Radioligands for imaging myocardial α- and β-adrenoceptors

Alpha- and beta-adrenoceptors play an important role in the control of heart function. According to their molecular, biological, and pharmacological characteristics, they are subdivided into α1-, α2- and β1-, β2-, β3-, β4-adrenoceptors. In cardiac disease, there is often a selective downregulation of β1-adrenoceptors associated with a relative increase in β2- and α1-adrenoceptors. Functional imaging techniques like single-photon emission tomography (SPECT) and positron emission tomography (PET) provide the unique capability for non-invasive assessment of cardiac adrenoceptors. Radioligands with high specific binding to cardiac α- and β-adrenoceptors suitable for radiolabelling are required for clinical studies. The non-selective β-adrenoceptor antagonist [11C]CGP-12177 was used to quantify β-adrenoceptor density using PET in patients with heart disease. New non-selective ligands (e. g. [11C]CGP-12388, [18F]CGP-12388, [11C]carazolol and [18F]fluorocarazolol) are currently evaluated; β1-selective radioligands (e. g. [11C]CGP-26505, [11C]bisoprolol, [11C]HX-CH 44) and β2-selective radioligands (e. g. [11C]formoterol, [11C]ICI-118551) were assessed in animals. None of them turned out as suitable for cardiac PET.

Potential radioligands for imaging cardiac α1-adrenoceptors are based on prazosin. Whereas [11C]prazosin shows low specific binding to myocardium, its derivative [11C]GB67 looks more promising. The putative α2-adrenoceptor radioligand [11C]MK-912 shows high uptake in rodent myocardium but has not yet been evaluated in man.

A number of radioligands were evaluated for assessing cardiac adrenoceptors using PET. New radioligands are needed to provide more insight into cardiac pathophysiology which may influence the therapeutic management of patients with cardiovascular disease.

Arrhythmogenic right ventricular cardiomyopathy: an update on pathophysiology, genetics, diagnosis, and risk stratification

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy accounting for life-threatening ventricular tachyarrhythmias and sudden death in young individuals and athletes. Over the past years, mutations in desmosomal genes have been identified as disease-causative. However, genetic heterogeneity and variable phenotypic expression alongside with diverse disease progression still render the evaluation of its prognostic implication difficult. ARVC was initially entered into the canon of cardiomyopathies of the World Health Organization in 1995, and international efforts have resulted in the 2010 modified diagnostic criteria for ARVC. Despite all additional insights into pathophysiology, clinical management, and modern risk stratification, under-/misdiagnosing of ARVC remains a problem and hampers reliable statements on the incidence, prevalence, and natural course of the disease.This review provides a comprehensive overview of the current literature on the pathogenesis, diagnosis, treatment, and prognosis of ARVC and sheds some light on potential new developments in these areas.

[Acute coronary syndrome: peri-interventional antithrombotic therapy]

In patients with acute coronary syndrome (ACS), the periinterventional antithrombotic treatment has become increasingly important for the choice of reperfusion strategy and as an adjunct pharmacological treatment prior, during and after percutaneous coronary interventions (PCI). In NSTE-ACS and early invasive strategy (<48 h), treatment with ASA, clopidogrel and heparin - unfractionated heparin (UFH) preferred - should be initiated as soon as possible. Direct thrombin inhibitors are an alternative to heparin, particularly in the setting of increased risk of bleeding and heparin-induced thrombocytopenia. In highrisk patients, an so-called upstream therapy with glycoprotein IIb/IIIa inhibitors (tirofiban, eptifibatide) is recommended as an adjunct to PCI. In STEMI, primary PCI is the reperfusion therapy of choice and should be supported by early adjunct treatment with ASA, clopidogrel, UFH and glycoprotein IIb/IIIa inhibitors (abciximab, eptifibatide). "Facilitated" PCI with thrombolytics is not recommended because of increased mortality and complication rates.

Aminoterminal B-type pro-natriuretic peptide as a marker of recovery after high-risk coronary artery bypass grafting in patients with ischemic heart disease and severe impaired left ventricular function

BACKGROUND

Aminoterminal B-type pro-natriuretic peptide (NT-proBNP) is a reliable indicator of heart failure severity. Levels of NT-proBNP are markedly increased in patients with coronary artery disease (CAD) and severely impaired left ventricular (LV) function. The aim of our study was to assess the impact of NT-proBNP levels after high-risk coronary artery bypass grafting (CABG) with regard to recovery potential.

METHODS

Between 1998 and 2004, 121 patients with CAD and severely impaired LV function, who were undergoing CABG, were investigated. Their mean age was 64 +/- 11 years. All patients were in New York Heart Association (NYHA) Class III/IV status; LV ejection fraction (EF) was 20 +/- 6%. All survivors underwent follow-up (59 +/- 34 months) spiroergometric, electrocardiographic (ECG) and echocardiographic assessment and were tested for routine blood controls and NT-proBNP levels (Roche, Mannheim, Germany).

