Adolescent ; Electrocardiography ; Female ; Humans ; Myocarditis ; complications ; physiopathology ; Tachycardia, Ventricular ; etiology ; physiopathology

Based on human ventricular single cell mathematical model, a two-dimensional mesh of ventricular wall tissue was constructed. Through the increasing of the concentration of extracellular K+, we simulated the propagation of spiral wave in a condition under the influence of ischemia in 2-D human ventricular tissue. The results showed that along with the increase of ischemic level and size, the instability of spiral waves increased, and under the influence of certain ischemic level and size, spiral waves broke up. Through this simulation study of the effects of ischemia on spiral waves in 2-D human ventricular tissue, we explained the corresponding mechanism of the maintenance of ventricular tachycardia and the cause of ventricular fibrillation under the influence of ischemia.
Arrhythmias, Cardiac ; etiology ; physiopathology ; Computer Simulation ; Heart Ventricles ; Humans ; Models, Cardiovascular ; Myocardial Ischemia ; complications ; physiopathology ; Tachycardia, Ventricular ; etiology ; physiopathology ; Ventricular Fibrillation ; etiology ; physiopathology

Systemic sclerosis (SS) is a connective tissue disease and cardiac involvement is common. Primary cardiac involvement such as conduction system disturbances and arrhythmias can also occur. However, reports of sustained ventricular tachycardia (VT) are rare. We report a case of catheter ablation of sustained ventricular tachycardia in a patient with systemic sclerosis using a conventional mapping system. A 64-yr-old woman with a 10-yr history of SS was referred for management of her ventricular tachycardia. There was no structural abnormality in cardiac chambers. However, electrophysiologic study revealed electrical substrate of ventricular tachycardia which could be ablated with pacemapping and substrate mapping. This case demonstrated successful conventional mapping and catheter ablation in a hemodynamically unstable patient with SS.
*Catheter Ablation ; Electrocardiography ; Female ; Humans ; Middle Aged ; Scleroderma, Systemic/*complications/*diagnosis ; Tachycardia, Ventricular/*etiology/physiopathology/*surgery

We describe a 51-yr-old man presenting with syncope due to torsade de pointes. The torsade de pointes was refractory to conventional medical therapy, including infusion of isoproterenol, MgSO4, potassium, lidocaine, and amiodarone. His past history, physical findings, and hormone study confirmed that QT prolongation was caused by anterior hypopituitarism that developed as a sequela of hemorrhagic fever with renal syndrome. The long QT interval with deep inverted T wave was completely normalized 4 weeks after starting steroid and thyroid hormone replacement. Hormonal disorders should be considered as a cause of torsade de pointes, because this life-threatening arrhythmia can be treated by replacing the missing hormone.
Hemorrhagic Fever with Renal Syndrome/*complications/physiopathology ; Hormone Replacement Therapy ; Human ; Hypopituitarism/drug therapy/*etiology/physiopathology ; Male ; Middle Age ; Tachycardia, Ventricular ; Torsades de Pointes/drug therapy/*etiology/physiopathology

OBJECTIVETo study the application of abnormal electrophysiological substrate mapping for guiding ablation of ventricular tachycardias in arrhythmogenic right ventricular cardiomyopathy (ARVC-VTs) using a non-contact mapping system.

METHODSDynamic substrate mapping was performed in three male ARVC patients during sinus rhythm. The sites of the earliest activation, exit point and activation sequence were mapped for each induced VT.

RESULTSThree different patterns of substrates were determined in 3 patients, which located in right ventricular outflow tract, anterior right ventricular wall, and anterolateral right ventricular wall, respectively. Five different clinical VTs [mean CL (348 +/- 65) ms] were induced. Of 5 VTs, three were originated from substrate or boundary of substrate, and two had a remote origin. One VT conducted through the substrate. Linear ablations were created between the sites of the earliest ventricular activation and the VT exit point, or across the critical isthmus. The five clinical VTs were successfully ablated. There were no VT recurrences during 20 months of follow-up.

CONCLUSIONSDefining the abnormal electrophysiologic VT substrates is useful for understanding the mechanisms of ARVC-VTs and determining an ablation strategy. Linear ablation across a critical isthmus or between the earliest activation and the exit point can effectively cure these arrhythmias.

Adult ; Arrhythmogenic Right Ventricular Dysplasia ; etiology ; physiopathology ; therapy ; Catheter Ablation ; methods ; Electrophysiologic Techniques, Cardiac ; Humans ; Male ; Tachycardia, Ventricular ; complications ; physiopathology ; therapy

To investigate an association between surface electrocardiographic (ECG) parameters and sustained ventricular tachycardia (VT) in children after repair of congenital heart disease (CHD), data were obtained and analyzed in three groups (group I, 7 postoperative patients with episode of sustained VT (4 tetralogy of Fallot (TOF), 2 double outlet right ventricle (DORV), 1 truncus arteriosus); group II, 14 children with postoperative TOF not associated with VT; group III, 14 normal children). Mean age at the onset of sustained VT was 129+/-77 months (range 60-232); mean age at corrective surgery, 44+/-33 months (range 10-102); mean follow-up period after surgery, 84+/-74 months (range 20-185); the duration from repair to the onset of sustained VT, range 1-185 months. Compared to group II and III, group I showed longer QRS duration (group I, 137+/-10 msec; group II, 114+/-22 msec; group III, 65+/-12 msec) and shorter corrected J to Tmax interval (group I, 209+/-24 msec; group II, 272+/-44 msec; group III, 249+/-18 msec). QT and corrected QT, J to Tmax interval, and their dispersions in group I and II are significantly different from those of group III. In conclusion, QRS duration and corrected J to Tmax interval could be helpful to predict ventricular tachycardia in postoperative CHD.
Adolescence ; Child ; Child, Preschool ; Electrocardiography ; Female ; Heart Defects, Congenital/surgery* ; Heart Defects, Congenital/physiopathology ; Human ; Infant ; Male ; Tachycardia, Ventricular/etiology*

OBJECTIVETo evaluate the electrocardiographic (ECG) characteristics and results of radiofrequency catheter ablation (RFCA) of idiopathic ventricular tachycardia or premature ventricular contractions (VT/PVCs) originating in the vicinity of atrioventricular annulus.

