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Background: Cellular replacement strategies using embryonic stem cells (ESCs) and their cardiac derivatives are emerging as novel experimental therapeutic paradigms for the treatment of post-myocardial infarction (MI) left ventricular (LV) dysfunction; however, their potential proarrhythmic risk remains unclear.Objective: The purpose of this study was to investigate the functional effect and proarrhythmic risk of ESC transplantation in a mouse model of MI.Methods: We compared the functional effects and proarrhythmic risk of direct intramyocardial transplantation of 3 × 10(5) undifferentiated mouse ESCs (MI+ESC group, n = 33) and mouse ESC-derived cardiomyocytes (MI+ESC-CM group, n = 40) versus culture medium (MI group, n = 33) at the infarct border zone in a mouse model of acute MI. LV performance was assessed with serial cardiac magnetic resonance imaging (MRI) at 1 and 3 week(s) post-MI, and invasive LV pressure measurement was assessed (dP/dt) at 4 weeks before sacrifice for histological examination. Furthermore, electrophysiological study was also performed in another set of animals in each group (n = 24) to assess for proarrhythmias after transplantation.Results: In vitro cellular electrophysiological study demonstrated that ESC-CMs exhibit arrhythmogenesis including automaticity, lengthened action potential duration, and depolarized resting membrane potential. At 4 weeks, the MI+ESC-CM group (21/40, 53%) had a higher mortality rate compared with those in the MI group (10/33, 30%, P = .08) and in the MI+ESC group (7/33, 21%, P = .012). Electrophysiological study showed a significantly higher incidence of inducible ventricular tachyarrhythmias in the MI+ESC-CM group (13/24, 54%) compared with in the MI group (6/24, 21%, P = .039) and in the MI+ESC group (5/24, 21%, P = .017). Cardiac MRI showed similar improvement in LV ejection fraction in the MI+ESC and MI+ESC-CM groups compared with in the MI group at 1 week (27.5% ± 3.8%; 30.3% ± 5.2% vs. 12.4% ± 1.4%; P < .05) and 3 weeks (29.8% ± 3.9%; 27.0% ± 4.8% vs. 10.6% ± 2.8%; P < .05) post-MI, respectively. Furthermore, invasive hemodynamic assessment at 4 weeks showed significant similar improvement in LV +dP/dt in the MI+ESC (2,644 ± 391 mmHg/s, P < .05) and MI+ESC-CM groups (2,539 ± 389 mmHg/s; P < .05) compared with in the MI group (2,042 ± 406 mmHg/s).Conclusions: Our results demonstrate that transplantation of undifferentiated ESCs and ESC-CMs provides similar improvement in cardiac function post-MI. However, transplantation of ESC-CMs is associated with a significantly higher prevalence of inducible ventricular tachyarrhythmias and early mortality than transplantations with ESCs. [ABSTRACT FROM AUTHOR]

Herba Epimedii, Fructus Ligustri Lucidi and Fructus Psoraleae are three frequently used Chinese herbs traditionally used for tonifying the 'kidney system'. They were selected for the present study to formulate an herbal preparation with a weight ratio of 5:4:1 based on their phytochemical, nature, documented treatment efficacy and toxicity. The dosing effects (1 g/day, 0.5 g/day and 0.175 g/day) of the antiosteoporosis function of the water extract of this formula were tested in ovariectomy- and calcium deficiency-induced osteoporotic rats. Eleven weeks of herbal treatment demonstrated a beneficial effect on the preservation of bone mineral density (BMD) at the femur neck in a dose-dependent manner with the preference for higher dosage. No significant increase in uterus weight was observed in the herbal formula treated rats. In addition, microarray data of kidney tissue revealed that this herbal formula was able to down-regulate the expression of phase II drug metabolizing enzymes, similar to the effects of estrogens. [ABSTRACT FROM AUTHOR]

BACKGROUND: Atrial fibrillation (AF) that occurs as a frequent complication of myocardial infarction (MI) is associated with a poor clinical outcome. It nonetheless remains uncertain whether AF that occurs transiently during MI is associated with a subsequent increased risk of the development of AF and ischemic stroke. METHODS: We retrospectively studied the impact of transient AF on the long-term risk of the occurrence of AF, ischemic stroke, and mortality in 431 consecutive patients (mean [+/- SEM] age, 64 +/- 1 years; 75% men). All patients had experienced an acute inferior ST-segment-elevation MI and had preserved left ventricular ejection fraction (LVEF) [> 45%]. RESULTS: All patients were in sinus rhythm on hospital admission, and transient AF was observed in 59 patients (13.7%) during their hospitalization for MI. On hospital discharge, all patients were in sinus rhythm and had been prescribed antiplatelet agents alone as antithrombotic therapy. Patients in whom transient AF developed during MI were older (mean age, 70 +/- 1.4 vs 64 +/- 0.7 years, respectively; p < 0.01) and more likely to be women (37% vs 23%, respectively; p < 0.02) compared with those without AF. At 1-year follow-up, the incidence of AF (22.0% vs 1.3%, respectively; p < 0.01) and ischemic stroke (10.2% vs 1.8%, respectively; p < 0.01) was higher in patients with transient AF than in those without transient AF. The total mortality rate was nonetheless similar (5.6% vs 6.8%, respectively; p = 0.73); Cox regression analysis demonstrated that age > 65 years and transient AF during MI were independent predictors of the subsequent occurrence of AF and the development of ischemic stroke. CONCLUSION: Transient AF complicating acute inferior MI is associated with an increased future risk of AF occurrence and ischemic stroke in patients with preserved LVEF, despite the use of antiplatelet therapy. [ABSTRACT FROM AUTHOR]

