High-risk screening for Anderson-Fabry disease in patients with cardiac, renal, or neurological manifestations.

Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder caused by abnormalities in the α-galactosidase (Gal) A gene (GLA; MIM:300644). The reduced activity of the lysosomal enzyme, α-galactosidase A (α-Gal A) leads to classic early manifestations and vascular disease of the heart, kidneys, and brain. As a high-risk screening for symptomatic AFD using an enzymatic assay on dried blood spot samples, we enrolled 2325 individuals (803 females and 1522 males; median age: 66 years) with cardiac, renal, or neurological manifestations that met at least one of the following criteria: (a) family history of early-onset cardiovascular diseases; (b) typical classic manifestations, such as acroparesthesias, clustered angiokeratoma, cornea verticillata, and hypo-anhidrosis; (c) proteinuria; (d) receiving dialysis; (e) left ventricular hypertrophy on electrocardiography or echocardiography; or (f) history of stroke. Ninety-two patients displayed low α-Gal A activity. Four males and two females had different pathogenic GLA mutations (0.26%) including a novel mutation c.908-928del21. Four males (0.17%) harbored the GLA c.196G>C (p.E66Q) variant. This simple screening protocol using dried blood spot samples is useful for early diagnosis of AFD in high-risk and underdiagnosed patients suffering from various cardiac, renal, or neurological manifestations.

Unexpectedly High Prevalence of Coronary Spastic Angina in Patients With Anderson-Fabry Disease.

BACKGROUND: Although we and others have reported cases of patients with Anderson-Fabry disease (AFD) complicated by coronary spastic angina (CSA), the prevalence of CSA in these patients remains unknown. Methods and Results: We performed the acetylcholine-induced provocation test, according to the Japanese guidelines for the diagnosis and treatment of patients with CSA, in 9 consecutive patients having 5 independent AFD pedigrees. Coronary spasms were provoked in conjunction with symptoms and ECG ischemic changes in 8 of 9 (89%) patients with AFD. CONCLUSIONS: We found an unexpectedly high prevalence of CSA in patients with AFD.

Insight into specific pro-arrhythmic triggers in Brugada and early repolarization syndromes: results of long-term follow-up.

The pro-arrhythmic triggers in Brugada and early repolarization syndromes (BrS, ERS) have not been analyzed systematically except for case reports. We clinically investigated the circumstances which precede/predispose to arrhythmic events in these syndromes during long-term follow-up. A detailed history from the patients/witnesses was taken to investigate the antecedent events in the last few hours that preceded syncope/ventricular fibrillation (VF); medical records, ECG and blood test from the emergency room (ER) were reviewed. 19 patients that fulfilled the investigation criteria were followed up for 71 ± 49 months (34-190 months). Prior to the event (syncope/VF), the patients were partaking different activities in the following decreasing order; drinking alcoholic beverage, having meal, and getting up from sleep, exercise. 3 patients reported mental/physical stress prior to the event and 2 patients developed VF several days after starting oral steroid for treatment of bronchial asthma. In the ER, elevated J-wave amplitude (0.27 ± 0.15 mV) was found with 58 % of the patients having hypokalemia. After electrolyte correction and cessation of steroids, the following day plasma K+ (4.2 ± 0.3 mEq/L, P < 0.001) was significantly increased and J-wave amplitude (0.13 ± 0.1 mV, P < 0.001) was remarkably reduced. Three patients were kept on oral spironolactone/potassium supplements. During follow-up for 71 ± 49 (34-190) months, among 4 patients with VF recurrence, one patient developed VF after taking oral steroid. In ERS and BrS, hypokalemia and corticosteroid therapy add substantial pro-arrhythmic effects, but potentially treatable. Stopping steroid therapy and avoiding hypokalemia had excellent long-term outcome.

Late Gadolinium Enhancement on Cardiac MRI Correlates with QT Dynamicity Represented by QT/RR Relationship in Patients with Ventricular Arrhythmias.

