Burden Of Ventricular Arrhythmias Research Articles

Lower spatial QRS-T angle rules out sustained ventricular arrhythmias in children with hypertrophic cardiomyopathy.

Corrected QT interval and spatial peaks QRS-T angles were retrospectively assessed in 133 paediatric hypertrophic cardiomyopathy patients (12.4±6.6 years) with versus without ventricular arrhythmias of 30 seconds or longer. Significance, positive/negative predictive values, and odds ratios were calculated based on receiver operating characteristic curve cut-off values. In total, 10 patients with ventricular arrhythmias were identified. Although the corrected QT interval did not differentiate those with versus without ventricular arrhythmias, the spatial peaks QRS-T angle did (151.4±19.0 versus 116.8±42.6 degrees, respectively, p<0.001). At an optimal cut-off value (124.1 degrees), the positive and negative predictive values of the spatial peaks QRS-T angle were 15.4 and 100.0%, respectively, with an odds ratio of 25.9 (95% CI 1.5-452.2). In children with hypertrophic cardiomyopathy, the spatial peaks QRS-T angle is associated with ventricular arrhythmia burden with high negative predictive value and odds ratio.

Effect of Continued Cardiac Resynchronization Therapy on Ventricular Arrhythmias After Left Ventricular Assist Device Implantation

Cardiac resynchronization therapy (CRT) reduces ventricular arrhythmia (VA) burden in some patients with heart failure, but its effect after left ventricular assist device (LVAD) implantation is unknown. We compared VA burden in patients with CRT devices in situ who underwent LVAD implantation and continued CRT (n= 39) to those who had CRT turned off before discharge (n= 26). Implantable cardioverter-defibrillator (ICD) shocks were significantly reduced in patients with continued CRT (1.5 ± 2.7 shocks per patient vs 5.5 ± 9.3 with CRT off, p= 0.014). There was a nonsignificant reduction in cumulative VA episodes per patient with CRT continued at discharge (42 ± 105 VA per patient vs 82 ± 198 with CRT off, p= 0.29). On-treatment analysis by whether CRT was on or off identified a significantly lower burden of VA (17 ± 1 per patient-year CRT on vs 37 ± 1 per patient-year CRT off, p <0.0001) and ICD shocks (1.2 ± 0.3 per patient-year CRT on vs 1.7 ± 0.3 per patient-year CRT off, p= 0.018). In conclusion, continued CRT is associated with significantly reduced ICD shocks and VA burden after LVAD implantation.

Increased Incidence of VentricularArrhythmias in Patients WithAdvancedCancer and ImplantableCardioverter-Defibrillators.

This study evaluated the incidence of ventricular arrhythmia and implantable cardioverter-defibrillator (ICD) therapies in patients with a diagnosisof cancer. Cardiac disease and cancer are prevalent conditions and share common predisposing factors. Nostudies have assessed the impact of cancer on the burden of ventricular arrhythmia in patients with cancer andICDs. Retrospective study of patients with an ICD and cancer who were followed from January 2007 to June 2015. Rates of ventricular tachycardia (VT) and ventricular fibrillation (VF) before and after patients' cancers were diagnosed were evaluated by searching device data collection systems. Rates were adjusted for length of follow-up and compared using the Wilcoxon test, and times to first therapy following diagnosis (stages I to III vs. IV) were compared using Kaplan-Meier curves and log-rank test. Among 1,598 patients with an ICD, 209 patients (13.1%) had a pathological diagnosis of malignancy; and in 102 patients (6.4%), malignancy was diagnosed following device insertion. After the diagnosis of cancer, 32% of patients experienced VT/VF over 23.2 ± 23.6 months, and the frequency of arrhythmic events was significantly increased after the diagnosis (1.19 ± 0.32 vs. 0.12 ± 0.21 episodes per month, respectively; p= 0.03). The incidence of VT/VF was markedly higher in patients with stage IV cancer than in those with earlier stages (p= 0.03). In this group, the incidence of VT/VF was 41.2%, with an average of 7.2 ± 18.5 events per patient, all of whom received ICD shocks. The rate of ICD deactivation in stage IV patients was 35.3%. Inappropriate therapies occurred in 13.7%, and atrial fibrillation was themost frequent cause. One-third of patients who had received ICDs developed ventricular arrhythmia after a diagnosis of cancer. The incidence was significantly higher in those with advanced metastatic disease. Findings underscore the need to discuss ICD management as part of end-of-life care.

