Attacks Of Ventricular Tachycardia Research Articles

Ventricular tachycardia initiation patterns on electrograms of implantable defibrillator devices

Abstract Introduction Sudden cardiac death is an unexpected death from a cardiac origin attributed by arrhythmias such as ventricular fibrillation (VF) and ventricular tachycardia (VT). The predominant treatment to terminate VT and VF is the implantation of an implantable cardioverter defibrillator (ICD). Currently, VT initiation in specific and small cohorts such as structural heart disease and reduced left ventricular ejection fraction patients have been explored. However, there is limited literature comparing the association between VT initiation patterns and defibrillators therapy outcome. This study aimed to investigate the most prevalent type of VT initiation from stored electrograms on ICDs and to explore the association between VT initiation pattern and therapy outcome (i.e., the ability to terminate VT). Method 344 stored electrograms amongst 65 patients from an existing database were visually inspected to classify VT initiation pattern as sudden onset (not preceded by premature ventricular complexes), non-sudden onset (preceded by premature ventricular complexes) and pacing-induced (device induced). Wilcoxon rank sum and Fisher’s Exact tests were used to assess differences between these groups. Mixed-effect logistic regression models accounting for multiple events occurring in individual patients were used to investigate association between the VT initiation pattern and therapy outcome. Results The mean age for the study group was 53±20 years and 54 (83%) subjects were males. Aetiology includes: 29 ischemic heart disease (45%), 10 hypertrophic cardiomyopathy (15%), 8 dilated cardiomyopathy (12%) and 18 other conditions (28%). Non-sudden onset VT (51%) was the most prevalent type of VT initiation pattern on defibrillators followed by sudden onset (44%) and pacing induced (5%). Non-sudden onset was 3 times more likely than the other 2 groups combined to be associated with unsuccessful therapies with an OR: 3.05 (95% confidence interval: 1.14, 8.15); p =0.03. There was no association between pacing-induced onset and unsuccessful therapies with an OR: 0.33 (95% confidence interval: 0.03, 3.33); p = 0.35. No association was identified for any of the three initiation patterns versus the other two combined and unsuccessful therapies when mixed-effect models were constructed. Discussion/ Conclusion: This study is consistent with other findings showing that non-sudden onset (51%) is the most prevalent VT onset. Pacing-induced VT accounted for 5% of VT with the predominant reason for initiation being undersensing of R-waves leading to pacing on the T-wave. This study reiterates the importance of programming strategies to prevent pacing induced VT. No associations were found with VT initiation and therapy outcome with mixed-effect models, possibly due to pseudo-replication being a limitation of this study. Prospective studies should be carried out in future to attempt to maximise success rate and establish the most effective treatment in ICDs.

Sympathetic denervation — a promising method for treatment of ventricular tachyarrhythmia in children

Ventricular tachycardia is a rare but potentially life-threatening arrhythmia. Ventricular tachycardia in patients with structural pathology and cardiac channelopathies is associated with the highest risk of sudden cardiac death. The stratification of patients depending on the risk of developing a life-threatening arrhythmia determines the choice of treatment method. Left cardiac sympathetic denervation is a surgical method of treatment aimed at preventing attacks of ventricular tachycardia. The antiarrhythmic effect of sympathetic denervation has been proven in both experimental and clinical studies. Currently, the technique of left cardiac sympathetic denervation consists of a video-assisted sympathectomy by thoracoscopic access, which makes the procedure safe and effective. Left cardiac sympathectomy is used in the treatment of patients with recurrent ventricular tachycardia despite adequate medical therapy. The authors recommend the use of left cardiac sympathectomy in those types of channelopathies, in which stress is the main proven provoking factor of ventricular tachycardia.

Surgical Ablation of Ventricular Tachycardia.

Surgery for ventricular tachycardia (VT) is indicated in patients in whom pharmacotherapy or catheter ablation is ineffective or frequent VT attacks are not suppressed or with frequent activation of implantable cardioverter defibrillator. In ischemic VT, resection of fibrous endocardium combined with encircling cryothermia at the border between the infarcted and normal myocardium is performed. In surgery for VT associated with cardiomyopathy, close collaboration between the physician and surgeon is important and intraoperative mapping using electro-anatomic mapping system is helpful. In VT associated with cardiac tumors, cryothermia of the thinned subepicardial myocardium at the edge of the tumor is recommended in addition to resection of tumors.