RESULTS

The survival rate after 8 years was 70%. All survivors received follow-up assessment. Among survivors the median NT-proBNP level at follow-up was 896 (521 to 1,687) pg/ml. The maximum oxygen uptake was 14.6 +/- 4.9 ml/min/kg, and EF increased to 42% at follow-up among all survivors. On dichotomizing survivors into two groups with NT-proBNP levels above and below the median, the post-operative body mass index was significantly higher in the high NT-proBNP group (p = 0.036). EF (p = 0.028) and NYHA classification (p < 0.05) improved significantly in both groups, with a tendency toward higher EF in the low NT-proBNP group.

CONCLUSIONS

Patients undergoing a high-risk CABG procedure have a survival rate comparable to heart transplantation patients and show a potential for clinical and myocardial recovery. NT-proBNP use a useful marker for recovery after a high-risk CABG procedure, with significant correlation with clinical parameters.

Akutes Koronarsyndrom

Bei Patienten mit akutem Koronarsyndrom erlangte die peri-interventionelle antithrombotische Therapie in den vergangenen Jahren zunehmend Bedeutung für die Wahl der bevorzugten Reperfusionsstrategie und der adjuvanten medikamentösen Behandlung vor, während und nach perkutanen Koronarinterventionen (PCI).

Bei NSTE-ACS und früh-invasiver Therapiestrategie (<48 h) sollte möglichst frühzeitig eine Behandlung mit Azetylsalizylsäure (ASS), Clopidogrel und Heparin (UFH bevorzugt) eingeleitet werden. Direkte Thrombininhibitoren stellen insbesondere bei erhöhter Blutungsneigung oder heparininduzierter Thrombozytopenie eine Alternative zu unfraktioniertes Heparin (UFH) dar.

Bei Patienten mit hohem Risiko sollte ,,upstream“ ein Glykoprotein-IIb/IIIa- Inhibitor (Eptifibatid, Tirofiban) eingesetzt werden. Bei STEMI stellt die primäre PCI die Reperfusionstherapie der Wahl dar und sollte durch frühzeitige Gabe von ASS, Clopidogrel, UFH und Glykoprotein-IIb/IIIa-Inhibitoren (Abciximab, Eptifibatid) unterstützt werden. UFH wird dabei gegenüber niedermolekularem Heparin wegen geringerer Blutungsraten und besserer Möglichkeit zur Antagonisierung favorisiert. Eine so genannte facilitated PCI mit Thrombolytika wird wegen höherer Mortalität und Komplikationsraten nicht empfohlen.

[Right ventricular tachyarrhythmias--diagnostics and therapy]

Ventricular tachyarrhythmias originating from the right ventricle frequently occur in young, apparently healthy patients with rare underlying cardiac diseases. Among these are arrhythmogenic right ventricular cardiomyopathy (ARVC), idiopathic right ventricular outflow-tract tachycardia (RVOVT), and Brugada syndrome (BrS). All harbor the risk of sudden cardiac death, whereas they differ substantially as to diagnosis, therapy and prognosis. This is the reason why detailed investigations are an essential prerequisite for further efficient individualized management strategies which are mainly directed to prevent sudden cardiac death and to minimize the risk of arrhythmia recurrences in affected patients, respectively. Both antiarrhythmic drug therapy, catheter ablation, and the implantation of an automatic cardioverter defibrillator may, therefore, be a first-line therapeutic option in tailored treatment regimens. This review is a summary of the available literature on pathogenesis, diagnosis, treatment, and prognosis of such diseases associated with right ventricular tachyarrhythmias.

Cardiothoracic Surgery after Heart and Heart-Lung Transplantation

OBJECTIVE

We sought to examine our management and the outcomes of cardiothoracic procedures after heart and heart lung transplantation.

METHODS

We performed a retrospective review of cardiothoracic surgical procedures carried out between 1990 and 2004 in patients who had previously undergone heart or heart-lung transplantation at our institution.

RESULTS

Twenty-one out of 340 patients (6.2 %) were identified. Cardiothoracic surgery was performed 44.4 +/- 33 months (range 1 - 115 months) after transplantation. Predominant types of surgery were coronary artery bypass grafting due to allograft vasculopathy (n = 5), aortic surgery due to acute dissection (n = 3), biventricular assist device implantation due to acute rejection (n = 1), tricuspid valve repair (n = 1), multiple cardiac surgical procedures including coronary artery bypass grafting, retransplantation, and tricuspid valve replacement (n = 2), explantation of a functionless heterotopic transplanted heart (n = 1). Lung surgery was performed in six patients due to pneumonia (n = 2), primary lung carcinoma (n = 3), lung torsion following heart-lung transplantation (n = 1). All patients underwent either lobectomy or segmental lung resection. Single lung retransplantation (n = 2) after prior heart-lung transplantation due to bronchiolitis obliterans was performed. In one patient a pneumonectomy (n = 1) due to severe chronic rejection of the contralateral lung was performed. Six subsequent deaths after cardiothoracic procedures were recorded after 1, 4, 78, 163, 205, and 730 days, respectively. Causes of death were advanced carcinoma (n = 1), multi-organ failure due to sepsis (n = 2), sudden heart death (n = 2), and advanced heart failure (n = 1). Fifteen out of 21 patients having undergone cardiothoracic procedures (71.4 %) survived the observation period of 56.6 +/- 34 months (range 1 - 114).

