Clinical Significance of QRS Duration During Ventricular Pacing

To clarify the clinical significance of an abnormally prolonged paced QRS duration, we studied 114 patients who had undergone pacing for atrioventricular block (AVB). Patients were divided into two groups: group I consisted of 29 patients with at least one paced QRS duration greater than or equal to 180 msec during the follow-up period; group II consisted of 85 patients with paced QRS durations less than 180 msec. The clinical background, QRS complexes before pacing, and the echocardiographic findings were assessed. Males (P less than 0.05), those with H-V block (P less than 0.05) and a wider QRS complex of conducted and escape beats (both P less than 0.01) were dominant in group I. The incidence of underlying heart disease was greater in group I than in group II (83% vs 32%, P less than 0.01). Reduced left ventricular ejection fraction (LVEF) and increased left ventricular end-diastolic dimension (LVDd) were more prominent in group I than in group II (LVEF 0.49 +/- 0.17 vs 0.68 +/- 0.10, P less than 0.01, LVDd 57.1 +/- 7.9 mm vs 48.5 +/- 5.6 mm, P less than 0.01). The paced QRS duration correlated with LVEF (r = -0.61) and LVDd (r = 0.81). A paced QRS duration greater than or equal to 180 msec was sensitive and specific for a LVEF less than 0.5 (83.3% and 85.2%) and LVDd greater than or equal to 60 mm (100% and 81.4%). We conclude that patients with a prolonged paced QRS duration have more serious heart disease, and the paced QRS duration can be a useful indicator of impaired LV function.     

Effects of potassium iodide, colchicine and dapsone on the generation of polymorphonuclear leukocyte-derived oxygen intermediates

The effects of potassium iodide, colchicine and dapsone on the in vitro generation of polymorphonudear leukocyte (PMN)-derived oxygen intermediates were investigated. These three drugs have beneficial effects on those conditions in which PMNs play an important pathogenetic role. Three oxygen intermediates, superoxide anion (O₂^?), hydrogen peroxide (H₂ O₂), hydroxyl radical (OH·) and chemiluminescence were included in assay studies. Dose response studies were performed with therapeutic doses of the drugs (10 μM–1 mM). We found that both potassium iodide and dapsone significantly suppressed the generation of oxygen intermediates, except for O₂^?. Colchicine decreased OH · production. Our results show that these agents to some extent exert their anti-inflammatory effects by interfering with the PMN-dependent production of oxygen intermediates, thus conferring protection from auto-oxidative tissue injury. This may account for their clinical efficacy in many PMN-mediated dermatological diseases.     

Clinical and Electrophysiological Characteristics of Atrial Standstill

NAKAZATO, Y., et al .: Clinical and Electrophysiological Characteristics of Atrial Standstill . To clarify the clinical and electrophysiological characteristics of atrial standstill (AS) we studied 11 patients (7 males and 4 females), whose average age was 62 years and who were followed over a period of 4–179 months. Underlying heart disease was present in nine patients and two cases were idiopathic. Major clinical symptoms in the 11 cases included Adams-Stokes attacks, and dyspnea on exertion. In the standard 12-lead ECGs obtained on admission, the P wave was absent in six cases. Atrial flutter (AF) was noted in 3, atrial fibrillation (Af) in 1, and multifocal atrial tachycardia in 1. In some cases, the ECG initially showed AF or Af, and was transformed after several years into ectopic atrial tachycardia or an ectopic atrial rhythm with a markedly decreased amplitude of the P wave. Finally, the P wave disappeared over a prolonged period. When intracardiac mapping was performed, the atrial electrograms tended to diminish at the site of high, mid-lateral right atrium (RA). Electrograms were remained present in the vicinity of the tricuspid valve (TV) annulus. A repeated mapping and pacing study conducted in two patients revealed that the "silent" area spread toward the lower site of RA. During the average follow-up period of 64 months, four patients died. The interval until death in one patient with myocarditis was 6 months, and in another with dilated cardiomyopathy (DCM) it was 8 months. It appears that the atrial muscular lesion starts in the high lateral RA and progresses toward the lower RA, then to the vicinity of the TV annulus. A diffuse and progressive disturbance may occur not only in the atrial muscle, but also in the atrioventricular conduction system in patients with AS who had progressive myocarditis or DCM.     