Ventricular Tachycardia as the Initial Presentation of Missed Kawasaki Disease in a Teenager

Introduction: Ventricular Tachycardia (VT) can be a life threatening condition and is not typically seen in otherwise healthy children. We report the first case, to our knowledge, of an otherwise healthy teenager with sustained VT as the presenting symptom for missed Kawasaki Disease (KD). Case presentation: A 14 year old, healthy male was brought by ambulance to the emergency department due to sudden onset chest pain and palpitations at rest. Physical exam revealed an oriented, conversant teen without murmurs, crackles or hepatomegaly. His EKG demonstrated wide complex tachycardia with a right bundle branch block morphology and superior axis at a rate of 213 bpm (Figure 1) consistent with VT from the left ventricle. He was an active soccer player with no prior history of palpitations, chest pain, syncope, recent illness or illicit drug use. Two doses of adenosine were administered without effect. A limited echocardiogram revealed normal appearing systolic function in the setting of tachycardia. The possibility of Belhassen’s VT, a rare but typically benign form of VT that is responsive to calcium channel blockers and most commonly seen in otherwise healthy teenagers, was considered. Two doses of Verapamil were administered without effect. Next, concern arose for papillary muscle VT. Two boluses of lidocaine were administered without effect. During an IV bolus of sotalol he became unresponsive and hemodynamically unstable requiring a synchronized cardioversion to restore sinus rhythm. A complete echocardiogram in sinus rhythm demonstrated dilated coronary arteries (CA), regional wall motion abnormalities and low normal function concerning for KD. Extensive questioning for history of possible KD was negative. However, CT imaging demonstrated mild diffuse right CA dilation with multiple focal aneurysms, a large, calcified left main CA aneurysm impinging on the LAD origin, and a diffusely hypoplastic left circumflex CA with restricted flow (Figure 2), and cardiac MRI revealed dilated and aneurysmal proximal CAs and a large transmural infarct of the basal anterior and anterolateral left ventricle, consistent with a remote history of KD. His VT was determined to be secondary to scar associated with infarct. He underwent an implantable loop recorder placement (family refused an ICD) and was discharged home on beta blocker and anticoagulation therapy. Discussion: KD is a well described ailment of childhood known to cause a vasculitis preferentially affecting the coronary arteries. With prompt and appropriate treatment, outcomes are favorable; however, when not recognized, patients may develop serious sequelae secondary to CA aneurysms. This is the first case of VT as the presenting symptom for missed KD in a teenager, increasing our knowledge of KD presentation and should also remind clinicians to broaden the differential diagnosis in new onset ventricular tachycardia.

The Role of Ventricular Tachycardia in LVAD Patients and Clinical Outcomes

Introduction Ventricular tachycardia (VT) is common in patients with end-stage heart failure, and pose additional risks in patients who have left ventricular assist devices (LVAD). We set out to examine if development of VT increases risk of mortality post-LVAD and the odds of developing right ventricular failure (RVF). Hypothesis New onset VT increases both the risk of 1-year mortality post-LVAD and the odds of developing RVF. Methods We performed a single-center retrospective analysis of 295 patients who received a continuous-flow durable LVAD (HeartMate II or HeartWare VAD) between Jan. 1st 2006 through Dec. 31st 2016. We stratified patients to 2 cohorts: those who had positive or negative history of VT pre-LVAD and those who developed VT post-LVAD. A survival analysis based on 1-year survival was performed to find predictors of mortality and association with RVF. RVF severity was defined according to the new INTERMACS criteria. Results In patients with and without a history of VT, 113 (67%) and 74 (58%) respectively developed VT post-LVAD. Baseline characteristics were similar among all cohorts (Table 1). Survival analysis demonstrated that both new onset VT (Figure 1) and recurrence of VT did not increase the risk of 1 year mortality post-LVAD. Additionally, univariable analysis in patients without history of VT pre-LVAD showed that VT increased the odds of developing severe RVF (Table 2) (OR 6.20, p=0.020, 95%CI [1.33 - 29.0]), but this was no longer significant in multivariable analysis. Conclusions New onset and recurrent VT do not appear to be associated with increased mortality in LVAD patients. While there is a signal that new onset VT may increase the odds of severe RVF in patients without VT history pre-LVAD, this needs to be addressed prospectively and in larger cohorts.

