis groups, respectively. Septic animals at 3 and 7 days exhibited an increased wet lung/total body weight and heart weight/total body weight. A significant increase in total cardiac troponin I (cTnI) and C Reactive Protein (CRP) and endothelin-1 (ET-1) was also observed with an increased duration of sepsis. Myocardial ET-1 concentration in the 7-day post-sepsis group was significantly elevated compared to the sham and 1-day post-sepsis groups. Sepsis also produced a significant decrease in the mean arterial pressure in the 7-day post-sepsis group and tachycardia in the 1-, 3-, and 7-day post-sepsis groups compared to the sham group. A significant prolongation of the left ventricular isovolumic relaxation rate constant, tau, and left ventricular end-diastolic pressure in the 1-, 3- and 7-day post-sepsis groups compared to the sham group was observed. In addition, a significant decrease in the rates of left ventricular relaxation (-dP/dt) and contraction (+dP/dt) in the 3- and 7-day post-sepsis groups compared to the sham and 1-day post-sepsis group was observed. Sepsis produced a significant upregulation in the expression of myocardial TRADD, cytosolic active caspase-3, the Bax/Bcl(2) ratio, and the mitochondrial release of cytochrome C in the 3- and 7-day post-sepsis groups. We observed a progressive increase in the number of TUNEL positive nuclei, cytosolic caspase-3 activation and co-localization of PARP in the nuclei at 1, 3 and 7 days post-sepsis. These data suggest that the progression of sepsis from 1 day to 3-7 days produce distinct cardiodynamic characteristics with a more profound effect during later stages. The sepsis-induced decline in myocardial performance correlates with the induction of myocardial apoptosis.

Cardiomyocyte-restricted over-expression of C-type natriuretic peptide prevents cardiac hypertrophy induced by myocardial infarction in mice

OBJECTIVE

Infused C-type natriuretic peptide (CNP) was recently found to play a cardioprotective role in preventing myocardial ischaemia/reperfusion (I/R) injury and improving cardiac remodelling after myocardial infarction (MI) in rats. Our study aimed to investigate the effect of cardiomyocyte-specific CNP over-expression on I/R injury and MI in transgenic mice.

METHODS AND RESULTS

We generated transgenic (TG) mice over-expressing CNP in cardiomyocytes. Elevated CNP expression on RNA and protein levels was demonstrated by RNase-protection assay and radioimmunoassay. Male TG mice and age-matched wild-type (WT) littermates were subjected to 1-hour global myocardial ischaemia and 23 h of reperfusion or permanent ligation of the coronary artery for 3 weeks. Infarct size did not differ between the WT and TG groups in mice subjected to I/R. In mice that underwent permanent ligation of coronary arteries, both left and right ventricular hypertrophy were prevented by CNP over-expression 3 weeks post-MI. Histological analysis revealed less necrosis, muscular degeneration and inflammation in infarcted TG mice. Impairment of cardiac function was less pronounced in transgenic animals than in the wild-type controls.

CONCLUSIONS

Over-expression of CNP in cardiomyocytes does not affect I/R-induced infarct size but prevents cardiac hypertrophy induced by MI. Therefore, CNP may represent a potent therapeutic target for the treatment of patients with cardiac hypertrophy induced by myocardial infarction or other aetiology.

Cardiac matrix metalloproteinase-2 expression independently induces marked ventricular remodeling and systolic dysfunction

Although enhanced cardiac matrix metalloproteinase (MMP)-2 synthesis has been associated with ventricular remodeling and failure, whether MMP-2 expression is a direct mediator of this process is unknown. We generated transgenic mice expressing active MMP-2 driven by the α-myosin heavy chain promoter. At 4 mo MMP-2 transgenic hearts demonstrated expression of the MMP-2 transgene, myocyte hypertrophy, breakdown of Z-band registration, lysis of myofilaments, disruption of sarcomere and mitochondrial architecture, and cardiac fibroblast proliferation. Hearts from 8-mo-old transgenic mice displayed extensive myocyte disorganization and dropout with replacement fibrosis and perivascular fibrosis. Older transgenic mice also exhibited a massive increase in cardiac MMP-2 expression, representing recruitment of endogenous MMP-2 synthesis, with associated expression of MMP-9 and membrane type 1 MMP. Increases in diastolic [control (C) 33 ± 3 vs. MMP 51 ± 12 μl; P = 0.003] and systolic (C 7 ± 2 vs. MMP 28 ± 14 μl; P = 0.003) left ventricular (LV) volumes and relatively preserved stroke volume (C 26 ± 4 vs. MMP 23 ± 3 μl; P = 0.16) resulted in markedly decreased LV ejection fraction (C 78 ± 7% vs. MMP 48 ± 16%; P = 0.0006). Markedly impaired systolic function in the MMP transgenic mice was demonstrated in the reduced preload-adjusted maximal power (C 240 ± 84 vs. MMP 78 ± 49 mW/μl2; P = 0.0003) and decreased end-systolic pressure-volume relation (C 7.5 ± 1.5 vs. MMP 4.7 ± 2.0; P = 0.016). Expression of active MMP-2 is sufficient to induce severe ventricular remodeling and systolic dysfunction in the absence of superimposed injury.

Blood pressure variability is more important than blood pressure level in determination of end-organ damage in rats

OBJECTIVE

This study was designed to determine how important a novel risk factor of elevated blood pressure variability (BPV) is in the determination of end-organ damage by comparison with the classic risk factor of a high blood pressure (BP) level.

METHODS AND RESULTS

The effects of haemodynamics on cardiovascular morphology were evaluated by univariate and multivariate regression analysis in two different rat models with an enlarged distribution of haemodynamics. In male sham-operated and sinoaortic-denervated Wistar-Kyoto rats and spontaneously hypertensive rats (n = 34), BPV was more important than BP in cardiac and renal damage and aortic hypertrophy. BPV and BP had independent effects, explaining 59.4% of the variation in damage to these organs. In male (n = 44) and female (n = 46) F1 hybrids of Sprague-Dawley rats and spontaneously hypertensive rats, the greater importance of BPV than BP was further demonstrated in left ventricular hypertrophy, glomerular damage and aortic hypertrophy. The phenomenon was more evident in females than males for cardiovascular hypertrophy. BPV and BP or BPV alone had independent effects, explaining 46.9% (male) or 37.5% (female) of the variation in damage to these organs.

