J. De Sutter

Long term results of cardioverter-defibrillator implantation in patients with right ventricular dysplasia and malignant ventricular tachyarrhythmias

OBJECTIVE To study the outcome of patients with arrhythmogenic right ventricular dysplasia treated with an implantable cardioverter-defibrillator (ICD) for ventricular tachyarrhythmias complicated by haemodynamic collapse. DESIGN Observational study. SETTING University hospital. PATIENTS Nine consecutive patients (eight male, one female; mean (SD) age, 36 (18) years) with arrhythmogenic right ventricular dysplasia presenting with ventricular tachycardia and haemodynamic collapse (n = 6) or ventricular fibrillation (n = 3), treated with an ICD. MAIN OUTCOME MEASURES Survival; numbers of and reasons for appropriate and inappropriate ICD interventions. RESULTS After a mean (SD) follow up of 32 (24) months, all patients were alive. Six patients received a median of 19 (range 2–306) appropriate ICD interventions for events detected in the ventricular tachycardia window; four received a median of 2 (range 1–19) appropriate ICD interventions for events detected in the ventricular fibrillation window. Inappropriate interventions were seen for sinus tachycardia (18 episodes in three patients), atrial fibrillation (three episodes in one patient), and for non-sustained polymorphic ventricular tachycardia (one episode in one patient). CONCLUSIONS Patients with arrhythmogenic right ventricular dysplasia and malignant ventricular arrhythmias have a high recurrence rate requiring appropriate ICD interventions, but they also often have inappropriate interventions. Programming the device is difficult because this population develops supraventricular and ventricular tachyarrhythmias with similar rates.

Electrocardiographic and morphometric features in patients with ventricular tachycardia of right ventricular origin

Objective To study differences between repetitive monomorphic ventricular tachycardia (RMVT) of right ventricular origin, and ventricular tachycardia in arrhythmogenic right ventricular dysplasia (ARVD). Patients Consecutive groups with RMVT (n = 15) or ARVD (n = 12), comparable for age and function. Methods Analysis of baseline, tachycardia, and signal averaged ECGs, clinical data, and right endomyocardial biopsies. Pathological findings were related to regional depolarisation (QRS width) and repolarisation (QT interval, QT dispersion). Results There was no difference in age, ejection fraction, QRS width in leads I, V1, and V6, and QT indices. During ventricular tachycardia, more patients with ARVD had a QS wave in V1 (p < 0.05). There were significant differences for unfiltered QRS, filtered QRS, low amplitude signal duration, and the root mean square voltage content. In the absence of bundle branch block, differences became non-significant for unfiltered and filtered QRS duration. Mean (SD) percentage of biopsy surface differed between RMVT and ARVD: normal myocytes (74(3.4)% v 64.5(9.3)%; p < 0.05); fibrosis (3(1.7)% v 8.9(5.2)%; p < 0.05). When all patients were included, there were significant correlations between fibrosis and age (r = 0.6761), and fibrosis and QRS width (r = 0.5524 for lead I; r = 0.5254 for lead V1; and r = 0.6017 for lead V6). Conclusions The ECG during tachycardia and signal averaging are helpful in discriminating between ARVD and RMVT patients. There are differences in the proportions of normal myocytes and fibrosis. The QRS duration is correlated with the amount of fibrous tissue in patients with ventricular tachycardia of right ventricular origin.

Triplane tissue Doppler imaging: a novel three-dimensional imaging modality that predicts reverse left ventricular remodelling after cardiac resynchronisation therapy

Background: Several two-dimensional (2-D) tissue Doppler imaging (TDI) echocardiographic techniques have proved useful to identify responders to cardiac resynchronisation therapy (CRT). Recently a 3-D probe allowing simultaneous acquisition of TDI data in three imaging planes became available. Objective: To evaluate the value of triplane TDI to predict reverse left ventricular (LV) remodelling after CRT. Methods: Sixty patients with heart failure, scheduled for CRT, underwent triplane echocardiography with simultaneous TDI acquisition before and 6 months after implantation. From the triplane dataset a 3-D LV volume was generated and LV volumes and ejection fraction were calculated. Intraventricular dyssynchrony was quantitatively analysed by evaluating time from onset of the QRS complex to peak myocardial systolic velocity in 12 LV segments from the triplane dataset and calculation of the standard deviation (Ts-SD-12). Clinical response was defined as an improvement of at least one New York Heart Association class. Reverse LV remodelling was defined as ⩾15% decrease of LV end-systolic volume at 6 months’ follow-up. Results: Responders to CRT had significantly more LV dyssynchrony at baseline than non-responders (mean (SD) Ts-SD-12: 42 (14) vs 22 (12), p<0.001). A cut-off value of 33 ms for baseline Ts-SD-12, acquired from the triplane TDI dataset, yielded a sensitivity of 89% with a specificity of 82% to predict clinical response to CRT; sensitivity and specificity to predict reverse LV remodelling were 90% and 83%, respectively. Conclusion: Triplane TDI echocardiography predicts clinical response and reverse LV remodelling 6 months after CRT implantation.