BACKGROUND: The distribution of late gadolinium enhancement (LGE) on the cardiac MRI (CMR) indicates myocardial fibrosis and provides information of possible reentry substrates. QT dynamicity reflecting repolarization abnormalities has gained attention as a potential prognostic predictive factor. OBJECTIVE: To clarify the correlation between the LGE distribution on CMR and QT dynamicity represented by the QT/RR relationship. METHODS: CMR and QT/RR analyses using Holter monitoring were performed in 34 patients (24 males, 60 ± 11 years) with ventricular tachycardia (VT) and/or ventricular fibrillation (VF). The LGE on CMR was scored using a 4-point score in 17 left ventricular segments. The sum of the LGE scores was calculated for each patient. The QT/RR slope and daytime/nighttime QT/RR ratio (day/night ratio) were calculated. The correlation between the slope or the day/night QT/RR ratio and late enhancement findings was analyzed. RESULTS: All patients were divided into 23 LGE positive (LGE(+)) and 11 LGE negative (LGE(-)) patients. The slopes of the QTe/RR and QTa /RR were significantly steeper in the LGE(+) than in LGE(-) patients (0.21 ± 0.03 vs 0.13 ± 0.02; P < 0.001, 0.19 ± 0.03 vs 0.13 ± 0.02; P < 0.001, respectively), and both slopes were significantly correlated with the total LGE scores (r = 0.83, P < 0.001; r = 0.71, P < 0.001, respectively). In the LGE(+) patients, the QTe day/night (1.37 ± 0.38 vs 0.91 ± 0.33; P = 0.002) and QTa day/night ratios (1.33 ± 0.26 vs 1.06 ± 0.30; P = 0.011) were significantly greater than those in the LGE(-) patients. CONCLUSION: The LGE distribution was closely related to the QT dynamicity, suggesting that a combination of these markers can be a powerful tool for understanding the background pathophysiology.

Repolarization characteristics in early repolarization and brugada syndromes: insight into an overlapping mechanism of lethal arrhythmias.

INTRODUCTION: We reported impaired QT-rate dependence in early repolarization syndrome (ERS); however, contemporary data have shown peak incidence of sudden cardiac death (SCD) in ERS and Brugada syndrome (BrS) at mid-night and early morning. Taken together, we analyzed the nocturnal QT-rate dependence in both syndromes. METHODS AND RESULTS: A total of 172 subjects were enrolled: 11 ERS, 11 BrS patients, 50 subjects with an uneventful ER pattern (ERP), and 100 non-J-wave control subjects. Ambulatory ECG-derived parameters (QT, QTc, and QT/RR slope) and day-night QT difference were analyzed and compared. Among the groups, there was no significant difference in the average QT or QTc; however, the 24-hour QT/RR slope was significantly smaller in ERS and BrS patients (0.103 ± 0.01 and 0.106 ± 0.01, respectively) than in the control group (0.156 ± 0.03, P < 0.001). Detailed analysis showed a lower day-night QT difference in ERS and BrS patients (19 ±18.7 and 24 ±14 milliseconds, respectively) than in the controls (40 ± 22 milliseconds, P = 0.007) with the lowest QT/RR slopes seen in the ERS and BrS groups from 0 to 3:00 am (QT/RR; 0.076 ± 0.02 vs. 0.092 ± 0.04 vs. 0.117 ± 0.04, for the ERS, BrS, and controls, respectively, P = 0.004) and from 3 to 6 am (QT/RR 0.074 ± 0.03 vs. 0.079 ± 0.02 vs. 0.118 ± 0.04, P < 0.001). CONCLUSION: In a large population of age- and gender-matched groups, both ERS and BrS patients showed attenuated QT-rate dependence and impaired QT day-night modulation that may provide a baseline reentrant substrate. Importantly, QT/RR maladaptation was most evident at mid-night and early morning, which may explain the propensity of such patients to develop SCD during this critical period.

Three cases of corticosteroid therapy triggering ventricular fibrillation in J-wave syndromes.

We describe three cases of J-wave syndrome in which ventricular fibrillation (VF) was probably induced by corticosteroid therapy. The patients involved were being treated with prednisolone for concomitant bronchial asthma. One of the three patients had only one episode of VF during her long follow-up period (14 years). Two patients had hypokalemia during their VF episodes. Corticosteroids have been shown to induce various types of arrhythmia and to modify cardiac potassium channels. We discuss the possible association between corticosteroid therapy and VF in J-wave syndrome based on the cases we have encountered.

[Effect of Pulse Wave Synchronization on T1 Value in Cardiac T1 Mapping: Is Pulse Wave Synchronization a Substitute for Electrocardiogram Gating?]