CONCLUSION

BPV is a more critical determinant than BP level for cardiac damage, renal lesions and aortic hypertrophy in rats, strongly suggesting the significance of BPV control for the protection of these organs.

Left atrial volume in end-stage renal disease: a prospective cohort study

BACKGROUND

End-stage renal disease (ESRD) is a high-risk condition and left ventricular hypertrophy (LVH) is the strongest risk factor in this population.

OBJECTIVE AND METHODS

Since the prognostic value of left atrial (LA) size in ESRD is still unknown, we performed a prospective cohort study aimed at testing the prognostic value of LA volume in a cohort of 249 ESRD patients.

RESULTS

Both un-indexed and indexed LA volume (LAV) was significantly higher in dialysis patients than in healthy subjects (P < 0.001). On multivariate analysis only left ventricular mass index (LVMI), LV ejection fraction (LVEF), ratio of early (E) to late atrial (A) mitral Doppler peak flow velocity (E/A ratio) and antihypertensive treatment maintained an independent association with LAV. During the follow-up 113 patients died. LAV added significant prognostic power to a multivariate Cox model of all-cause death and the model based on height provided the best data fit. Notably, this index maintained an independent predictive value for death (P = 0.03) also when LVMI and LVEF were jointly forced into the Cox's model. Neither crude nor body surface area (BSA)-adjusted LAV had an independent association with death when tested in the Cox model including LVMI and LVEF.

CONCLUSIONS

In patients with ESRD, LAV indexed for height displays prognostic value beyond and above that provided by LV mass and function.

Cardiomyopathy in motor neuron diseases

OBJECTIVE

Myocardial involvement in motor neuron diseases (MND) is an uncommon feature. In amyotrophic lateral sclerosis (ALS) abnormalities of the autonomic nervous system affecting cardiac function have been described, for the hereditary spastic paraplegias (HSP) comparable manifestations are unknown. This study observed ALS and HSP patients with coexisting cardiomyopathy without major cardial risk factors.

METHODS

Four patients with definite ALS and two pHSP patients. In all patients detailed clinical, cardiological, electrophysiological and laboratory data were analysed. In two ALS patients skeletal muscle biopsy was performed.

RESULTS

In all investigated MND patients cardiomyopathy was present. Beside hyperlipoproteinaemia and mild hypertension in one case, none of the patients showed major cardiovascular risk factors. There was no evidence for a secondary cause of cardiomyopathy like coronary heart disease, myocarditis, or mitochondrial damage mimicking MND.

CONCLUSION

This report could not conclude that the occurrence of cardiomyopathy is rare logically. Although an underlying pathophysiological cause was not obvious, it is proposed that in all MND patients a routine cardiological evaluation should be performed.

Hypocalcemic Heart Failure in Thalassemic Patients

Hypocalcemic cardiomyopathy in primary or secondary hypoparathyroidism is usually refractory to conventional treatment of cardiac failure. We report the case of a thalassemic patient with severe cardiac failure that might have been attributed to several factors, such as hemosiderosis, hypomagnesemia, and hypocalcemia, refractory to conventional cardiac therapy. Cardiac echocardiography showed impaired biventricular performance, and laboratory analyses revealed hypoparathyroidism due to hemosiderosis. When concomitant treatment of heart failure and calcium supplementation was initiated, correction of hypocalcemia resulted in clinical and laboratory improvement, providing strong evidence in support of our hypothesis about hypocalcemic myocardiopathy.

Blockade of NF-kappaB improves cardiac function and survival after myocardial infarction

NF-kappaB is a key transcription factor that regulates inflammatory processes. In the present study, we tested the hypothesis that blockade of NF-kappaB ameliorates cardiac remodeling and failure after myocardial infarction (MI). Knockout mice with targeted disruption of the p50 subunit of NF-kappaB (KO) were used to block the activation of NF-kappaB. MI was induced by ligation of the left coronary artery in male KO and age-matched wild-type (WT) mice. NF-kappaB was activated in noninfarct as well as infarct myocardium in WT+MI mice, while the activity was completely abolished in KO mice. Blockade of NF-kappaB significantly reduced early ventricular rupture after MI and improved survival by ameliorating congestive heart failure. Echocardiographic and pressure measurements revealed that left ventricular fractional shortening and maximum rate of rise of left ventricular pressure were significantly increased and end-diastolic pressure was significantly decreased in KO+MI mice compared with WT+MI mice. Histological analysis demonstrated significant suppression of myocyte hypertrophy as well as interstitial fibrosis in the noninfarct myocardium of KO+MI mice. Blockade of NF-kappaB did not ameliorate expression of proinflammatory cytokines in infarct or noninfarct myocardium. In contrast, phosphorylation of c-Jun NH2-terminal kinase was almost completely abolished in KO+MI mice. The present study demonstrates that targeted disruption of the p50 subunit of NF-kappaB reduces ventricular rupture as well as improves cardiac function and survival after MI. Blockade of NF-kappaB might be a new therapeutic strategy to attenuate cardiac remodeling and failure after MI.

Ventricular fibrosis suggested by cardiovascular magnetic resonance in adults with repaired tetralogy of fallot and its relationship to adverse markers of clinical outcome

BACKGROUND

Late morbidity and mortality remain problematic after repair of tetralogy of Fallot (TOF). We hypothesized that fibrosis detected by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) would be present in adults with repaired TOF and would be related to adverse markers of outcome.

