Andreas Hagendorff

European association of echocardiography recommendations for the assessment of valvular regurgitation. Part 2: Mitral and tricuspid regurgitation (native valve disease)

Mitral and tricuspid are increasingly prevalent. Doppler echocardiography not only detects the presence of regurgitation but also permits to understand mechanisms of regurgitation, quantification of its severity and repercussions. The present document aims to provide standards for the assessment of mitral and tricuspid regurgitation.

Recommendations for the echocardiographic assessment of native valvular regurgitation: an executive summary from the European Association of Cardiovascular Imaging

Valvular regurgitation represents an important cause of cardiovascular morbidity and mortality. Echocardiography has become the primary non-invasive imaging method for the evaluation of valvular regurgitation. The echocardiographic assessment of valvular regurgitation should integrate the quantification of the regurgitation, assessment of the valve anatomy and function, as well as the consequences of valvular disease on cardiac chambers. In clinical practice, the management of patients with valvular regurgitation thus largely integrates the results of echocardiography. It is crucial to provide standards that aim at establishing a baseline list of measurements to be performed when assessing regurgitation.

Reduced cardiac conduction velocity and predisposition to arrhythmias in connexin40-deficient mice

Intercellular channels of gap junctions are formed in vertebrates by the protein family of connexins and allow direct exchange of ions, metabolites and second messenger molecules between apposed cells (reviewed in [1-3]). In the mouse, connexin40 (Cx40) protein has been detected in endothelial cells of lung and heart and in certain heart muscle cells: atrial myocytes, cells of the atrial ventricular (AV) node and cells of the conductive myocardium, which conducts impulses from the AV node to ventricular myocyctes [3]. We have generated mice homozygous for targeted disruption of the Cx40 gene (Cx40-/-mice). The electrocardiograph (ECG) parameters of Cx40-/- mice were very prolonged compared to those of wild type (Cx40+/+) mice, indicating that Cx40-/- mice have lower atrial and ventricular conduction velocities. For 6 out of 31 Cx40-/- animals, different types of atrium-derived abnormalities in cardiac rhythm were recorded, whereas continuous sinus rhythm was observed for the 26 Cx40+/+ and 30 Cx40+/- mice tested. The expression levels of other connexins expressed in heart (Cx37, Cx43 and Cx45) were the same in Cx40-/- and Cx40+/+ mice. Our results demonstrate the function of Cx40 in the regulation and coordination of heart contraction and show that cardiac arrhythmogenesis can not only be caused by defects in the ion channels primarily involved in cellular excitation but also by defects in intercellular communication through gap junction channels. As the distribution of Cx40 protein is similar in mouse and human hearts, further functional analysis of Cx40 should yield relevant insights into arrhythmogenesis in human patients.

Conduction Disturbances and Increased Atrial Vulnerability in Connexin40-Deficient Mice Analyzed by Transesophageal Stimulation

BACKGROUND Recently, it has been reported that connexin40 (Cx40) deficiency in targeted mouse mutants is associated with a prolongation of P-wave and QRS complex duration on surface electrograms. The specific effects of Cx40 deficiency on sinus node function, sinoatrial, and atrioventricular conduction properties as well as on atrial vulnerability have not yet been investigated systematically by electrophysiological analysis. METHODS AND RESULTS Fifty-two mice (18 Cx40(+/+), 15 Cx40(+/-), and 19 Cx40(-/-) mice) were subjected to rapid atrial transesophageal stimulation after anesthesia with avertin. A significant prolongation of sinus node recovery time was noticed in Cx40(-/-) mice compared with Cx40(+/-) and Cx40(+/+) mice (287.8+/-109.0 vs 211.1+/-61.8 vs 204.4+/-60.9 ms; P<0.05). In addition, Wenckebach periodicity occurred at significantly longer atrial pacing cycle lengths in Cx40(-/-) mice than in Cx40(+/-) or Cx40(+/+) mice (93. 3+/-11.8 vs 83.9+/-9.7 vs 82.8+/-8.0 ms, P<0.05). Analysis of 27 Cx40(-/-) mice showed a significant increase in intra-atrial conduction time and atrioventricular conduction time compared with 52 Cx40(+/-) and 31 wild-type (Cx40(+/+)) mice. Furthermore, in Cx40(-/-) mice, atrial tachyarrhythmias could be induced frequently by atrial burst pacing, whereas no atrial arrhythmias were inducible in heterozygous or wild-type mice. CONCLUSIONS This study demonstrates that Cx40 deficiency is associated with sinoatrial, intra-atrial, and atrioventricular conduction disturbances. In atrial myocardium of the mouse, Cx40 deficiency results in increased atrial vulnerability and might contribute to arrhythmogenesis.