Catheter Ablation of Idiopathic Ventricular Arrhythmias Arising From the Cardiac Outflow Tracts - Recent Insights and Techniques for the Successful Treatment of Common and Challenging Cases.

Ventricular arrhythmias (VA), like premature ventricular contractions (PVC) and ventricular tachycardia (VT) in patients without structural heart disease (idiopathic VA), mainly arise from the right and left ventricular outflow tracts (RVOT/LVOT). The prognosis for OT VA is generally good in the majority of patients, but there is potential for developing dilated cardiomyopathies from the high burden of VA, as well as a certain risk for sudden cardiac death because of fast monomorphic VT or polymorphic VT triggered by short-coupling PVC. Radiofrequency catheter ablation (RFCA) has evolved into a widely accepted treatment strategy for patients suffering from VAs. A detailed knowledge of surface ECGs and complex cardiac anatomy, especially within the ventricular OTs, is essential for the understanding of cardiac OT-VAs and highly related to safe and successful RFCA procedures. This review article focuses on RFCA of idiopathic VA arising from the cardiac OT as well as adjacent regions and will illustrate recent insights and technical issues. (Circ J 2016; 80: 1073-1086).

Aberrant sodium influx causes cardiomyopathy and atrial fibrillation in mice.

Increased sodium influx via incomplete inactivation of the major cardiac sodium channel Na(V)1.5 is correlated with an increased incidence of atrial fibrillation (AF) in humans. Here, we sought to determine whether increased sodium entry is sufficient to cause the structural and electrophysiological perturbations that are required to initiate and sustain AF. We used mice expressing a human Na(V)1.5 variant with a mutation in the anesthetic-binding site (F1759A-Na(V)1.5) and demonstrated that incomplete Na+ channel inactivation is sufficient to drive structural alterations, including atrial and ventricular enlargement, myofibril disarray, fibrosis and mitochondrial injury, and electrophysiological dysfunctions that together lead to spontaneous and prolonged episodes of AF in these mice. Using this model, we determined that the increase in a persistent sodium current causes heterogeneously prolonged action potential duration and rotors, as well as wave and wavelets in the atria, and thereby mimics mechanistic theories that have been proposed for AF in humans. Acute inhibition of the sodium-calcium exchanger, which targets the downstream effects of enhanced sodium entry, markedly reduced the burden of AF and ventricular arrhythmias in this model, suggesting a potential therapeutic approach for AF. Together, our results indicate that these mice will be important for assessing the cellular mechanisms and potential effectiveness of antiarrhythmic therapies.

Abstract 19337: Transcoronary Delivery of Allogeneic Cardiac Stem Cells Reduces Ventricular Arrhythmia Inducibility in a Post Myocardial Infarction Swine Model

Introduction: Post myocardial infarction (MI) patients are at risk of scar related ventricular tachycardia (VT). Hypothesis: Stem cell therapy reduces post-MI scar size, potentially leading to a reduction in the risk of ventricular arrhythmias (VA). Methods: A post-MI scar model of VT was created by transient occlusion of the mid left anterior descending artery in 56 swine. Five weeks after infarct creation 29 subjects were treated with allogeneic cardiac stem cells (CSC): 10 underwent transcoronary delivery of CSC, 9 direct transepicardial delivery (via a minithoracotomy) and 10 underwent a combined transcoronary and VT substrate guided (late potentials) direct transendocardial CSC delivery procedure using an electroanatomic mapping system. Of the remainder, 8 subjects underwent a “sham” transepicardial procedure and 19 served as controls. Seventeen weeks after infarct creation an electrophysiological study was performed in each subject to assess for ventricular arrhythmia inducibility. VA inducibility was compared in each group vs. the control group. Results: Of the 19 control subjects, 17 were inducible (89,5 %). As presented in the figure, CSC delivery with a combined transcoronary/transendocardial approach was associated with a significant reduction in VT inducibility rates compared to controls (20 % vs. 89,5 %; p value 0,001). Subjects treated with transcoronary CSC also experienced significantly lower VA inducibility rates (40 % vs. 89,5 %; p value 0,009). There were no differences in VA inducibility compared with controls in patients in the “sham” (62,5 % vs 89,5 %; p value 0,136) or the transepicardial group (66,7 % vs 89,5 %; p value 0,290). Conclusions: Combined transcoronary and VT substrate-guided transendocardial CSC delivery is associated with a significant reduction in VA inducibility in a post-MI swine model. Future human studies should evaluate the effects of allogeneic CSC therapy on ventricular arrhythmia burden in post-MI patients.