Characteristics of ventricular tachycardia and long-term treatment outcome in patients with dilated cardiomyopathy complicated by lamin A/C gene mutations

BackgroundDilated cardiomyopathy caused by lamin A/C gene (LMNA) mutation is complicated with atrioventricular (AV) conduction disturbances, malignant ventricular arrhythmias, and progressive severe heart failure. Radiofrequency catheter ablation (RFCA) of ventricular tachycardia (VT) has been reported to be challenging due to the high recurrence rate in patients with LMNA-related cardiomyopathy. However, electrophysiological and histopathological characteristics of VT substrate remain to be fully elucidated. Methods and resultsWe experienced 6 familial patients with LMNA-related cardiomyopathy in 3 pedigrees (6 males, 43.7±4.5 [SD] years). All patients had first VT attack at 50±6.6 [SD] years of age, and 4 underwent RFCA for incessant VT. Their electrocardiograms during VT showed similar QRS morphologies, characterized by an inferior axis, SR pattern in aVR, and QS pattern in aVL, suggesting the origin of the basal anterior ventricle. Indeed, the VTs had multiple exits around the basal anterior ventricular septum in all RFCA cases. Although we performed multiple RFCA procedures including epicardial ablation and surgical cryoablation, all cases experienced VT recurrences in 4.5±6.4 [SD] months after last procedure. All patients developed end-stage heart failure with frequent VT events, and died at 59.5±3.6 years of age (severe heart failure in 5 and lung disease in 1). In three autopsy cases with RFCA, fibrofatty degeneration was noted in the AV node. In addition, in the deep basal ventricular septum, inhomogenous fibrotic degenerated tissue was noted beyond the reach of RF lesions. ConclusionsThese results demonstrate that patients with LMNA-related cardiomyopathy are characterized by VTs refractory to RFCA probably because of the deep intramural focus at the basal ventricular septum, resulting in poor prognosis with progressive severe heart failure despite all available optimized therapies. Thus, we should consider heart transplantation in their early 50s when several VT events begin to occur.

Progression of myocardial fibrosis in hypertrophic cardiomyopathy: mechanisms and clinical implications.

AimsMyocardial fibrosis as detected by late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) is a powerful prognostic marker in hypertrophic cardiomyopathy (HCM) and may be progressive. The precise mechanisms underlying fibrosis progression are unclear. We sought to assess the extent of LGE progression in HCM and explore potential causal mechanisms and clinical implications.Methods and resultsSeventy-two HCM patients had two CMR (CMR1-CMR2) at an interval of 5.7 ± 2.8 years with annual clinical follow-up for 6.3 ± 3.6 years from CMR1. A combined endpoint of heart failure progression, cardiac hospitalization, and new onset ventricular tachycardia was assessed. Cine and LGE imaging were performed to assess left ventricular (LV) mass, function, and fibrosis on serial CMR. Stress perfusion imaging and cardiac energetics were undertaken in 38 patients on baseline CMR (CMR1). LGE mass increased from median 4.98 g [interquartile range (IQR) 0.97–13.48 g] to 6.30 g (IQR 1.38–17.51 g) from CMR1 to CMR2. Substantial LGE progression (ΔLGE ≥ 4.75 g) occurred in 26% of patients. LGE increment was significantly higher in those with impaired myocardial perfusion reserve (<MPRI 1.40) and energetics (phosphocreatine/adenosine triphosphate <1.44) on baseline CMR (P ≤ 0.01 for both). Substantial LGE progression was associated with LV thinning, increased cavity size and reduced systolic function, and conferred a five-fold increased risk of subsequent clinical events (hazard ratio 5.04, 95% confidence interval 1.85–13.79; P = 0.002).ConclusionMyocardial fibrosis is progressive in some HCM patients. Impaired energetics and perfusion abnormalities are possible mechanistic drivers of the fibrotic process. Fibrosis progression is associated with adverse cardiac remodelling and predicts an increased risk of subsequent clinical events in HCM.