METHOD AND RESULTS

LGE was scored in the right and left ventricles (RV and LV) of 92 adult patients who had undergone TOF repair. RV LGE was seen in all patients at surgical sites located in the outflow tract (99%) or the site of ventricular septal defect patching (98%) and in the inferior RV insertion point (79%) and trabeculated myocardium (24%). LV LGE (53%) was located at the apex consistent with apical vent insertion (49%), in the inferior or lateral wall consistent with infarction (5%), or in other areas (8%). Patients with supramedian RV LGE score were older (38 versus 27 years, P<0.001) and more symptomatic (38% versus 8% in New York Heart Association class II or greater, P=0.001), had increased levels of atrial natriuretic peptide (7.3 versus 4.9 pmol/L, P=0.041), and had a trend to higher brain natriuretic peptide (12.3 versus 7.2 pmol/L, P=0.086), exercise intolerance (maximum VO2 24 versus 28 mL.min(-1).kg(-1), P=0.021), RV dysfunction (RV end-systolic volume 61 versus 55 mL/m2, P=0.018; RV ejection fraction 50% versus 56%, P=0.007), and clinical arrhythmia (26% versus 10%, P=0.039). Non-apical vent LV LGE also correlated with markers of adverse outcome. In a multivariate model, RV LGE remained a predictor of arrhythmia.

CONCLUSIONS

RV and LV LGE were common after TOF repair and were related to adverse clinical markers, including ventricular dysfunction, exercise intolerance, and neurohormonal activation. Furthermore, RV LGE was significantly associated with clinical arrhythmia.

Cardiac Involvement in Mulibrey Nanism: Characterization with Magnetic Resonance Imaging

Mulibrey nanism (MUL) is an autosomal recessive disorder that is enriched in the Finnish population. Variable degrees of pericardial and myocardial involvement can lead to heart failure and premature death. The purpose of this study was using magnetic resonance imaging (MRI) to assess structural and functional abnormalities of the MUL cardiopathy in all four cardiac chambers as well as in the pericardium. Thirty-one patients with MUL (mean age 27, range 15-50 years) and 16 controls (mean age 31, range 19-45 years) were examined with a Siemens Vision 1.5-T imager. Ten patients had undergone pericardiectomies to relieve symptoms of constrictive pericarditis. In surgery performed 0.5-25 years before MRI, the removed pericardium was found to be thickened and consisting of scarlike fibrosis. Turbo spin echo images were obtained for assessment of pericardial thickness, and breath hold left ventricular (LV) short axis and four-chamber cine images were obtained for the volumetric data. In MRI, pericardial thickness was normal (under 3.4 mm) in all patients with MUL. In the 10 pericardiectomized patients, the remnants of the pericardium were of normal thickness as well. The LV septum (p = 0.01) and posterior wall (p<0.001) were hypertrophied and end-diastolic volumes of both ventricles (p<0.05) were reduced in all patients. The LV systolic function was preserved. The volume chance during the first third of diastole (p = 0.030), the absolute peak filling rate (p = 0.047), and the time to peak rate of LV diastolic filling (p = 0.030) indicated restrictive LV diastolic filling. The right ventricular ejection fraction and contraction of both atria were reduced.

Factors associated with impaired clinical status in long-term survivors of tetralogy of Fallot repair evaluated by magnetic resonance imaging

OBJECTIVES

The purpose of this study was to identify independent factors associated with impaired clinical status in late survivors of tetralogy of Fallot (TOF) repair.

BACKGROUND

Repair of TOF often results in chronic pulmonary regurgitation (PR) and right ventricular (RV) dilation, which have been linked to late morbidity and mortality. However, determinants of clinical status late after TOF repair have not been fully characterized.

METHODS

The clinical and laboratory data of 100 consecutive patients with repaired TOF (median 21 years after repair) who completed a cardiac magnetic resonance imaging protocol were analyzed. Impaired clinical status was defined as New York Heart Association (NYHA) functional class > or =III.

RESULTS

Of the patients, 88 were in NYHA functional class I or II and 12 were in NYHA functional class III. The degree of PR and indexed RV end-diastolic volume were not associated with impaired clinical status. By multivariate analysis, a lower left ventricular (LV) ejection fraction (EF) (odds ratio [OR] = 3.88 for 10% decrease, p = 0.002) and older age at TOF repair (OR = 1.70 for 5-year increase, p = 0.013) were the strongest independent factors associated with impaired clinical status. Among RV variables, a lower RV EF was the strongest independent factors associated with poor clinical status (OR = 2.41 for 10% decrease, p = 0.01). The LV EF correlated with RV EF (r = 0.58, p < 0.001).

CONCLUSIONS

Moderate or severe LV or RV systolic dysfunction, but not PR fraction or RV diastolic dimensions, is independently associated with impaired clinical status in long-term survivors of TOF repair. The close relationship between LV EF and RV EF suggests unfavorable ventricular-ventricular interaction.

MR imaging of acquired fetal brain disorders

INTRODUCTION

Acquired fetal brain disorders represent the third indication of fetal brain MRI, after ventricular dilatation and malformations of the central nervous system.

DISCUSSION

MRI is an adequate imaging technique for evaluating fetal brain damage. Fetal brain response to brain injury may be acute, chronic or a combination of acute and chronic. An acute response is not as common in the fetal brain as in the postnatal period. A chronic response or the combination of chronic and acute response are the most common responses of the fetal brain to injury, whatever its origin. MRI also provides the natural history of acquired fetal brain lesions with regard to the stage of development.

Chronic treatment with carvedilol improves ventricular function and reduces myocyte apoptosis in an animal model of heart failure

BACKGROUND

Beta blocker treatment has emerged as an effective treatment modality for heart failure. Interestingly, beta-blockers can activate both pro-apoptotic and anti-apoptotic pathways. Nevertheless, the mechanism for improved cardiac function seen with beta-blocker treatment remains largely unknown. Carvedilol is a non-selective beta-blocker with alpha-receptor blockade and antioxidant properties. We therefore studied the impact of the effects of carvedilol in an animal model of end-stage heart failure.

RESULTS

To test whether chronic treatment with beta-blockade decreases apoptosis, we treated myopathic turkeys with two dosages of carvedilol, 1 mg/kg (DCM1) and 20 mg/kg (DCM20), for four weeks and compared them to non-treated DCM animals (DCM0) and to control turkeys (CON). Echocardiographic measurements showed that non-treated DCM animals had a significantly lower fractional shortening (FS) when compared to CON (68.73 +/- 1.37 vs. 18.76 +/- 0.59%, p < 0.001). Both doses of carvedilol significantly improved FS (33.83 +/- 10.11 and 27.73 +/- 6.18% vs. 18.76 +/- 0.59% for untreated DCM, p < 0.001). DCM left ventricles were characterized by a higher percentage of apoptotic nuclei when compared to CON (5.64 +/- 0.49 vs. 1.72 +/- 0.12%, respectively p < 0.001). Both doses of carvedilol significantly reduced the number of apoptotic nuclei (2.32 +/- 0.23% and 2.36 +/-6% 1 mg and 20 mg/kg respectively).

