Po-Hsien Chu

The Gln–Arg 191 polymorphism of the human paraoxonase gene is not associated with the risk of coronary artery disease among Chinese in Taiwan

Paraoxonase (PON1) is a high density lipoprotein-associated enzyme capable of hydrolyzing lipid peroxides, and thus, might protect lipoproteins from oxidation. A common polymorphism due to an amino acid substitution (Gln-Arg) at codon 191 is considered to be a major determinant of variation in serum PON1 activity. Recent studies have suggested that the PON1-191 polymorphism is an independent risk factor for coronary atherosclerosis in patients with or without diabetes mellitus. The association of PON1-191 polymorphism genotypes and coronary artery disease (CAD) among Chinese subjects in Taiwan was examined. The genotype of 218 angiographically documented CAD patients and the same number of age- and sex-matched control subjects was determined. Genotypes AA, AB and BB were present in 25 (11%), 102 (47%) and 91 (42%) of control subjects, respectively, and in 30 (14%), 96 (44%) and 92 (42%) of CAD patients, respectively (chi2 = 0.57, P = 0.75 between groups). The frequency of the A allele was 0.36 for the control group and 0.35 for CAD patients (P = 0.94). No significant differences in the PON1-191 genotype frequencies could be found between groups when multivariate logistic regression analysis was performed, or different subgroups of age, sex or risk factors were analyzed. Among control subjects, there was also no significant difference between genotypes of the PON1-191 polymorphism and various clinical and lipid variables. In conclusion, our data suggest that there is no association between the Gln-Arg 191 polymorphism of the human PON1 gene and CAD among Chinese subjects in Taiwan.

Video-assisted mitral valve operations

BACKGROUND Video-assisted endoscopy has been applied frequently in the management of a variety of surgical diseases. However, it has rarely been applied in mitral valve surgery. METHODS We report 2 patients who received emergency operations for thrombosis of a mitral prosthesis (patient 1, a 68-year-old man) and acute mitral regurgitation due to rupture of anterior chordae (patient 2, a 75-year-old woman). They both had severe congestive heart failure. Cardiogenic shock was noted in patient 2. The mitral valve was approached through a right anterior minithoracotomy with the aid of an endoscope by means of projected images on the video monitor under femorofemoral cardiopulmonary bypass. The aorta was not cross-clamped, and the myocardium was protected by continuous coronary perfusion with hypothermic fibrillatory arrest. The left atrium was entered posterior to the interatrial groove. Thrombectomy and mitral valve repair were performed successfully. RESULTS The duration of extracorporeal circulation was 204 and 147 minutes, respectively. Both patients recovered from the operation rapidly with uneventful postoperative courses. CONCLUSIONS Our preliminary results suggest that video-assisted endoscopic cardiac surgery is technically feasible and could be performed in the milieu of open heart surgery.

Characterization of Atrioventricular Nodal Reentry With Continuous Atrioventricular Node Conduction Curve by Double Atrial Extrastimulation

BACKGROUND Characterization of typical atrioventricular nodal reentrant tachycardia (AVNRT) with continuous AVN conduction (A1A2/A2H2) curves by double atrial extrastimulation (A1A2A3) has never been systematically studied. METHODS AND RESULTS This study was composed of 33 patients with typical AVNRT and continuous AVN conduction curves (group 1) and 103 patients with AVNRT and discontinuous AVN conduction curves (group 2). Using A1A2A3 with predefined fast pathway-conducted A2, we examined the effects of slow pathway ablation on the A2A3/A3H3 curves in both groups. In group 1, anterograde AVN effective refractory period (272+/-33 versus 277+/-47 ms, P>0.05) and AVN Wenckebach block cycle length (320+/-45 versus 343+/-59 ms, P>0.05) remained unchanged after ablation. A2H2max was shorter in group 1 than group 2 (237+/-89 versus 395+/-72 ms, P<0.05) at baseline. It shortened in group 2 (395+/-72 versus 221+/-78 ms, P<0.001) but remained unchanged in group 1 (237+/-89 versus 214+/-59 ms, P>0.05) after ablation. A1A2A3 could further disclose discontinuous A2A3/A3H3 curves in 29 patients of group 1. A3H3max shortened in both groups (375+/-81 versus 238+/-82 ms, P<0.001, and 419+/-104 versus 220+/-78 ms, P<0.001, respectively) in a similar fashion. Successful ablation resulted in loss of the left portion of the A2A3/A3H3 curves in the 4 patients of group 1 with continuous A2A3/A3H3 curves. CONCLUSIONS Use of A1A2A3 could expose discontinuous A2A3/A3H3 curves in most patients with continuous A1A2/A2H2 curves. Significant shortening of A3H3max after ablation may be indicative of successful elimination of AVNRT.