Tekrarlayan Ventriküler Taşikardi Atağı ile Başvuran Bir Olguda İntrakardiyak Kitle ve Uzun Dönem İzlemi

Çocukluk çağında kardiyak tümörler nadir görülmektedir. En sık görülen primer kardiyak tümörler rabdomiyom ve fibromlardır. Teratom, miksoma ve hemanjiyomlar ise daha nadir görülmektedirler. Kardiyak tümörler; obstrüksiyona bağlı göğüs ağrısı, senkop, siyanoz gibi bulgulara, perikardiyal efüzyona, kalp yetersizliğine ve ani kardiyak ölüme yol açabilen, medikal tedaviye dirençli ventriküler taşikardi, supraventriküler taşikardi gibi hayatı tehdit edici aritmilere neden olabilmektedirler. Bu çalışmada, tekrarlayan ventriküler taşikardi atakları olan ve interventriküler septum apikal bölgesinde yerleşmiş olup, ventrikül içine uzanım gösteren kardiyak tümörlü yedi yaşındaki kız olgunun uzun dönem izleminin sunulması amaçlanmıştır. Cerrahi eksizyon mümkün olmayan ve tekrarlayan ventriküler taşikardi ataklarına yol açan intrakardiyak kitlelerde tedavi yaklaşımları tartışılmıştır.

Increased risk of ventricular tachycardia and cardiovascular death in patients with myocarditis during the long-term follow-up: A national representative cohort from the National Health Insurance Research Database.

The incidence of acute myocarditis complicated with ventricular tachycardia (VT) is unknown. This study aimed to investigate the association between myocarditis and the incidence of VT and mortality. We also aimed to determine the independent predictors that increased the VT risk in those patients. From 2000 to 2004, 13,250 patients with a history of myocarditis were identified from the Taiwan National Health Insurance Research Database. The same number of individuals without heart disease with a matched sex and underlying diseases were selected as the control group. The long-term risks of life-threatening ventricular arrhythmias and mortality in patients with a history of myocarditis were investigated by an adjusted Cox proportional hazards regression. After a mean follow-up of 10.4 ± 2.94 years (interquartile range: 12, 10.19–12), the myocarditis patients showed a higher incidence of new onset VT events compared with healthy controls (5.4% [519 per 100,000 person-year] in the myocarditis group vs, 0.47% [43 per 100,000 person-year] in the healthy controls; adjusted hazard ratio [HR]: 16.1, 95% confidence interval [CI]: 12.4–20.9; P < .001). A higher incidence of cardiovascular death was noted in the myocarditis group than healthy controls (6.52% vs 3.18%; HR: 2.42, 95% CI: 2.14–2.73; P < .001) after adjusting for the multivariate confounders including sex, age, underlying comorbidities, and medications. The results of this study suggested that there was higher incidence of life-threatening VT and mortality during the very long-term follow-up in patients with a history of myocarditis. Future work should focus on an in-depth risk stratification of VT in myocarditis patients.

Using cardiovascular imaging modalities to determine cardiac disorders before starting sports activities.

We re-examined children who had previously been declared eligible to participate in competitive sports activities for cardiac disorders, using cardiac investigation protocol. Total of 250 children (224 males [89.6%], and 26 females [10.4%]) between the ages of 8 and 17 years who had just started or were already engaged in sports activities were included in the study. Participants had detailed physical examination evaluated by a pediatric cardiologist. Those with findings suggesting cardiac disorder in their history and/or physical examinations, and/or 12-channel electrocardiography (ECG) were examined with echocardiography (ECHO), 24-hour Holter monitoring, and exercise test. Mean duration of participation in sports activities was 13 months. Among all, 10.4% of the children had abnormalities on ECG. ECHO demonstrated cardiomyopathy in 1, mitral valve prolapse in 2, tricuspid insufficiency in 2, and mitral insufficiency in 1 participant. Holter monitoring revealed non-sustained ventricular tachycardia attacks in 1, and supraventricular tachycardia in another child. Three were ultimately disqualified from partaking in competitive sports. Sports and medical communities must work together to establish study protocols to prevent sudden death related to sports and to make these activities safer for athletes. Pediatric cardiology consultation for young athletes before they start sports activities is needed.