CONCLUSIONS

Carvedilol improves ventricular function. Furthermore, treatment with carvedilol decreased the incidence of apoptosis in cardiac myocytes from failing hearts at both doses. These data suggest that the inhibition of apoptosis with carvedilol may lead to improvement in ventricular function and may underlie a beneficial effect of beta-blockade independent of heart rate lowering effects.

Correlation of Connexin43 Expression and Late Ventricular Potentials in Nonischemic Dilated Cardiomyopathy

Nonischemic dilated cardiomyopathy (DCM) is associated with a high risk of sudden cardiac death. Signal-averaged electrocardiography (SAECG) is a useful clinical tool for detecting late ventricular potentials (LP). Gap junction alterations have recently been shown to be involved in the pathogenesis of ventricular arrhythmias in DCM; however, the possible relationship between gap junctional connexin43 (C x 43) expression and SAECG has not yet been evaluated. In the present study 16 patients (47+/-13 years) with DCM who had undergone SAECG testing were evaluated. In each patient, the expression of C x 43 proteins was qualitatively and quantitatively determined using immunoconfocal microscopy and right ventricular biopsy specimens. The level of expression of C x 43 protein was defined as the proportion of tissue area occupied by C x 43 (percent tissue area) in each test area. The abundance and distribution of the C x 43 signal was assessed in relation to LP. Late ventricular potentials were positive in 5 patients (LP (+) group) and negative in 11 patients (LP (-) group). The incidence of sustained ventricular tachycardia in the LP (+) group was higher than that in the LP (-) group (80% vs 18%, p=0.04). The percent tissue area of C x 43 in the LP (+) group was significantly lower than that in the LP (-) group (p=0.02). Furthermore, C x 43 protein in the LP (+) group was distributed more heterogeneously than that in the LP (-) group (p=0.001). The heterogeneous expression of C x 43 protein may contribute to impaired ventricular conduction, which may be related to the LP detected on SAECG.

Exercise MR imaging in the assessment of pulmonary regurgitation and biventricular function in patients after tetralogy of fallot repair

PURPOSE

To assess the responses of pulmonary regurgitation (PR) and biventricular function to submaximal exercise by using a magnetic resonance (MR) imaging exercise protocol with young adult patients who underwent tetralogy of Fallot repair at a young age.

MATERIALS AND METHODS

Fifteen patients with corrected tetralogy of Fallot (mean age, 17.5 years +/- 2.5 [SD]) underwent MR imaging at rest and during exercise for the evaluation of PR and biventricular function. Results were compared with findings from 16 control subjects (mean age, 17.5 years +/- 2.3). Mean age at tetralogy of Fallot repair was 2.1 years +/- 1.6, and mean follow-up time after repair was 15.4 years +/- 2.6. Exercise level at MR imaging was calculated individually and corresponded to 60% of peak oxygen uptake. The parameters of cardiac function obtained at rest and during exercise were compared by using a paired t test. An unpaired t test was used to compare parameters of cardiac function between patients and control subjects.

RESULTS

PR decreased during exercise (from 27 mL/m(2) +/- 17 to 23 mL/m(2) +/- 15; P =.012). At rest, right ventricular (RV) ejection fraction was normal (>47%) in 80% of patients. RV response to exercise in the patient group was abnormal compared with response in the control group, as demonstrated by an increase in RV end-diastolic volume index (132 mL/m(2) +/- 36 to 137 mL/m(2) +/- 38; P =.041) and no significant change in end-systolic volume index or ejection fraction. In only one patient, RV ejection fraction increased by more than 5%. Left ventricular response was not different between patients and control subjects.

CONCLUSION

MR imaging is well suited to assess cardiac response to exercise, and findings revealed a decrease in PR and an abnormal RV response to exercise in patients with corrected tetralogy of Fallot.

Contribution of cardiac muscle cell disorganization to the clinical features of hypertrophic cardiomyopathy

Heart failure rarely develops in the setting of hypertrophic cardiomyopathy (HCM). Because of this, cardiac muscle cell disorganization (CD), which is a histologic characteristic of HCM, is not believed to be responsible for the development of systolic dysfunction. The aim of the present study was to clarify whether CD can cause systolic dysfunction and ventricular dilation in patients with HCM. Sixteen hearts from patients with HCM obtained at autopsy were divided into two groups: group A (n = 11), without biventricular dilation, and group B (n = 5), with dilation. Specimens consisting of transverse and longitudinal tissue sections of the ventricles were prepared, and the extent of CD and interstitial fibrosis was quantified, using light microscopy. None of the patients in group A had had chronic congestive heart failure, while all of the patients in group B had died of congestive heart failure. In group B, CD was not limited to the interventricular septum. Rather, diffuse CD was observed in both ventricular free walls. The extent of CD was significantly greater in group B than in group A, while the degree of interstitial fibrosis was similar in the two groups (13.6% in group A vs 14.6% in group B). These results suggest that CD may be responsible for systolic dysfunction and ventricular dilation.

Oxidative stress-mediated cardiac cell death is a major determinant of ventricular dysfunction and failure in dog dilated cardiomyopathy

Cell death has been questioned as a mechanism of ventricular failure. In this report, we tested the hypothesis that apoptotic death of myocytes, endothelial cells, and fibroblasts is implicated in the development of the dilated myopathy induced by ventricular pacing. Accumulation of reactive oxygen products such as nitrotyrosine, potentiation of the oxidative stress response by p66(shc) expression, formation of p53 fragments, release of cytochrome c, and caspase activation were examined to establish whether these events were coupled with apoptotic cell death in the paced dog heart. Myocyte, endothelial cell, and fibroblast apoptosis was detected before indices of severe impairment of cardiac function became apparent. Cell death increased with the duration of pacing, and myocyte death exceeded endothelial cell and fibroblast death throughout. Nitrotyrosine formation and p66(shc) levels progressively increased with pacing and were associated with cell apoptosis. Similarly, p50 (DeltaN) fragments augmented paralleling the degree of cell death in the failing heart. Moreover, cytochrome c release and activation of caspase-9 and -3 increased from 1 to 4 weeks of pacing. In conclusion, cardiac cell death precedes ventricular decompensation and correlates with the time-dependent deterioration of function in this model. Oxidative stress may be critical for activation of apoptosis in the overloaded heart.

