Osamu Hano

Relationship Between Atrial Conduction Defects and Fractionated Atrial Endocardial Electrograms in Patients with Sick Sinus Syndrome

The relationship between abnormal atrial electrograms (AAE) recorded during sinus rhythm by endocardial calheter mapping of the right atrium and the afrial conduction defects of sinus impulses or single atrial extrastimuli was investigated in 44 patients with sick sinus syndrome. The patients were divided into two groups on the basis of the presence (n = 29) or absence (n = 15) of AAE recorded during sinus rhythm. The P wave duration in the AAE (+) Group patients was 137 ± 14 msec, and 125 ± 15 msec in (he AAE (−) Group; P < 0.02. The intraatrial conduction time of sinus impulses in the AAE (+) Group was 54 ± 12 msec, and 39 ± 9 msec in the AAE (−) Group; P < 0.001. The interatrial conduction time in the AAE (+) Group was 101 + 14 msec, and 78 ± 16 msec in the AAE (−) Group; P < 0.001. In the AAE (+) Group, H (38%) patients ha d a sinus node recovery time > 4 seconds, whereas in the AAE (−) Group there was only one (6%) patient; P < 0.03. AAE showed a specificity of 93% and a positive predictive accuracy of 91% in predicting inducibility of atrial fibrillation. The sensitivity was 35% and the negative predictive accuracy was 42%. Sustained atrial fibrillation was induced in ten (35%) patients of the AAE (+) Group, and in one (7%) patient of the AAE (−) Group; P < 0.05. These data suggest that in patients with sick sinus syndrome who possess abnormal endocardial eJectrograms in sinus rhythm within the right atrium have: (1) a significantly longer P wave duration: (2) a significantly longer intraatrial and interafrial conduction time of sinus impulses; and (3) a significantly greater sinus node dysfunction and higher incidence of induction of sustained atriai fibrillation. It is concluded that there are significantly greater atrial conduction defects in patients with sick sinus syndrome who possess AAE within the right atrium during sinus rhythm.

Repetitive Atrial Firing and Fragmented Atrial Activity Elicited by Extrastimuli in the Sick Sinus Syndrome With and Without Abnormal Atrial Electrograms

Endocardial catheter mapping of the right atrium during sinus rhythm and programmed atrial stimulation were performed in 50 patients with sick sinus syndrome to investigate the relationship between abnormal atrial electrograms recorded during sinus rhythm and some determinants of the atrial vulnerability such as repetitive atrial firing and fragmented atrial activity elicited by single extrastimulus. The patients were divided into 2 groups on the basis of the presence (Group I) or absence (Group II) of abnormal atrial electrograms recorded during sinus rhythm. In Group I (N = 32), repetitive atrial firing was induced in 23 (72%) patients, and in Group II (N = 18) in 6 (33%) patients; p less than 0.01. The repetitive atrial firing zone was 41 ± 37 ms in Group I and 12 ± 18 ms in Group II; p less than 0.001. Fragmented atrial activity was induced in 30 (94%) patients from Group I, and in 8 (44%) patients from Group II; p less than 0.0001. The fragmented atrial activity zone was 47 ± 42 ms in Group I and 14 ± 19 ms in Group II; p less than 0.0001. The atrial electrogram width at the premature beat (A2; p < 0.02) and the maximum A2/A1 ratio (p < 0.002) were 178 ± 53 ms and 196% ±40%, respectively in Group I, and 141 ±36 ms and 159% ± 30%, respectively in Group II. Atrial fibrillation was induced in 13 (41%) patients from Group I, and in 1 (6%) patient from Group II (p < 0.01). These data suggest a significantly greater vulnerability of the atrial muscle to atrial fibrillation in patients with sick sinus syndrome who possess abnormal atrial electrograms than in those who do not.

Supernormal atrial conduction and its relation to atrial vulnerability and atrial fibrillation in patients with sick sinus syndrome and paroxysmal atrial fibrillation

The purpose of this study was to evaluate prospectively the relationship between supernormal atrial conduction (SNC) and the atrial vulnerability to fibrillation in patients with sick sinus syndrome (SSS) and paroxysmal atrial fibrillation (PAF). Programmed atrial stimulation was performed in 32 age-matched control patients (group I), 26 with SSS but without tachyarrhythmias (group II), and 24 with both SSS and PAF (group III) to assess some determinants of atrial vulnerability, SNC, and atrial fibrillation inducibility. Supernormal atrial conduction was observed in 20 (63%) patients of group I, 12 (46%) patients of group II, and 5 (21%) patients of group III (group I vs group III; p < 0.002). The SNC zone was 46 +/- 44 msec in group I, 36 +/- 42 msec in group II, and 12 +/- 24 msec in group III. (group I vs group III; p < 0.001). The absence of SNC showed a specificity of 89% and a positive predictive accuracy of 79% in predicting inducibility of atrial fibrillation. The sensitivity was 33% and the negative predictive accuracy was 52%. The SNC zone showed a significant inverse correlation with P wave duration (r = -0.32; p < 0.003), intraatrial conduction time (r = -0.28; p < 0.02), and maximum conduction delay (r = -0.23; p < 0.05). The maximum decrease in conduction time during supernormal conduction showed a significant inverse correlation with P wave duration (r = -0.27; p < 0.02), intraatrial conduction time (r = -0.26; p < 0.02), and with the maximum conduction delay (r = -0.27; p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of sympathetic nerve activity on ventricular arrhythmogenicity in the dog with chronic hypokalemia

