Association between left atrial low-voltage area and induction and recurrence of macroreentrant atrial tachycardia in pulmonary vein isolation for atrial fibrillation

BACKGROUND

The relationship between induction and recurrence due to atrial tachycardia (AT) and left atrial (LA) matrix progression after atrial fibrillation (AF) ablation remains unclear.

METHODS

One hundred fifty-two consecutive patients with paroxysmal and persistent AF who underwent pulmonary vein isolation (PVI) and cavo-tricuspid isthmus (CTI) ablation and achieved sinus rhythm before the procedure were classified into three groups according to the AT pattern induced after the procedure: group N (non-induced), F (focal pattern), and M (macroreentrant pattern) in 3D mapping.

RESULTS

The total rate of AT induction was 19.7% (30/152) in groups F (n = 13) and M (n = 17). Patients in group M were older than those in groups N and F, with higher CHADS2/CHA2DS2-VASc values, left atrial enlargement, and low-voltage area (LVA) size of LA. The receiver operating characteristic curve determined that the cut-off LVA for macroreentrant AT induction was 8.8 cm2 (area under the curve [AUC]: 0.86, 95% confidence interval [CI]: 0.75-0.97). The recurrence of AT at 36 months in group N was 4.1% (5/122), and at the second ablation, all patients had macroreentrant AT. Patients with AT recurrence in group N had a wide LVA at the first ablation, and the cut-off LVA for AT recurrence was 6.5 cm2 (AUC 0.94, 95%CI 0.88-0.99). Adjusted multivariate analysis showed that only LVA size was associated with the recurrence of macroreentrant AT (odds ratio 1.21, 95%CI 1.04-1.51).

CONCLUSIONS

It is important to develop a therapeutic strategy based on the LVA size to suppress the recurrence of AT in these patients.

Triggers of Ventricular Fibrillation in Patients With Inferolateral J-Wave Syndrome

BACKGROUND

There are few data on ventricular fibrillation (VF) initiation in patients with inferolateral J waves.

OBJECTIVES

This multicenter study investigated the characteristics of triggers initiating spontaneous VF in inferolateral J-wave syndrome.

METHODS

A total of 31 patients (age 37 ± 14 years, 24 male) with spontaneous VF episodes associated with inferolateral J waves were evaluated to determine the origin and characteristics of triggers. The J-wave pattern was recorded in inferior leads in 11 patients, lateral leads in 3, and inferolateral leads in 17.

RESULTS

The VF triggers (n = 37) exhibited varying QRS durations (176 ± 21 milliseconds, range 119-219 milliseconds) and coupling intervals (339 ± 46 milliseconds, range 250-508 milliseconds) with a right (70%) or left (30%) bundle branch block (BBB) pattern. Trigger patterns were associated with J-wave location: left BBB triggers with inferior J waves and right BBB triggers with lateral J waves. Electrophysiologic study was performed for 22 VF triggers in 19 patients. They originated from the left or right Purkinje system in 6 and from the ventricular myocardium in 10 and were undetermined in 6. Purkinje vs myocardial triggers showed distinct electrocardiographic characteristics in coupling interval and QRS-complex duration and morphology. Abnormal epicardial substrate associated with fragmented electrograms was identified in 9 patients, with triggers originating from the same region in 7 patients. Catheter ablation resulted in VF suppression in 15 patients (79%).

CONCLUSIONS

VF initiation in inferolateral J-wave syndrome is associated with significant individual heterogeneity in trigger characteristics. Myocardial triggers have electrocardiographic features distinct from Purkinje triggers, and their origin often colocalizes with an abnormal epicardial substrate.

Effects of color–emotion association on facial expression judgments

Color and emotion are metaphorically associated in the human mind. This color–emotion association affects perceptual judgment. For example, stimuli representing colors can affect judgment of facial expressions. The present study examined whether colors associated with happiness (e.g., yellow) and sadness (e.g., blue and gray) facilitate judgments of the associated emotions in facial expressions. We also examined whether temporal proximity between color and facial stimuli interacts with any of these effects. Participants were presented with pictures of a happy or sad face against a yellow-, blue-, or gray-colored background and asked to judge whether the face represented happiness or sadness as quickly as possible. The face stimulus was presented simultaneously (Experiment 1) or preceded for one second by the colored background (Experiment 2). The analysis of response time showed that yellow facilitated happiness judgment, while neither blue nor gray facilitated sadness judgment. Moreover, the effect was found only when the face and color stimuli were presented simultaneously. The results imply that the association of sadness with blue and gray is weak and, consequently, does not affect emotional judgment. Our results also suggest that temporal proximity is critical for the effect of the color–emotion association (e.g., yellow–happiness) on emotional judgment.