PURPOSE: We investigated whether peripheral pulse synchronization (PPUS) can be an alternate method for electrocardiographic synchronization (ECGS) in measuring myocardial T1 values in cardiac magnetic resonance imaging (CMRI). METHODS: T1 map imaging was performed on 49 patients undergoing CMRI using the 5s (3s) 3s modified Look-Locker inversion recovery (MOLLI) method for both ECGS and PPUS. The short-axis images of basal, mid, and apical segments were obtained. The T1 map images were analyzed using an image processing system, and T1 values were obtained for each cardiac segment. To assess the degree of agreement between T1 values obtained from ECGS and PPUS, the Bland-Altman analysis and the estimating intraclass correlation coefficient (ICC) were performed for the average T1 value of the entire myocardium and T1 values of each cardiac segment. Also, to evaluate whether PPUS imaging is possible in the diastole phase, we measured the length of systole in the electrocardiogram and the length of transmission (R-R') from R in the electrocardiogram to R (R') in the pulse waveform. RESULTS: From the comparison of T1 values, a good agreement of ICC was confirmed between the ECGS and PPUS (whole myocardium: 0.97, apical: 0.93, mid: 0.98, and basal: 0.97). The results of the Bland-Altman analysis also indicated good agreement. Moreover, it was shown that the heart was imaged in the diastole phase even with the default scan parameters of PPUS. CONCLUSION: Our results indicated that PPUS can be an alternate method for ECGS.

Impaired ventricular repolarization dynamics in patients with early repolarization syndrome.

INTRODUCTION: Almost all current investigations on early repolarization syndrome (ERS) have focused on the J-wave characteristics and ST-segment configuration; however, few have reported on ventricular repolarization indexes in ERS. METHODS AND RESULTS: A total of 145 subjects were enrolled: 10 ERS patients, 45 uneventful ER pattern (ERP) subjects, and 90 healthy controls without J waves or ST-segment elevation. Ambulatory ECG-derived parameters (QT, QTc(B), QTc(F), T peak-Tend(Tpe), and QT/RR slope) were measured and statistically compared. Among the groups, there was no significant difference in the average QT and QTc(B); however, ERS patients had the shortest QTc(F) and longest Tpe (QTc(F): 396.2 ± 19 vs 410.4 ± 20 vs 419.2 ± 19 milliseconds, P = 0.036, Tpe: 84.9 ± 12 vs 70.4 ± 11 vs 66.9 ± 15 milliseconds, P < 0.001, for the ERS, ERP, and control groups, respectively). Importantly, the 24-hour QT/RR slope was significantly smaller in the ERS than ERP and control groups (QT/RR: 0.105 ± 0.01 vs 0.154 ± 0.02 vs 0.161 ± 0.03, respectively; P < 0.001). When analyzing the diurnal and nocturnal QT/RR slopes, ERS patients had small diurnal and nocturnal QT/RR slopes while the ERP and control groups had large diurnal and small nocturnal QT/RR slopes (diurnal QT/RR: 0. 077 ± 0.01 vs 0.132 ± 0.03 vs 0.143 ± 0.03, P < 0.001; nocturnal QT/RR: 0.093 ± 0.02 vs 0.129 ± 0.03 vs 0.130 ± 0.04, P = 0.02 in the ERS, ERP, and control groups, respectively). CONCLUSION: ERS patients had a continuously depressed diurnal and nocturnal adaptation of the QT interval to the heart rate. Such abnormal repolarization dynamics might provide a substrate for reentry and be an important element for developing ventricular fibrillation in the ERS cohort.

Enhanced transmural dispersion of repolarization in patients with J wave syndromes.

INTRODUCTION: Recently, great attention has been paid to the risk stratification of asymptomatic patients with an electrocardiographic early repolarization (ER) pattern. We investigated several repolarization parameters including the Tpeak-Tend interval and Tpeak-Tend/QT ratio in healthy individuals and patients with J wave syndrome who were aborted from sudden cardiac death. METHODS AND RESULTS: Ninety-two subjects were enrolled: 12 patients with ventricular fibrillation associated with J waves, 40 healthy subjects with an uneventful ER pattern and 40 healthy control subjects (C) without any evident J waves. Using ambulatory electrocardiogram recordings, the average QT interval, corrected QT interval (QTc), Tpeak-Tend (Tp-e) interval, which is the interval from the peak to the end of the T wave, and Tp-e/QT ratio were calculated. Using ANOVA and post hoc analysis, there was no significant difference in the average QT and QTc in all 3 groups (QT; 396 ± 27 vs 405 ± 27 vs 403 ± 27 m, QTc; 420 ± 26 vs 421 ± 21 vs 403 ± 19 milliseconds in the C, ER pattern and J groups, respectively). The Tp-e interval and Tp-e/QT ratio were significantly more increased in the J wave group than the ER Pattern group (Tp-e: 86.7 ± 14 milliseconds vs 68 ± 13.2 milliseconds, P < 0.001, Tp-e/QT; 0.209 ± 0.04 vs 0.171 ± 0.03, P < 0.001), but they did not significantly differ between the C and ER pattern groups (Tp-e: 68.6 ± 7.5 vs 68 ± 13.2, P = 0.97, Tp-e/QT 0.174 ± 0.02 vs 0.171 ± 0.03, P = 0.4). CONCLUSION: As novel markers of heterogeneity of ventricular repolarization, Tpeak-Tend interval and Tp-Te/QT ratio are significantly increased in patients with J wave syndromes compared to age and sex-matched uneventful ER.