Abstract 13981: Predictive Value of Local Prolonged Electro-Mechanical Interval in the Concealed Stage of Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

Introduction: The concealed stage of ARVD/C is associated with increased risk of life-threatening arrhythmias. However, presymptomatic arrhythmic risk stratification of ARVD/C mutation carriers is challenging. Activation delay is a hallmark of arrhythmogenesis. Deformation imaging may unmask activation delay in the absence of ECG and structural abnormalities. Methods: From the merged transatlantic ARVD/C database three groups were compared 1) mutation-positive definite ARVD/C patients (n=108), 2) asymptomatic mutation carriers (AMC) not fulfilling Task-Force criteria (TFC) and without history of ventricular arrhythmias (n=35) and 3) healthy controls (n=50). All underwent echocardiographic deformation imaging and ECG according to TFC. As a surrogate for local activation delay the electro-mechanical interval (EMI) was measured, defined as time between first ECG-detected deflection and local onset of shortening. Arrhythmic outcome (PVC count, VT) of AMC was correlated to EMI and ECG TFC. Results: EMI was prolonged in all RV segments in ARVD/C patients. In AMC prolonged EMI was detected in the subtricuspid area in 17/35 subjects, Terminal Activation Duration ≥ 55ms was the only TFC-defined ECG abnormality found in this group (9/35). After a mean follow-up of 3.1±2.7 years 11/35 subjects experienced an increase in ventricular arrhythmia burden. Prolonged subtricuspid EMI was the only parameter significantly correlated to ventricular arrhythmias during follow-up (Figure 1). Conclusions: Deformation imaging reveals activation delay in all ARVD/C patients. In AMC prolonged EMI in the subtricuspid area is often detected without any additional abnormalities. Prolonged EMI is a new parameter unmasking activation delay in early ARVD/C stages and may contribute to risk stratification.

Abstract 16480: Characteristics and Outcomes of Patients With Papillary Muscle Ventricular Arrhythmias

Introduction: We sought to investigate the characteristics and outcomes of patients who underwent RF ablation of PM ventricular arrhythmias (VA) in our center. Results: 26 patients were included, median age was 66 years (16 to 85), 46% female, all with normal LVEF. PM VAs were PVCs in 68% patients, and PVC + VT in 32%. Site of origin was the LV infero-septal PM in 73%, LV antero-lateral PM in 15% and right ventricular RV septal PM in 12%. 46% of patients showed other VAs in addition to the one originating from the PMs; in 33% of these patients, additional VAs were 2 or more. These VAs were mostly PVCs (92%), localized in the LVOT (64% - 56 % in the basal LV and 44% in the aortic cusps) and the septal RVOT (36%). The only additional VT was fascicular. All the PMs and mappable additional VAs were ablated with RF energy through an irrigated catheter and the aid of ICE; a remote magnetic navigation system (RMS) was used in half of the procedures. In one case, PVC suppression required additional epicardial ablation. Major complications occurred in 2 patients (8%): 1 pericardial effusion (the patient underwent ablation of a crista terminalis premature atrial complex in the same procedure) and 1 pseudoaneurysm. Acute success (PM VA suppression/non-inducibility) was achieved in 96% of patients (the patient with pericardial effusion could be anticoagulated further and the procedure was stopped). After a median follow-up period of 8 (4-14) months, long-term success (no PM VT recurrence or PVC burden reduced by 80% off antiarrhythmic drugs) was 92% after a single procedure, 96% after repeat procedures. When considering additional VAs, the only recurrence was a parahisian RVOT PVC. No difference in acute or overall long-term success was observed when comparing RMS-guided vs standard procedures (respectively 92% vs 100 % and 100% vs 92%; P = NS). Conclusion: PM VAs are most commonly PVCs originating from the LV infero-septal PM and are frequently (48%) associated with an additional ventricular focus (LVOT &gt; RVOT &gt;&gt; fascicular VT). RF ablation is safe and effective in eliminating or significantly reduce the burden of PM VAs, as well the extra-PM foci that are commonly encountered in this population. RMS guided ablation is not inferior to standard ablation in this subset of patients.