Sympathetic nerve abnormality in an adolescent patient with cardioinhibitory vasovagal syncope

A 15 year-old-Japanese girl was admitted to our ward because of syncope. Electrocardiography (ECG) demonstrated sinus bradycardia with heart rate of 52/min. Holter ECG showed no arrhythmia related to syncope. Coronary enhanced computed tomography and cardiac magnetic resonance imaging showed no abnormal findings. Head-up tilt test revealed syncope with sinus arrest. ¹²³I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy revealed focally decreased uptake on the anterior wall of the left ventricle but generally maintained uptake of MIBG. Finally, she was diagnosed with cardioinhibitory vasovagal syncope (CIVS). Sympathetic nerve abnormalities seemed to be related to CIVS in this patient. <Learning objective: Vasovagal syncope (VVS) is a common clinical event and is the most common type of syncope. A decrease in sympathetic nervous system activity as indicated by HRV and disturbance in myocardial adrenergic innervation may be one of the pivotal factors in some type 2B (cardioinhibition type) VVS patients without other diseases.>.

Incidence and Characteristics of Coronary Artery Spasms Related to Atrial Fibrillation Ablation Procedures - Large-Scale Multicenter Analysis

BACKGROUND

Coronary artery spasms (CASs), which can cause angina attacks and sudden death, have been recently reported during catheter ablation. The aim of the present study was to report the incidence, characteristics, and prognosis of CASs related to atrial fibrillation (AF) ablation procedures.Methods and Results:The AF ablation records of 22,232 patients treated in 15 Japanese hospitals were reviewed. CASs associated with AF ablation occurred in 42 of 22,232 patients (0.19%). CASs occurred during ablation energy applications in 21 patients (50%). CASs also occurred before ablation in 9 patients (21%) and after ablation in 12 patients (29%). The initial change in the electrocardiogram was ST-segment elevation in the inferior leads in 33 patients (79%). Emergency coronary angiography revealed coronary artery stenosis and occlusions, which were relieved by nitrate administration. No air bubbles were observed. A comparison of the incidence of CASs during pulmonary vein isolation between the different ablation energy sources revealed a significantly higher incidence with cryoballoon ablation (11/3,288; 0.34%) than with radiofrequency catheter, hot balloon, or laser balloon ablation (8/18,596 [0.04%], 0/237 [0%], and 0/111 [0%], respectively; P<0.001). CASs most often occurred during ablation of the left superior pulmonary vein. All patients recovered without sequelae.

CONCLUSIONS

CASs related to AF ablation are rare, but should be considered as a dangerous complication that can occur anytime during the periprocedural period.

A Case with Recurrent Free-Floating Ball Thrombi in Left Atrium

Patient: Female, 74

Final Diagnosis: Left atrial ball thrombus

Symptoms: Abdominal discomfort • dyspnea

Medication: —

Clinical Procedure: —

Specialty: Cardiology

High-Aspect-Ratio Ridge Structures Induced by Plastic Deformation as a Novel Microfabrication Technique

Wrinkles on thin film/elastomer bilayer systems provide functional surfaces. The aspect ratio of these wrinkles is critical to their functionality. Much effort has been dedicated to creating high-aspect-ratio structures on the surface of bilayer systems. A highly prestretched elastomer attached to a thin film has recently been shown to form a high-aspect-ratio structure, called a ridge structure, due to a large strain induced in the elastomer. However, the prestretch requirements of the elastomer during thin film attachment are not compatible with conventional thin film deposition methods, such as spin coating, dip coating, and chemical vapor deposition (CVD). Thus, the fabrication method is complex, and ridge structure formation is limited to planar surfaces. This paper presents a new and simple method for constructing ridge structures on a nonplanar surface using a plastic thin film/elastomer bilayer system. A plastic thin film is attached to a stress-free elastomer, and the resulting bilayer system is highly stretched one- or two-dimensionally. Upon the release of the stretch load, the deformation of the elastomer is reversible, while the plastically deformed thin film stays elongated. The combination of the length mismatch and the large strain induced in the elastomer generates ridge structures. The morphology of the plastic thin film/elastomer bilayer system is experimentally studied by varying the physical parameters, and the functionality and the applicability to a nonplanar surface are demonstrated. Finally, we simulate the effect of plasticity on morphology. This study presents a new technique for generating microscale high-aspect-ratio structures and its potential for functional surfaces.

