Mobility of the Intimal Flap and Thrombus Formation in Aortic Dissection: A Transesophageal Echocardiographic Study

The mechanisms of the motion of the intimal flap and of thrombus formation in acute or chronic aortic dissection are not definitively elucidated. Transesophageal echocardiography seems to be a technique of choice to analyze the flow in the true and false lumina. Twenty-one consecutive patients were studied in order to define the mobility of the intimal flap, the color Doppler flow patterns, the presence of spontaneous echocardiographic contrast, and thrombus formation at different levels of the aorta. The results suggest that clotted false lumen is more often seen in chronic aortic dissection at the level of the descending thoracic aorta. However, thrombosed false lumen in the aortic arch is suggestive of a retrograde aortic dissection. In cases of complete obliteration of the false lumen, the differentiation between aortic dissection and aortic ectasia with mural thrombus may be extremely difficult.     

Meta-Analysis of Positive Blood Cultures During Transesophageal Echocardiography

We have reviewed ten prospective studies of bacteremia with transesophageal echocardiography (TEE) in 720 patients. The incidence of TEE related positive culture is low, and general recommendation for antibiotic prophylaxis during TEE is not warranted.     

Determination of the structure of [Nle7]-endothelin by 1H NMR

[Nle⁷]-endothelin was synthesized and studied by ¹H NMR and distance geometry calculations. The NMR study was performed first in DMSO-d₆ and then in 50% acetonitrile/water since this peptide aggregates in pure water. In both cases, all spin systems were identified and assigned with the aid of two-dimensional spectroscopy (2D): COSY (for scalar couplings) and NOESY (for dipolar couplings). On the basis of the acetonitrile/water NMR parameters, and using the DISGEO program, a three-dimensional structure of [Nle⁷]-endothelin is proposed and discussed.     

Autotumour reactive T-cell clones among tumour-infiltrating T lymphocytes in B-cell non-Hodgkin's lymphomas

Summary. Seventy-three T-cell clones (TCC) were established from tumour-infiltrating lymphocytes-T (TIL-T) derived from lymph nodes involved by B-cell non-Hodgkin's lymphomas (B-NHL) in nine patients with different histological subtypes and clinical stages. 40 TCC (55%) expressed the CD25 Ag and were also able to proliferate in the presence of irradiated autologous B-NHL cells. Among them, 23 autotumour (AuTu) proliferative TCC were found not to proliferate to autologous EBV-transformed B-cell lines, indicating that the proliferative reactivity of these TCC was preferentially directed at autologous B-NHL cells. Tested against autologous B-NHL cells, only three AuTu prolifera- tive TCC (CD8 ⁺) showed a significant level of cytotoxicity (specific lysis > 15%). In blocking experiments, the AuTu proliferative reactivity of three TCC from one patient was strongly inhibited by anti-DR and anti-DQ mAbs, whereas that of three TCC from another patient was not affected by either anti-MHC class I or class II (DR., DP, DQ) mAbs. These findings suggest that the recognition of autologous B-NHL cells by AuTu proliferative TCC may occur through MHC-restricted as well as MHC-unrestricted mechanisms.     

Successful Catheter Ablation of Atrial Fibrillation

Catheter Ablation of AF. Introduction: Catheter ablation of a case of incessant atrial fibrillation was attempted using linear right atrial lesions created by sequential applications of radiofrequency energy.
Methods and Results: A 46-year-old patient had incessant episodes of atrial fibrillation. He had previously undergone successful radiofrequency catheter ablation of a common atrial flutter. Antiarrhythmic drugs including amiodarone and various drug combinations were ineffective. A 7-French specially designed 14-polar catheter with interelectrode distance of 3 mm was used to create linear lesions in the right atrium. Each electrode was 4 mm in length and able to transmit radiofrequency energy. Three linear lesions, two longitudinal and one transverse that connected the two longitudinal lesions, were created using 30 radiofrequency applications of 10 to 40 W. The final application interrupted an atrial fibrillation that had been persistent for 55 minutes. No sustained atrial fibrillation was inducible despite repeated pacing maneuvers. There was no complication. In short-term follow-up of 3 months, the patient has been free of arrhythmias without antiarrhythmic medication.
Conclusion: Successful catheter ablation of human atrial fibrillation is feasible using linear atrial lesions created by radiofrequency energy delivery. Further studies are mandatory to ascertain the efficacy and safety of this procedure, as well as to assess different catheter techniques.     

Reliability and Reproducibility of QRS Duration in the Selection of Candidates for Cardiac Resynchronization Therapy

Reliability and Reproducibility of QRS Duration . Background: A QRS >120 ms remains the recommended criterion for the selection of cardiac resynchronization therapy (CRT) candidates. However, the reproducibility of this measurement has not been studied thoroughly. Methods: QRS duration was measured by 3 experienced cardiologists and by automatic measurement on 228 electrocardiograms (ECGs) randomly collected from 188 subjects, including neonates, healthy adults, patients with complete and incomplete bundle branch block, and CRT candidates. All ECGs were recorded at a 25 mm/s sweep speed. Forty recordings were duplicated and 50 ECGs were recorded at both 25 and 50 mm/s. Results: Significant interobserver differences (P < 0.001) were found between each combination of paired observers, with an up to 50‐ms absolute variability between cardiologists and low concordance with computerized measurements. Intraobserver absolute variability was also significant (P < 0.01) for the 3 observers. These significant differences persisted (P < 0.01) when focusing our interest on the ECGs in the 100–140 ms range (defined as at least one out of the 4 measures in this range). Considering the 120 ms limit, 22 (27.5%) ECGs were differently classified by at least one of the cardiologists. We observed similar interobserver differences between each combination of paired observers with a 50 mm/s sweep speed. Conclusion: Manual QRS duration measurements were associated with significant inter‐ and intraobserver variability and low concordance with computerized measurements. The measurement of QRS is, therefore, operator‐dependent and a reevaluation of the measurement methods may be essential to develop clinical and investigative standards. (J Cardiovasc Electrophysiol, Vol. 21, pp. 890‐892, August 2010)