BACKGROUND: The comparative outcomes of subcutaneous implantable cardioverter-defibrillator (S-ICD) and transvenous ICD (T-ICD) have not been well studied. The aim of this study was to evaluate the safety and efficacy of currently available S-ICD and T-ICD. METHODS: The study included 86 patients who received an S-ICD and 1:1 matched to those who received single-chamber T-ICD by gender, age, diagnosis, left ventricular ejection fraction (LVEF), and implant year. The clinical outcomes and implant complications were compared between the two groups. RESULTS: The mean age of the 172 patients was 45 years, and 129 (75%) were male. The most common cardiac condition was hypertrophic cardiomyopathy (HCM, 37.8%). The mean LVEF was 50%. At a mean follow-up of 23 months, the appropriate and inappropriate ICD therapy rate were 1.2% vs. 4.7% (χ = 1.854, P = 0.368) and 9.3% vs. 3.5% (χ = 2.428, P = 0.211) in S-ICD and T-ICD groups respectively. There were no significant differences in device-related major and minor complications between the two groups (7.0% vs. 3.5%, χ = 1.055, P = 0.496). The S-ICD group had higher T-wave oversensing than T-ICD group (9.3% vs. 0%, χ = 8.390, P = 0.007). Sixty-five patients had HCM (32 in S-ICD and 33 in T-ICD). The incidence of major complications was not significantly different between the two groups. CONCLUSIONS The efficacy of an S-ICD is comparable to that of T-ICD, especially in a dominantly HCM patient population. The S-ICD is associated with fewer major complications demanding reoperation.
Adult ; Cardiomyopathy, Hypertrophic ; physiopathology ; therapy ; Death, Sudden, Cardiac ; prevention & control ; Defibrillators, Implantable ; Electrocardiography ; Female ; Humans ; Male ; Middle Aged ; Tachycardia, Ventricular ; physiopathology ; therapy

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

No abstract available.
Adolescent ; Adrenergic beta-Antagonists/therapeutic use ; Calcium Channel Blockers/therapeutic use ; Cardiomyopathy, Hypertrophic, Familial/complications/genetics/*pathology/physiopathology/therapy ; Electric Countershock ; Electrocardiography ; Female ; Genetic Predisposition to Disease ; Heart Failure/etiology/therapy ; Heart Septum/drug effects/*pathology/physiopathology/ultrasonography ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Pedigree ; Phenotype ; Tachycardia, Ventricular/etiology/therapy ; Treatment Outcome ; Ventricular Outflow Obstruction/etiology

OBJECTIVEEctopic atrial tachycardia (EAT) is a common type of supraventricular tachycardia in pediatric population, and it can be resistant to antiarrhythmic drugs and lead to tachycardia induced cardiomyopathy (TIC) if not properly managed. This study assessed the clinical course and response to treatment of EAT in children.

METHODA retrospective review included 144 children at the First Hospital of Tsinghua University diagnosed with EAT from January 2009 to April 2014. The clinical detailed history, 12 lead ECG, 24-h Holter recording, echocardiography, response to therapy and follow-up were analyzed.

