A Case of Chronic Heart Failure Complicated by Primary Biliary Cholangitis and Skeletal Myopathy.

Several autoantigens related to inflammatory myopathy have been identified. Antimitochondrial antibody M2 (AMA-M2) is known as one of the serologic hallmarks of primary biliary cholangitis (PBC). There have been several reports on the association between AMA-M2 and various types of inflammatory myopathy, including cardiomyopathy. We report a case of a 58-year-old man with decompensated heart failure who also had PBC and skeletal inflammatory myopathy. Endomyocardial biopsy revealed severe fibrotic replacement of the myocardium without massive inflammatory infiltration, which was pathologically similar to what happens in dilated cardiomyopathy (DCM). Although the potential relationship between chronic autoimmune inflammation and DCM has been discussed, the concept of the inflammatory DCM has not yet been established. When we see elevated liver enzymes, and which is not simply due to congestive hepatopathy, we should consider the coexisting disease such as PBC.

Possible Coronary Sequelae of Kawasaki Disease in an Elderly Man.

Kawasaki disease (KD) is an acute self-limited syndrome that predominantly affects children. Coronary sequelae have been identified to be responsible for a small, but significant percentage of young adults who present with myocardial ischemia. In this study, we present a case of an elderly patient with possible coronary sequelae of KD. A 76-year-old man was referred to our outpatient department for silent myocardial ischemia. Axial images of coronary computed tomography showed multiple lumens in the proximal left anterior descending (LAD) artery. Coronary angiography demonstrated braid-like appearance in the proximal and distal segment of the LAD. Coronary intervention was successfully performed for the proximal LAD lesion using directional atherectomy (DCA) catheter. Microscopic examination of the DCA specimens showed the following histological features: tissues in densely hyalinized fibrosis with occasional microcalcification, or those containing a number of smooth muscle cells (SMCs) with myxoid extracellular matrix. There was paucity of cholesterin crystals and aggregation of foamy cells. In addition, scarcely any inflammatory cell filtration was identified. In the section of SMC-containing samples, formation of multiple re-canalized vessels embracing endothelial cells was confirmed. These histopathologic findings indicated that the present coronary artery lesion has a high possibility of very late cardiovascular sequelae caused by arteritis due to KD, rather than arteriosclerosis. This is the oldest adult case with coronary artery disease possibly resulting from KD sequelae. This case highlights that KD sequelae must be considered as a cause of coronary artery lesion even in older patients.

The peak-to-end of the T wave in the limb ECG leads reflects total spatial rather than transmural dispersion of ventricular repolarization in an anthopleurin-A model of prolonged QT interval.

BACKGROUND: Previous studies have showed that the interval between the peak and the end of the T wave (Tp-e) is a marker of transmural dispersion of ventricular repolarization. OBJECTIVE: We studied the relationship between (a) the Tp-e on local pseudo transmural electrograms (pseudo transmural Tp-e) or limb leads of body surface electrocardiogram (surface Tp-e) and (b) the intracardiac left ventricular (LV) repolarization during a drug-induced QT-interval prolongation. METHODS: Using open-chested canine intact hearts treated by anthopleurin-A, transmural LV electrograms were recorded via needle electrodes placed in the basoanterior, midanterior, apicoanterior, basolateral, midlateral, and apicolateral LV wall. Recovery time (RT) was calculated as an index of local repolarization at each transmural unipolar electrode. RESULTS: This model showed slower heart rate-dependent heterogeneous distribution of ventricular repolarization both along the basal to apical axis and along the transmural axis. RT was longer at the LV apex than at the base and longer in the lateral than in the anterior wall during the slower heart rate. A high correlation was found between surface Tp-e and total LV dispersion. In contrast, pseudo transmural Tp-e correlated with transmural RT dispersion. The shortest RT in the heart roughly corresponded to the peak, as did the longest RT with the end of the T wave on the surface electrocardiogram. CONCLUSION: During drug-induced QT-interval prolongation with a large apicobasal and anterolateral dispersion of ventricular repolarization, the Tp-e in the limb leads expresses spatial (total) distribution of repolarization in the whole left ventricle.

[Cardiogenic shock due to takotsubo cardiomyopathy during induction therapy for acute myeloid leukemia].