Recurrent ventricular fibrillation related to hypokalemia in early repolarization syndrome.

We describe a case of early repolarization syndrome in which augmented J waves were documented during an electrical storm associated with hypokalemia. The patient was referred to our hospital for therapy to treat recurrent ventricular fibrillation (VF). The 12-lead electrocardiogram showed giant J waves associated with hypokalemia during multiple episodes of VF. Although antiarrhythmic agents or deep sedation were not effective for the VF, an intravenous supplementation of potassium completely suppressed the VF with a reduction in the J-wave amplitude. Our report discusses the possible relationship between hypokalemia and VF in early repolarization syndrome.

Site of transmural late gadolinium enhancement on the cardiac MRI coincides with the ECG leads exhibiting terminal QRS distortion in patients with ST-elevation myocardial infarctions.

Large infarcts are associated with a terminal QRS-distortion in ST-elevation myocardial infarction (STEMI) patients. Late gadolinium enhancement (LGE) on the cardiac MRI (CMR) can depict an infarct distribution. However, less is known about the relationship between the LGE findings and QRS-distortion on admission, including the best ECG-lead location to reveal the QRS-distortion (DIS-lead) in STEMI patients. Fifty STEMI patients successfully treated with percutaneous coronary intervention were classified into two groups according to whether the QRS-distortion was positive (+) or negative (-). The LGE on a recent CMR was classified into 12 left ventricular segments (Basal-Middle-Apical × Anterior-Septal-Inferior-Lateral). The coincidences between the segmental LGE scores and DIS-lead were investigated. All patients were divided into 23 QRS-distortion (+) and 27 QRS-distortion (-) groups. The total LGE score was significantly greater in the QRS-distortion (+) group (14.7 ± 6.8 versus 9.6 ± 6.2, P < 0.01). The highest LGE score in 96% of QRS-distortion (+) patients was 4, and a score 4 segment indicated a good selection of the DIS-lead (86.4%). QRS-distortion in the ECG on admission represents severe transmural infarction in the LGE using CMR, which represents large infarcts in STEMI patients.

Clinical and genetic investigation of a Japanese family with cardiac fabry disease. Identification of a novel α-galactosidase A missense mutation (G195V).

Fabry disease is an X-linked lysosomal storage disorder caused by mutations of the α-galactosidase A gene (GLA), and the disease is a relatively prevalent cause of left ventricular hypertrophy mimicking idiopathic hypertrophic cardiomyopathy. We assessed clinically 5 patients of a three-generation family and also searched for GLA mutations in 10 family members. The proband had left ventricular hypertrophy with localized thinning in the basal posterior wall and late gadolinium enhancement (LGE) in the near-circumferential wall in cardiovascular magnetic resonance images and her sister had vasospastic angina pectoris without organic stenosis of the coronary arteries. LGE notably appeared in parallel with decreased α-galactosidase A activity and increased NT-pro BNP in our patients. We detected a new GLA missense mutation (G195V) in exon 4, resulting in a glycine-to-valine substitution. Of the 10 family members, 5 family members each were positive and negative for this mutation. These new data extend our clinical and molecular knowledge of GLA gene mutations and confirm that a novel missense mutation in the GLA gene is important not only for a precise diagnosis of heterozygous status, but also for confirming relatives who are negative for this mutation.

Antimitochondrial Antibody-associated Myopathy with Slowly Progressive Cardiac Dysfunction.

