Michio Usui

Arterial Remodeling at the Reference Site After Angioplasty in the Atherosclerotic Rabbit Model

Recent studies suggest that arterial remodeling plays an important role in restenosis and that remodeling at the reference site may also occur. To assess the chronic effect of the reference site remodeling on angioplasty results, we evaluated reference site remodeling in an experimental atherosclerotic restenosis model. Histological sections of iliac stenoses and their associated proximal reference segments from 50 atherosclerotic rabbits killed 4 weeks after angioplasty were analyzed. Lumen area (LA), external elastic lamina area (EEL), and intimal plus medial areas (I+M) were measured at the lesion (L) and reference (R) sites. Angiography was performed preangioplasty, immediately postangioplasty, and 4 weeks postangioplasty. Restenosis was defined as an angiographic loss/gain ratio of greater than 50% at follow-up angiography. Twenty-three lesions were restenotic (R+) and 32 were not (R-). There was no difference in reference site diameters (RD) between these two groups at the time of angioplasty. However, RDs were significantly smaller in the R+ group than in the R- group (1.24+/-0.18 versus 1.52+/-0.28 mm, n=55, P<.01) at 4-week follow-up. Morphometric analysis also showed a smaller LA(R) in the R+ group (0.85+/-0.27 versus 1.06+/-0.37 mm2, n=55, P<.02), whereas there was no difference in I+M(R) between the two groups. EEL(R) significantly correlated with EEL(L), LA(R), and I+M(R) in both groups combined (r=.53, n=55, P<.0001; r=.62, n = 55, P < .0001; and r = .86, n = 55, P < .0001, respectively). Remodeling can favorably and unfavorably affect both the lesion and the reference sites and appears to occur in parallel and proportionately at both sites. These data suggest that angiographic measurement of late percent stenosis using reference site diameters may lead to an underestimation of the percent luminal narrowing in restenotic lesions because unfavorable remodeling occurs in both the lesion and reference sites in restenotic vessels.

Diagnostic criteria for penetrating atheromatous ulcer of the thoracic aorta.

An autopsy case of penetrating atheromatous ulcer of the ascending thoracic aorta is presented. The triplet imaging findings of mediastinal dilatation, interstitial pulmonary hemorrhage and pericardial effusion were diagnostic for penetrating atheromatous ulcer at the posterior wall of the ascending thoracic aorta. Immediate surgical treatment is indicated when these three findings emerge during examination.

Complete His-ventricular block, atrial flutter and ventricular tachycardia as arrhythmogenic activities in a patient with takotsubo cardiomyopathy

An association of atrial arrhythmias with takotsubo cardiomyopathy (TTC) has not been described previously. Here we report a 65-year-old male patient with TTC. The sudden appearance of atrioventricular block and subsequent bradycardia are believed to be key contributing factors for the development of TTC. Both ventricular tachyarrhythmia and various atrial arrhythmias, such as atrial flutter and atrial fibrillation, were observed during the initial management of the patients TTC. We speculate that both the left ventricular contractile dysfunction and the arrhythmogenic activities may share a common underlying etiology in advanced heart failure patients with TTC. <Learning objective: We describe a case of TTC complicated by ventricular tachycardia, atrial tachyarrhythmias, and an atrioventricular conduction disturbance and discuss the etiology of arrhythmogenic activities in TTC.>.

Is Chiari Network a Benign Structure in Routine Pacemaker Implantation

Background: Chiari network (CN) is the developmental remnants with fine filamentous membrane, and thought to be benign components in electrophysiology. We report a CN patient (pt) with incapable lead manipulation during dual-chamber pacemaker implantation (PMI) and reviewed lead-trouble cases systematically. Case Presentation: A 61-year-old male pt with complete AV block underwent PMI. Anomalous venous drainage was not found and pacemaker leads were inserted into right ventricle (RV) and right atrium (RA) through left axillary vein. The manipulation of both leads was restricted tightly at the tined tips on the postero-inferior RA. Both tips of the leads were entangled with the intra-cavitary structures. Flexing force with deflectable electrophysiology 6Fr-catheter, snare catheter and large-tip (7Fr) ablation catheter did not remove the entangled structures. The myocardial bioptome removed successfully the leads from RA. Histological examination of the entangled tissue at the tined tip of the extirpated RV lead showed normal endomyocardial structures consistent with CN. Discussion and Conclusion: CN had been detected in RA on the preoperative ultrasound echocardiogram (UCG). We have performed 133 pacemaker implantations from January, 2006 to December, 2010 and found RA lead trapping in 3 cases (2.3%). We consider that current complication is not very rare. Careful pre-operative UCG evaluation may provide the further information and awareness on CN-related pacemaker lead trouble.

[Shoshin beriberi after 20-year use of an alternative medicine].

症例は42歳, 女性. 進行する浮腫, 全身倦怠感にて来院. 心エコー上右心負荷所見が強く当初原発性肺高血圧症を疑った. 入院後急性増悪しショック, 急性腎不全となったが右心カテーテル所見より脚気心が疑われビタミンB1投与により速やかに循環動態が改善した. 健康に関心が強く健康食品を中心とした食生活を送っていた事がビタミンB1欠乏の原因と考えられ, 偏った健康知識が致命的となりかねなかった教訓深い症例と考えられた.

Modes of Initiation of Two Types of Atrial Reentry in a Patient with Typical Atrial Flutter: Isthmus-dependent Micro-reentry versus Macro-reentry

We studied the modes of initiation of two types of atria] reentrant tachycardias (i.e., microreentry isthmus tachycardia and counterclockwise atrial flutter) in a 39‐year‐old male with typical atrial flutter. Rapid atrial pacing from proximal coronary sinus at a cycle length of 220 msec initiated micro‐reentry isthmus tachycardia (non‐sustained), while rapid atrial pacing at a cycle length of 210 msec initiated sustained atrial flutter circulating counterclockwise around the tricuspid annulus. It was suggested that initiation of the counterclockwise atrial flutter was associated with a pacing‐induced conduction block in the entire width of the isthmus, whereas initiation of the micro‐reentry isthmus tachycardia was associated with a pacing‐induced conduction block in a limited segment of the isthmus (i.e., partial isthmus block).