Value of cardiac magnetic resonance imaging in the setting of familiar cardiomyopathy: A step toward pre-clinical diagnosis

A 24-years-old asymptomatic man was referred to our Institution for screening of familiar idiopathic dilated cardiomyopathy (CMP) due to the important family history of dilated CMP with associated severe burden of ventricular arrhythmias (Fig. 1). His father and a first-degree father's cousin were indeed both affected by idiopathic dilated CMP, which was diagnosed in their third decade after an episode of sustained ventricular tachycardia (VT); both underwent implantable cardioverter defibrillator (ICD) implantation for secondary prevention of sudden cardiac death (SCD) and subsequently experienced multiple appropriate ICD interventions. Due to further dilatation and dysfunction of the left ventricle (LV) and worsening of the arrhythmic burden as well as heart failure symptoms despite optimal medical therapy, they were finally referred to heart transplantation at the age of 40 and 45 years, respectively. In addition, two more first-degree father's cousins died suddenly at the age of 14 and 47 years. The histologic examination of the explanted heart of proband's father showed multiple areas of dense fibrosis with intra-myocardial and sub-epicardial patchy distribution (Fig. 2A –B, Mallory trichromic stain: blue areas); myocyte apoptotic and degenerative phenomena were also observed (Fig. 2C–D, arrows). Of note, a strong family history of breast cancer was also present in the family (Fig. 1). Fig. 2Cardiomyopathy-related myocardial morphological changes are shown in histological sections of the explanted heart of the proband's father. They consist of a spectrum of changes beginning with focal degeneration and necrosis of cardiomyocytes with no or minimal cellular response, followed by myofiber loss and replacement of the cardiomyocytes with varying degrees of fibrosis. Low magnification shows intra-myocardial (A) and sub-epicardial (B) areas of dense fibrotic scar with patchy distribution (blue with Mallory trichromic stain). Higher magnification reveals foci of myocardial degeneration with vacuolization of cardiomyocytes (panel C–D, arrows, Hematoxylin and Eosin stain). Necrotic cardiomyocytes exhibit homogeneously brightly eosinophilic sarcoplasm with pyknotic or karyorrhectic nuclei (panels C–D, arrows). View Large Image Figure Viewer Download Hi-res image

Ventricular Tachycardia Precipitated by the Use of the Diet Supplement Hydroxycut Gummies.

Dietary supplements have a long history of causing adverse effects. Ventricular arrhythmias have not been described with Hydroxycut Gummies. To report a case of ventricular arrhythmia after prolonged use of a popular dietary supplement, Hydroxycut Gummies. An 18-year-old female with no significant past medical history presented with life-threatening ventricular arrhythmia following about 10 days of use of Hydroxycut Gummies, a legal dietary supplement previously unreported to cause this complication. The patient received external cardioversion due to progressive decline in mental status and persistent hypotension and was initiated on intravenous procainamide at an outside hospital. Left ventricular ejection fraction was 45% to 50%, and cardiac MRI showed no definite finding of infarct, myocarditis, or fibrosis. Beta-blocker therapy was initiated, and there was a progressive reduction in ventricular arrhythmia burden with an improvement of symptoms over the next few days. Two and a half months after the initial hospitalization, follow-up Holter monitor revealed occasional accelerated idioventricular rhythm events and a significant reduction in, but still occasional, long monomorphic ventricular tachycardia events. None of the ingredients listed in this product have been associated with cardiac dysrhythmias in the literature. One phytochemical potentially in the product is alpha-quinidine, which could be the cause of the adverse event. However, there was no other identifiable etiology for the ventricular tachycardia, which resolved after the discontinuation of supplement and the addition of beta-blocker therapy. Hydroxycut Gummies should be considered a probable cause of this patient's arrhythmia given the lack of another etiology and a Naranjo Scale score of 6.