Circulating intermediate CD14++CD16+monocytes are increased in patients with atrial fibrillation and reflect the functional remodelling of the left atrium

AIMS

A recent large clinical study demonstrated the association between intermediate CD14++CD16+monocytes and cardiovascular events. However, whether that monocyte subset contributes to the pathogenesis of atrial fibrillation (AF) has not been clarified. We compared the circulating monocyte subsets in AF patients and healthy people, and investigated the possible role of intermediate CD14++CD16+monocytes in the pathophysiology of AF.

METHODS AND RESULTS

This case-control study included 44 consecutive AF patients without systemic diseases referred for catheter ablation at our hospital, and 40 healthy controls. Patients with systemic diseases, including structural heart disease, hepatic or renal dysfunction, collagen disease, malignancy, and inflammation were excluded. Monocyte subset analyses were performed (three distinct human monocyte subsets: classical CD14++CD16-, intermediate CD14++CD16+, and non-classical CD14+CD16++monocytes). We compared the monocyte subsets and evaluated the correlation with other clinical findings. A total of 60 participants (30 AF patients and 30 controls as an age-matched group) were included after excluding 14 AF patients due to inflammation. Atrial fibrillation patients had a higher proportion of circulating intermediate CD14++CD16+monocytes than the controls (17.0 ± 9.6 vs. 7.5 ± 4.1%, P < 0.001). A multivariable logistic regression analysis demonstrated that only the proportion of intermediate CD14++CD16+monocytes (odds ratio: 1.316; 95% confidence interval: 1.095-1.582, P = 0.003) was independently associated with the presence of AF. Intermediate CD14++CD16+monocytes were negatively correlated with the left atrial appendage flow during sinus rhythm (r= -0.679, P = 0.003) and positively with the brain natriuretic peptide (r = 0.439, P = 0.015).

CONCLUSION

Intermediate CD14++CD16+monocytes might be closely related to the pathogenesis of AF and reflect functional remodelling of the left atrium.

A Simultaneous Evaluation of Occupational Stress and Depression in Patients with Lifestyle-related Diseases

Objective Karoshi, which is the Japanese term for death from over-work, is usually the extreme result of cardiovascular diseases, and occupational stress plays a pivotal role in the pathogenesis. Depression is closely associated with atherosclerotic cardiovascular disease. The present study was undertaken to examine the relationship between occupational stress and depression. Methods We enrolled 231 consecutive outpatients with lifestyle-related diseases such as diabetes, hyperlipidemia and hypertension were enrolled. Occupational stress was measured by qualitative constructs assessing job control, job demands, and worksite social support using a job content questionnaire (JCQ). The job strain index measured by the ratio of job demands to job control was used as an indicator of the occupational stress. Depression was evaluated by the Self-rating Depression Scale (SDS). Results A univariate linear regression analysis showed the SDS scores to be positively correlated with job demands and the job strain index and negatively correlated with job control and worksite social support. Multiple regression analyses to predict the SDS scores demonstrated that job demands were positively associated with SDS scores and job control and worksite social support were negatively associated with SDS scores after controlling for other variables. The job strain index was positively related to SDS scores. Conclusion Occupational stress expressed as the job strain index was strongly associated with depression. By simultaneously using the SDS and JCQ, the health conditions of patients could be classified based on occupational stress and mental stress, and this classification could help to promote a healthy work environment and guide individual workers.

Global Thrombosis Test - a possible monitoring system for the effects and safety of dabigatran

Background

Dabigatran is an alternative to warfarin (WF) for the thromboprophylaxis of stroke in patients with non-valvular atrial fibrillation (NVAF). The advantage of dabigatran over WF is that monitoring is not required; however, a method to monitor the effect and the safety of dabigatran is not currently available. The Global Thrombosis Test (GTT) is a novel method to assess both clot formation and lysis activities under physiological conditions.

Objective

The aim of this study was to evaluate whether treatment with dabigatran might affect shear-induced thrombi (occlusion time [OT], sec) by the GTT, and to investigate the possibility that the GTT could be useful as a monitoring system for dabigatran.

Patients/Methods

The study population consisted of 50 volunteers and 43 NVAF patients on WF therapy, who were subsequently switched to dabigatran. Using the GTT, the thrombotic status was assessed one day before and 1 month after switching anticoagulation from WF to dabigatran.