A pediatric case of Brugada syndrome diagnosed by fever-provoked ventricular tachycardia.

Brugada syndrome is a rare channelopathy associated with the SCN5A gene that causes fatal ventricular arrhythmias. This case of Brugada syndrome, in which ventricular tachycardia (VT) was provoked by high fever, is the first report in a Korean child. The boy had retinoblastoma of his left eye diagnosed at 16 months of age. After chemotherapy, he contracted a catheter-related infection with a high fever up to 41℃ leading to monomorphic VT. This was characterized as having right bundle branch block morphology, superior axis deviation, and a heart rate of 212/min. Direct current cardioversion recovered the VT to sinus rhythm after a lack of response to amiodarone and lidocaine. A second attack of VT that was not controlled by cardioversion, however, responded to lidocaine. The baseline electrocardiogram showed a long PR interval and QRS duration, and the patient's grandfather had a history of Brugada syndrome. A mutation in SCN5A was identified in this patient, his father, and his grandfather. The patient was treated with quinidine and followed up for 1 year.

Ventricular tachycardia in pregnancy causing maternal death

Ventricular tachycardia (VT) is rarely observed during pregnancy. Its presence may indicate an underlying cardiac structural abnormality, or undiagnosed congenital arrhythmic disease. However, some pregnant women with VT have structurally normal hearts. There are few reports of new onset VT during pregnancy in absence of structural heart disease. We describe a case of ventricular tachycardia in pregnant woman with no previous heart disease. A 27-year-old, G2P0 + 0 + 1 + 0, at 39 weeks of gestation, presented with episodes of light headedness, vomiting, shortness of breath, and chest discomfort. There was cyanosis with respiratory rate of 56/min and heart rate of 136/min, regular. ECG showed multiple episodes of non-sustained VT with left bundle branch morphology, consistent with VT originating from the right ventricular outflow tract. Considering the diagnosis as VT, the patient was administered bolus doses of amiodarone, followed by maintenance dose. The condition worsened, and the patient expired within 1 hour of admission.

Utility of a novel risk score for prediction of ventricular tachycardia and cardiac death in chronic Chagas disease - the SEARCH-RIO study

The SEARCH-RIO study prospectively investigated electrocardiogram (ECG)-derived variables in chronic Chagas disease (CCD) as predictors of cardiac death and new onset ventricular tachycardia (VT). Cardiac arrhythmia is a major cause of death in CCD, and electrical markers may play a significant role in risk stratification. One hundred clinically stable outpatients with CCD were enrolled in this study. They initially underwent a 12-lead resting ECG, signal-averaged ECG, and 24-h ambulatory ECG. Abnormal Q-waves, filtered QRS duration, intraventricular electrical transients (IVET), 24-h standard deviation of normal RR intervals (SDNN), and VT were assessed. Echocardiograms assessed left ventricular ejection fraction. Predictors of cardiac death and new onset VT were identified in a Cox proportional hazard model. During a mean follow-up of 95.3 months, 36 patients had adverse events: 22 new onset VT (mean±SD, 18.4±4‰/year) and 20 deaths (26.4±1.8‰/year). In multivariate analysis, only Q-wave (hazard ratio, HR=6.7; P<0.001), VT (HR=5.3; P<0.001), SDNN<100 ms (HR=4.0; P=0.006), and IVET+ (HR=3.0; P=0.04) were independent predictors of the composite endpoint of cardiac death and new onset VT. A prognostic score was developed by weighting points proportional to beta coefficients and summing-up: Q-wave=2; VT=2; SDNN<100 ms=1; IVET+=1. Receiver operating characteristic curve analysis optimized the cutoff value at >1. In 10,000 bootstraps, the C-statistic of this novel score was non-inferior to a previously validated (Rassi) score (0.89±0.03 and 0.80±0.05, respectively; test for non-inferiority: P<0.001). In CCD, surface ECG-derived variables are predictors of cardiac death and new onset VT.