BACKGROUND: The close proximity of left atrium (LA) and esophagus during radiofrequency ablation for atrial fibrillation (AF) predisposes to thermal injury resulting in atrio-esophageal fistula. This work proposes to study the anatomic relationship between the esophagus and the LA wall using multidetector computed tomography (MDCT) three-dimensional (3D) 'Navigator' reconstruction technique. METHODS: Forty-five consecutive patients (37 men, mean age 52.7+/-14.1 years) with preradiofrequency ablation MDCT scans of the thorax for AF were recruited. Length and type (continuous or interrupted) of fat pad between esophagus and LA were evaluated. The position, width, and length of the esophagus in contact (without fat pad) with the LA were determined by using 'Navigator' software on the endocardial view of LA. RESULTS: The fat pad was continuous in 4% (2 of 45) and interrupted in 96% (43 of 45) patients. The mean width and length of esophageal-LA contact in 43 cases with interrupted fat pad was 24.0+/-5.8 mm (range 10.5-35.3 mm) and 41.9+/-11.6 mm (5.4-64 mm), respectively. There was an inverse relationship between the lengths of the esophageal-LA contact and the upper fat pad (r=-0.50, P=0.001). The esophagus was located to the left, right, and midline of the LA in 40, 2, and 1 patients, respectively, and the esophagus was in contact with and overrode the PV orifice in 22 and 4 patients, respectively. CONCLUSION: Direct esophageal-LA contact without the intervening fat pad was present in 96% of the cases, with 93% of esophagi lying to the left of the LA and 51% in contact with a PV orifice. Three-dimensional Navigator imaging technique has enhanced the visualization of the anatomical information of the esophagus, LA wall, and PV orifices that may be used to avoid thermal injury to the esophagus during LA ablation procedure. [ABSTRACT FROM AUTHOR]

Hypertension is related to sodium intake, and many patients with essential hypertension are overweight and have the metabolic syndrome. We therefore studied microsatellite markers close to the thiazide-sensitive Na-Cl cotransporter on chromosome 16 and a quantitative trait locus for abdominal obesity-metabolic syndrome (AOMS2) on chromosome 17, which have been found to be linked to hypertension in a previous genome scan in Chinese. There were 84 hypertensive subjects (44 men, 40 women, age 53±13 years) and 88 normotensive controls (40 men, 48 women, age 54±13 years) recruited. Specific oligonucleotide primers were used to amplify genomic DNA spanning the microsatellite markers D16S3396 and D17S1303 that consist of ATA and GATA repeats, respectively. We did not find any association between D16S3396 and blood pressure. In contrast, the distribution of D17S1303 genotypes differed between hypertensive subjects and normal controls (P=0.014). The number of GATA repeats correlated inversely with diastolic blood pressure (r=-0.18, P=0.02) and body mass index (r=-0.12, P=0.01). Nine GATA repeats in D17S1303 were associated with hypertension (OR 2.19, 95%CI 1.08-4.44, P=0.027), while 14 GATA repeats were associated with normotension (OR 0.26, 95%CI 0.10-0.66, P=0.002). The diastolic blood pressure in those with or without the (GATA)9 allele was 85.9±13.6 and 79.2±13.6?mmHg respectively (P=0.01), and in those with or without the (GATA)14 allele it was 73.8±11.0 and 81.8±14.0?mmHg respectively (P=0.003). Our results provide further evidence that a gene predisposing to hypertension in Chinese is in the vicinity of the microsatellite D17S1303.Journal of Human Hypertension (2005) 19, 407-411. doi:10.1038/sj.jhh.1001835Published online 17 February 2005 [ABSTRACT FROM AUTHOR]