Stem cells for the heart, are we there yet?

Although several repair mechanisms have been described in the human heart, all fall too short to prevent clinical heart disease in most acute or chronic pathological cardiac conditions. Moreover, despite many breakthroughs in cardiovascular medicine, the complications of a myocardial infarction such as chronic heart failure remains a serious worldwide problem. Bone marrow stem cells could provide for a promising strategy to restore myocardial infarctions and prevent postinfarct congestive heart failure, because there is growing body of evidence that bone marrow stem cells, such as mesenchymal stem cells, can generate new cardiomyocytes in animals and humans. In this review, we will discuss important issues on stem cell therapy for cardiac regeneration after myocardial infarction, which might be of paramount importance when considering future human trials.

QT dispersion is not related to infarct size or inducibility in patients with coronary artery disease and life threatening ventricular arrhythmias

OBJECTIVE To relate QT parameters to infarct size and inducibility during electrophysiological studies. DESIGN Analysis of a prospective register. SETTING University hospital. PATIENTS 64 patients with coronary artery disease and documented life threatening ventricular arrhythmias. INTERVENTIONS Measurements of QT-max, QTc-max, and QT dispersion (QT-d) on a simultaneous 12 lead ECG (50 mm/s). Estimation of myocardial infarct size with radionuclide left ventricular ejection fraction (LVEF), echocardiography (left ventricular end diastolic diameter, LVEDD), and a defect score based on a quantitative stress redistribution 201-thallium perfusion study. Electrophysiological study to assess inducibility. RESULTS Mean (SD) QT parameters were: QT-max 440 (50) ms, QTc-max 475 (46) ms, and QT-d 47 (20) ms. Mean (SD) estimates of infarct size were: LVEF 34 (13)%, LVEDD 61 (9) mm, and defect score 18 (11). There was no significant correlation between any index of infarct size and QT parameters. QT parameters were not significantly different between patients with inducible (n = 57) and non-inducible arrhythmias (n = 7) (QT-max: 416 (30) v 443 (51) ms, p = 0.18; QTc-max 485 (34) v 473 (47) ms, p = 0.34; QT-d 47 (12) v 47 (21) ms, p = 0.73). Non-inducible patients had a significant lower defect score: 8 (9)v 19 (11), p = 0.02, but comparable LVEF: 38 (12)% v 34 (12)%, p = 0.58, and LVEDD: 54 (10) v 61 (8) mm, p = 0.13. CONCLUSIONS QT parameters are not influenced by infarct size and do not predict inducibility during electrophysiological study in patients with coronary artery disease and malignant ventricular arrhythmias. In contrast, the amount of scar tissue determined by perfusion imaging is strongly correlated with inducibility.

Improved identification of viable myocardium using second harmonic imaging during dobutamine stress echocardiography

OBJECTIVE To determine whether, compared with fundamental imaging, second harmonic imaging can improve the accuracy of dobutamine stress echocardiography for identifying viable myocardium, using nuclear imaging as a reference. PATIENTS 30 patients with chronic left ventricular dysfunction (mean (SD) age, 60 (8) years; 22 men). METHODS Dobutamine stress echocardiography was carried out in all patients using both fundamental and second harmonic imaging. All patients underwent dual isotope simultaneous acquisition single photon emission computed tomography (DISA-SPECT) with99mtechnetium-tetrofosmin/18F-fluorodeoxyglucose on a separate day. Myocardial viability was considered present by dobutamine stress echocardiography when segments with severe dysfunction showed a biphasic sustained improvement or an ischaemic response. Viability criteria on DISA-SPECT were normal or mildly reduced perfusion and metabolism, or perfusion/metabolism mismatch. RESULTS Using fundamental imaging, 330 segments showed severe dysfunction at baseline; 144 (44%) were considered viable. The agreement between dobutamine stress echocardiography by fundamental imaging and DISA-SPECT was 78%, κ = 0.56. Using second harmonic imaging, 288 segments showed severe dysfunction; 138 (48%) were viable. The agreement between dobutamine stress echocardiography and DISA-SPECT was significantly better when second harmonic imaging was used (89%, κ = 0.77, p = 0.001v fundamental imaging). CONCLUSIONS Second harmonic imaging applied during dobutamine stress echocardiography increases the agreement with DISA-SPECT for detecting myocardial viability.