RESULTThe onset of EAT occurred at any age with a distribution with positive skewness, 57 children ≤1 years, 22 children > 1 - 3 years, 25 children > 3 - 6 years and 40 children ≥ 6 years of age. The percentages of the three tachycardia types were 36. 1% (n = 52) for incessant EAT, 52. 8% (n = 76) for paroxysmal EAT and 11. 1% (n = 16) for sporadic EAT, respectively. There were 115 patients received drug therapy in our hospital and in 72 cases the EAT was completely controlled. Antiarrhythmic therapy had been discontinued in 35 children with complete control. Normal sinus rhythm was observed by telemetry or Holter within 4 to 90 days and the mean duration of medical therapy was 310 days (range 15 to 608 days) in these children. The combination of sotalol and propafenone showed better effectiveness for control of children with EAT (54%, 41/76), compared with single sotalol (36%, 24/66) and the combination of amiodarone and metoprolol (30%, 7/23) (χ2 = 6. 296, P = 0. 043). Tachycardia type was able to predict the response to antiarrhythmic drugs for children with EAT, sporadic tachycardia had best control rate on pharmacological therapy compared with paroxysmal tachycardia and incessant tachycardia (94% (15/16) vs. 67% (42/63) vs. 42% (15/36), χ2 = 17. 925, P = 0. 000) . Acute success of radiofrequency ablation (RFA) in children who showed poor response to antiarrhythmic drugs was achieved in 45 of 49 (92%), ultimate success was achieved in 33 of 49 (67%). The incidence of TIC secondary to EAT was 18. 1% (n =26), and left ventricular ejection-fraction (LVEF) returned to normal in 23 children after successful control of EAT ((61 ± 4) % vs. (43 ± 5) %, t = - 10. 036, P = 0. 000). Side effects including abnormal thyroid function (in 3) and abnormal liver function (in 1) occurred in 4 (17%) of 23 children who received amiodarone and disappeared when amiodarone was discontinued.

CONCLUSIONEAT in children predominantly occurred in young infants and children. Incessant EAT comprised a great percentage. The combination of sotalol and propafenone provided the best results for control of children with EAT. RFA should be considered as a preferred treatment for older children who displayed poor response to medical therapy.

Amiodarone ; Anti-Arrhythmia Agents ; Cardiomyopathies ; Catheter Ablation ; Child ; Child, Preschool ; Echocardiography ; Electrocardiography ; Humans ; Infant ; Retrospective Studies ; Sotalol ; Tachycardia, Ectopic Atrial ; drug therapy ; physiopathology ; Tachycardia, Supraventricular ; drug therapy ; Ventricular Function, Left

A patient with non-ischaemic cardiomyopathy, and pre-existing atypical atrial flutter and left bundle branch block, developed broad complex tachycardia. In this unique and uncommon case of double tachycardia, we discuss the diagnostic approach of ventricular tachycardia in patients with broad complex tachycardia, and the use of different contemporary algorithms to help diagnose ventricular tachycardia and differentiate it from supraventricular tachycardia with aberrant conduction.
Algorithms ; Atrial Flutter ; complications ; diagnosis ; Bundle-Branch Block ; physiopathology ; Cardiomyopathies ; complications ; diagnosis ; Diagnosis, Differential ; Echocardiography ; Electrocardiography ; Humans ; Male ; Middle Aged ; Tachycardia, Supraventricular ; diagnosis ; physiopathology ; Tachycardia, Ventricular ; diagnosis ; physiopathology

OBJECTIVETo evaluate factors for predicting ventricular arrhythmia, the clinical effect of drugs on patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), and their long-term outcomes.

METHODSSix patients diagnosed with CPVT underwent a series of electrocardiograms and 24-hour Holter monitoring. β-blockers were recommended for all patients, while some patients were also prescribed propafenone and 1 patient underwent catheter-based renal sympathetic denervation (RDN). The characteristics of electrocardiogram, arrhythmia and long-term outcomes were monitored.

RESULTSSyncope episodes did not occur any longer in 1 patient on β-blocker, but recurred in 3 other patients and 2 patients died (one due to his cessation of metoprolol for 3 months). Inverted and/or bifid T waves and abnormal U wave were observed in the precordial leads. T wave alternans was observed in 4 patients in the precordial leads. These abnormal electrocardiogram features disappeared or diminished with β-blocker treatment. All spontaneous episodes of ventricular tachycardia occurred prior to sinus tachycardia and frequent polymorphic premature ventricular contractions.

CONCLUSIONSBifid and/or inverted T waves, T wave alternans and abnormal U waves together with sinus tachycardia and frequent premature ventricular contractions are indicator for predicting ventricular arrhythmia and assessing the effect of β-blockers. Compliance with β-blocker treatment is a strong indicator of outcome.

