Background-Biventricular pacing has been proposed to improve symptoms and exercise capacity in patients with advanced heart failure and wide electrocardiographic wave complexes. This study investigated the effect of biventricular pacing on reverse remodeling and the underlying mechanisms. Methods and Results-Twenty-five patients with NYHA class III to IV heart failure and electrocardiographic wave complex duration Ͼ140 ms receiving biventricular pacing therapy were assessed serially up to 3 months after pacing and when pacing was withheld for 4 weeks. Tissue Doppler echocardiography was performed using a 6-basal, 6-mid segmental model to assess the time to peak sustained systolic contraction (T S ). There was significant improvement of ejection fraction, dP/dt, and myocardial performance index; decrease in mitral regurgitation, left ventricular (LV) end-diastolic (205Ϯ68 versus 168Ϯ67 mL, PϽ0.01) and end-systolic volume (162Ϯ54 versus 122Ϯ42 mL, PϽ0.01); and improved 6-minute hall-walk distance and quality of life score after pacing for 3 months. The mechanisms of benefits were as follows: (1)

Background-Patients with heart failure are frequently hospitalized for fluid overload. A reliable method for chronic monitoring of fluid status is therefore desirable. We evaluated an implantable system capable of measuring intrathoracic impedance to identify potential fluid overload before heart failure hospitalization and to determine the correlation between intrathoracic impedance and standard measures of fluid status during hospitalization. Methods and Results-Thirty-three patients with NYHA class III and IV heart failure were implanted with a special pacemaker in the left pectoral region and a defibrillation lead in the right ventricle. Intrathoracic impedance was regularly measured and recorded between the lead and the pacemaker case. During hospitalizations, pulmonary capillary wedge pressure and fluid status were monitored. Ten patients were hospitalized for fluid overload 25 times over 20.7Ϯ8.4 months. Intrathoracic impedance decreased before each admission by an average of 12.3Ϯ5.3% (PϽ0.001) over an average of 18.3Ϯ10.1 days. Impedance reduction began 15.3Ϯ10.6 days (PϽ0.001) before the onset of worsening symptoms. There was an inverse correlation between intrathoracic impedance and pulmonary capillary wedge pressure (

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Despite current interest in the biology and diagnostic application of plasma cell-free DNA (1 ), there is little knowledge regarding the cellular origin of this DNA. Recently, we have used a sex-mismatched bone marrow transplantation model to study the relative contributions of hematopoietic and nonhematopoietic cells to circulating DNA (2 ). We have demonstrated that the predominant proportion of plasma DNA originates from the hematopoietic system (2 ). However, the proportions of cell-free plasma DNA originating from other organs (e.g., heart, liver, and kidneys) remain unknown. We therefore investigated the contribution of the heart, liver, and kidneys to circulating DNA with use of sex-mismatched heart, liver, and renal transplantation models, respectively.Sex-mismatched heart, liver, and renal transplantation patients were recruited for the study. Twenty-one patients who had received heart transplants were recruited from the Grantham Hospital, Hong Kong. Fourteen of these heart transplantation patients were females with male donors, whereas the remaining 7 were males with female donors. Four sex-mismatched liver transplantation patients at the Pediatric Surgical Unit of the Department of Surgery, Prince of Wales Hospital were recruited; two of these patients were females with male donors and the other two were males with female donors. Six sexmismatched renal transplantation patients were recruited from the Department of Medicine and Therapeutics of the Prince of Wales Hospital. Three of these patients were females with male donors, whereas the remaining three were males with female donors. Informed consent was obtained from all individuals. None of these transplantation recipients had evidence of graft rejection or graft-vshost disease. Ten healthy individuals were also recruited with informed consent.Peripheral blood samples were collected into EDTA tubes from all participants. The blood samples were subjected to centrifugation at 1600g for 10 min, followed by microcentrifugation at 16 000g for 10 min (Eppendorf Centrifuge 5415D) to obtain cell-free plasma (3 ). DNA was extracted with use of the QIAamp Blood Kit (Qiagen) according to the "blood and body fluid protocol" as recommended by the manufacturer (4 ). We used 400 L of plasma per column for DNA extraction. We then subjected 5 L (of an elution volume of 50 L) of the extracted plasma DNA to real-time quantitative PCR for the ␤-globin and SRY genes as described previously (5 ), using a PE Applied Biosystems 7700 Sequence Detector.