Colorectal Carcinomas Following Ulcerative Colitis in Japanese Patients

Abstract: Colorectal carcinomas occuring following ulcerative colitis in Japanese patients discussed in the literature were analyzed in order to review their characteristics. 1) Of the 74 cases reported from 1962 to November 1989, 29 were males and 45 were females. The sex differences in Japanese ulcerative colitis were almost 1: 1, so females with colorectal carcinomas occured more often than males. 2) Male patients had a bimodal peak in their 30's and 40's, while female patients had the peak in their 40's and 50's. More colorectal carcinomas were found among younger people than in the general population. 3) Universal colitis was the most common type of colorectal cancer occuring following ulcerative colitis. 57 patients out of 74 were classified into this type. 4) The duration of the disease prior to the diagnosis of colorectal cancer was generally 10 years or longer. 5) The rectum was the commonest site of cancer, and was seen in 44 cases out of 74. Rectosigmoid colon carcinomas occurred in 61 of 74 cases. 6) Histologically, colonic malignancy associated with ulcerative colitis was an adenocarcinoma, displaying a wide spectrum of differentiation. Poorly differentiated (4 males and 6 females) and signet ring cell carcinoma (3 males and 5 females) were also reported. 7) The so-called type 4 tumor occurred in 3 males and 6 females out of a total of 74 cases. This type of tumor is usually rare in colorectal cancer. 8) Most of the patients with early carcinomas had suffered from ulcerative colitis for more than 15 years and the characteristics of their macroscopic appearance were protruded lesions. 9) Foci of dysplasia accompanied carcinoma in as many as 80% of the Japanese cases reported. (56 out of 74 cases) Based on these, we should take consideration that: 1) Patients with pancolitis lasting more than 10 years whose forms are chronically active or intermittently active should be recognized as a high-risk group. 2) Full colonoscopy every one or two years may be sufficient to find dysplasia as well as carcinoma even if the condition of disease is stable. 3) Protruded lesions should be biopsied to detect early cancer as well as dysplasia on colonoscopy. 4) A change in the disease condition, i. e. rectal bleeding, weight loss and a change of bowel habits should not be mistaken for an exacerbation of colitis and should be investigated without fail.     

Anti-oxidant effects of gold compounds

The anti-oxidant efficacy, in vitro, of the gold compounds auranofin (AF) and gold sodium thiomalate (GST) was examined by studying their effects on the generation of reactive oxygen species (ROS) using zymosan-stimulated polymorphonuclear leukocytes (PMNs) and a cell-free, xanthine-xanthine oxidase system. The oxygen species investigated were the superoxide radical anion (O2-), hydrogen peroxide (H2O2) and the hydroxyl radical (OH.). AF had an inhibitory effect on ROS production by PMNs. In particular, OH. generation was significantly suppressed in a dose-dependent fashion. AF did not inhibit ROS production in the cell-free system. GST produced only a small degree of inhibition at higher concentrations. These findings suggest that AF may play an important role in the inhibition of respiratory bursts and the generation of inflammatory reaction products. Since the products of the respiratory burst, especially potent oxidants such as OH. and H2O2, are thought to be important inflammatory mediators, it is postulated that the blockade of toxic ROS generation by AF affects rheumatoid as well as dermatological inflammation and tissue damage.     

Paroxysmal Atrioventricular Block Induced During Head-Up Tilt Testing in an Apparently Healthy Man

Paroxysmal AV Block During HUT Testing. Introduction : Prolonged asystole during head-up tilt testing has been reported, but the occurrence of paroxysmal AV block appears to he rare.
Methods and Results : A 25-year-old man with no history of syncope underwent head-up tilt testing. After 11 minutes of 80° tilting, he developed syncope with paroxysmal AV block and asystole lasting 10.5 seconds. However, this response was not reproduced during a subsequent tilt test 4 weeks later. Treadmill exercise testing and Holter monitoring showed no abnormalities. Power spectral analysis of heart rate variability revealed a marked increase in sympathetic activity several minutes before the induction of paroxysmal AV block.
Conclusion : We report a case of paroxysmal AV block that occurred during head-up tilt testing but did not recur on a subsequent test in an apparently healthy young man.