Results

The OT was 524.9 ± 17.0 sec in volunteers whereas that of NVAF patients on WF therapy was 581.7 ± 26.3 sec. The switch from WF to dabigatran significantly prolonged OT (784.5 ± 19.3 sec). One patient on WF therapy and 12 patients on dabigatran therapy were shown to have OT > 900 sec.

Conclusion

The GTT could be used to assess the risk of dabigatran-related bleeding complications.

Vasospastic Angina in Identical Twins

Patient: Male, 58

Final Diagnosis: Vasospastic angina

Symptoms: Chest pain

Medication: —

Clinical Procedure: Medical treatment

Specialty: Cardiology

Topographic variability of the left atrium and pulmonary veins assessed by 3D-CT predicts the recurrence of atrial fibrillation after catheter ablation

BACKGROUND

Catheter ablation (CA) is an established therapy for atrial fibrillation (AF). However, the assessment of anatomical information and predictors of AF recurrence remain unclear. We investigated the relationship between anatomical information on the left atrium (LA) and pulmonary veins (PVs) from three-dimensional computed tomography images and the recurrence of AF after CA.

METHODS

Sixty-seven consecutive AF patients (mean age: 62±10 years, median AF history: 42 (12; 60) months, mean LA size: 41±7 mm, paroxysmal: 56%) underwent CA and were followed for 19±10 months. The segmented surface areas (antral, posterior, septal, and lateral) and dimensions (between the anterior and posterior walls, the right inferior PV and mitral annulus [MA], the right superior PV and MA, the left superior PV and MA, and the mitral isthmus) of the LA were evaluated three dimensionally using the NavX system. The cross-sectional areas of the PVs were also evaluated.

RESULTS

After the follow-up period, 49 patients (73%) remained free from AF. A multivariate analysis showed that the diameter of the mitral isthmus and cross-sectional area of the right upper PV were associated with AF recurrence (odds ratio: 1.070, CI: 1.02-1.12, p=0.001; odds ratio: 0.41, CI: 0.21-0.77, p=0.006).

CONCLUSION

Enlargement of the mitral isthmus and a smaller right superior PV cross-sectional area were associated with AF recurrence.

Coconut atrium in long-standing rheumatic valvular heart disease

Patient: Male, 76

Final Diagnosis: Rheumatic valvular heart disease

Symptoms: Breathlessness and leg edema

Medication: —

Clinical Procedure: Medical treatment for heart failure

Specialty: Cardiology

Reduction in coronary microvascular resistance through cardiac resynchronization and its impact on chronic reverse remodelling of left ventricle in patients with non-ischaemic cardiomyopathy

AIMS

Left bundle branch block (LBBB) induces mechanical dyssynchrony, thereby compromising the coronary circulation in non-ischaemic cardiomyopathy. We sought to examine the effects of cardiac resynchronization therapy (CRT) on coronary flow dynamics and left ventricular (LV) function.

METHODS AND RESULTS

Twenty-two patients with non-ischaemic cardiomyopathy (New York Heart Association class, III or IV; LV ejection fraction, ≤35%; QRS duration, ≥130 ms) were enrolled. One week after implantation of the CRT device, coronary flow velocity and pressure in the left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCx) were measured invasively, before and after inducing hyperemia by adenosine triphosphate administration, with two programming modes: sequential atrial and biventricular pacing (BiV) and atrial pacing in patients with LBBB or sequential atrial and right ventricular pacing in patients with complete atrioventricular block (Control). We assessed hyperemic microvascular resistance (HMR, mean distal pressure divided by hyperemic average peak velocity) and the relationship between the change in HMR and mid-term LV reverse remodelling. Hyperemic microvascular resistance was lower during BiV than during Control (LAD: 1.76 ± 0.47 vs. 1.54 ± 0.45, P < 0.001; LCx: 1.92 ± 0.42 vs. 1.73 ± 0.31, P = 0.003). The CRT-induced change in HMR of the LCx correlated with the percentage change in LV ejection fraction (R = -0.598, P = 0.011) and LV end-systolic volume (R = 0.609, P = 0.010) before and 6 months after CRT.

CONCLUSION

Cardiac resynchronization therapy improves coronary flow circulation by reducing microvascular resistance, which might be associated with LV reverse remodelling.

Prophylactic catheter ablation of ventricular tachycardia before cardioverter-defibrillator implantation in patients with non-ischemic cardiomyopathy: Clinical outcomes after a single endocardial ablation

BACKGROUND

Outcomes related to prophylactic catheter ablation (PCA) for ventricular tachycardia (VT) before implantable cardioverter-defibrillator (ICD) implantation in non-ischemic cardiomyopathy (NICM) are not well characterized. We assessed the efficacy of single endocardial PCA in NICM patients.