Adolescent ; Adrenergic beta-Antagonists ; therapeutic use ; Adult ; Child ; Electrocardiography ; Electrocardiography, Ambulatory ; Female ; Humans ; Male ; Tachycardia, Ventricular ; drug therapy ; physiopathology ; Treatment Outcome

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

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

Medically refractory ventricular tachycardia (VT) storm can be controlled with radiofrequency catheter ablation (RFCA), however, it may be difficult to control in some patients with hemodynamic overload. We experienced a patient with intractable VT storm controlled by hemodynamic unloading. The patient had mid-septal hypertrophic cardiomyopathy with an implantable cardioverter defibrillator (ICD) back-up. Because of the severe mid-septal hypertrophy, his left ventricle (LV) had an hourglass-like morphology and showed apical ballooning; the focus of VT was at the border of apical ballooning. Although we performed VT ablation because of electrical storm with multiple ICD shocks, VT recurred 1 hour after procedure. As the post-RFCA monomorphic VT was refractory to anti-tachycardia pacing or ICD shock, we reduced the hemodynamic overload of LV with beta-blockade, hydration, and sedation. VT spontaneously stopped 1.5 hours later and the patient has remained free of VT for 24 months with beta-blockade alone. In patients with VT storm refractory to antiarrhythmic drugs or RFCA, the mechanism of mechano-electrical feedback should be considered and hemodynamic unloading may be an essential component of treatment.
Cardiomyopathy, Hypertrophic/complications/diagnosis/*physiopathology/therapy ; Catheter Ablation ; Electrocardiography ; Gated Blood-Pool Imaging ; Heart Catheterization ; Humans ; Male ; Middle Aged ; Tachycardia, Ventricular/diagnosis/etiology/*physiopathology/therapy ; Takotsubo Cardiomyopathy/complications/diagnosis/*physiopathology/therapy

PURPOSE: We hypothesized that Purkinje potential and their preferential conduction to the left ventricle (LV) posteroseptum during sinus rhythm (SR) are part of reentrant circuits of idiopathic left ventricular tachycardia (ILVT) and reentry anchors to papillary muscle. MATERIALS AND METHODS: In 14 patients with ILVT (11 men, mean age 31.5+/-11.1 years), we compared Purkinje potential and preferential conduction during SR with VT by non-contact mapping (NCM). If clear Purkinje potential(SR) was observed in the LV posteroseptum and the earliest activation site (EA) of preferential conduction at SR (EASR) was well matched with that of VT (EAVT), EASR was targeted for radiofrequency catheter ablation (RFCA). Also, the anatomical locations of successful ablation sites were evaluated by echocardiography in five additional patients. RESULTS: 1) All induced VTs exhibited clear Purkinje potential(VT) and preferential conduction in the LV posteroseptum. The Purkinje potential(VT) and EAVT was within 5.8+/-8.2 mm of EASR. However, the breakout sites of VT were separated by 30.2+/-12.6 mm from EAVT to the apical side. 2) Purkinje potential(SR) demonstrated a reversed polarity to Purkinje potential(VT), and the interval of Purkinje potential(SR)-QRS was longer than the interval of Purkinje potential(VT)-QRS (p<0.02) 3) RFCA targeting EASR eliminated VT in all patients without recurrence within 23.3+/-7.5 months, and the successful ablation site was discovered at the base of papillary muscle in the five additional (100%) patients. CONCLUSION: NCM-guided localization of EASR with Purkinje potential(SR) matches well with EAVT with Purkinje potential(VT) and provides an effective target for RFCA, potentially at the base of papillary muscle in patients with ILVT.
Adult ; Catheter Ablation ; Electrophysiology ; Female ; Humans ; Male ; Purkinje Fibers/*physiology ; Tachycardia, Ventricular/*physiopathology/surgery ; Ventricular Dysfunction, Left/*physiopathology/surgery ; Young Adult