LAU, C.-P., ET AL.: Reversal of Left Ventricular Remodeling by Synchronous Biventricular Pacing in Heart Failure. Synchronous biventricular pacing is a new nonpharmacological supplemental treatment of advanced heart failure associated with electromechanical conduction delay. However, the role of pac ing on left ventricular remodeling is unknown. Eleven patients with New York Heart Association Class III to IV heart failure, a ¡eft ventricular ejection fraction < 35%, and a QRS duration > 140 ms received a biventricular dual chamber pacemaker. Serial echocardiography, 6-minute hall walk, and Minnesota Liv ing with Heart Failure quality-of-life (QOL) questionnaire were performed before and after up to 3 months of pacing. At 3 months there was a significant increase in fractional shortening (P < 0.001), ejection frac tion (P < 0.001), and cardiac output (P < 0.05). The left ventricular end-diastolic volume (245 ± 70 vs 185 ± 37 mL, P < 0.05),, and mitral régurgitation were reduced (P < 0.05), and diastolic filling time was lengthened (P < 0.05). There were also improvements in heart failure symptoms, an increase in 6-minute walk distance, and a decrease in QOL scores. Syn chronous biventricular pacing for 3 months was associated with hemodynamic improvements, reversal of left ventricular remodeling, and increase in left ventricular systolic function, and a decrease in secondary mitral régurgitation. (PACE 2000; 23[Pt.II]:l 722-1725) pacing, heart failure, biventricular, remodeling, left ventricle

Amplatzer septal occluder (AGA Med. Co., USA) is a novel device for occlusion of atrial septal defect. We present our experience of transcatheter closure of atrial septal defects using Amplatzer septal occluder in 45 adult Chinese patients (age range 18-69 years). The size of atrial septal defect varied from 14-28 (23 +/- 4) mm. Cardiac catheterization revealed a pulmonary-to-systemic shunt ratio ranging from 1.4-2.8 (mean 2.0 +/- 0.4). The procedure was successful in 44 (98%) patients. Displacement of the device requiring surgical removal occurred in one (2%) patient and minor wound complication occurred in two (4%) patients. Total procedure time was 67 +/- 16 minutes and the fluoroscopy time was 25 +/- 8 min. Immediate post-procedure and pre-discharge echocardiography revealed complete abolition of shunt in 42 (93%) and trivial residual shunt in 3 (7%) patients. The average follow-up period was 16 +/- 6 months (range 2 months to 3 years) months. None of the patients had developed other major complication at follow-up. Cathet Cardiovasc Intervent 2001;52:373-377.

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Green fluorescent protein (GFP) is an excellent biosensor as a result of its ability to be easily monitored in a wide variety of applications. Enzymes and proteins have been used as biological indicators to evaluate the immediate efficacy of industrial procedures, such as blanching, pasteurization, and disinfection treatments, as well as to monitor the satisfactory preservation of a product subjected to disinfection or sterilization. The purpose of this work was to study GFP stability in chlorinated water for injection (WFI) and chlorinated buffered solutions at various pH ranges, with and without agitation, to evaluate the exposure time required for chlorine to decrease 90% of its fluorescence intensity (decimal reduction time, D-value, min, 25 degrees C). Fluorescence intensity (Ex/Emmax = 394/509 nm) was measured immediately after the addition of GFP (8.0-9.0 microg/mL) into buffered or unbuffered chlorine solutions with or without constant stirring. With solutions constantly stirred, GFP fluorescence decreased abruptly on contact with chlorine in concentrations greater than 150 ppm, with D-values between 1.3 min (147 ppm chlorine) and 1.7 min (183 ppm chlorine). In phosphate buffered chlorine solutions (pH = 7.15 +/- 0.08), GFP retained its structure between 52 and 94 ppm, but protein stability decreased 10-fold when exposed to 110 ppm chlorine. The recovery of GFP fluorescence intensity due to renaturation was observed between 30 and 100 ppm chlorine in WFI (final pH = 11.01 +/- 0.23) without stirring. Stirring enhanced the contact between GFP and chlorine throughout the assay and provided a more accurate D-value evaluation. GFP performed as a suitable fluorescent marker for monitoring disinfection effectiveness.