METHODSNineteen patients with idiopathic VT/PVCs underwent conventional electrophysiological study and RFCA were included in this analysis. The 12 leads (ECG) characteristics were also analyzed.

RESULTSThe VT/PVCs were originated in the vicinity of mitral annulus in 10 cases, including anterolateral (n = 5), posterolateral (n = 3) and posteroseptal (n = 2). The VT/PVCs were originated in the vicinity of tricuspid annulus in the rest 9 cases, including the free wall (n = 5) and the septal portion (n = 4). The 12-lead ECG patterns of VT/PVCs originating in the vicinity of atrioventricular annulus were helpful for determine the site of RFCA. The VT/PVCs were successfully eliminated by RFCA in all cases.

CONCLUSIONThe exact origin of VT/PVCs originating in the vicinity of atrioventricular annulus could be determined by 12-leads ECG analysis and can be successfully and safely cured by RFCA.

Adult ; Aged ; Catheter Ablation ; methods ; Electrocardiography ; Female ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Tachycardia, Ventricular ; etiology ; physiopathology ; therapy ; Treatment Outcome ; Tricuspid Valve ; physiopathology ; Ventricular Premature Complexes ; etiology ; physiopathology ; therapy

Electrical instability easily induces a unidirectional conduction block, resulting in ventricular tachycardia (VT) or even fibrillation (VF). Cardiac memory affects dynamic electrical characteristics through previous pacing so that it makes the memory important in arrhythmia study. This paper investigates the impact of the rapid pacing duration on cellular excitability and its mechanism. Based on the canine endocardial single cell, a one-dimensional tissue model was developed. Simulations were realized with OpenMP parallel programming method. The results showed that with repetitive pacing, the cellular excitability became low while the conduction velocity decreased. Accumulation of intracellular [Ca2+]i and [Na+]i and depletion of [K+]i led to the shift of membrane current-voltage curves, changing the membrane resistance. Excitability determined by the resistance at the large width of stimulus pulse, therefore, it suggested that [Ca2+]i and [K+]i-induced memory formed the ionic substrates for the alteration of excitability.
Action Potentials ; Animals ; Computer Simulation ; Dogs ; Electric Stimulation ; Electrocardiography ; Heart Conduction System ; physiopathology ; Myocardial Contraction ; physiology ; Myocytes, Cardiac ; physiology ; Refractory Period, Electrophysiological ; physiology ; Tachycardia, Ventricular ; etiology ; physiopathology ; Ventricular Fibrillation ; etiology ; physiopathology

Malignant lymphoma can involve the cardiac cavity or myocardium as a mass. Clinical symptoms of its cardiac involvement are usually absent or nonspecific, making the diagnosis of the cardiac involvement very difficult before death. We experienced a patient with secondary myocardial non-Hodgkin's lymphoma presenting with sustained ventricular tachycardia (VT) as a primary clinical problem. A 39-yr-old woman visited our hospital because of dyspnea and palpitation for 7 days. Physical examination revealed rapid heart beat with variable intensity of the first heart sound and soft mass in the lower abdomen. VT with a cycle length of 480 msec was recorded in resting 12-lead electrocardiogram. Two well-circumscribed hypo-echogenic round masses were demonstrated in the interventricular septum and left ventricular posterior wall. Cytological examination of aspirated pericardial fluid and percutaneous needle biopsy of the abdominal mass revealed a diffuse large cell type non-Hodgkin's lymphoma. Myocardial masses and ventricular tachycardia resolved with chemotherapy using cyclophosphamide, adriamycin, vincristine and prednisone regimen. To our best knowledge, the same case as ours has not been reported previously.
Abdominal Neoplasms/secondary ; Adult ; Biopsy, Needle ; Bundle-Branch Block ; Echocardiography ; Electrocardiography ; Female ; Heart Neoplasms/*pathology ; Humans ; Lymphoma, Non-Hodgkin/*complications/diagnosis/*pathology ; Myocardium/*pathology ; Tachycardia, Ventricular/*etiology/physiopathology

Mushroom exposures are increasing worldwide. The incidence and fatality of mushroom poisoning are reported to be increasing. Several new syndromes in mushroom poisoning have been described. Rhabdomyolytic mushroom poisoning is one of new syndromes. Russula subnigricans mushroom can cause delayed-onset rhabdomyolysis with acute kidney injury in the severely poisoned patient. There are few reports on the toxicity of R. subnigricans. This report represents the first record of R. subnigricans poisoning with rhabdomyolysis in Korea, describing a 51-year-old man who suffered from rhabdomyolysis, acute kidney injury, severe hypocalcemia, respiratory failure, ventricular tachycardia, cardiogenic shock, and death. Mushroom poisoning should be considered in the evaluation of rhabdomyolysis of unknown cause. Furthermore, R. subnigricans should be considered in the mushroom poisoning with rhabdomyolysis.
Acute Kidney Injury/*etiology ; Basidiomycota/isolation & purification/*pathogenicity ; Electrocardiography ; Heart Ventricles/physiopathology ; Humans ; Male ; Middle Aged ; Mushroom Poisoning/*diagnosis/microbiology/mortality ; Rhabdomyolysis/*etiology ; Shock, Cardiogenic/*etiology ; Tachycardia, Ventricular/etiology