CONCLUSIONS

Reasons for cardiothoracic procedures after prior heart or heart-lung transplantation were allograft vasculopathy, aortic dissections years after transplantation, chronic rejection, and either lung infections or malignancies. Surgical repair can be performed with an acceptable operative risk and good long-term survival rates.

Arrhythmien aus dem rechten Ventrikel

Right ventricular arrhythmias predominantly occur in young patients with rare cardiac diseases. Underlying cardiac conditions include idiopathic right ventricular outflow-tract tachycardia (RVOT-VT), arrhythmogenic right ventricular cardiomyopathy (ARVC), Brugada syndrome, and postoperative congenital heart disease (i.e. tetralogy of Fallot). According to the underlying cardiac disease, there are significant differences in the diagnostic and therapeutic management and prognosis which is mainly determined by life-threatening ventricular arrhythmia recurrences and sudden cardiac death. To provide optimal treatment for affected patients, a detailed diagnostic evaluation and risk stratification is mandatory. Tailored treatment strategies aim at the suppression or effective termination of recurrent ventricular tachyarrhythmias and prevention of sudden death by antiarrhythmic drug therapy, catheter ablation, and the implantation of cardioverter-defibrillators. This review summarizes the current knowledge on pathogenesis, diagnosis, treatment and prognosis of those conditions that are associated with arrhythmias originating from the right ventricle.

Stroke volume and mitral annular velocities

The aim of this study was to assess the impact of stroke volume (SV) on mitral annular velocities derived from tissue Doppler imaging (TDI). To this end, conventional echocardiographic variables and TDI derived mitral annular velocities (S', E', A') were obtained in 14 patients (pts) with increased SV (due to primary mitral (n=12) (ISV group)), in 41 pts with reduced SV (due to ischemic (n=27) or dilated cardiomyopathy (n=9) or hypertensive heart disease (n=5) (RSV group)) and 29 asymptomatic controls with normal SV (CON group). Systolic (S') and early diastolic (E') mitral annular velocities were elevated in the ISV group in the comparison to the CON group, but were significantly reduced in the RSV group. Late diastolic annular velocities (A') did not differ between the ISV and the CON group, but were lowest in the RSV group. On simple linear regression analysis, SV was significantly related to S' (r=0.74, p<0.001), to E' (r=0.74, p<0.001) and to A' (r=0.43, p<0.01). On multiple regression analysis, SV was a stronger independent predictor of S' and E' than conventional systolic or diastolic echocardiographic variables. Thus, stroke volume has a significant impact on TDI derived systolic (S') and early diastolic (E') mitral annular velocities. This should be considered, when TDI is used in the evaluation of LV performance or in the estimation of filling pressures.

[Aneurysm of the subclavian artery after operatively corrected coarctation of the aorta: 20 years of follow-up and review of the current literature]

We report of long-term follow-up of a combined fusiform aneurysm of the right subclavian artery extending to the thyreocervical trunk (3.2 x 2.8 x 2.2 cm (width x height x depth)) in a 33-year old patient. As a newborn, the clinical diagnosis of an aortic isthmus stenosis was made without need for intervention at this stage. Further development of the child remained unremarkable until the age of eleven years when he experienced dizziness after sporting activities. Due to clinically proven progress, cardiac catheterization was performed and confirmed the initial diagnosis of a juxtaductale stenosis of the aortic isthmus, which was operated thereafter with an end-to-end anastomosis. Furthermore, an aneurysm of the right subclavian artery was revealed. Since then, non-invasive routine follow-up showed no significant worsening of this aneurysm, which extends to the thyreocervical trunk. The patient has been event free and completely asymptomatic. This case report illustrates the more than twenty years of follow-up of an asymptomatic combined fusiform aneurysm of the subclavian artery and thyreocervical trunk and provides a review of the literature on this topic.

Arterial hypertension and ischaemic stroke

OBJECTIVES

Arterial hypertension is, besides age, the number one risk factor for ischaemic stroke. Patients with arterial hypertension frequently present with additional coexisting vascular risk factors interacting in a complex way.

MATERIAL AND METHODS

This paper reviews the benefit of antihypertensive treatment, as well as different treatment options of arterial hypertension and their side-effects.