Abnormal Cardiac Conduction and Morphogenesis in Connexin40 and Connexin43 Double-Deficient Mice

Connexin40-deficient (Cx40−/−/Cx43+/+) and connexin43-heterozygous knockout mice (Cx40+/+/Cx43+/−) are viable but show cardiac conduction abnormalities. The ECGs of adult double heterozygous animals (Cx40+/−/Cx43+/−) suggest additive effects of Cx40 and Cx43 haploinsufficiency on ventricular, but not on atrial, conduction. We also observed additive effects of both connexins on cardiac morphogenesis. Approximately half of the Cx40−/−/Cx43+/+ embryos died during the septation period, and an additional 16% died after birth. The majority of the latter mice had cardiac hypertrophy in conjunction with common atrioventricular junction or a ventricular septal defect. All Cx40−/−/Cx43+/− progeny exhibited cardiac malformations and died neonatally. The most frequent defect was common atrioventricular junction with abnormal atrioventricular connection, which was more severe than that seen in Cx40−/−/Cx43+/+ mice. Furthermore, muscular ventricular septal defects, premature closure of the ductus arteriosus, and subcutaneous edema were noticed in these embryos. Cx40+/−/Cx43−/− embryos showed the same phenotype (ie, obstructed right ventricular outflow tract) as reported for Cx40+/+/Cx43−/− mice. These findings demonstrate that Cx43 haploinsufficiency aggravates the abnormalities observed in the Cx40−/− phenotype, whereas Cx40 haploinsufficiency does not worsen the Cx43−/− phenotype. We conclude that the gap-junctional proteins Cx40 and Cx43 contribute to morphogenesis of the heart in an isotype-specific manner.

Transverse Conduction Capabilities of the Crista Terminalis in Patients With Atrial Flutter and Atrial Fibrillation

OBJECTIVES In this study, the transverse conduction capabilities of the crista terminalis (CT) were determined during pacing in sinus rhythm in patients with atrial flutter and atrial fibrillation. BACKGROUND It has been demonstrated that the CT is a barrier to transverse conduction during typical atrial flutter. Mapping studies in animal models provide evidence that this is functional. The influence of transverse conduction capabilities of the CT on the development of atrial flutter remains unclear. METHODS The CT was identified by intracardiac echocardiography. The atrial activation at the CT was determined during programmed stimulation with one extrastimulus at five pacing sites anteriorly to the CT in 10 patients with atrial flutter and 10 patients with atrial fibrillation before and after intravenous administration of 2 mg/kg disopyramide. Subsequently, atrial arrhythmias were reinduced. RESULTS At baseline, pacing with longer coupling intervals resulted in a transverse pulse propagation across the CT. During shorter coupling intervals, split electrograms and a marked alteration of the activation sequence of its second component were found, indicating a functional conduction block. In patients with atrial flutter, the longest coupling interval that resulted in a complete transverse conduction block at the CT was significantly longer than that in patients with atrial fibrillation (285 +/- 49 ms vs. 221 +/- 28 ms; p < 0.05). After disopyramide administration, a transverse conduction block occurred at longer coupling intervals as compared with baseline (287 +/- 68 ms vs. 250 +/- 52 ms; p < 0.05). Subsequently, a sustained atrial arrhythmia was inducible in 15 of 20 patients. This was atrial flutter in three patients with previously documented atrial fibrillation and in eight patients with history of atrial flutter. Mapping revealed a conduction block at the CT in all of these patients. CONCLUSIONS It was found that the CT provides transverse conduction capabilities and that the conduction block during atrial flutter is functional. Limited transverse conduction capabilities of the CT seem to contribute to the development of atrial flutter.