Introduction: Radiofrequency (RF) catheter ablation currently is used for treatment of cardiac arrhythmias. Although the success rate is high for almost all supraventricular tachycardias (SVT), this technique has some drawbacks, especially when pulmonary veins (PV) are targeted for treatment of atrial fibrillation (AF). Additionally, new techniques for isolation of the PVs have the drawback that they can be used only for PV isolation and not for routine treatment of other SVTs. The aim of this study was to report on the safety and efficacy of a new cryoablation system for treatment of all SVTs. Methods and Results: Forty-nine patients with SVT (38 men; age 48 years, range 23-76) were enrolled in the study. Five patients were withdrawn from the study before they underwent cryoablation. The remaining 44 patients were treated with cryoablation (22 AF, 15 atrial flutter, 3 accessory pathway, 2 AV nodal reentrant tachycardia, 1 AV junction ablation for permanent AF, 1 atrial tachycardia). Cryoablation was performed with the CryoCor[TM] cryoablation system, which uses a precooling system and N2O as a refrigerant. The number of freezes applied varied according to the index arrhythmia treated. Successful isolation of PVs was performed in 20 of (96%) 21 AF patients and 53 of 55 veins. The overall acute success was 98% (43/44). Fifty-three PVs were isolated (2.5/patient). The success rate was 100% (23/23) for right-sided procedures. The average and nadir temperatures reached in right-sided and left-sided procedures were -77°C and -80°C and -75°C and -78°C, respectively. No acute PV stenosis was seen. Conclusion: This novel cryoablation system appears to be safe and can successfully treat different types of SVTs, including AF. Isolation of PVs is possible without producing stenosis. Despite the high blood flow in the right atrial isthmus and PVs, bidirectional conduction block can be achieved. [ABSTRACT FROM AUTHOR]

The effects of oral nitrendipine and oral propranolol, alone and in combination, on AV conduction have been examined in 11 patients with essential hypertension in whom arterial pressure was not adequately controlled despite treatment with thiazide diuretics. The study was performed double-blind. After a drug free period of 1 week, the patients received two 7 day courses of drug therapy after initial control measurements. Five of the eleven patients were randomised to receive nitrendipine 20 mg daily, the other six patients received propranolol (Inderal LA 160 mg daily) for the first week of therapy. During week 2, 10 patients received combined therapy. In the 10 patients who completed the study, oral nitrendipine, given either alone or in combination with oral propranolol, had no significant effect on resting PR, QRS, QT intervals nor on AV conduction as assessed by ambulatory electrocardiography. Propranolol did not affect the resting PR interval but significantly increased PR intervals on the ambulatory ECG recordings during single and combined therapy. However the maximum PR intervals remained within normal limits. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the impact of transcatheter radiofrequency ablation on quality-of-life (QOL) and exercise capacity in patients with paroxysmal supraventricular tachycardia (SVT) on stable medical therapy and the extent of symptomatic benefits of this treatment in patients with SVT of different clinical severity. A total of 55 patients with SVT on stable medications for 3 months were randomly selected for either radiofrequency ablation treatment (46 patients) or continuation of medical therapy (medical control group, 9 patients). Severity of SVT was classified based on the frequency and duration of SVT episodes, hemodynamic disturbance, and the presence of preexcited atrial fibrillation during an episode. Treadmill exercise capacity (Bruce protocol) and QOL (questionnaire study and interview) were assessed before and at 3-month intervals for 1 year after the radiofrequency procedure and at 3 months in the medical control group. Thirty-six of 46 patients were successfully ablated in one session, and a QOL measure before and at 3 months after ablation in these patients showed an improvement in total scores for 'General Health Questionnaire' (20.3 +/- 6.2 vs 16.9 +/- 5.3, P < 0.01), 'Somatic Symptoms Inventory' (73.0 +/- 6.0 vs 76.1 +/- 4.1, P < 0.02), and 'Sickness Impact Profile' (12.6 +/- 1.7 vs 4.9 +/- 3.9, P < 0.01). This improvement in QOL was progressive and sustained over a 1-year period. Major arrhythmia limitations, such as apprehension of strenuous activities and long distance travel, were alleviated after a successful procedure. The extent of improvement in QOL was significant for patients considered to have 'mild' or 'severe' arrhythmia.(ABSTRACT TRUNCATED AT 250 WORDS) [ABSTRACT FROM AUTHOR]

Objective: To investigate the association between raised blood pressure and dysglycemia.Research Design and Methods: We studied the association between raised blood pressure and dysglycemia in 1,862 subjects in the Hong Kong Cardiovascular Risk Factor Prevalence Study cohort. We determined the factors predicting the development of diabetes and hypertension in 1,496 subjects who did not have either condition at baseline.Results: Diabetes and hypertension were both related to age, obesity indexes, blood pressure, glucose, HDL cholesterol, and triglycerides. Of subjects with diabetes, 58% had raised blood pressure. Of subjects with hypertension, 56% had dysglycemia. BMI and blood glucose 2 h after a 75-g oral glucose load were independent predictors of new-onset diabetes. Age, systolic blood pressure, and 2-h glucose were independent predictors of new-onset hypertension. BMI, systolic blood pressure, and 2-h glucose were independent predictors of the development of diabetes and hypertension together.Conclusions: Diabetes and hypertension share common etiological factors. Patients with diabetes or hypertension should be screened and managed for the precursor of the other condition. [ABSTRACT FROM AUTHOR]