RESULTS

Patients with definite arterial hypertension, but also patients with so-called normal or high-normal blood pressure are at increased risk to develop stroke and other cardiovascular complications. Vascular remodelling of small and large vessels provoked by arterial hypertension is the initial step in the development of atherosclerosis and lipohyalinosis. Vascular remodelling can be improved or even normalized by antihypertensive treatment with angiotensin-converting-enzyme inhibitors and angiotensin-I-receptor antagonists showing the most convincing effects. Angiotensin-converting-enzyme inhibitors and angiotensin-I-receptor antagonists have the lowest rate of side-effects, however, economic restraints hinder their general application. Statins are needed to treat dyslipidaemia. They also lower blood pressure and have a synergistic effect with the above two antihypertensive components in lowering blood pressure. In hypertensive patients, risk of stroke and other cardiovascular complications is determined by the blood pressure level and the presence or absence of target organ damage and the interaction with other risk factors, such as cigarette smoking, dyslipidaemia, and diabetes. These high-risk patients should be treated even more aggressively than usual.

CONCLUSIONS

In the vast majority of patients and healthy individuals, target blood pressure should be as high as or below 120/80 mmHg to minimize the occurrence of stroke and other cardiovascular complications.

Genetics of arrhythmogenic right ventricular cardiomyopathy--status quo and future perspectives

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a primary myocardial disorder of unknown origin. In recent years, the disease has been recognized as a major cause of ventricular tachyarrhythmias and sudden cardiac death in young patients with apparently normal hearts. Although characteristic structural, imaging and electrocardiographic features are included in a proposed catalogue of diagnostic criteria, the correct diagnosis of ARVC often remains difficult. Much effort has been undertaken to enlarge the knowledge on pathophysiological mechanisms of the disease. The role of molecular genetics for the pathogenesis of ARVC is discussed in the following review. On the basis of linkage analyses in large families affected by ARVC, there is growing evidence for genetic alterations in ARVC, which, in the majority of chromosomal loci (seven) reported so far, follow a Mendelian autosomal-dominant pattern of inheritance with variable penetrance and polymorphic phenotype. Besides this, two autosomal-recessive forms of ARVC are known. These can be differentiated from the autosomal-dominant forms not only in terms of the mode of inheritance but also as to their specific phenotype: patients with Naxos disease exhibit characteristic hair and skin abnormalities and experience a more severe course of disease. Patients with another autosomal-recessive form display the typical but milder signs of ARVC together with opacifications of the crystalline lens. So far, two mutations in cardiac genes responsible for the development of ARVC have been reported. A homozygous two base pair deletion in the gene encoding for the cytoskeletal protein plakoglobin seems to account for the evolution of Naxos disease. The second mutation affecting the cardiac ryanodine receptor gene was found in patients with ARVC-2. Routine genetic testing of patients or relatives with a suspected diagnosis of ARVC is not available at present but may become the future gold standard with potential implications for a better understanding of the pathogenesis and management of the disease.

Radioligands for imaging myocardial alpha- and beta-adrenoceptors

Alpha- and beta-adrenoceptors play an important role in the control of heart function. According to their molecular, biological, and pharmacological characteristics, they are subdivided into alpha(1)-, alpha(2)- and beta(1)-, beta(2)-, beta(3)-, beta(4)-adrenoceptors. In cardiac disease, there is often a selective downregulation of beta(1)-adrenoceptors associated with a relative increase in beta(2)- and alpha(1)-adrenoceptors. Functional imaging techniques like single-photon emission tomography (SPECT) and positron emission tomography (PET) provide the unique capability for non-invasive assessment of cardiac adrenoceptors. Radioligands with high specific binding to cardiac alpha- and beta-adrenoceptors suitable for radiolabelling are required for clinical studies. The non-selective beta-adrenoceptor antagonist [(11)C]CGP-12177 was used to quantify beta-adrenoceptor density using PET in patients with heart disease. New non-selective ligands (e. g. [(11)C]CGP-12388, [(18)F]CGP-12388, [(11)C]carazolol and [(18)F]fluorocarazolol) are currently evaluated; beta(1)-selective radioligands (e. g. [(11)C]CGP-26505, [(11)C]bisoprolol, [(11)C]HX-CH 44) and beta(2)-selective radioligands (e. g. [(11)C]formoterol, [(11)C]ICI-118551) were assessed in animals. None of them turned out as suitable for cardiac PET. Potential radioligands for imaging cardiac alpha(1)-adrenoceptors are based on prazosin. Whereas [(11)C]prazosin shows low specific binding to myocardium, its derivative [(11)C]GB67 looks more promising. The putative alpha(2)-adrenoceptor radioligand [(11)C]MK-912 shows high uptake in rodent myocardium but has not yet been evaluated in man. A number of radioligands were evaluated for assessing cardiac adrenoceptors using PET. New radioligands are needed to provide more insight into cardiac pathophysiology which may influence the therapeutic management of patients with cardiovascular disease.

Mitral valve surgery in patients with poor left ventricular function

BACKGROUND

Mitral valve surgery for the correction of secondary mitral valve regurgitation (MR) in cardiomyopathy is associated with a poor outcome. Numerous studies have identified a severe left ventricular dysfunction as an indicator for a poor prognosis. The aim of the study was to asses the follow-up after mitral valve surgery and severe left ventricular dysfunction.