Color-coded Doppler imaging of the vena contracta as a basis for quantification of pure mitral regurgitation

The narrowest central flow region of a jet is defined as the vena contracta. This term is applied also to the contracted zone of the Doppler color flow image of a jet at its passage through an incompetent mitral valve. The clinical applicability of measuring the size of the vena contracta by transthoracic color-coded Doppler echocardiography for estimating the severity of mitral regurgitation (MR) was evaluated. In 78 of 82 patients with angiographically proved MR, a coherent flow image across the valve was visualized. The maximal diameter in the apical long-axis view was considered as a representative value for the size of the vena contracta. In comparison with the maximal left atrial velocity pixel area, this parameter revealed higher correlations to the angiographic degree of MR and to the regurgitant volume (r = 0.94 vs 0.72, and 0.83 vs 0.71, respectively). The highest positive and negative predictive accuracies for differentiating mild-to-moderate from severe MR were determined for a diameter of 6.5 mm (88 and 96%, respectively). Because the vena contracta is directly related to the severity of MR, it is concluded that it is helpful to use this parameter instead of the maximal velocity pixel area for semiquantitative grading.

Echocardiographic reference ranges for normal cardiac chamber size: results from the NORRE study.

AIMS Availability of normative reference values for cardiac chamber quantitation is a prerequisite for accurate clinical application of echocardiography. In this study, we report normal reference ranges for cardiac chambers size obtained in a large group of healthy volunteers accounting for gender and age. Echocardiographic data were acquired using state-of-the-art cardiac ultrasound equipment following chamber quantitation protocols approved by the European Association of Cardiovascular Imaging. METHODS A total of 734 (mean age: 45.8 ± 13.3 years) healthy volunteers (320 men and 414 women) were enrolled at 22 collaborating institutions of the Normal Reference Ranges for Echocardiography (NORRE) study. A comprehensive echocardiographic examination was performed on all subjects following pre-defined protocols. There were no gender differences in age or cholesterol levels. Compared with men, women had significantly smaller body surface areas, and lower blood pressure. Quality of echocardiographic data sets was good to excellent in the majority of patients. Upper and lower reference limits were higher in men than in women. The reference values varied with age. These age-related changes persisted for most parameters after normalization for the body surface area. CONCLUSION The NORRE study provides useful two-dimensional echocardiographic reference ranges for cardiac chamber quantification. These data highlight the need for body size normalization that should be performed together with age-and gender-specific assessment for the most echocardiographic parameters.

Role of multimodality cardiac imaging in the management of patients with hypertrophic cardiomyopathy: an expert consensus of the European Association of Cardiovascular Imaging Endorsed by the Saudi Heart Association.

Taking into account the complexity and limitations of clinical assessment in hypertrophic cardiomyopathy (HCM), imaging techniques play an essential role in the evaluation of patients with this disease. Thus, in HCM patients, imaging provides solutions for most clinical needs, from diagnosis to prognosis and risk stratification, from anatomical and functional assessment to ischaemia detection, from metabolic evaluation to monitoring of treatment modalities, from staging and clinical profiles to follow-up, and from family screening and preclinical diagnosis to differential diagnosis. Accordingly, a multimodality imaging (MMI) approach (including echocardiography, cardiac magnetic resonance, cardiac computed tomography, and cardiac nuclear imaging) is encouraged in the assessment of these patients. The choice of which technique to use should be based on a broad perspective and expert knowledge of what each technique has to offer, including its specific advantages and disadvantages. Experts in different imaging techniques should collaborate and the different methods should be seen as complementary, not as competitors. Each test must be selected in an integrated and rational way in order to provide clear answers to specific clinical questions and problems, trying to avoid redundant and duplicated information, taking into account its availability, benefits, risks, and cost.

Emergency echocardiography: the European Association of Cardiovascular Imaging recommendations.

Emergency echocardiography : the European Association of Cardiovascular Imaging recommendations