Clinical Case Session I: Sunday 3 May 2015, 10:00-11:00 * Room: Venecia

Clinical Case Session I: Sunday 3 May 2015, 10:00-11:00 * Room: Venecia

(745) - MicroRNA Expression Pattern in Patients with Ventricular Tachycardia and End-Stage Heart Failure

(745) - MicroRNA Expression Pattern in Patients with Ventricular Tachycardia and End-Stage Heart Failure

VENTRICULAR ARRHYTHMIAS IN HOSPITALIZED HFPEF PATIENTS

Non sustained Ventricular arrhythmias (NSVA) are frequently noted in patients admitted with acute decompensated diastolic heart failure. However, the long term predictive value of NSVA in this setting is unclear. The objective was to elucidate the burden of ventricular arrhythmias in patients

Abstract 16820: CaMKIIδc Transgenic Mice Develop Spontaneous Ventricular Arrhythmias Which Can Be Suppressed by Inhibition of Late Na+ Current

Introduction: It has been shown that activated CaMKII can phosphorylate cardiac Na+ channels that leads to an enhanced late Na current (INaL). We hypothesized that enhanced INaL plays an important role in arrhythmogenesis linked to increased CaMKII activity. To test this hypothesis we determined the effect of a selective INaL inhibitor GS-967 on spontaneously occurring ventricular arrhythmias in mice overexpressing CaMKIIδc (TG). Methods: TG (n=6) and wild type (WT, n=3) mice at age 8 week (wk) were instrumented with telemetry transmitters to record ECG. ECG were recorded continuously starting 1 wk post- surgery (age 9 wk) until age 19 wk. Incidence and burden of arrhythmias were evaluated at ages 9, 11, 13, 15, 17 and 19 wks using DSI ECG Pro software. At age 17 wk, when arrhythmia burden was relatively stable, mice were treated with a single dose of GS-967 (1 mg/kg, i.p.) or vehicle. After 4 days of washout, the treatment was repeated in a cross-over manner. Arrhythmia burden was quantified over a duration of 15-hours post-treatment. Using patch clamp technique, INaL was measured in ventricular myocytes isolated from both TG and WT mice at 17 wk age. Results: Incidence and burden of spontaneous ventricular arrhythmias increased progressively with age in TG mice. Between age 9 and 11 wks, 50% of TG mice had an arrhythmia burden ≥ 5 minutes/24 hours. The incidence increased to 83% at wk 13, 15, 17 and to 100% at 19 wks and the burden increased to 71 ± 35 min/24 hr at 17 wk. A single dose of GS-967 significantly decreased arrhythmia burden from 42.5 ± 9.6 min (treated with vehicle) to 9.4 ± 4.3 min (p&lt;0.05) during a 15-hr period. No arrhythmias were observed in WT mice during the course of the study. INaL was enhanced by more than 2-fold in myocytes isolated from TG mice compared to WT (0.2±0.03 vs. 0.08±0.02 pA/pF, n=16 each, p&lt;0.05). GS-967 caused a concentration-dependent reduction of INaL (50.5±3.4% at 0.3 μM, n=7; and 91±5.2% at 1 μM, n=4). Conclusions: This is the first report to show a reduction of spontaneously occurring ventricular arrhythmias by inhibition of INaL indicating a key role for INaL in CaMKII associated arrhythmogenesis.