METHODS

Between 1994 and 2000, 31 patients with mitral regurgitation and a left ventricular ejection fraction of below thirty percent undergoing isolated repair (n = 16) or replacement (n = 15) were investigated. All patients received maximal drug therapy. Twenty-one patients were New York Heart Association (NYHA) class III and 10 were class IV. Follow-up with echocardiography, ECG, and chest x-ray was performed in 87 % of the survivors. The mean duration of follow-up was 39 +/- 16 months.

RESULTS

The mean duration of ICU and hospital stay was 3.6 +/- 2.1 days and 8.1 +/- 5.4 days, respectively. The 1-, 2-, and 5-year survival rates were 91 %, 84 %, and 77 %, respectively. NYHA class improved from 3.3 +/- 0.8 to 2.1 +/- 0.7 at follow-up (p < 0.01). The ejection fraction improved from 23.1 +/- 6.6 % to 36 +/- 6.8 % at follow-up (p < 0.02). Freedom from readmission for heart failure was 85 %, 79 %, and 68 % at 1-, 2-, and 5 years, respectively.

CONCLUSIONS

Mitral valve surgery improves left ventricular function and reduces heart failure severity in patients with MR and cardiomyopathy. High-risk mitral valve surgery may be an alternative to heart transplantation in selected patients.

Electrophysiologic investigation in Brugada syndrome; yield of programmed ventricular stimulation at two ventricular sites with up to three premature beats

INTRODUCTION

Numerous reports on the inducibility of ventricular tachyarrhythmias (VT) in patients with atypical right bundle branch block and right precordial ST-elevation (Brugada syndrome) are based on multicentre studies that have used different stimulation protocols. Therefore, we prospectively investigated the inducibility of VT in these patients using a uniform protocol.

METHODS

In 41 consecutive patients (29 males) showing a pattern of right bundle branch block and ST-elevation, programmed ventricular stimulation was performed in the right ventricular apex with up to three premature stimuli at sinus rhythm and at four different paced cycle lengths (500, 430, 370, and 330 ms) until refractoriness was reached or reproducible induction of a sustained (>30s) VT occurred. If a VT was not reproducibly inducible, the same protocol was repeated in the right ventricular outflow tract.

RESULTS

A history of life-threatening events defined as syncope (n=17) or aborted sudden cardiac death (n=13) was present in 30 patients (73%); 11 individuals were asymptomatic. Inducibility (68%) was similar between symptomatic (n=21, 70%) and asymptomatic patients (n=7, 64%). In 16 (39%) patients, VT were reproducibly inducible. If patients were only stimulated in the right ventricular apex, inducibility rate decreased to 39%. If only two premature beats at two sites were used it was as low as 32%. The mean coupling intervals of the second and third premature stimuli inducing sustained VT were short: 189+/-21 ms vs 186+/-22 ms, respectively. Forty-four percent of all patients (i.e. 64% of the inducible patients) had inducible VT only with coupling intervals shorter than 200 ms.

CONCLUSIONS

The stimulation protocol markedly influences the extent of inducibility of VT in patients with right bundle branch block and ST-segment elevation. These findings question the significance of previous multicentre studies using different stimulation protocols and should have implications for further studies.

Activation of the cardiac interleukin-6 system in advanced heart failure

OBJECTIVES

The study objective was to assess the cardiac expression of interleukin-6 (IL6) and its receptor (IL6R) in advanced heart failure.

BACKGROUND

While IL6 plasma levels are elevated and associated with an impaired prognosis in advanced heart failure, little is known about the intracardiac expression of the IL6 system.

METHODS

Heart tissue was obtained from 20 patients (n=10, idiopathic dilated cardiomyopathy, age 44+/-15 years; n=10, ischemic cardiomyopathy, age 55+/-8 years) at the time of transplantation. Left and right ventricular tissue was subjected to in situ hybridization, Northern blot analysis, and RT-PCR. Signals were quantified by densitometric scanning and corrected for G3PDH-mRNA levels. Right ventricular biopsy specimens (n=11) of patients with arrhythmias and normal cardiac function served as controls. In addition, data were correlated with cardiac catheterization and echocardiography data obtained at transplant evaluation.

RESULTS

Ventricular IL6 and IL6R transcripts were detected in all explant specimens examined. Expression of both mRNA species was higher than in controls (P=0.001). Left ventricular IL6 mRNA levels correlated positively with heart rate (r=0.77; P=0.009), pulmonary capillary wedge pressure (r=0.53; P=0.03), right atrial pressure (r=0.77; P=0.003), and inversely with left ventricular ejection fraction (r=-0.61; P=0.03). Right ventricular IL6 mRNA levels correlated inversely with cardiac index (r=-0.48; P=0.05). IL6R expression did not correlate with hemodynamic data.