METHODS

We retrospectively analyzed 101 consecutive NICM patients with sustained VT. We compared clinical outcomes of patients who underwent PCA (ABL group) with those who did not (No ABL group). Successful PCA was defined as no inducible clinical VT. We also compared the clinical outcomes of patients with successful PCA (PCA success group) with those of the No ABL group. Endpoints were appropriate ICD therapy (shock and anti-tachycardia pacing) and the occurrence of electrical storm (ES).

RESULTS

PCA was performed in 42 patients, and it succeeded in 20. The time to ES occurrence was significantly longer in the ABL group than in the No ABL group (p=0.04). The time to first appropriate ICD therapy and ES occurrence were significantly longer in the PCA success group than in the No ABL group (p=0.02 and p<0.01, respectively).

CONCLUSION

Single endocardial PCA can decrease ES occurrence in NICM patients. However, high rates of VT recurrence and low success rates are issues to be resolved; therefore, the efficacy of single endocardial PCA is currently limited.

A super-elderly case of abdominal aortic aneurysm associated with chronic disseminated intravascular coagulation

Chronic disseminated intravascular coagulation (DIC) is a well-known complication of aortic aneurysm. A 91-year-old Japanese woman was admitted to our hospital because of massive purpura of the lower limbs. The presence of abdominal aortic aneurysm (AAA) had been pointed out from the age of 80 years, and its diameter had gradually increased. The AAA was composed of two portions, that is, a large upper and a small lower portion, and a large mural thrombosis was observed in the lower portion. The laboratory data led to the diagnosis of DIC, and AAA was the only identifiable cause of coagulopathy. The time course of exacerbation of AAA was consistent with the progression of thrombocytopenia and purpura. Therefore, we concluded that AAA was the underlying cause of DIC. Since DIC in aortic aneurysms is associated with excessive fibrinolysis, tranexamic acid was administered as anti-fibrinolytic therapy. After that, coagulopathy was drastically improved. Our patient responded successfully to anti-fibrinolytic therapy for coagulopathy. The present case illustrates the importance of evaluation of the diameter of an aneurysm as well as intraluminal thrombosis, which may play an important role in coagulopathy including DIC. It is necessary to monitor coagulation and fibrinolysis for the follow-up of patients with AAA. <Learning objective: We present a case report of an aged Japanese woman with abdominal aortic aneurysm associated with disseminated intravascular coagulation, and anti-fibrinolytic therapy drastically ameliorated her condition. Our case illustrates the importance of evaluation of the diameter of an aneurysm as well as conducting follow-up monitoring of coagulation and fibrinolysis.>.

Dabigatran in the peri-procedural period for radiofrequency ablation of atrial fibrillation: efficacy, safety, and impact on duration of hospital stay

Purpose

Dabigatran is effective for both the prevention of stroke and bleeding in patients with atrial fibrillation (AF). However, the safety and efficacy of the use of dabigatran in the peri-procedural period for radiofrequency catheter ablation (RFCA) of AF is unknown. Therefore, the purpose of this study was to evaluate the safety and efficacy of dabigatran in the peri-procedural period for RFCA of AF and the duration of hospital stay.

Methods

Consecutive patients (n = 227) who underwent RFCA for AF were prospectively analyzed. Peri-procedural anticoagulant therapy with dabigatran (n = 101, D group) was compared with warfarin and heparin bridging (n = 126, W group). Dabigatran was discontinued 12–24 h before and restarted 3 h after the procedure. Warfarin was stopped 3 days before the procedure and unfractionated heparin was administered.

Results

Ischemic stroke occurred in one patient of the D group (0.8 %). There was no significant difference between the two groups in the incidence of major bleeding (three cases of cardiac tamponade in each group and one case of intracranial bleeding in the W group, p = 0.93) or minor bleeding (five cases in the D group vs. five in the W group, p = 0.54). The duration of hospital stay was significantly shorter in the D group than in the W group (7.2 vs. 10.3 days, p = 0.0001).

Conclusions

Peri-procedural anticoagulation therapy with dabigatran for RFCA of AF was equally safe and effective compared with warfarin and heparin bridging. The use of dabigatran for RFCA of AF shortened the duration of hospital stay.