Cardiovascular determinants and prognostic significance of CC Chemokine Ligand-18 (CCL18/PARC) in patients with stable coronary artery disease

Chemokines are important mediators of angiogenesis, hematopoiesis and leucocyte trafficking. CC Chemokine Ligand-18 (CCL18)/ pulmonary and activation-regulated chemokine (PARC) is a circulating chemokine that plays a role in injury healing, physiological homing of mononuclear blood cells and inflammatory responses. CCL18/PARC is also expressed in atherosclerotic plaques. We prospectively evaluated CCL18/PARC levels and their cardiovascular and biological determinants in a large cohort of 285 patients with stable coronary heart disease who were subsequently followed for 3 years for hard cardiac events. It was found that CCL18/PARC levels were associated with decreased cardiac function, decreased exercise capacity and increased inflammatory parameters including interleukin-6 (IL-6) and hs-CRP. More importantly high CCL18/PARC levels were an independent predictor of future cardiovascular events. Therefore, CCL18/PARC is a potential diagnostic and prognostic parameter in patients with stable coronary artery disease.

Right atrial thrombus in an asymptomatic hemodialysis patient with malfunctioning catheter and patent foramen ovale

The creation of an accurate functioning arteriovenous fistula has been a long‐lasting problem in the hemodialysis setting. In spite of recent guidelines and largely because of the old age of the current dialysis population and a high incidence of diabetes mellitus, atherosclerosis, and related vascular problems, it is not always possible to create an adequate fistula. In that case, long‐term tunneled indwelling central vein catheters are a frequently used alternative. Of the many possible complications related to venous access in hemodialysis patients, catheter dysfunction is the most prevalent. We report a 23‐year‐old female hemodialysis patient in whom such malfunctioning was followed by echocardiography that revealed a large right atrial thrombus (RAT) in close contact to the tip of a long‐term indwelling catheter in the presence of a patent foramen ovale. Although RAT is a rare complication in hemodialysis patients, it has very specific therapeutic implications. The present patient underwent a successful surgical atrial thrombectomy. Our experience underscores that in cases of malfunctioning catheter, echocardiographic screening is mandatory.

Dilated cardiomyopathy caused by a novel TNNT2 mutation-added value of genetic testing in the correct identification of affected subjects.

Diagnosing familial dilated cardiomyopathy requires careful family history taking and clinical evaluation in first degree relatives. Based on the results of these findings the diagnosis may be established in the proband. However, due to the age-dependent expression of the disease, doubt may persist regarding the exact status of other family members, especially in young individuals. Here we present a family with DCM in whom we identified an underlying cardiac troponin T (TNNT2) mutation. Genetic testing was essential for the detection of asymptomatic carriers as well as for exclusion of the disease in other family members.

Validation of planar and tomographic radionuclide ventriculography by a dynamic ventricular phantom.

&NA; Although there is increasing interest in the automatic processing of tomographic radionuclide ventriculography (TRV) studies, validation is mainly limited to a comparison of TRV results with data from planar radionuclide ventriculography (PRV) or gated perfusion single photon emission computed tomography (SPECT). The aim of this study was to use a dynamic physical cardiac phantom to validate the ejection fraction (EF) and volumes from PRV and TRV studies. A new dynamic left ventricular phantom was constructed and used to obtain 21 acquisitions in the planar and tomographic mode. The directly measured volumes and EFs of the phantom during the acquisitions were considered as the gold standard for comparison with TRV and PRV. EFs were calculated from PRV by background‐corrected end‐diastolic and end‐systolic frames. Volumes and EFs were calculated from TRV by region growing with different lower thresholds to search for the optimal threshold. EF from PRV correlated significantly with the real EF (r = 0.94, P = 0.00). The optimal threshold value for volume calculation from TRV in 336 cases was 50% (r = 0.98, P = 0.00) yielding the best slope after linear regression. When considering these calculated end‐diastolic and end‐systolic volumes, EF correlated well (r = 0.99, P = 0.00) with the real EF, and this correlation was significantly (P = 0.04) higher than that of the EF from PRV. Our experiments prove that EF measured by TRV yields more accurate results compared with PRV in dynamic cardiac phantom studies.