A 45-year-old woman was referred to our hospital for the evaluation of proximal muscle weakness and serum creatine kinase elevation [corrected]. She had atrial fibrillation and left ventricular asynergy. She was diagnosed with myopathy, accompanied by cardiomyopathy of unknown etiology. She was treated with prednisolone. After long-term follow-up and a detailed examination, the patient was diagnosed with antimitochondrial antibody (AMA)-associated myopathy with cardiac involvement. Although the patient received medical treatment, including beta-blockers and prednisolone, her cardiac function deteriorated progressively. Physicians should consider AMA-associated myopathy when diagnosing myopathies of unknown etiology. The presence of cardiac involvement should be proactively investigated in AMA-associated myopathy.

Acute Myocardial Infarction in a 17-year-old High-school Girl.

We report an unusual case of acute myocardial infarction in a high school girl. The patient was 17 years of age and had multiple coronary risk factors, including marked obesity with a body mass index (BMI) of 42.7 kg/m2, dyslipidemia and glucose intolerance. She had been an on and off smoker since she was 13 years of age. Due to the recent Westernization of the lifestyle, the prevalence of metabolic syndrome in the young generation has been increasing in Japan. Cardiovascular disease based on lifestyle-related diseases may become more common in young people.

Acute and long-term results of bipolar radiofrequency catheter ablation of refractory ventricular arrhythmias of deep intramural origin.

BACKGROUND: Successful bipolar radiofrequency catheter ablation (RFCA) of refractory ventricular arrhythmias (VAs) has been reported. However, the efficacy, safety, and long-term outcomes of bipolar RFCA of VAs are not fully determined. OBJECTIVE: The purpose of this study was to evaluate the effectiveness and safety of bipolar RFCA in treating refractory VAs during long-term follow-up. METHODS: Eighteen patients who underwent bipolar RFCA for ventricular tachycardia (VT) at 7 institutions were retrospectively investigated. Underlying heart diseases included remote myocardial infarction (n = 3 [17%]) and nonischemic cardiomyopathy (n = 15 [83%]). Although unipolar RFCA was performed in all patients, either it failed to suppress VT or VT recurred. The interventricular septum, left ventricular free wall, and left ventricular summit were targeted for bipolar RFCA. RESULTS: Acute success (VT termination and/or noninducibility) was achieved with bipolar RFCA in 16 patients (89%). Complications during the procedure included complete atrioventricular block (n = 2) and coronary artery stenosis (n = 1). One patient underwent chemical ablation after bipolar RFCA failure. At 12-month follow-up, VT reoccurred in 8 patients (44%). However, in patients with recurrence, VT burden had decreased: only 4 patients underwent re-RFCA, and only 1 of the 4 required chemical ablation. In the remaining 4 patients, re-RFCA was not required, as VT was controlled by medication or an implantable cardioverter-defibrillator. CONCLUSION: Bipolar RFCA is useful for acute suppression of refractory VT. Although VT recurrence rates during long-term follow-up were relatively high, we observed a significant reduction in VT burden.

Anti-signal Recognition Particle Antibody-positive Necrotizing Myopathy with Secondary Cardiomyopathy: The First Myocardial Biopsy- and Multimodal Imaging-proven Case.

A 69-year-old Japanese woman was admitted to our hospital with progressive muscle weakness and dysphagia. She was taking pitavastatin for dyslipidemia. Her serum creatine kinase was 6,300 U/L. Pitavastatin was stopped, but her symptoms deteriorated, and cardiac congestion appeared. A muscle biopsy showed necrotizing myopathy (NM), and anti-signal recognition particle (SRP) antibody was positive. 18F-fluorodeoxyglucose-positron emission tomography showed an abnormal uptake, and magnetic resonance imaging showed abnormal gadolinium enhancement in the left ventricular wall. An endomyocardial biopsy revealed inflammatory cardiomyopathy. Steroid, tacrolimus, and intravenous immunoglobulins were effective against the symptoms. This is the first case of biopsy-proven secondary cardiomyopathy due to anti-SRP-positive NM.

Japanese Antibacterial Drug Management for Cardiac Sarcoidosis (J-ACNES): A multicenter, open-label, randomized, controlled study.

