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. .

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.

BACKGROUND A free-floating ball thrombus in the left atrium is a rare clinical condition. However, the diagnosis of this condition has been facilitated by the advent and development of echocardiography and multi-detector row computed tomography (MDCT) and several cases have been reported. CASE REPORT We report a case of a 75-year-old woman who had recurrent giant spherical thrombi in the left atrium. She was diagnosed with chronic atrial fibrillation at 52 years of age. A pacemaker implantation was performed at 54 years of age because of a complete atrioventricular block; and mitral valve replacement was performed for severe mitral regurgitation at 62 years of age. She had a history of cerebral infarction and she was under treatment for chronic heart failure. Despite intensive anticoagulant therapy, she developed ball thrombi in the left atrium three times in six months. During hospitalization for acute myocardial infarction treated with percutaneous catheter intervention, transthoracic echocardiography and computed tomography (CT) revealed a free-floating giant spherical thrombus in the left atrium. She was treated with intensive anticoagulation therapy and the left atrial ball thrombus disappeared; however, two ball thrombi in the left atrium and left atrial appendage recurred after three months. Surgical removal of the thrombi and closure of the left atrial appendage were performed. Unfortunately, a ball thrombus in the left atrium recurred again after a further three months. CONCLUSIONS The present case highlights the difficulty of treating refractory thrombi in the left atrium.

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.

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.

Vasospastic Angina in Identical Twins.

BACKGROUND: The clinical conditions of various diseases, including coronary artery disease, are determined by genetics and the environment. Previous investigations noted the significance of genetic mutations and polymorphisms in cases of coronary spasm. CASE REPORT: We report on monozygotic identical twins who almost simultaneously presented with vasospastic angina. The 58-year-old younger twin was admitted to our hospital because of persistent chest pain. An electrocardiogram showed an inverted T wave in the left precordial leads. Coronary angiographies revealed a short left main trunk (LMT) and 50% stenosis at the proximal portion of the left anterior descending artery (LAD). Infusion of acetylcholine to his left coronary artery caused marked vasoconstriction associated with a sensation of chest oppression. Nitroglycerine completely reversed this response. Based on these findings, we diagnosed Twin A with vasospastic angina. At nearly the same time, his identical twin brother was diagnosed with vasospastic angina at another hospital. Comparison of both coronary angiograms indicated similar structure of coronary vessels, including short LMT and mild stenosis at the proximal portion of LAD. CONCLUSIONS: These 2 cases highlight the importance of genetic factors in the pathogenesis of vasospastic angina. It may be important for individuals to receive medical attention if their identical twin presents with vasospastic angina.

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.

Coconut atrium in long-standing rheumatic valvular heart disease.

BACKGROUND: Complete calcification of the left atrium (LA) is called "coconut atrium", which decreases the compliance of LA, leading to the elevation of LA pressure that is transmitted to the right-side of the heart. The pathogenesis of LA calcification in patients with rheumatic heart disease is unknown; however, possible mechanisms include chronic strain force in the atrial wall and inflammation. We report here a patient with long-standing rheumatic valvular heart disease with coconut atrium. CASE REPORT: A 76-year-old man presented with breathlessness and leg edema due to right-sided heart failure. He was diagnosed with rheumatic fever at 8 years of age. Mitral commissurotomy and the mitral and aortic valve replacement were previously performed to treat mitral and aortic valvular stenosis. The profile view of the chest X-ray indicated a diffuse calcified outline of the LA wall. A transthoracic echocardiogram revealed pulmonary hypertension and dilatation of both atria. Moreover, computed tomography showed nearly circumferential calcification of the LA wall. Despite intense medical treatment, he succumbed to heart failure. An autopsy demonstrated that the LA was markedly dilated, its wall was calcified, and its appearance was similar to the surface of an atherosclerotic aorta. Microscopic examination revealed intensive calcification in the endocardium. Minimal accumulation of inflammatory cells was noted. Although slight fibrosis was observed, the cardiac musculature was preserved. CONCLUSIONS: To the best of our knowledge, this is the first report that identifies the histological changes of LA calcification associated with long-standing rheumatic valvular heart disease.

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.

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. .

Visualization of the antegrade fast and slow pathway inputs in patients with slow-fast atrioventricular nodal reentrant tachycardia.