Impact of adenosine-provoked acute dormant pulmonary vein conduction on recurrence of atrial fibrillation

INTRODUCTION

Adenosine can be associated with acute recovery of conduction to the pulmonary veins (PVs) immediately after isolation. The objective of this study was to evaluate whether the response to adenosine predicts atrial fibrillation (AF) recurrence after a single ablation procedure in patients with paroxysmal AF.

METHODS AND RESULTS

A total of 109 consecutive patients (61 ± 10 years; 91 males) with drug-refractory paroxysmal AF who underwent AF ablation were analyzed. After PV antrum isolation (PVAI), dormant PV conduction was evaluated by an administration of adenosine in all patients. No acute reconnections were provoked by the adenosine in 70 (64.2%) patients (Group-1), but they were provoked in at least one side of the ipsilateral PVs in 39 (35.8%) patients (Group-2). All adenosine-provoked dormant conductions were successfully eliminated by additional ablation applications. By 12 months after the initial procedure, 72 (66.1%) patients were free of AF recurrences without any antiarrhythmic drugs. A Cox regression multivariate analysis of the variables including the adenosine-provoked reconductions, age, gender, duration of AF, presence of hypertension or structural heart disease, left atrial size, left ventricular ejection fraction, and body mass index demonstrated that adenosine-provoked reconductions were an independent predictor of AF recurrence after a single ablation procedure (hazard ratio: 1.387; 95% confidence interval: 1.018-1.889, P = 0.038). At the repeat session for recurrent AF, conduction recovery was observed similarly in both groups (P = 0.27).

CONCLUSION

Even after the elimination of any adenosine-provoked dormant PV conduction, the appearance of acute adenosine-provoked reconduction after the PVAI was an independent predictor of AF recurrence after a single AF ablation procedure.

Prevalence, electrophysiological properties, and clinical implications of dissociated pulmonary vein activity following pulmonary vein antrum isolation

The objective of this study was to investigate the prevalence, electrophysiologic properties, and clinical implications of dissociated pulmonary vein (PV) activity after PV antrum isolation (PVAI) in patients with paroxysmal atrial fibrillation (AF). One hundred seventy-three consecutive patients (61 ±10 years old, 141 men) with drug-refractory paroxysmal AF who underwent AF ablation were analyzed. After identification of arrhythmogenic foci, PVAI was performed in all patients. Of the total 346 isolated ipsilateral PVs, 97 (28.0%) were silent, 35 (10.1%) demonstrated isolated ectopic beats, 209 (60.4%) demonstrated a regular ectopic rhythm, and 5 (1.4%) demonstrated fibrillatory activity. The culprit thoracic vein was identified in 77 patients (44.5%). After isolation of ipsilateral PVs, venous activity was observed in 68 (79.1%) and 178 (68.5%) PVs among the 86 PVs with AF triggers and 260 PVs without AF triggers, respectively (p = 0.06). There was no significant difference in the incidence of acute PV reconnections exposed by adenosine triphosphate between the 97 silent ipsilateral PVs and 209 ipsilateral PVs with dissociated PV activity after the PVAI (20.6% vs 19.1%, p = 0.78). After a mean follow-up of 48.7 ± 7.9 months there was no significant difference in rates of freedom from atrial tachyarrhythmias after a single procedure between patients with and those without dissociated activity (62.1% vs 63.3%, p = 0.74, log-rank test). In conclusion, although dissociated PV activity appearing after PV isolation is an important electrophysiologic finding to prove bidirectional conduction block between the left atrium and the PV during the procedure, the clinical implications might be limited.

Shape Memory Behavior of Ti-Ni Thin Films Annealed at Various Temperatures

Ti-Ni thin films with three different types of compositions, titanium-rich Ti-Ni, near equiatomic TiNi and nickel-rich Ti-Ni were prepared by sputtering. The sputter-deposited films were annealed at various temperatures between 773 and 973K in order to crystallize. After the heat treatment, the shape memory behavior was examined with a thermomechanical tester. The shape memory behavior of the near equiatomic composition films was not affected by the heat treatment. On the other hand, the shape memory behavior of the other composition films strongly depended on the annealing temperature. As the annealing temperature increases, the martensitic and reverse martensitic transformation temperatures of the nickel-rich films decreased and those of the titanium-rich films increased. These opposite behaviors of the transformation temperatures can be explained by the opposite dependence of the precipitation of the second phase on the annealing temperature. All the nickel-rich films exhibited good shape memory effect over a wide range of stress, while all the titanium-rich films exhibited a small plastic strain only in the stress range where the shape changes associated with both the R-phase and the martensitic transformations were observed.