Endothelin receptor blockade reduces ventricular dysfunction and injury after reoxygenation

BACKGROUND

Reoxygenation of hypoxic myocardium during repair of congenital heart defects results in poor ventricular function and cellular injury. Endothelin-1 (ET-1), a potent vasoconstrictor that increases during hypoxia, may suppress myocardial function and activate leukocytes. The objective was to determine whether administration of an endothelin receptor antagonist could improve ventricular function and decrease cardiac injury after hypoxia and reoxygenation.

METHODS

Fourteen piglets underwent 90 minutes of ventilator hypoxia, 1 hour of reoxygenation on cardiopulmonary bypass, and 2 hours of recovery (controls). Nine additional animals received an infusion of Bosentan, an ET(A/B) receptor antagonist, (5 mg/kg per hour) during hypoxia and reoxygenation.

RESULTS

Right and left ventricular dP/dt in controls decreased to 78% and 52% of baseline, respectively, after recovery (p < 0.05). In contrast, Bosentan-treated animals had complete preservation of RV dP/dt and less depression of LV dP/dt. Bosentan reduced the hypoxia and reoxygenation-induced elevation of ET-1 and iNOS mRNA at the end of recovery (p < 0.05). Bosentan-treated animals had diminished myocardial myeloperoxidase activity and lipid peroxidation compared with controls (p < 0.05). Myocardial apoptotic index, elevated by hypoxia and reoxygenation, was lower in the Bosentan-treated animals (p < 0.05).

CONCLUSIONS

Endothelin-1 receptor antagonism improved functional recovery and decreased leukocyte-mediated injury after reoxygenation. The reduction in cardiac cell death might also improve long-term outcome after reoxygenation injury.

Heart graft monitoring by the ventricular evoked response

Monitoring of the negative slew rate of the evoked T wave has been proposed as a noninvasive diagnostic tool to follow heart transplant recipients. The clinical contribution of this measurement on telemetrically recorded, paced unipolar ventricular electrograms was evaluated in the detection of grade 3 acute allograft rejection. Thirteen patients undergoing heart transplantation received a DDD pacemaker connected to two epimyocardial leads. Electrograms were recorded and digitized after each endomyocardial biopsy (EMB). The maximum slew rate of the descending slope of the repolarization phase (RSP) was extracted and normalized. A 20% downward shift of RSP from the reference value was considered abnormal. Results of signal processing were blinded during the first 6 months. Eleven patients completed the 6 months blinded period and two patients died. A total of 101 EMB were graded according to the International Society for Heart and Lung Transplantation classification. Grade 3 was assigned to 9 EMB. A significant difference was found between RSP values measured during grade 3 rejection episodes and other RSP values (P < 0.001). A diagnostic model consisting of a single threshold test confirmed the ability of RSP to predict significant signs of rejection on EMB (P < 0.0001). The sensitivity of RSP in detecting grade 3 rejections was 100%, specificity was 81%, negative predictive value 100%, and positive predictive value 35%. The use of RSP as a noninvasive monitoring tool to pose the indication for a biopsy would avoid 73% of EMB. Monitoring of transplanted hearts based on the analysis of the ventricular evoked response is promising and may markedly reduce the number of EMB.

'Tako-Tsubo' transient ventricular dysfunction: a case report

During admission for investigation of dysphagia, an 82-year-old woman suddenly complained of dyspnea, which was followed by cardiogenic shock. Her symptoms, electrocardiogram, echocardiogram and laboratory data were compatible with an extensive acute anterior myocardial infarction. Emergency cardiac catheterization showed no atheromatous narrowing in any coronary artery. However, the contractions of the left and right ventricles were diffusely and severely impaired, except for some hyperkinesis of the basal area. The asynergy, as well as the abnormalities on the ECG, improved almost to normal by the 35th hospital day. An endomyocardial biopsy from the right ventricle during the acute phase showed atypical myocardial damage with proliferation of fine collagen fibers and small round-cell infiltration including polymorphologic leukocytes. This type of transient cardiac disorder has recently been described in Japan, and is called 'Tako-tsubo cardiomyopathy' because of the characteristic appearance of the left ventricular asynergy. In the present case, ventricular asynergy was not limited to the left ventricle, but was also present in the right ventricle.

Transgenic rat hearts expressing a human cardiac troponin T deletion reveal diastolic dysfunction and ventricular arrhythmias

OBJECTIVE

Familial hypertrophic cardiomyopathy (FHC) due to mutations of cardiac troponin T (cTnT) is associated with a high frequency of sudden death even in the absence of cardiac hypertrophy. To investigate the causal relationship of cTnT mutations and this particular phenotype, we sought to establish a transgenic rat model for the disease.

METHODS

Transgenic rats were generated expressing human wild-type cTnT or two truncated cTnT molecules (del ex16, del ex15/16), resulting from an intron 15 splice donor site mutation previously observed in FHC patients. Transgenic rat hearts were characterized by histology, immunohistochemistry and in the 'working heart'.

RESULTS

Human wild-type and del ex16 cTnT were stably expressed and incorporated into the sarcomere of transgenic cardiomyocytes. Del ex16 transgenic rats revealed a lower level of expression (4-5%) than human wt cTnT animals (25-40%). In the 'working heart' model del ex16 hearts exhibited significant systolic and diastolic dysfunction without cardiac hypertrophy. In contrast, human wt cTnT hearts showed improved contractile performance and moderate myocardial hypertrophy. After 6 months of daily physical exercise one del ex16 rat died suddenly and three out of five del ex16 hearts revealed ventricular tachycardia/fibrillation. No arrhythmia was observed in human wt cTnT expressors. Myofibrillar disarray was present in del ex16 hearts after training but not in human wild-type cTnT rats or non-transgenic controls.