Abstract 18963: Clinical Significance of Daytime Vs. Nighttime Cheyne-stokes Respiration in Systolic Heart Failure Patients: Findings From 24- Hour Polygraphic Recordings

Purpose: Cheyne Stokes respiration, that is periodic apnea/hyperpnea of central origin (CSR), has been separately described both during night (nCSR) and daytime (dCSR) in HF and associated with worse prognosis. The relationships between severity of nCSR and of dCSR have not yet been established. Methods: we enrolled 439 consecutive HF patients (aged 65±13 years, 76% males; NYHA class III-IV 33%, LVEF: 32±9%, mean±SD) on current guideline-directed therapy (96% betablockers, 94% ACE-inhibitors/angiotensin receptor blockers, 22% CRT). All patients underwent a 24hour cardiorespiratory polygraphic recording (nasal flow plus chest and abdomen respirograms) for detection of hypo/apnea phenomenon, clinical and neurohormonal evaluation, cardiopulmonary exercise testing, echocardiography and Holter monitoring. Results: four groups were identified according to severity of nCSR (AHI &lt;5, 17%; mild, 5 to 15, 24%; moderate, 15 to 30, 30%; severe, &gt;30, 29%) and dCSR (normal, apnea/hypopnea index, AHI &lt;5, 38%; mild, 5 to 15, 32%; moderate, 15 to 30, 29%; severe, &gt;30, 9%); nocturnal obstructive apnea prevalence (AHI &gt;5) was 10% (1% daytime). Notably, in patients with significant (AHI&gt;15) nCSR, dCSR had the highest prevalence (daytime AHI&gt;15, 71%, daytime AHI&gt;30, 26%). Both severe dCSR and nCSR were associated (p&lt;0.01) with age, male gender, NYHA class III-IV, nonsustained ventricular tachycardia at Holter monitoring, higher plasma NT-proBNP and norepinephrine, lower pVO2, ventilatory inefficiency as assessed by the slope of ventilation to carbon dioxide production, LV dilatation (assessed by end-systolic and diastolic diameters) and hypertrophy (assessed by LV indexed mass), right ventricular dimension. Severe dCSR, but not nCSR, was associated with lower LVEF, increased prevalence of atrial fibrillation and diabetes. Conclusions: significant dCSR is prevalent in HF, namely in patients with more severe nCSR (AHI&gt;15). Both dCSR and nCSR are associated with neurohormonal activation, greater left and right ventricular volumes, increased ventricular arrhythmic burden and lower functional capacity, while lower LVEF as well atrial fibrillation are associated with dCSR only. Risk stratification and therapeutic strategies should consider dCSR.

Perioperative beta-blockers for preventing surgery-related mortality and morbidity.

Perioperative beta-blockers for preventing surgery-related mortality and morbidity.

Catheter Ablation for Ventricular Tachyarrhythmias in Patients Supported by Continuous-Flow Left Ventricular Assist Devices

Ventricular arrhythmias (VAs) are common after implantation of a left ventricular assist device (LVAD) and in a subset of patients may be refractory to medication. Morbidity from VA in this population includes right ventricular failure (RVF). We sought to evaluate the efficacy of catheter ablation for VA in patients with LVAD. A retrospective analysis of patients supported by continuous-flow LVAD referred for catheter ablation of ventricular tachycardia (VT) between 2008 and the present was performed. Seven patients were referred for VT ablation an average of 236 ± 292 days after LVAD implantation. Three patients (42.9%) developed RVF in the setting of intractable arrhythmias. A transfemoral approach was used for six patients (85.7%) and an epicardial for one patient (14.3%). The clinical VT was inducible and successfully ablated in six patients (85.7%). The location of these arrhythmias was apical in three cases (42.9%). A total of 13 VTs were ablated in seven patients. Although the majority had reduction in VA frequency, recurrent VAs were observed in six patients (85.7%). One patient (14.3%) experienced a bleeding complication after the procedure. For patients with a high VA burden after LVAD implantation, VT ablation is safe and feasible, but VA frequently recurs.

Cardiac sympathetic denervation in patients with refractory ventricular arrhythmias or electrical storm: Intermediate and long-term follow-up