Adenosine triphosphate exposes dormant pulmonary vein conduction responsible for recurrent atrial tachyarrhythmias: importance of evaluating the dormant conduction during the re-do ablation procedure

A 61-year-old man suffered from atrial tachycardia (AT) following pulmonary vein isolation (PVI) treatment of atrial fibrillation. During a re-do procedure, all pulmonary veins (PVs) were isolated from the left atrium (LA) and programmed stimulation could not induce any atrial arrhythmias. Adenosine triphosphate exposed dormant PV-LA conduction at the right superior PV. PV firing during the reconnection caused AT with the same P-wave morphology as clinical AT. For 6 months after the elimination of that dormant PV conduction, the patient has been free of any AT. Evaluation of dormant PV conduction was effective in curing the recurrent AT after PVI.

Expression of Toll-like receptors on human platelets

INTRODUCTION

Platelets play a crucial role in arterial thrombosis, which is the main cause of acute coronary syndrome. Some mycobacteriums, such as Chlamydia pneumoniae, were associated with progression of atherosclerosis and they are interacted with Toll-like receptors (TLRs), which have been defined as pathogen-associated molecular pattern recognition molecules in innate immunity. In the present study, we examined whether human platelets express TLRs.

MATERIALS AND METHODS

Human platelets were obtained from healthy volunteers and the mRNA and protein level of TLRs on platelets and Meg-01 cells, megakaryoblastic cell line, were investigated.

RESULTS

Reverse transcription-polymerase chain reaction (RT-PCR) demonstrated that TLR1 and TLR6 mRNA were expressed in platelets and Meg-01 cells. Furthermore, interferon-gamma up-regulated their mRNA levels in dose and time dependent manners after stimuli. Both TLR1 and TLR6 proteins in platelets were detected by Western blotting, and their expression of platelets was more than that of Meg-01 cells. Flow cytometry analysis revealed the expression of TLR1 and TLR6 on the cell surface of Meg-01 cells. Furthermore, immunohistochemical analysis using human coronary thrombi obtained from patients with acute coronary syndrome confirmed the expression of TLR1 and TLR6 on platelets.

CONCLUSION

In summary, we demonstrated that human platelets and Meg-01 cells expressed a family of TLRs for the first time, and our findings indicated that platelets might recognize antigens directly via TLRs. Our findings suggest a possibility that platelets have the ability to recognize the antigens via TLRs and that there are mechanistic relations between infectious inflammation and atherosclerotic vascular diseases.

[Results of two-step tuberculin skin test against medical and nursing school students and treatment according to the results of the test]

To assess the risk of tuberculosis infection in medical and nursing school students, tuberculin skin tests were carried out in the two-step manner. The second tuberculin skin test was repeated two weeks later excluding those who were strongly positive in the first test. BCG vaccination was done with the consent of students who showed negative reaction twice. Medical interview and revaluation of prior routine chest radiogram were made on students who were strongly positive. Prophylactic INH medication was considered to those who are at high risk of tuberculosis. Eight hundred thirty eight students underwent the two-step tuberculin skin test, and among them, 771 students showed the positive reaction on the first test (92.0%) which included 58 weakly positive (6.9%), 347 intermediately positive (41.4%) and 366 strongly positive (43.7%) and 2 not-measurable (0.2%), and 65 students were negative (7.8%). The average size of the erythema was 30.9 +/- 18.8 mm on the first test and 37.9 +/- 20.6 mm on the second test. Twenty one students were negative on the second tuberculin skin test, and among them, 15 received BCG vaccination. Out of eight students who were vaccinated with BCG in 1999 and were followed up in the next year, 6 (75.0%) converted to positive. Strongly positive reaction was seen in 28 students (3.3%) and one of them underwent prophylactic medication of INH according to her family history of exposure to tuberculosis.

Clinical trial of acetazolamide in SCA6, with assessment using the Ataxia Rating Scale and body stabilometry

OBJECTIVE

To investigate the effect of acetazolamide on spinocerebellar ataxia type 6 (SCA6).

METHODS

Acetazolamide (250-500 mg/day) was administered orally for 88 weeks to 6 patients with SCA6, and its effect was quantitatively monitored using the Ataxia Rating Scale (ARS) and body sway analysis by stabilometry.

RESULTS

During administration of acetazolamide, the ARS score and the amplitude of body sway were significantly reduced compared with before administration. However, the response became weaker after 1 year of treatment.

CONCLUSION

Although this was an open trial, the results suggested that acetazolamide can temporarily reduce the severity of symptoms during the progression of SCA6.