CONCLUSION

A human cTnT deletion overexpressed in transgenic rats exerts a dominant-negative effect and mimics the phenotype of FHC with diastolic dysfunction and arrhythmias. By contrast, human cTnT wild-type animals reveal a gain of function and cardiac hypertrophy without arrhythmias.

Symptomatic systolic ventricular failure

Over the past 20 to 30 years there have been significant advances in the management of heart failure related to improved understanding of pathophysiology, better methods of assessment, and improved drug treatments. The aims of treatment have broadened, with increased emphasis on earlier intervention. Clinical research activity in this area has been considerable, increasingly allowing an evidence-based approach to management. Most earlier trials of treatment were relatively short-term, small-group studies with various clinical end points, including severity of symptoms, exercise performance, and left ventricular function assessment; however, increasingly a higher standard of evidence has been required, including a provision of reliable, large-scale mortality trial data. This has been further encouraged, if not mandated, by the relatively recent appreciation that some agents may demonstrate dissociation of treatment effects, possibly dose related, with improved short-term outcomes but adverse effects on survival with prolonged treatment. The general principles of management of congestive heart failure encompass patient evaluation and confirmation of the diagnosis, consideration, and correction of underlying remediable causes and precipitating factors, pharmacological treatment, patient education and counseling, and planned follow-up, as summarized in recently published guidelines. This review focuses primarily on the available randomized controlled clinical trial evidence related to the pharmacological treatment of the clinical congestive heart failure syndrome. Other aspects of management, such as patient education, counseling, and planned follow-up, should be regarded as complementary to pharmacological treatment and important to ensure compliance and optimal long-term outcomes.

Global biventricular dysfunction in patients with asymptomatic coronary artery disease may be caused by myocarditis

BACKGROUND

The causal role of asymptomatic critical coronary artery obstruction in patients presenting with severe global biventricular dysfunction but no evidence of myocardial infarction is uncertain.

METHODS AND RESULTS

Among 291 patients aged >40 years undergoing a noninvasive (2-dimensional echocardiography) and invasive (catheterization, coronary angiography, and biventricular endomyocardial biopsy, 6 to 8 samples/patient) cardiac study because of progressive heart failure (New York Heart Association functional class III or IV) with global biventricular dysfunction and no history of myocardial ischemic events, 7 patients (2.4%; 7 men; mean age, 49+/-6.9 years) had severe coronary artery disease (3 vessels in 4 patients; 2 vessels in 1 patient, proximal occlusion of left anterior descending coronary artery in 2 patients). Left ventricular end-diastolic diameter and ejection fraction by 2-dimensional echocardiography were 73+/-10.5 mm and 23+/-6.5%, respectively, and right ventricular end-diastolic diameter and ejection fraction were 39+/-7 mm and 29+/-7.2%, respectively. Biopsy specimens showed extensive lymphocytic infiltrates with focal myocytolysis meeting the Dallas criteria for myocarditis in all patients (in 5 patients with and 2 patients without fibrosis). Cardiac autoantibodies were detected with indirect immunofluorescence in the serum of 2 patients with active myocarditis. The 2 patients with active inflammation received prednisone (1 mg. kg-1. d-1 for 4 weeks followed by 0.33 mg. kg-1. d-1 for 5 months) and azathioprine (2 mg. kg-1. d-1 for 5 months) in addition to conventional drug therapy for heart failure. At 8-month overall follow-up, cardiac volume and function improved considerably in immunosuppressed patients but remained unchanged in conventionally treated patients, of whom 1 died.

CONCLUSIONS

Global biventricular dysfunction in patients with severe asymptomatic coronary artery disease and no evidence of previous myocardial infarction may be caused by myocarditis. Histologic findings may influence the treatment.

The time course of cardioprotection induced by GR79236, a selective adenosine A1-receptor agonist, in myocardial ischaemia-reperfusion injury in the pig

The cardioprotective effects of the selective adenosine A1-receptor agonist, GR79236 (N-[(1S, trans)-2-hydroxycyclopentyl]adenosine), were examined in a porcine model of myocardial ischaemia-reperfusion injury. When pigs were subjected to a 50-min coronary artery occlusion followed by 3-h reperfusion, GR79236 (10 nmol/kg, i.v.) significantly reduced infarct size whether given 10 min before the onset of ischaemia or reperfusion. This effect was independent of the bradycardia induced by GR79236, as it was also observed in animals in which heart rate was maintained by electrical pacing. However, GR79236 administered 10 min after reperfusion did not reduce infarct size. GR79236 had no effect on the incidence or outcome of ventricular dysrhythmias in this pig model of infarction. Similarly, ischaemic preconditioning (IPC, 2 x 10-min ischaemia and 10-min reperfusion) significantly reduced infarct size. The selective adenosine A1-receptor antagonist, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; 3.3 micromol/kg, i.v.), abolished the haemodynamic and cardioprotective effects of GR79236 and the cardioprotective effects of IPC in anaesthetised pigs. In conclusion, GR79236 exerted a marked cardioprotective effect in a porcine model of myocardial ischaemia-reperfusion injury, provided that it was administered before reperfusion. This suggests that GR79236 may have clinical utility in the treatment of various aspects of ischaemic heart disease.

[Late effects of radiofrequency fulguration: report of five cases]

Radiofrequency fulguration is the definitive treatment of several supraventricular and ventricular arrhythmias. During radiofrequency application, the conduction in a specific zone is interrupted as a consequence of cellular necrosis and edema. The disappearance of edema, minutes or hours after the procedure, allows the reappearance of conduction and arrhythmias. On the other hand, the definitive lesion is larger than the one caused acutely, due to the progression of the scar. We report five patients, in whom there was an apparent failure of the fulguration, since at the end of the procedure there was conduction in the fulgurated zone, the tachycardia was inducible or pre excitation and arrhythmias reappeared during the follow up. All five were subjected to a new electrophysiological study and in all, fulguration had been effective. We conclude that these late effects of fulguration are due to the slow progression of fibrosis, that continues days or weeks after the procedure.