Unusual Cause of Inappropriate Implantable Cardioverter Defibrillators’ Shock: Tremor

Implantable cardioverter defi brillators are widely used for primary and secondary prevention from sudden death. These devices terminate attacks of ventricular tachycardia and ventricular fi brillation by applying direct current shock, if it necessary. Despite these benefi cal effects, inappropriate shocks are important side effects of implantable cardioverter defi brillators. Inappropriate implantable cardioverter defi brillator shocks impair life quality by causing pain and psychological side-effects, and even induce new arrhytmias. In this paper we present a case of inappropriate implantable cardioverter defi brillator shock due to tremor.

症例 心室頻拍を初発とし,冠動脈瘤および拡張型心筋症類似の病態を呈した1例

症例 心室頻拍を初発とし,冠動脈瘤および拡張型心筋症類似の病態を呈した1例

Heartmate II Inflow Cannula Position on Chest X-Ray Predicts Inotrope Dependence

<h3>Purpose</h3> We hypothesized that LVAD inflow cannula malposition contributes to numerous negative outcomes after device implantation. We further hypothesized that inflow cannula malposition may be determined by early post-operative CXR. <h3>Methods and Materials</h3> We reviewed CXR from 79 consecutive Heartmate II implantations (bridge to transplant or destination therapy). We measured LVAD inflow cannula position relative to the sternum on 1st upright PA and Lateral chest x-ray. [figure 1] We evaluated the following explanatory variables: age, LV diameter, redo sternotomy, BMI, cannula angle relative to sternum on PA CXR, cannula angle relative to sternum on Lateral CXR. We used multivariate logistic regression to evaluate the following implantation complications: TIA, stroke, post-implantation inotrope dependence, hemolysis, thrombosis, new ventricular tachycardia, and death. <h3>Results</h3> Cannula angle on PA CXR is associated with inotrope dependence (OR 1.12, p=0.001). All patients (n=16) with cannula angles outside of the range of 4° to 54° on PA CXR or -45° to 59° on lateral CXR experienced at least one of the studied complications. Additionally, increased BMI is associated with inotrope dependence (OR 1.14, p=0.045) and death (OR 1.13, p=0.049). Redo sternotomy is associated with new onset ventricular tachycardia (OR 5.97, p=0.03). LV diameter is associated with hemolysis (OR 0.27, p=0.043). <h3>Conclusions</h3> All patients with extreme inflow cannula angles experienced at least one major complication. Across all ranges, inflow cannula angulation on PA CXR predicted inotrope dependence. Secondary variables including BMI, redo sternotomy, and small LV were associated with major complications. Technical aspects of LVAD implantation remain paramount in assuring optimum outcomes.

PP-291 UNUSUAL CONCEALED ACCESSORY PATHWAY ABLATION: CASE REPORT

Methods: A 63-year-old-woman was admitted to the emergency department with complaints of palpitation, breathlessness and dizziness. At the admission she was conscious and her systolic blood pressure was 80mmhg. At the ECG there was sustained ventricular tachycardia (Figure 1). In the ED, because of hemodynamic impairment, defibrillation with 30 j was performed and sinus rhythm was restored. After 600mg loading dose of amiodorone, intravenous maintenance therapy was continued. At the same hour two non-sustained ventricular tachycardia attacks happened. Her biochemical parameters demonstrated a potasium concentration of 2.8mmol/L, creatinine 0.8mg/dl (0.72–1.25) and sodium 137mmol/L (136–145). Transthoracic echocardiography was performed and ejection fraction was found 60% and other measurements were normal. 60mEq/L potassium replacement was given to the patient and the control potassium was 3.7mmol/L. The patient had been using amlodipine 10mg, indapamide 1.5mg and acetylsalicylic acid 100mg per day for ten years because of hypertension. The patient was complaining from intermittent chest pain so coronary angiography was performed and normal coronary arterial anatomy was observed. It was thought that VT had occurred because of hypokalemia induced by indapamide so indapamide treatment was stopped. The K was 4.5mmol/L after one week follow up. The patient was followed-up in the coronary care unit and was discharged on the eighth day of admission without any VT attacks. Conclusions: Clinicians should keep in mind that the antihypertensive drug indapamine can cause life threatening ventricular tachycardias because of its hypokalemia side effect. Therefore we emphasize that serum potassium and ECG must be carefully monitored during indapamide therapy.

