A Case Report of a Rare Heterozygous Variant in the Desmin Gene Associated With Hypertrophic Cardiomyopathy and Complete Atrioventricular Block.

Hypertrophic cardiomyopathy (HCM) is the primary cause of sudden cardiac death in children and adolescents. Patients with HCM frequently have ventricular tachycardia and ventricular fibrillation, although complete atrioventricular block (CAVB) is very rare. We report a case of HCM with CAVB in an 8-year-old girl who underwent transvenous implantable cardioverter-defibrillator placement after resuscitation. In this patient, we identified a de novo heterozygous missense variant, Arg406Trp (c.1216C > T), in the desmin (DES) gene. Pathogenic variants in the DES gene result in cardiomyopathy, conduction disorders, and skeletal muscle weakness. This recently identified variant may cause HCM with CAVB.

La cardiomyopathie hypertrophique (CMH) est la première cause de mort subite d'origine cardiaque chez les enfants et les adolescents. Les patients atteints de CMH présentent fréquemment une tachycardie ventriculaire et une fibrillation ventriculaire, bien que le bloc auriculo-ventriculaire complet (BAVC) soit très rare. Nous rapportons un cas de CMH avec BAVC chez une fillette de 8 ans qui a reçu un défibrillateur cardioverteur implantable par voie transveineuse après réanimation. Chez cette patiente, nous avons isolé un variant faux sens hétérozygote de novo, Arg406Trp (c.1216C > T), dans le gène de la desmine (DES). Les variants pathogènes du gène DES entraînent une cardiomyopathie, des troubles de la conduction et une faiblesse des muscles squelettiques. Ce variant récemment identifié peut causer une CMH avec BAVC.

Back somersault-induced atrioventricular nodal reentrant tachycardia - A case of a 15-year-old promising gymnast.

A male 15-year-old promising gymnast suffered palpitations, which emerged only after landing a round-off back somersault. The performance induced an attack of regular narrow QRS complex tachycardia that was highly reproducible. Not a single element of the performance, but a whole sequence of round-off back somersault was required to induce the attack. An electrophysiologic study revealed an intra-nodal dual pathway causing atrioventricular nodal reentrant tachycardia (AVNRT). A complication of a tiny atrial septal defect (ASD) was incidentally detected, thus we initially suspected a causal relation of ASD as the platypnea-orthodeoxia syndrome. However, it was denied as the major mechanism of attack because of a very faint shunt flow and no-induction of hypoxemia during a round-off back somersault. The major triggering mechanisms of a whole sequence of round-off back somersaults were speculated to be related to transient atrial overload and autonomic imbalance induced by a swift postural-axial change together with an intense Valsalva maneuver with the maximal level of breath holding. The AVNRT attack was successfully treated by radiofrequency catheter ablation and has never recurred even by a whole sequence of round-off back somersaults. Currently he is a healthy and active gymnast with no symptoms. .

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.

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.

Late gadolinium enhancement of cardiac magnetic resonance imaging indicates abnormalities of time-domain T-wave alternans in hypertrophic cardiomyopathy with ventricular tachycardia.

BACKGROUND: The presence of myocardial scar detected by late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging has been described as a good independent predictor of mortality in patients with hypertrophic cardiomyopathy (HCM). Time-domain T-wave alternans (TWA) is also a potential predictor of cardiac mortality in patients with left ventricular dysfunction. OBJECTIVE: The purpose of this study was to elucidate the relationship between LGE distribution and TWA in patients with HCM. METHODS: CMR and TWA analyses using Holter monitoring were performed in 42 patients with HCM. The average transmural extent of LGE was scored as 1-4 in each segment, and the sum of the LGE scores (total LGE score) was calculated for each patient. The correlation between the maximal time-domain TWA voltage and LGE findings was analyzed, and the differences in time-domain TWA voltage, total LGE score, and cardiac function assessed by CMR imaging in the presence or absence of ventricular tachycardia (VT) were also compared. RESULTS: The total LGE score was significantly and positively correlated with the maximal time-domain TWA voltage (r = 0.59; P < .001). Furthermore, the total LGE score and maximal time-domain TWA voltage were significantly greater in patients who had episodes of VT (n = 21) than in those without VT (23 ± 7 vs. 10 ± 8; P < .001 and 87 ± 26 µV vs. 62 ± 12 µV; P < .001, respectively). However, the left ventricular ejection fraction did not statistically differ between patients with VT and those without VT (56% ± 14% vs. 61% ± 7%; P = .102). CONCLUSION: The magnitude of the localized LGE was significantly correlated with abnormalities in ventricular repolarization as assessed by TWA and QT dispersion.

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.

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.