Altered collagen concentration in mitral valve leaflets: biochemical and finite element analysis

BACKGROUND

Ischemic mitral regurgitation or ventricular wall motion abnormalities will alter the stress distribution in the mitral valve. We hypothesize that in response, the regional collagen concentration will be altered and will significantly impact the stress distribution in the mitral valve.

METHODS

Two sheep served as normal (sham) controls. Two other sheep had coronary ligation resulting in abnormal ventricular wall motion. Four sheep underwent ligation to infarct the posteromedial papillary muscle, resulting in ischemic regurgitation. After 4 or 8 weeks, the mitral valves were excised, and the anterior leaflet sections were subjected to an assay for collagen concentration. Next, in a finite element model, to simulate changes in collagen concentration, the tissue stiffness was increased by 20%, and then decreased by 20%. In another model, the thickness of the tissue was increased by 20%, and then combined with decreased tissue stiffness. Physiologic loading pressures were applied, and leaflet stress, chordal stress, and coaptation results were analyzed.

RESULTS

The average collagen concentration in the normal sheep leaflets was 59.2% (dry weight), 50.6% in the ischemic controls, and 45.8% in the papillary muscle infarct group. Collagen concentration was greatest at the midline and decreased toward the commissures. Increased tissue stiffness resulted in increased leaflet and chordal stresses, as well as reduced coaptation. Decreased stiffness resulted in the opposite. Increased tissue thickness reduced leaflet and chordal stresses, but also reduced coaptation. The combination of increased tissue thickness and decreased stiffness demonstrated the greatest reduction in leaflet and chordal stress, while maintaining normal leaflet coaptation.

CONCLUSIONS

The observed changes may demonstrate an early effort to compensate for increased leaflet stress. Microstructural alterations may demonstrate an early effort to compensate for altered physiologic loading to reduce stress and maintain coaptation. It is crucial in repairing or partially replacing thickened tissue that normal geometry and physiology be restored.

Systolic ventricular dysfunction causes selective diaphragm atrophy in rats

In order to examine the relative impairment of the diaphragm and other skeletal muscles in systolic ventricular dysfunction (VD), their structure and function were compared between rats with VD induced by left coronary artery ligation (n = 17) and sham-operated rats (Co, n = 10). In addition, in an attempt to unravel the mechanism of the observed impairment, we examined alterations in insulin-like growth factor-I (IGF-I) serum levels and IGF-I expression in the liver, diaphragm, and gastrocnemius. In a second series of rats (VD, n = 5 and Co, n = 5) hemodynamic measurements were performed. All measurements were performed 3 mo after the operation. Infarct size averaged 32 +/- 10 and 44 +/- 20% in the two series, respectively (NS). Hemodynamic measurements revealed a decrease in left ventricular peak systolic pressure of 19% (p < 0. 05). Significant diaphragm atrophy (weight: 622 +/- 52 mg in VD versus 750 +/- 54 mg in Co, p < 0.0005), without alterations in diaphragm contractile properties was present in VD animals. For all animals combined, the reduction in diaphragm weight was related to infarct size (r = -0.74, p < 0.001). No alterations were observed in the other inspiratory and peripheral muscles. ATPase staining of the diaphragm showed atrophy of type I and type IIx/b fibers, their cross-sectional area (CSA) being reduced by 13 and 16%, respectively (p < 0.05). There were no signs of myopathic alterations. IGF-I expression was increased by 55% in the diaphragm of rats with VD (p < 0.05). IGF-I expression in the liver and gastrocnemius and serum IGF-I levels were unaltered. These data suggest the presence of compensatory mechanisms aimed at minimizing diaphragmatic fiber atrophy. We conclude that systolic VD caused: (1) selective diaphragm atrophy, which was related to infarct size; (2) a decrease in diaphragm type I and IIx/b CSA not associated with myopathic changes; (3) an increase in the IGF-I mRNA content of the diaphragm. The selective diaphragm involvement in the present study may be related to the moderate degree of ventricular dysfunction induced.

Late ventricular potentials and heavy drinking

OBJECTIVES

To assess the effects of chronic drinking on detection of low amplitude signals, and to determine the relation between late ventricular potentials (LVP) and liver biopsy findings.

DESIGN

Prospective study.

SETTING

General hospital.

PATIENTS

41 consecutive chronic alcoholics without known pre-existing heart disease.

METHODS

About four days after each patient's last alcoholic drink, ECG, echocardiography, signal averaged electrocardiogram, liver biopsy, and blood tests were performed.

RESULTS

Twenty eight per cent of patients had evidence of LVP. There was a correlation between the percentage of steatosis of the hepatic biopsy and the amplitude of the last 40 ms of average QRS (P = 0.04), the duration of the terminal low amplitude QRS signal (P = 0.05), and the number of positive criteria of late potentials (P = 0.02).

CONCLUSIONS

Chronic drinking sufficient to cause steatosis is associated with positive findings on the signal averaged ECG.

Lone ventricular cardiomyopathy, 1993-1996

OBJECTIVE

To identify subjects with univentricular idiopathic structural and/or functional myocardial disorders (as defined) and to describe the characteristic features.

DESIGN

Over a period of 4 years, 1993-1996, all adult subjects were obtained consecutively from a centralised referral cardiological service. The subjects had to fulfil a set of formulated diagnostic criteria for each isolated type of univentricular disease-symptomatic or asymptomatic. The subjects were diagnosed on the basis of clinical features, supported by electrocardiographic, radiological and echocardiographic evidence of lone ventricular disease, with a further definition of abnormalities based on appropriately selected standard left and right heart assessments, inter alia: (i) cardiac catheterisation, including coronary arteriography and pulmonary angiography; (ii) radio-isotope studies-mibiscan; (iii) ventilation perfusion scan; and (iv) laboratory tests to identify likely cause(s) of diffuse myocardial damage as well as to recognise nonspecific effects of tissue damage and organ dysfunction.

SETTING

A referral cardiological service of a tertiary academic hospital, which provides a consultative service for inpatients and ambulatory cases. All subjects were studied on admission to hospital.