A 61-year-old man admitted for pancytopenia was diagnosed with acute myeloid leukemia. On day 26 of induction therapy, the patient suddenly developed cardiogenic shock. The ultrasound cardiogram showed imaging features typical of takotsubo cardiomyopathy. Cardiogenic shock caused by takotsubo cardiomyopathy is rare in patients with hematological malignancies but is a severe complication during chemotherapy.

Inverted Takotsubo contractile pattern caused by pheochromocytoma with tall upright T-waves, but not typical deep T-wave inversion.

We describe a 36-year-old woman with inverted Takotsubo cardiomyopathy caused by pheochromocytoma crisis. In the acute phase, her electrocardiogram showed ST segment depression in lead II, III, aVF and V2 through V5. On day 14, tall upright T-waves were observed in leads V2 through V5 despite heart failure and basal to midventricular ballooning improved on day 4, and all electrocardiographic abnormalities finally normalized after surgical removal of the pheochromocytomas. This is the first report of electrocardiographic course of inverted Takotsubo cardiomyopathy, and these findings seem as if the inverted electrocardiographic findings are contrary to those of apical ballooning.

Focal atrial tachycardia refractory to radiofrequency catheter ablation originating from right atrial appendage.

A 44-year-old female presented with incessant, drug-refractory atrial tachycardia (AT). An electrophysiological study suggested focal abnormal automaticity, and localized the AT origin to the apex of the right atrial appendage (RAA). Repeated radiofrequency catheter ablation to the site of the earliest endocardial activation during AT failed. At surgery, right atrial appendectomy terminated the AT. On macroscopic findings, the cavity of the RAA became a dead-end before the apex. In patients with drug and radiofrequency catheter ablation, refractory focal AT arising from the RAA, especially the apex of the RAA, in our opinion surgical treatment could be considered in the lack of efficacy of ablation.

Antiarrhythmic vs. pro-arrhythmic effects depending on the intensity of adrenergic stimulation in a canine anthopleurin-A model of type-3 long QT syndrome.

AIMS: The effects of adrenergic activity and beta-blockade were studied in a canine experimental model of type-3 long QT syndrome (LQT3) induced by application of anthopleurin-A. METHODS AND RESULTS: Boluses of epinephrine at 0.5 and/or 1.0 microg/kg were administered before and after propranolol, 0.3 mg/kg, and the distribution of the ventricular repolarization and the development of polymorphic ventricular tachyarrhythmia (VA) were assessed. Using needle electrodes, transmural unipolar electrograms were recorded across the left ventricle (LV) and right ventricle (RV). Activation-recovery interval (ARI) was measured in each electrogram to estimate local repolarization during RV pacing at the cycle length of 750 ms after the creation of complete atrioventricular block. Before propranolol, epinephrine, 0.5 microg/kg, did not induce VA in any experiment. However, a dose of 1.0 microg/kg induced polymorphic VA following multiple premature ventricular complex (PVC) in four of six experiments. Epinephrine, 0.5 microg/kg, shortened ARI at all sites and lessened LV transmural ARI dispersion. Neither ARI nor its dispersion could be determined after 1.0 microg/kg of epinephrine because of the induction of PVC, polymorphic VA, or both. Propranolol (i) prevented epinephrine-induced PVC and polymorphic VA in all experiments, (ii) slightly prolonged ARI at all sites, along with a decrease in LV transmural ARI dispersion, and (iii) reversed the epinephrine-induced shortening of ARI. CONCLUSION: In this LQT3 model, an increase in adrenergic activity by epinephrine had dose-dependent, opposite effects on ventricular electrical stability. Since beta-adrenergic blockade suppressed epinephrine-induced PVC and polymorphic VA, it might be considered for supplemental therapy to suppress VA in patients presenting with LQT3.

Mutational analysis of block and facilitation of HERG current by a class III anti-arrhythmic agent, nifekalant.

Chemicals and toxins are useful tools to elucidate the structure-function relationship of various proteins including ion channels. The HERG channel is blocked by many compounds and this may cause life-threatening cardiac arrhythmia. Besides block, some chemicals such as the class III anti-arrhythmic agent nifekalant stimulate HERG at low potentials by shifting its activation curve towards hyperpolarizing voltages. This is called "facilitation". Here, we report mutations and simulations analyzing the association between nifekalant and channel pore residues for block and facilitation. Alanine-scanning mutagenesis was performed in the pore region of HERG. The mutations at the base of the pore helix (T623A), the selectivity filter (V625A) and the S6 helix (G648A, Y652A and F656A) abolished and S624A attenuated both block and facilitation induced by the drug. On the other hand, the mutation of other residues caused either an increase or a decrease in nifekalant-induced facilitation without affecting block. An open-state homology model of the HERG pore suggested that T623, S624, Y652 and F656 faced the central cavity, and were positioned within geometrical range for the drug to be able to interact with all of them at the same time. Of these, S649 was the only polar residue located within possible interaction distance from the drug held in its blocking position. Further mutations and flexible-docking simulations suggest that the size, but not the polarity, of the side chain at S649 is critical for drug induced facilitation.