Jervell and Lange–Nielsen Syndrome: Homozygous Missense Mutation of KCNQ1 in a Turkish Family

Long QT syndrome is one of the most common cardiac ion channel diseases, but its morbidity and mortality rate can be lessened with an early diagnosis and proper treatment. This cardiac ventricular repolarization abnormality is characterized by a prolonged QT interval and a propensity for ventricular tachycardia (VT) of the torsades de pointes type. The long QT syndrome represents a high risk for presyncope, syncope, cardiac arrest, and sudden death. Jervell and Lange-Nielsen syndrome (JLNS) is a recessively inherited form of long QT syndrome characterized by profound sensorineural deafness and prolongation of the QT interval. Findings have shown that JLNS occurs due to homozygous and compound heterozygous pathogenic variants in KCNQ1 or KCNE1. A 3.5-year-old girl presented to the hospital with recurrent syncope, seizures, and congenital sensorineural deafness. Her electrocardiogram showed a markedly prolonged QT interval, and she had a diagnosis of JLNS. The sequence analysis of the proband showed the presence of a pathogenic homozygous missense variant (c.728G>A, p.Arg243His). Heterozygous mutations of KCNQ1 were identified in her mother, father, and sister, demonstrating true homozygosity. Even with high-dose beta-blocker therapy, the patient had two VT attacks, so an implantable cardioverter defibrillator was fitted. The authors suggest early genetic diagnosis for proper management of the disease in the proband and genetic counseling for both the proband and the girl's extended family.

Right ventricle anatomy can predict new onset ventricular tachycardia in patients with repaired tetralogy of Fallot

Results Nine patients had ventricular tachyarrhythmia (6%) during follow-up. Patients who developed ventricular tachyarrhythmia were older (42.5 [34.9-50.2] vs. 29 [21-40] years; p=0.01), had a later repair (12.8 [6.2-13.9] vs. 4.4 [2-8] years; p=0.02), larger akinetic right ventricular outflow track (RVOT) region (Figure ) (length 55 [34-60] vs. 30 [20-40] mm; p=0.002) and a lower RV ejection fraction (42 [40-52] vs. 53 [51-55] %; p=0.01), compared to the other patients. On univariate Cox analysis, RVOT akinetic region length and RV ejection fraction were predictive of ventricular tachyarrhythmia. On stepwise Cox regression analysis, the RVOT akinetic region length was the only remaining predictor (Hazard ratio 1.05, 95% Confidence Interval 1.01-1.08 per mm; p=0.004). The survival ROC curve analysis indicated a cut-off value of 30mm as a predictor of VA during 6 year follow-up with an AUC of 0.77, sensitivity of 83% and specificity of 61%. RVOT akinetic area length >30mm predicted reduced VA-free survival (Logrank p=0.002).

Therapy-resistant ventricular tachycardia caused by amiodarone-induced thyrotoxicosis: a case report of electrical storm

Electrical storm is a challenging diagnosis for the clinician and requires detailed evaluation of the patient. Amiodarone is frequently used for the cessation of ventricular tachycardia attacks. Within antiarrhythmic effects of amiodarone, there are some harmful effects of the recent drug. Thyroid gland toxicity is one of the most important adverse effects of amiodarone and is called amiodarone-induced thyrotoxicosis. Thyrotoxicosis may alter arrhythmia and lead to frequent ventricular tachycardia attacks. Herein, we report a case of electrical storm caused by amiodarone-induced thyrotoxicosis.