Clinical experience in managing Fusarium solani keratitis.

Fusarium solani keratitis is a rare ocular infectious disease. The clinical characteristics and treatment methods of 18 patients with culture proven F. solani keratitis between July 1997 and December 2003 and with a follow‐up period of more than 4 months were analysed retrospectively. The patients were divided into two groups based on the severity of keratitis. Group A (n = 13) displayed non‐severe keratitis and were treated with debridement, lamellar keratectomy and antifungal medication. Group B (n = 5) displayed severe keratomycosis and were treated with lamellar keratectomy combined with amniotic membrane transplantation (AMT) and antifungal medication. In group A, wound healing did not interfere with the integrity of the anterior chamber. The mean re‐epithelialisation time was 12.67 days (range: 5–21 days). All patients were free of major immediate postoperative complications. In group B, AMT preserved the anterior chamber integrity in two cases, but failed to do so in the other three cases. Therapeutic patch grafts were required in these three cases. Non‐severe F. solani keratitis is best treated with superficial keratectomy. Timely AMT combined with lamellar keratectomy appears to be an adjuvant therapy for severe keratomycosis and avoiding emergent therapeutic penetrating keratoplasty. However, AMT was effective in cases involving non‐suppurative Fusarium keratitis.

Mycotic aneurysm of the superior mesenteric artery in a young woman

Aneurysm of the superior mesenteric artery (SMA) is rare. We, in this study, present the case of a 21‐year‐old woman with a history of heroin abuse who was admitted to our hospital for infective endocarditis complicated by floating vegetation at the posterior mitral valve. After receiving 2‐week antibiotic treatment, the patient had acute abdominal pain. Computed tomography demonstrated an aneurysm at the SMA. The mycotic aneurysm was resected and the mitral valve was repaired successfully. This report reviews the pathophysiology of mycotic aneurysms of the SMA and role of computed tomography in the differential diagnosis of this condition from acute mesenteric ischaemia.

Gender differences in baseline variables, therapies and outcomes in Chinese patients with acute myocardial infarction

We prospectively studied the gender differences of baseline variables, therapies, and outcomes among a cohort of 369 Chinese patients with acute myocardial infarction from 1990 to 1995. There were 277 male and 92 female patients. The male gender had a younger mean (+/-SD) age (61.5+/-10.7 vs. 67.1+/-11.7 years, P<0.0001). Hypercholesterolemia (201.2+/-44.2 vs. 187.5+/-43.7 mg/dl, P=0.0111) and obesity (25.0 vs. 15.9%, P=0.0494) were more prominent in the female. Smoking was more prevalent in the male (78.3 vs. 18.5%, P<0.0001). The male group also had more frequent use of thrombolytic agents (19.1 vs. 9.8%, P=0.0377), beta-blockers (61.7 vs. 47.8%, P=0.0191) and heparin (25.3 vs. 12.0%, P=0.0075); but less use of angiotensin-converting enzyme inhibitors (6.9 vs. 15.2%, P=0.0149). The condition on admission was worse in the female group (Killip classification (1.5+/-0.9 vs. 1.9+/-1.0, P=0.0022), myocardial failure (8.7 vs. 2.9%, P=0.0178) and cardiomegaly (65.2 vs. 53.1%, P=0.0419). During a follow-up duration of 26.4+/-24.1 and 22.9+/-23.9 months respectively, the mortality rate was lower in the male (19.5 vs. 30.4%, P=0.0288). However after adjustment for the effect of age, the differences in Killip classification, myocardial failure, cardiomegaly and mortality became insignificant.

On-line multiplane transesophageal echocardiography for balloon mitral commissurotomy.

This study describes in detail the technique and results of on-line multiplane transesophageal echocardiographic guidance of balloon mitral commissurotomy in 150 consecutive patients with symptomatic mitral stenosis. The mitral valve area improved significantly and there were no in-hospital deaths, strokes, or emergency valve operations.

Exercise-induced myocardial ischaemia complicated by paroxysmal complete atrioventricular block

This study describes a case of exercise‐induced myocardial ischaemia accompanied by complete atrioventricular block (CAVB). A 59‐year‐old man with major depression, treated with regular imipramine and lithium for 20 years, experienced syncope episodes during exercise. Exercise, testing initially, identified ST depression in the inferior leads, and later found CAVB resulting in syncope and seizure. The patient recovered completely after resuscitation. Myocardial ischaemic markers were negative, but 35% stenosis was detected in the distal left main coronary artery by angiography. The combined use of verapamil, nitrate and aspirin was treated as the possible coronary spasm. Repeat treadmill caused negative ischaemic study or exercise‐induced arrhythmia, 7 days later. The pathophysiology of the very rare exercise‐induced paroxysmal CAVB has been reviewed.