Nifekalant hydrochloride suppresses severe electrical storm in patients with malignant ventricular tachyarrhythmias.

BACKGROUND: Some patients with an implantable cardioverter-defibrillator (ICD) suffer from burst of inappropriate multiple discharges (severe electrical storm), and because the current therapeutic options are limited, the effect of nifekalant hydrochloride, a new class III drug, on severe electrical storm was investigated in the present study. METHODS AND RESULTS: Ninety-one consecutive patients treated with ICD were included in the study (M 70; mean age 58 years; left ventricular ejection fraction 45+/-15%). Severe electrical storm was defined as more than 10 ICD discharges within 1 h. During a mean follow-up period of 30+/-13 months, 41/91 (45%) patients had appropriate ICD therapy for arrhythmias and severe electrical storm occurred in 11 of them (12%) at 20+/-18 months after ICD implantation. The mean number of ICD discharges/h during severe electrical storm was 18+/-12. In 4 of 10 patients, severe electrical storm was successfully suppressed by a combination of deep sedation and beta-blocking agent; 6 other patients were refractory to this treatment, but severe electrical storm was successfully suppressed by intravenous administration of nifekalant hydrochloride with no adverse effects. CONCLUSIONS: Nifekalant hydrochloride is an effective and safe treatment for severe electrical storm.

Phosphatidylinositol 3,4,5-trisphosphate and Ca2+/calmodulin competitively bind to the regulators of G-protein-signalling (RGS) domain of RGS4 and reciprocally regulate its action.

RGS (regulators of G-protein signalling) are a diverse group of proteins, which accelerate intrinsic GTP hydrolysis on heterotrimeric G-protein a subunits. They are involved in the control of a physiological behaviour known as 'relaxation' of G-protein-gated K+ channels in cardiac myocytes. The GTPase-accelerating activity of cardiac RGS proteins, such as RGS4, is inhibited by PtdIns(3,4,5)P3 (phosphatidylinositol 3,4,5-trisphosphate) and this inhibition is cancelled by Ca2+/calmodulin (CaM) formed during membrane depolarization. G-protein-gated K+ channel activity decreases on depolarization owing to the facilitation of GTPase-activating protein activity by RGS proteins and vice versa on hyperpolarization. The molecular mechanism responsible for this reciprocal control of RGS action by PtdIns(3,4,5)P3 and Ca2+/CaM, however, has not been fully elucidated. Using lipid-protein co-sedimentation assay and surface plasmon resonance measurements, we show in the present study that the control of the GTPase-accelerating activity of the RGS4 protein is achieved through the competitive binding of PtdIns(3,4,5)P3 and Ca2+/CaM within its RGS domain. Competitive binding occurs exclusively within the RGS domain and involves a cluster of positively charged residues located on the surface opposite to the Ga interaction site. In the RGS proteins conserving these residues, the reciprocal regulation by PtdIns(3,4,5)P3 and Ca2+/CaM may be important for their physiological regulation of G-protein signalling.

Alpha1-syntrophin-deficient skeletal muscle exhibits hypertrophy and aberrant formation of neuromuscular junctions during regeneration.

Alpha1-syntrophin is a member of the family of dystrophin-associated proteins; it has been shown to recruit neuronal nitric oxide synthase and the water channel aquaporin-4 to the sarcolemma by its PSD-95/SAP-90, Discs-large, ZO-1 homologous domain. To examine the role of alpha1-syntrophin in muscle regeneration, we injected cardiotoxin into the tibialis anterior muscles of alpha1-syntrophin-null (alpha1syn-/-) mice. After the treatment, alpha1syn-/- muscles displayed remarkable hypertrophy and extensive fiber splitting compared with wild-type regenerating muscles, although the untreated muscles of the mutant mice showed no gross histological change. In the hypertrophied muscles of the mutant mice, the level of insulin-like growth factor-1 transcripts was highly elevated. Interestingly, in an early stage of the regeneration process, alpha1syn-/- mice showed remarkably deranged neuromuscular junctions (NMJs), accompanied by impaired ability to exercise. The contractile forces were reduced in alpha1syn-/- regenerating muscles. Our results suggest that the lack of alpha1-syntrophin might be responsible in part for the muscle hypertrophy, abnormal synapse formation at NMJs, and reduced force generation during regeneration of dystrophin-deficient muscle, all of which are typically observed in the early stages of Duchenne muscular dystrophy patients.