Left and bilateral cardiac sympathetic denervation (CSD) have been shown to reduce burden of ventricular arrhythmias acutely in a small number of patients with ventricular tachyarrhythmia (VT) storm. The effects of this procedure beyond the acute setting are unknown. The purpose of this study was to evaluate the intermediate and long-term effects of left and bilateral CSD in patients with cardiomyopathy and refractory VT or VT storm. Retrospective analysis of medical records for patients who underwent either left or bilateral CSD for VT storm or refractory VT between April 2009 and December 2012 was performed. Forty-one patients underwent CSD (14 left CSD, 27 bilateral CSD). There was a significant reduction in the burden of implantable cardioverter-defibrillator (ICD) shocks during follow-up compared to the 12 months before the procedure. The number of ICD shocks was reduced from a mean of 19.6 ± 19 preprocedure to 2.3 ± 2.9 postprocedure (P < .001), with 90% of patients experiencing a reduction in ICD shocks. At mean follow-up of 367 ± 251 days postprocedure, survival free of ICD shock was 30% in the left CSD group and 48% in the bilateral CSD group. Shock-free survival was greater in the bilateral group than in the left CSD group (P = .04). In patients with VT storm, bilateral CSD is more beneficial than left CSD. The beneficial effects of bilateral CSD extend beyond the acute postsympathectomy period, with continued freedom from ICD shocks in 48% of patients and a significant reduction in ICD shocks in 90% of patients.

Remote monitoring of a high-risk patient with Brugada syndrome: association of different arrhythmic manifestations

We report on the remote arrhythmia monitoring of a 34-year-old man with highly symptomatic Brugada syndrome, who initially presented with syncope, paroxysmal atrial fibrillation, and spontaneous coved-type electrocardiogram. The patient received a dual-chamber implantable cardioverter-defibrillator (ICD) with Home Monitoring™ facilities and experienced recurrent ICD shocks for spontaneous ventricular fibrillation (VF) episodes during the first year after ICD implantation. Remote monitoring revealed an increased burden of premature ventricular complexes and atrial arrhythmias each time VF spontaneously occurred. Atrial and ventricular arrhythmias were effectively suppressed by low-dose quinidine without severe side effects.

Life-threatening arrhythmias in children with Andersen-Tawil syndrome

Clinical manifestation of the Andersen-Tawil syndrome (ATS) considerably vary and may include facial and skeletal dysmorphology, periodic paralysis, and ventricular arrhythmia (VA). Typical ECG features are enlarged U wave, QU prolongation, polymorphic ventricular premature beats, non-sustained polymorphic and bidirectional VT. Although the burden of VA is high, life-threatening events such as sudden cardiac death (SCD) are uncommon. This study assesses the risk of life-threatening arrhythmia requiring implantable cardioverter-defibrillator (ICD) in children with ATS. Methods: From 1998 to 2011, 8 consecutive pts from unrelated families (4 males) aged 6 to 12 with ATS were examined and followed up during 1 to 10 years. Examination includes family history, ECG, 24-hour Holter monitoring, echo, stress- and genetic testing. All patients were treated with beta-blockers. Two children with ICD were followed up during 2 and 7 years. Results: In 4 pts ATS was diagnosed due to syncope (from 2 to 12 episodes of syncope), in 3 cases it was revealed during examination before surgery for cleft palate. In all children, ATS manifests itself with facial and skeletal dysmorphic features and VA. Periodic paralysis took place in 3 pts. QU interval varies from 500 to 650 ms; QUc varies from 590 to 717 ms. All pts demonstrate polymorphic VT and 3 patients have bidirectional VT. SCD in family members at ages 10 days, 1 month, 29 years, 30 years and 36 years is observed in 3 families (with three SCD cases being observed in one family). All SCD victims had dysmorphic facial features. Recurrent syncope (despite antiarrhythmic therapy) required ICD implantation in 2 cases. Two and 12 ICD shocks terminated ventricular fibrillation (11 episodes of VF were associated with syncope) were registered in these pts during first year after ICD implantation. In all other 6 pts, beta-blocker therapy significantly depressed VA and syncope. However, it does not influence QU prolongation. Despite the fact that syncope are not registered any more, child from the family with multiple cases of SCD, who has extremely long QUc (717 ms), is scheduled for ICD implantation. Conclusions: Polymorphic VA and very high values of QUc are common for ATS children. About 1/3 of children with ATS are exposed to a high risk of VF and should be considered for ICD implantation. They experience recurrent syncope or have multiple cases of SCD in families. For asymptomatic pediatric pts with ATS, prognosis seems to be favorable, but this deserves further investigation. The use of implantable loop recorders seems appropriate.