CONCLUSIONS

In advanced heart failure, cardiac IL6/IL6R mRNA expression is increased and may play a role in the pathophysiology of advanced heart failure.

Brugada syndrome and supraventricular tachyarrhythmias: a novel association?

INTRODUCTION

The Brugada syndrome is a distinct form of idiopathic ventricular fibrillation characterized by a unique ECG pattern consisting of a right bundle branch block-like aspect and ST segment elevation in leads V1 to V3. As a high induction rate of ventricular tachyarrhythmias has been reported in Brugada syndrome, we hypothesized that this also may be true for supraventricular tachycardias in these patients.

METHODS AND RESULTS

Between January 1995 and December 2000, we identified 35 consecutive patients with Brugada syndrome; 26 had a history of cardiac arrest or syncope and 9 were asymptomatic. All patients underwent electrophysiologic study, including an atrial and ventricular stimulation protocol. Ten patients (29%) were found to have supraventricular tachyarrhythmias (SVT) in addition to the Brugada syndrome. These 10 patients presented with aborted sudden cardiac death (n = 3) and/or a family history of sudden cardiac death (n = 4), syncope (n = 4), or primarily with a Brugada typical ECG, a positive family history, and palpitations (n = 2). Eight of them underwent genetic testing, but only 1 had a mutation in the SCN5A gene. In 6 patients, an AV nodal reentrant tachycardia was easily and reproducibly inducible. Two patients had clinical documented and inducible episodes of an atrial tachycardia (1 in addition to an AV nodal reentrant tachycardia). One patient had paroxysmal atrial fibrillation alternating with sinus rhythm, and 2 patients with accessory pathways were identified.

CONCLUSION

This is the first description of an association of the Brugada syndrome with SVT. Thus, the arrhythmogenic substrate in Brugada syndrome may not be restricted to the ventricular level. Palpitations in this syndrome should raise the possibility of SVT. Conversely, in patients with SVT and aborted sudden cardiac death or syncope not related to SVT, the Brugada syndrome should be considered a possible additional electrophysiologic abnormality.

[MRI study of left ventricular function in patients with coronary disease and myocardial dysfunction before and after coronary revascularization]

PURPOSE

To evaluate left ventricular (LV) myocardial function in ten patients with coronary artery disease (CAD) preoperatively and 6 months after coronary bypass grafting (CABG) by cardiac MRI.

MATERIAL AND METHODS

Ten patients (mean 65.2 +/- 5.9 years) with angiographically proven CAD and an indication for elective CABG underwent prospective evaluation of global LV function and regional wall motion by Cine-MRI at rest using a multiphase FLASH-2D sequence following regions of interest (ROI)-defined diagnostics of regional myocardial wall motion by means of levocardiography. Within the ROIs a total of 613 LV myocardial segments were analyzed preceding and following surgical revascularization. Results were compared with the data of 10 healthy volunteers.

RESULTS

Preoperatively, patients showed reduced stroke volume and ejection fraction compared with volunteers (p < 0.01). Enddiastolic wall thickness (EDWT) and systolic wall thickening (SWT) were significantly lower in the patients (p < 0.01). Based on preoperative levocardiography ROI-defined myocardial segments showed a significantly lower preoperative EDWT in areas with wall motion abnormalities (7.4 +/- 2.5 mm; p < 0.01) than in normal myocardium (9.2 +/- 2.1 mm). Ejection fraction (p < 0.05), endsystolic wall thickness, and SWT (p < 0.01) improved significantly after bypass surgery. On ROI-defined analysis myocardial segments with impaired preoperative wall motion (n = 243) showed a significant increase of EDWT, ESWT and SWT (p < 0.01).

CONCLUSION

In patients with CAD, cardiac MRI enables the non-invasive determination of postinfarctional LV remodeling with an increased EDWT of myocardial segments with normal regional wall motion and of the improvement in global and regional myocardial function following coronary bypass surgery.

Pulmonary beta adrenoceptor density in arrhythmogenic right ventricular cardiomyopathy and idiopathic tachycardia

OBJECTIVE

In recent in vivo studies using positron emission tomography (PET) our group demonstrated that the myocardial beta adrenoceptor (betaAR) density is reduced in arrhythmogenic right ventricular cardiomyopathy (ARVC) and idiopathic right ventricular outflow tract tachycardia (RVO-VT) associated with an increased presynaptic catecholamine washout. It was hypothesised that the reduction of myocardial betaAR density is secondary to an increase of local catecholamines in the myocardium resulting from the presynaptic dysfunction since circulating plasma catecholamines were demonstrated to be unchanged in these conditions. To further prove this hypothesis of an organ-limited adrenergic nervous dysfunction of the heart, this study aimed to investigate betaAR density in another thoracic organ, the lung.

METHODS

Pulmonary and myocardial betaAR density was measured in 7 ARVC patients, 8 RVO-VT patients and in a group of healthy controls (n = 13) using the non-selective beta-blocker [11C]-CGP 12177 and PET.