Cerebral microbleeds and asymptomatic cerebral infarctions in patients with atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is a cardiac arrhythmia that does not infrequently induce ischemic strokes; however, little research has been reported on focal cerebral microangiopathic lesions in patients with AF. Recently cerebral microbleeds (CMBs) have been noticed for their potential implication in cerebral small vessel disease. Therefore, we had 2 goals in the present study: (1) to compare the prevalence of CMBs in patients with AF with that in patients without AF, and (2) to prove that CMBs could be a clinical predictive factor for the development of future cerebral microangiopathy in patients with AF without a history of symptomatic cerebral infarction in a prospective manner. METHODS: We performed yearly brain magnetic resonance imaging (MRI) assessments for a maximum of 5 years in 131 patients with AF and 112 control patients. Seventy-seven patients with AF underwent more than 3 yearly MRI scans. RESULTS: The Kaplan-Meier curve showed that the development of an asymptomatic cerebral infarction (ACI) was associated with the baseline presence of a CMB (P=.004). A multivariate Cox regression analysis revealed that the CMBs at baseline were significantly associated with an increment in not only the occurrence of ACIs (hazard ratio [HR], 5.414; 95% confidence interval [CI], 1.03-28.43; P=.046) but also in the consecutive development of CMBs (HR, 6.274; 95% CI, 1.43-27.56; P=.015). CONCLUSIONS: Patients with AF had a significantly higher prevalence of CMBs. The presence of CMBs in the baseline MRI may predict the consequent onset of an ACI and increase in CMBs in patients with AF.

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.

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.

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.

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.

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.

Recovery of advanced atrioventricular block by cilostazol.

We describe a case of advanced atrioventricular (AV) block, in which treatment with cilostazol was effective in recovering the AV conduction. The patient was referred to our hospital for close examination of the advanced AV block and permanent pacemaker implantation. Although the patient had experienced third-degree AV block with occasional AV synchrony for more than two days, the AV conduction completely recovered after treatment with oral cilostazol at 200 mg/day. Here we discuss the possible mechanism of the improvement in the AV conduction by cilostazol.

Peroxisomes are involved in biotin biosynthesis in Aspergillus and Arabidopsis.

Among the eukaryotes only plants and a number of fungi are able to synthesize biotin. Although initial events leading to the biosynthesis of biotin remain largely unknown, the final steps are known to occur in the mitochondria. Here we deleted the Aopex5 and Aopex7 genes encoding the receptors for peroxisomal targeting signals PTS1 and PTS2, respectively, in the filamentous fungus Aspergillus oryzae. In addition to exhibiting defects in the peroxisomal targeting of either PTS1 or PTS2 proteins, the deletion strains also displayed growth defects on minimal medium containing oleic acid as the sole carbon source. Unexpectedly, these peroxisomal transport-deficient strains also exhibited growth defects on minimal medium containing glucose as the sole carbon source that were remediated by the addition of biotin and its precursors, including 7-keto-8-aminopelargonic acid (KAPA). Genome database searches in fungi and plants revealed that BioF protein/KAPA synthase, one of the biotin biosynthetic enzymes, has a PTS1 sequence at the C terminus. Fungal ΔbioF strains expressing the fungal and plant BioF proteins lacking PTS1 still exhibited growth defects in the absence of biotin, indicating that peroxisomal targeting of KAPA synthase is crucial for the biotin biosynthesis. Furthermore, in the plant Arabidopsis thaliana, AtBioF localized to the peroxisomes through recognition of its PTS1 sequence, suggesting involvement of peroxisomes in biotin biosynthesis in plants. Taken together we demonstrate a novel role for peroxisomes in biotin biosynthesis and suggest the presence of as yet unidentified peroxisomal proteins that function in the earlier steps of biotin biosynthesis.

A case of idiopathic systemic capillary leak syndrome with high serum levels of G-CSF on exacerbation.

Systemic capillary leak syndrome (SCLS) is a life-threatening disorder which presents with periodic episodes of hypovolemic shock, due to plasma leakage to the extra-vascular space reflected by accompanying hypoalbuminemia, hemoconcentration and edema often with associated monoclonal gammopathy. We describe a 28-year-old woman with SCLS who required aggressive fluid resuscitation and was successfully treated with corticosteroid, terbutaline, and theophylline. At exacerbation, the levels of serum granulocyte colony-stimulating factor (G-CSF) were increased. Thus, G-CSF might play an important role and can be a useful biomarker for the severity of attacks in SCLS.

Spontaneous resolution of an accidental total coronary occlusion.

In December 2007, a woman was involved in a traffic accident. At first, her vital signs were normal, but electrocardiogram showed ST-segment elevation in the inferior leads. She was diagnosed as a blunt chest trauma-induced myocardial infarction. Her right coronary angiography showed total occlusion. She underwent an emergency coronary artery bypass surgery; 64-multi-detector-row computed tomography (64-MDCT) demonstrated an intravascular protruding lesion, which suggested subintimal hematoma. One month later, repeat coronary angiogram showed spontaneous recanalization, and 64-MDCT showed no discontinuous vessel wall. Coronary artery occlusion secondary to blunt chest trauma is rare, and it's even rarer to have spontaneous recanalization.