PARTICIPANTS

A set of criteria was formulated for each category of lone ventricular myopathy. A total of 30 patients were thus identified and included in the study-men and women ranging in age from 18 years to 84 years, with an average of 48 years. All were investigated after admission to hospital by means of a detailed set of investigations that rigorously excluded overt or occult causes of diffuse myocardial damage and any severe myocardial dysfunction secondary to haemodynamic conditions. Seven patients with significant coronary artery disease were excluded. Any subject with pulmonary or systemic hypertension was also excluded.

MAIN OUTCOME MEASURES

Total number of patients, number of patients in each subgroup were analysed by age, sex, clinical features, and by special investigation. The mode of presentation and electrocardiographic features were analysed separately.

RESULTS

Twenty-two left ventricular and 8 right ventricular cases of lone ventricular cardiomyopathy were diagnosed. All but 1 patient with right ventricular disease were symptomatic and 5 subjects with left ventricular myopathy were incidentally discovered. There were 17 men and 13 women in the series. Of the 8 patients with right ventricular disease, 6 were women, while of the 22 patients with left ventricular cardiomyopathy, 15 were men.

CONCLUSION

The study supports the previously described existence of lone ventricular idiopathic cardiomyopathy. Further studies are, however, indicated in order to define its prevalence and nature more accurately, as well as to describe any relationship with univentricular cardiomyopathies, and define the characteristics of each category and the possible evolutionary patterns. Right ventricular cardiomyopathy is a new entity which may pose difficult diagnostic challenges, while left ventricular disease is generally accepted as a stage in the clinical spectrum of classic idiopathic dilated cardiomyopathy.

Remodeling after myocardial infarction in humans is not associated with interstitial fibrosis of noninfarcted myocardium

OBJECTIVES

This study was specifically designed to evaluate whether noninfarcted hypertrophic myocardium in patients with end-stage heart failure after myocardial infarction (MI) is associated with an increase in interstitial fibrous tissue.

BACKGROUND

Postinfarction remodeling consists of complex alterations that involve both infarcted and noninfarcted myocardium. The question arises whether ventricular dysfunction is due to physical events, such as inadequate myocardial hypertrophy to compensate for increased tangential wall stress, or is caused by the development of progressive interstitial fibrosis in noninfarcted myocardium.

METHODS

Fifteen hearts were obtained as cardiac explants (n = 13) or at autopsy (n = 2) from patients with end-stage coronary artery disease. Sixteen normal hearts served as reference hearts. Samples were taken from the left ventricular (LV) wall that contained the infarcted area, the border area and noninfarcted myocardium remote from scar areas. Collagen was quantified biochemically and microdensitophotometrically. Collagen type I and III ratios were analyzed by using the cyanogen bromide method and immunohistochemical staining, followed by microdensitophotometric quantification.

RESULTS

In noninfarcted myocardium remote from the scar areas, total collagen levels and collagen type I/III ratios did not differ statistically from those in reference hearts. These observations contrasted with high total collagen content and high collagen type I/III ratios in scar and border areas.

CONCLUSIONS

Remodeling of LV myocardium after MI in patients with end-stage heart failure is not necessarily associated with interstitial fibrosis in noninfarcted hypertrophic myocardium remote from scar areas. This finding raises questions regarding therapeutic interventions designed to prevent or retard the development of interstitial fibrosis.

Familial right ventricular dysplasia with biventricular involvement and inflammatory infiltration. Heart Muscle Disease Study Group

The aetiology of right ventricular dysplasia/cardiomyopathy is presently unknown. A genetic background has been suggested, but myocarditis may play a part in its pathogenesis. Two familial cases of right ventricular dysplasia, one of whom had also a diagnosis of myocarditis, are reported. Both patients presented with ventricular arrhythmias. The father subsequently had a "flu-like" syndrome, heart failure, and biventricular dysfunction; "active" myocarditis was found at endomyocardial biopsy. Then the patient died suddenly. The daughter developed progressive biventricular dysfunction; then she was resuscitated from a cardiac arrest, and subsequently died suddenly. In both patients necropsy showed severe right ventricular atrophy and fibro-adipose substitution, associated with biventricular fibrosis. Inflammatory infiltration was also present in the first patient. This study shows the association of right ventricular dysplasia and myocarditis in the same family. These cases may represent a link between inherited and acquired ("inflammatory") forms of the disease.

Myocyte death in heart failure

Decompensated eccentric ventricular hypertrophy characterizes the transition from compensated pressure or volume over-load hypertrophy to myocardial dysfunction and failure. Myocyte loss is the major etiologic factor of wall thinning and chamber dilation and may condition the progression of the cardiac myopathy. Myocyte death can occur by apoptosis or necrosis, but the activation of the suicide program of myocytes exceeds necrotic cell death in the pathologic heart of ischemic origin. Whether reactive fibrosis constitutes a primary event in the initiation of ventricular dysfunction or a secondary reaction to myocyte death is an important unanswered question.

Aging does not affect the activation of the myocyte insulin-like growth factor-1 autocrine system after infarction and ventricular failure in Fischer 344 rats

To determine whether the attenuation in the growth capacity of myocytes in the overloaded aging heart is associated with an impairment in the activation of insulin-like growth factor-1 (IGF-1) and its receptor (IGF-1R) in the stressed cells, large myocardial infarcts were produced in Fischer 344 rats at 4 and 16 months of age, and the animals were killed 6 hours, 3 days, and 7 days later. After the documentation of cardiac failure, the unaffected myocytes were enzymatically dissociated, and the expression of IGF-1 and IGF-1R was measured at these three time points after surgery. The level of expression of IGF-1R mRNA increased at 3 days and remained elevated at 7 days in both age groups. In addition, an increase in IGF-1R protein in these cells was found, with no apparent difference with age. This phenomenon was coupled with an upregulation of IGF-1 mRNA of comparable magnitude in the younger and older animals. In contrast, the increases in the dimensional properties of myocytes were delayed and of smaller magnitude in the older infarcted rats. Moreover, the expression of atrial natriuretic factor, used as a molecular marker of myocyte cellular hypertrophy, was greater at 3 days in 4-month-old rats and at 7 days in 16-month-old rats. Thus, aging may affect the hypertrophic response of myocytes after infarction but has no impact on the ability of the cells to enhance the expression of IGF-1 and IGF-1R, which may sustain only in part the growth reserve mechanisms of the pathological heart.