RESULTS

Pulmonary betaAR density was similar in controls (12.4 +/- 1.7 pmol/g tissue), ARVC (11.6 +/- 1.7 pmol/g tissue, p = ns) and RVO-VT (12.8 +/- 2.0 pmol/g tissue, p = ns), whereas myocardial betaAR density was significantly reduced in ARVC (6.3 +/- 1.1 pmol/g tissue, p = 0.006) and RVO-VT (6.8 +/- 1.2 pmol/g tissue, p=0.02) as compared to controls (8.8+/-1.5 pmol/g tissue).

CONCLUSION

The unchanged pulmonary betaAR density in the presence of a previously described significant reduction in myocardial betaAR density in the same patient principally supports our pathophysiological hypothesis that the myocardial betaAR density may be reduced in ARVC and RVO-VT because of an increase in local synaptic catecholamine levels due to an organ-limited presynaptic adrenergic dysfunction of the heart. Since in the present study only pulmonary betaAR density was measured, future functional studies excluding pulmonary betaAR desensitisation are required to finally prove the unchanged pulmonary sympathetic innervation in ARVC and RVO-VT.

Signal characteristics of multichannel epicardial electrograms in chronic ischaemic and scarred myocardium: electromechanical mismatch indicates viability in regions of myocardial dysfunction

BACKGROUND

To predict the outcome after myocardial revascularisation, a clear separation between hibernation and/or repetitive stunning on the one hand and myocardial scarring on the other hand is of importance.

METHODS AND RESULTS

A total of 44 patients was included in this study. In 35 patients with chronic myocardial ischaemia and an indication for coronary bypass-surgery, epicardial mapping of local activation was performed. Nine patients with LV aneurysm and an indication for antitachycardia surgery were also included. For simultaneous recording of the local electrograms during sinus rhythm, a sock electrode with 102 bipolar leads was used. The regional myocardial contraction pattern was assessed from preoperative angiograms and regional myocardial metabolism (viability) from 18F-FDG PET, respectively. The results were projected on the grid of the intraoperative position of the sock electrode. This enabled regional comparison of electrogram characteristics to local contraction patterns and viability. For the characterisation of local electrograms, peak-to-peak amplitude and duration of activation were calculated using custom-made automated computer-algorithms. Dysfunctional but viable areas showed normal or almost normal electrographic signal characteristics. In contrast, dysfunctional and non-viable myocardium showed a distinct reduction of local amplitudes and prolongation of signal duration. These changes were even more intense in areas of LV aneurysms.

CONCLUSIONS

In patients with chronic ischaemic myocardium, a mismatch between mechanical function and local electrogram characteristics was observed in areas with preserved metabolism. Thus, normal epicardial electrograms in regions of myocardial dysfunction may be an indicator for myocardial viability.

Multislice cardiac spiral CT evaluation of atypical hypertrophic cardiomyopathy with a calcified left ventricular thrombus

We report a case of a 43-year-old male patient with an atypical nonobstructive hypertrophic cardiomyopathy and a calcified left ventricular thrombus, and present results of multislice computed tomography (MSCT) using retrospective electrocardiograph gating, which is a new modality in cardiac imaging. Obtaining virtually motion-free images with a temporal resolution of 250 ms in an optimized heart scan MSCT allows functional imaging with evaluation of impaired systolic and diastolic left ventricular wall motion.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy: need for an international registry. European Society of Cardiology and the Scientific Council on Cardiomyopathies of the World Heart Federation

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is a heart muscle disease characterized by peculiar right ventricular involvement and electrical instability that precipitates ventricular arrhythmias and sudden death. The purpose of the present consensus report of the Study Group of the European Society of Cardiology and the Scientific Council on Cardiomyopathies of the World Heart Federation is to review the considerable progress in our understanding of the etiopathogenesis, morbid anatomy, and clinical presentation of ARVD/C since its first description in 1977. This article will focus on the important but still unanswered issues, mostly regarding risk stratification, clinical outcome, and management of affected patients. Because ARVD/C is relatively uncommon and any one center may have experience with only a few patients, an international registry is being established to accumulate information and enhance the numbers of patients that can be analyzed to answer the pending questions. The registry also will facilitate pathologic, molecular, and genetics research on the etiology and pathogenesis of the disease. Furthermore, availability of an international database will enhance awareness of this largely unrecognized condition among the medical community. Physicians are encouraged to enroll patients in the International Registry of ARVD/C.

Contrast transcranial doppler ultrasound in the detection of right-to-left shunts : time window and threshold in microbubble numbers

BACKGROUND AND PURPOSE

Cardiac right-to-left shunts can be identified by transesophageal echocardiography (TEE) and by transcranial Doppler ultrasound (TCD) with the use of contrast agents and a Valsalva maneuver (VM) as provocation procedure. Currently, data on the appropriate timing of the VM, the use of a diagnostic time window, and a threshold in contrast agent microbubbles detected are insufficient.