Elevated parasympathetic nerve tone in isoproterenol-induced neurally mediated syncope during head-up tilt testing

To clarify the autonomic nerve mechanisms whereby isoproterenol induces vasovagal reaction, 32 patients with recurrent syncopal episodes of unknown origin underwent head-up tilt testing. Syncope was induced in 11 patients by a control tilt (control/+ group). The remaining 21 patients (control/- group) underwent the procedure during isoproterenol infusion. Syncope was induced in 13 (isoproterenol/+ group), but not in the remaining 8 patients (isoproterenol/- group). High-frequency component (HF) and low-frequency component (LF)/HF, which are indices of heart rate variability, were assessed for 2-min intervals at baseline (T1) during the initial phase (T2) and at the end (T3) of tilting in each test. The ratios of HF and LF/HF at T2/T1 and T3/T2 were calculated. The HF value at T3 in the control/+ group was greater than that in the control/- group (1.47+/-0.91 vs 0.75+/-0.34; p<0.05). The HF value at T3 in the isoproterenol/+ group was significantly greater than those in the isoproterenol/- group (1.19+/-1.04 vs 0.43+/-0.23; p<0.05). The HF value at T2 in the isoproterenol/+ tended to be greater than in the isoproterenol/- group (1.30+/-0.85 vs 0.66+/-0.53; p=0.07). The ratio of HF for T2/T1 in isoproterenol/+ was greater than in the other groups (2.04+/-1.26 in isoproterenol/+ vs 0.58+/-0.39 in control/-, 0.47+/-0.18 in control/+ and 0.71+/-0.45 in isoproterenol/-; p=0.0001), whereas that of HF for T3/T2 in the control/+ group was greater than in the other groups (1.48+/-0.62 in control/+ vs 0.97+/-0.33 in control/-; p<0.05, 0.79+/-0.35 in isoproterenol/- and 0.88+/-0.37 in isoproterenol/+; p<0.01). No difference was observed in either LF/HF or the ratio of LF/HF among the groups. The early and persistent increase in parasympathetic nerve tone provoked by isoproterenol plays an important role in enhancing the vasovagal reaction during head-up tilt testing.

Expression of adhesion molecules by human endothelial cells exposed to oxidized low density lipoprotein. Influences of degree of oxidation and location of oxidized LDL

The main objective of this study was to determine the influence of the degree of low density lipoprotein (LDL) oxidation and the location of oxidized LDL (oxLDL) on expression of adhesion molecules on endothelial cells (EC). OxLDL preparations 1-4 with different degrees of oxidative modification were studied. All preparations of oxLDL, after addition to the medium, stimulated the expression of intercellular adhesion molecule-1 (ICAM-1) by human umbilical vein endothelial cells (HUVEC) as determined by cell-ELISA. Concentration-dependent studies examining ICAM-1 expression by HUVEC showed that the minimal concentration of oxLDL which significantly stimulated ICAM-1 expression was 5 microg/ml, suggesting that the predicted physiological concentration of oxLDL in plasma may be not high enough to elicit a substantial increase of ICAM-1 expression in EC. In contrast, very small amounts (0.15 microg/well) of oxLDL-3 and 4, the more heavily oxidized LDL preparations, stimulated effectively ICAM-1 expression by HUVEC when located below the endothelial cell monolayer by immobilizing to type I collagen. The results suggest that the increased expression of ICAM-1 induced by accumulated oxLDL may be one of the mechanisms by which oxLDL contributes to atherogenesis.

Correlation of magnetic resonance imaging and histological findings in a large basilar tip aneurysm after coil embolization--case report

A 73-year-old female with a large basilar tip aneurysm underwent endovascular coil embolization with interlocking detachable coils (IDCs). The patient subsequently died of pneumonia 25 days after the embolization, and the aneurysm specimen was obtained at autopsy. Histological examination showed that the intraaneurysmal structure consisted of three layers. The outer layer was mildly organized thrombus surrounding the coils, the middle layer was disorganized clot, and the inner layer consisted of fresh blood clot. Gradient-echo magnetic resonance (MR) imaging taken before death had demonstrated a central region of high intensity and a peripheral low intensity region corresponding to the inner and middle-outer layers of the aneurysm, respectively. Intraaneurysmal placement of IDCs leads to the formation of a clot surrounding the coils. However, clot formation may be inadequate where the packing of the IDCs is incomplete. Comparison of the MR imaging and histological findings in this case show that gradient-echo MR imaging can assess thrombus and residual blood flow within the aneurysm.