BACKGROUND: Cardiac sarcoidosis (CS) is a noncaseating granulomatous disease of unknown etiology. Lifelong immunosuppressive therapy, most frequently using corticosteroids, is a standard therapy to control hypersensitivity of immune reactions and prevent inflammation. However, it sometimes causes various systemic adverse effects and requires dose escalation. Thus, additional therapy may be required for the treatment of this disease. Recently, Propionibacterium acnes (P. acnes) was reported as one of the etiologic agents of CS, indicating that antibacterial drugs (ABD) may be effective for the treatment of CS. The objective of this study was to investigate the effect of ABD treatment, in addition to standard corticosteroid therapy, in patients with CS. METHODS: The Japanese Antibacterial Drug Management for Cardiac Sarcoidosis (J-ACNES) trial was designed as a prospective, multicenter, randomized, open-label, controlled clinical trial. The patients will be randomized to receive either standard corticosteroid therapy plus ABD therapy (ABD group) or standard corticosteroid therapy (standard group). The primary endpoint is change in the total standardized uptake value at 6 months vs baseline using fluorine-18 fluorodeoxyglucose positron emission tomography and computed tomography. Secondary endpoints include efficacy, prognosis, and safety. RESULTS: The results of this study are currently under investigation. CONCLUSION: The J-ACNES trial will be the first prospective study assessing the clinical benefit and safety of ABD therapy, in addition to corticosteroid treatment, in patients with CS. Our findings may improve treatment of patients with CS, as additional ABD therapy reduces recurrence of inflammation and elucidates the mechanism of sarcoidosis.

[Usefulness of phase-sensitive inversion recovery in delayed enhanced cardiac MRI].

BACKGROUND: Delayed-enhancement MRI is a technique that has significant clinical usefulness, particularly for myocardial viability determination in ischemic heart disease. Delayed enhanced images have been acquired by using the inversion recovery(IR)method. It is necessary for the IR method to select optimal inversion time(TI). Recently, the phase-sensitive inversion recovery(PSIR)method has been developed to detect Gd-DTPA enhanced myocardium. PURPOSE: To compare the IR method with the PSIR method by acquiring Gd-DTPA solution phantoms A(0.05 mmol/l)and B(0.04 mmol/l)in various parameters. METHOD: Images were acquired using a turbo-fast low angle shot(t-flash)sequence in each method. RESULTS: The null point of signal intensity(SI)shortened as the flip angle(FA)and segments increased in the IR method. Excess segments also caused the duration of breath holding to be extended. The IR method might cause reversed SI between normal and Gd-DTPA enhanced myocardium if the optimal TI was not carefully selected. On the other hand, PSIR had no problem in obtaining phase-sensitive images that were converted into positive SI keeping inverse longitudinal magnetization. The PSIR method avoided the need to select optimal TI and loss of contrast. CONCLUSION: The PSIR method was a useful sequence for delayed-enhancement MRI to detect Gd-DTPA enhanced myocardium.

Late gadolinium enhancement on cardiac magnetic resonance represents the depolarizing and repolarizing electrically damaged foci causing malignant ventricular arrhythmia in hypertrophic cardiomyopathy.

BACKGROUND: The presence of a myocardial scar detected by late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) has been described as a predictor of all-cause mortality in hypertrophic cardiomyopathy (HCM). However, the detailed spatial relationship between LGE site and electrical abnormality is unclear in high-risk HCM with malignant arrhythmia. OBJECTIVE: The purpose of this study was to elucidate the detailed relationship between the site on CMR imaging and the electrically damaged site, a potential origin of ventricular arrhythmias in patients with HCM. METHODS: Fifty consecutive HCM patients underwent contrast-enhanced CMR. Of those patients, 18 patients with ventricular tachycardia underwent electrophysiology study including endocardial mapping of the left ventricle (LV). The LGE area was calculated at 12 different LV sites: anterior, lateral, posterior, and septal segments of the basal, middle, and apical portions. At each LV site, the bipolar electrogram, effective refractory period (ERP), and monophasic action potential were recorded. RESULTS: LGE-positive segments demonstrated a significantly lower amplitude (4.0 ± 2.8 mV vs 7.3 ± 3.6 mV; P < .001), longer duration (54.7 ± 17.8 vs 40.6 ± 7.8 ms; P < .001), longer ERP (320 ± 42 ms vs 284 ± 37 ms; P = .001), and longer monophasic action potential duration measured at 90% repolarization (321 ± 19 ms vs 283 ± 25 ms; P < .001) than did LGE-negative segments. The LGE area negatively correlated with the amplitude (r = -0.59; P < .001) and positively correlated with the duration (r = 0.64; P < .001), ERP (r = 0.44; P < .001), and action potential duration measured at 90% repolarization (r = 0.63; P < .001). All the observed VTs originated from LGE-positive segments. CONCLUSION: The spatial distribution of LGE significantly correlates with depolarizing and repolarizing electrical damage in high-risk HCM with malignant ventricular arrhythmia.