METHODS

Fifty-eight patients were investigated by both TEE and bilateral TCD of the middle cerebral artery. The following protocol with injections of 10 mL of the commercial galactose-based contrast agent Echovist was applied in a randomized way: (1) no VM, (2) VM for 5 seconds starting 2 seconds after the beginning of contrast injection, (3) VM for 5 seconds starting 5 seconds after the beginning of contrast injection, (4) VM for 5 seconds starting 8 seconds after the beginning of contrast injection, and (5) repetitive short VMs in between 2 and 13 seconds after the beginning of contrast injection. In addition to the single tests, we also tested the sensitivity and specificity of combined results of the tests with VM.

RESULTS

In 21 patients, a right-to-left shunt was demonstrated by TEE and contrast TCD (shunt positive). Twenty-one patients were negative in both investigations, no patient was positive on TEE and negative on TCD, and 16 patients were only positive on at least 1 TCD investigation but negative during TEE. Test 3 was the most appropriate test when combined with the results of 1 of the other tests with VM. The highest sensitivities were achieved with a diagnostic time window of 40 seconds and when the presence of a single microbubble was sufficient for the diagnosis of a shunt.

CONCLUSIONS

TCD performed twice with 2 provocation maneuvers with Echovist is a sensitive method to identify TEE-proven cardiac right-to-left shunts. The VM should be performed for 5 seconds starting at 5 seconds after the beginning of contrast injection.

Abnormalities of cardiac sympathetic innervation in arrhythmogenic right ventricular cardiomyopathy : quantitative assessment of presynaptic norepinephrine reuptake and postsynaptic beta-adrenergic receptor density with positron emission tomography

BACKGROUND

The frequent provocation of ventricular tachycardia by stress or catecholamines and the efficacy of antiarrhythmic drugs with antiadrenergic properties suggest an involvement of the cardiac adrenergic system in arrhythmogenesis in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). Previous studies demonstrated abnormalities of the presynaptic uptake-1 assessed by (123)I-MIBG-single-photon emission computed tomography.

METHODS AND RESULTS

This study investigated neuronal reuptake of norepinephrine (uptake-1) and beta-adrenergic receptor density in 8 patients with ARVC and 29 age-matched control subjects. All subjects underwent positron emission tomography with the volume of distribution (V(d)) of [(11)C]hydroxyephedrine ((11)C-HED) used to assess presynaptic norepinephrine reuptake, the maximum binding capacity (B(max)) of [(11)C]CGP-12177 ((11)C-CGP-12177) to assess postsynaptic beta-adrenergic receptor density, and [(15)O]H(2)O for quantification of myocardial blood flow. Patients with ARVC demonstrated a highly significant global reduction in postsynaptic beta-adrenergic receptor density compared with that in control subjects (B(max) of (11)C-CGP-12177: 5.9+/-1.3 vs 10.2+/-2.9 pmol/g tissue, P<0.0007), whereas the presynaptic uptake-1 tended toward reduction only (V(d) of (11)C-HED: 59.1+/-25.2 vs 71.0+/-18.8 mL/g tissue, NS). There were no differences in myocardial blood flow between the groups, and plasma norepinephrine was within normal limits in patients and control subjects.

CONCLUSIONS

The findings demonstrate a significant reduction of myocardial beta-adrenergic receptor density in patients with ARVC. This may result from a secondary downregulation after increased local synaptic norepinephrine levels caused by increased firing rates of the efferent neurons or as the result of impaired presynaptic catecholamine reuptake. These findings give new insights into the pathophysiology of arrhythmogenesis in ARVC, with potential impact on diagnostic evaluation and therapeutic management.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy: need for an international registry. Study Group on Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy of the Working Groups on Myocardial and Pericardial Disease and Arrhythmias of the European Society of Cardiology and of the Scientific Council on Cardiomyopathies of the World Heart Federation

Arrhythmogenic right ventricular (RV) dysplasia/cardiomyopathy (ARVD/C) is a heart muscle disease characterized by peculiar RV involvement and electrical instability that precipitates ventricular arrhythmias and sudden death. The purpose of the present consensus report of the Study Group on ARVD/C of the Working Groups on Myocardial and Pericardial Disease and Arrhythmias of the European Society of Cardiology and of the Scientific Council on Cardiomyopathies of the World Heart Federation is to review the considerable progress in our understanding of the etiopathogenesis, morbid anatomy, and clinical presentation of ARVD/C since it first was described in 1977. The present article focuses on important but still unanswered issues, mostly regarding risk stratification, clinical outcome, and management of affected patients. Because ARVD/C is relatively uncommon and any one center may have experience with only a few patients, an international registry is being established to accumulate information and enhance the numbers of patients that can be analyzed and thus answer pending questions. The registry also will facilitate pathological, molecular, and genetics research on the causes and pathogenesis of the ARVD/C. Furthermore, availability of an international database will enhance awareness of this largely unrecognized condition among the medical community. Physicians are encouraged to enroll patients in the International Registry of ARVD/C.