INTRODUCTION: Mapping of the antegrade fast pathway (A-FP) exact sites and antegrade slow pathway (A-SP) input locations has not been well described. METHODS: In 56 patients with slow-fast atrioventricular nodal reentrant tachycardia (SF-AVNRT), pacing during sinus rhythm and entrainment pacing during SF-AVNRT were performed at various sites in the triangle of Koch and coronary sinus (CS) to identify the A-FP and A-SP inputs. User-defined three-dimensional electro-anatomical mapping of the stimulus-His potential (St-H) interval and anatomical location was performed. The A-FP input was defined as the site of the shortest St-H interval, and A-SP input as the site of the shortest St-H interval and with a postpacing-interval equal to the tachycardia cycle length. The locations of the A-FP and A-SP inputs were mapped as a ratio of the distance between the His bundle (HB) and CS orifice (CSO), and the HB-CSO axis was divided into three zones: superior-, mid-, and inferior septum. The distance between the A-SP and A-FP inputs was calculated using the distance from each input to the HB and HB-CSO axis. RESULTS: Only 30 patients were included in this study because the A-SP mapping failed in 26. The A-SP input was distributed to the superior septum in four, mid- or inferior septum in 25, and CS in one. An A-SP input which was located less than 10 mm from the A-FP input was observed in one of four patients with a superior septum A-SP. CONCLUSIONS: An A-SP input at the superior septum seemed to be a potential risk for atrioventricular nodal injury during ablation.

Discrepancy between electrical and mechanical dyssynchrony in patients with heart failure and an electrical disturbance.

BACKGROUND: Cardiac resynchronization therapy (CRT) improves the survival rates of patients with heart failure, but 30-40% of them do not respond to CRT, partially because of the position of the left ventricular (LV) lead. The relationship between the electrical and mechanical activation of the left ventricle is unknown. The aim of this study was to compare the electrical and mechanical dyssynchrony. METHODS: We inserted electrode catheters into the coronary sinus (CS) and venous branches of the CS during CRT implantations and constructed electroanatomical contact maps in 16 patients using the EnSite NavX™ system. Mechanical activation was evaluated by speckle-tracking echocardiography and the latest mechanical and electrical sites were compared. The degrees of the electrical and mechanical delays of the implanted LV lead were also compared. RESULTS: The electroanatomical maps revealed that the latest electrical sites were anterior in one, anterolateral in five, lateral in eight, and posterolateral in two. Echocardiographic imaging revealed that the latest mechanical sites were anteroseptal in two, anterior in four, lateral in five, posterior in two, and inferior in three. The latest electrical and mechanical sites matched in only three patients. The degree of the local mechanical delay for the LV lead was significantly larger in the responders than nonresponders, whereas the local electrical delay did not differ. CONCLUSION: A discrepancy between the electrical and mechanical dyssynchrony might affect an adequate LV lead positioning.

Optimal strength and number of shocks at upper limit of vulnerability testing required to predict high defibrillation threshold without inducing ventricular fibrillation.

BACKGROUND: The upper limit of vulnerability (ULV) closely correlates with the defibrillation threshold (DFT). The aim of this study was to establish the optimal protocol for using the ULV test to predict high DFT (>20 J) without inducing ventricular fibrillation (VF). METHODS AND RESULTS: The 10-J and 15-J ULV test with 3 coupling intervals (-20, 0, and +20 ms to the peak of T-wave) and the DFT test were performed in 96 patients receiving implantable cardioverter defibrillator. ULV ≤ 10 J was confirmed in 47 (49%). ULV ≤ 15 J was confirmed in 70 (77%) of 91 patients (15-J ULV test could not be done in 5). The sensitivity and negative predictive value of both ULV >10 J and >15 J for predicting high DFT were 100%. The specificity and positive predictive value of ULV >15 J were higher than those for ULV >10 J (85% vs. 55%, 43% vs. 22%, respectively). The rate of VF inducibility for confirming ULV ≤ 15 J was lower than that for ULV ≤ 10 J (23% vs. 51%, P<0.0001). On analysis of single 15-J ULV test only at the peak of T-wave, VF was not induced in 79 of 91 patients, but 4 of these had high DFT. CONCLUSIONS: The 15-J ULV test with 3 coupling intervals could correctly identify high-DFT patients and reduce the necessity for VF induction at defibrillator implantation.