Arrhythmogenesis of T wave alternans associated with surface QRS complex alternans and the role of ventricular prematurity: observations from a canine model of LQT3 syndrome.

INTRODUCTION: T wave alternans (TWA) is characterized by cycle-to-cycle changes in the QT interval and/or T wave morphology. It is believed to amplify the underlying dispersion of ventricular repolarization. The aim of this study was to examine the mechanisms and arrhythmogenesis of TWA accompanied by QRS complex and/or blood pressure (BP) waveform alternans, using transmural ventricular electrogram recordings in an anthopleurin-A model of long QT syndrome. METHODS AND RESULTS: The cardiac cycle length was gradually shortened by interruption of vagal stimulation, and TWA was induced in six canine hearts. Transmural unipolar electrograms were recorded with plunge needle electrodes from endocardial (Endo), mid-myocardial (Mid), and epicardial (Epi) sites, along with the surface ECG and BP. The activation-recovery interval (ARI) was measured to estimate local refractoriness. During TWA, ARI alternans was greater at the Mid than the Epi/Endo sites, and it was associated with the development of marked spatial dispersion of ventricular repolarization. As TWA increased, ventricular activation of the cycles associated with shorter QT intervals displayed delayed conduction at the Mid sites as a result of a critically longer ARI of the preceding cycle and longer QT interval, while normal conduction was preserved at the Epi site. Delayed conduction at the Mid sites manifested as surface ECG QRS and BP waveform alternans, and spontaneous ventricular tachyarrhythmias developed in absence of ventricular prematurity. In other instances, in absence of delayed conduction during TWA, ventricular premature complexes infringed on a prominent spatial dispersion of ventricular repolarization of cycles with long QT intervals and initiated ventricular tachyarrhythmia. CONCLUSION: TWA accompanied by QRS alternans may signal a greater ventricular electrical instability, since it is associated with intramural delayed conduction, which can initiate ventricular tachyarrhythmia without ventricular premature complexes.

Triggers of ventricular tachyarrhythmias and therapeutic effects of nicorandil in canine models of LQT2 and LQT3 syndromes.

OBJECTIVES: We sought to identify the triggers of ventricular tachyarrhythmia (VTA) in experimental models of long QT type 2 (LQT2) and long QT type 3 (LQT3) syndromes. BACKGROUND: Most adverse cardiac events occurring in the long QT type 1 syndrome are related to sympathetic nerve activity. In contrast, various factors may trigger VTA in patients with LQT2 and LQT3. METHODS: The mode of onset of VTA and therapeutic effects of the potassium-adenosine triphosphate channel opener nicorandil were compared in canine models of LQT2 and LQT3, using three induction protocols: 1) bradycardia produced by atrioventricular block (BRADY); 2) programmed ventricular stimulation; and 3) electrical stimulation of the left stellate ganglion (left stellate stimulation [LSS]). Transmural unipolar electrograms were recorded, and the activation-recovery interval (ARI) was measured. RESULTS: Ventricular tachyarrhythmias developed during BRADY in all six experiments in the LQT3 model, but in none of the six experiments in LQT2. Programmed ventricular stimulation induced VTA in two experiments of the LQT2 model, but in none of the LQT3 experiments. Stimulation of the left stellate ganglion induced VTA in three experiments in LQT2 and in two experiments in LQT3. Nicorandil caused greater shortening of ARI and greater attenuation of transmural ARI dispersion in the LQT2 model than in the LQT3 model. After treatment with nicorandil, a single VTA was induced in the LQT2 model by LSS, whereas in the LQT3 model, VTA remained inducible by BRADY in four experiments and LSS in one experiment. CONCLUSIONS: An abrupt increase in sympathetic activity appeared arrhythmogenic in both models. Nicorandil attenuated the heterogeneity of ventricular repolarization and suppressed the induction of VTA in the LQT2 model, but had a limited therapeutic effect in the LQT3 model.