To examine the influence of sympathetic nerve activity on ventricular arrhyth mogenicity in the dog with chronic hypokalemia, an electrophysiologic study was performed before and after bilateral stellectomy (BS) in 10 dogs with chronic hypokalemia (2.8 ± 0.1 mEq/L), which was created by feeding a low-potassium diet and by administering furosemide over a four-week period, and the results were compared with those obtained from 10 dogs with normokalemia (4.7 ± 0.3 mEq/L) from being fed an ordinary diet over a four-week period. Before BS the incidence of electrically induced ventricular arrhythmias was higher in the hypokalemic than in the normokalemic dogs. After BS it was decreased considerably in the hypokalemic but not in the normokalemic dogs. Heterogeneity of effective refractory period (ΔERP), which was determined as the difference between the longest and shortest effective refractory periods in three sites of the right and left ventricles, was greater in the hypokalemic than in the normokalemic dogs before BS. The ΔERP decreased slightly in the two groups both before and after BS. There was, however, no significant difference in ΔERP in the two groups both before and after BS. Ventricular fibrillation threshold (VFT) was significantly lower in the hypokalemic dogs than in the nor mokalemic dogs before BS (p< 0.005). VFT was elevated in the two groups after BS. Percent increase in VFT after BS was significantly greater in the hypoka lemic than in the normokalemic dogs. In conclusion, sympathetic nerve activity may play an important role in the increase in ventricular arrhythmogenicity in the presence of chronic hypokalemia.

Congenital defect of the left pericardium with sick sinus syndrome

years. 5 Aortic stenosis is rare, bu t approximately 50% of patients with quadricuspid aortic valve have aortic regurgitation. 5 Two-dimensional transthoracic echocardiography has become the diagnostic test of choice, because the four cusps and their relative sizes can easily be seen. 4, 5 In addition, Doppler echocardiography is an excellent modality for assessing the degree of aortic regurgitat ion and its progression. 4 However, because of technical factors such as suboptimal echocardiographic windows or extensive aortic calcification, transthoracic echocardiography may occasionally be limited in visualizing the aortic valve. Transesophageal echocardiography overcomes many of the imaging l imitat ions of transthoracic echocardiography and can clearly delineate the aortic valve morphologic characteristics. 6 In our case the exact cause of the severe aortic regurgitat ion was not seen on transthoracic echocardiography. Transesophageal echocardiography was performed to assess the mitral valve, and the quadricuspid aortic valve was discovered incidentally. To the best of our knowledge this is the first case of quadricuspid aortic valve diagnosed exclusively by transesophageal echocardiography in the English language literature. In conclusion, a quadricuspid aortic valve is a rare congenital abnormali ty tha t usual ly can be diagnosed by transthoracic twodimensional echocardiography. A high degree of suspicion is required to make the diagnosis, because this abnormality can easily be overlooked. On occasion the transthoracic echocardiogram cannot show the quadricuspid na tu re of the aortic valve, and transesophageal echocardiography mus t be performed. REFERENCES

Incidence and electrophysiologic characteristics of supernormal atrial conduction in humans

The incidence and electrophysiologic characteristics of supernormal atrial conduction (SNC) were examined by cardiac stimulation in 53 control subjects. Their ages ranged from 15 to 71 years (mean age, 50 +/- 21 years) (mean +/- SD). There were 27 women and 26 men in the study. Conduction of premature atrial responses from the sinus node to the atrioventricular node (intraatrial conduction time) was supernormal in 27 (51%) subjects and conduction to the left atrium (interatrial conduction time) was supernormal in 35 (66%) subjects (difference not significant). At coupling intervals ranging between 440 and 240 ms, the conduction time of the premature beats was as much as 25 ms shorter than that of the basic driven beats. The maximum decrease in interatrial conduction time during the period of SNC was 13 +/- 5 ms and the maximum decrease in intraatrial conduction time was 9 +/- 3 ms (P < .001). The supernormal interatrial conduction zone was 71 +/- 29 ms and the supernormal intraatrial conduction zone was 57 +/- 25 ms (P < .05). There was a significant positive correlation between the SNC zone and the maximum decrease in conduction time (r = .82; P < .001). Supernormal atrial conduction was stable, reproducible, and remained constant in individual patients. Supernormal atrial conduction was found to be a relatively frequent phenomenon. There was a significantly greater SNC zone and maximum decrease in conduction time in interartrial conduction than in intraatrial conduction.(ABSTRACT TRUNCATED AT 250 WORDS)

A case of benign asbestos pleurisy as pleural bloody effusion

50才男性でアスベストにより血性胸水を生じた1例である.症例は30年間のアスベスト暴露歴を有し,昭和58年12月胸部写真で胸水貯留を無症候性に認め,昭和59年2月胸水が増加して入院精査した.胸水は血性滲出液で細胞診や細菌培養は陰性.喀痰中や気管支肺胞洗浄液中に多数のアスベスト小体が証明され,悪性腫瘍や結核などを否定し,無治療で経過観察をした. 6カ月後に胸水が減少し,胸膜肥厚や肺の線維化が認められ, 2年6カ月後の現在も悪性腫瘍の発生はなく,アスベストによる良性胸水貯留と考えられた.アスベストによる良性胸水貯留と診断しえた症例の報告は,本邦において少なく,その診断に気管支肺胞洗浄が有用と思われた.