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Cardiovascular AND Tachycardia, ventricular, [keywords]
- Complete Recovery From Severe Tachycardia-Induced Cardiomyopathy in a Patient With Ebstein's Anomaly. [JOURNAL ARTICLE]
- World J Pediatr Congenit Heart Surg 2014 Jun 23; 5(3):484-487.
We report the case of a young patient with repaired Ebstein's anomaly who developed severe tachycardia-induced cardiomyopathy and a large apical thrombus as a consequence of sustained atrial flutter with a 2:1 conduction. In spite of a dramatic course in hospital with prolonged mechanical resuscitation and extracorporeal membrane oxygenation, she survived and made a rapid and full recovery. This remarkable case underlines that atrial arrhythmias, the most common complication in adults with congenital heart disease, may have devastating outcomes when timely recognition is missed and treatment delayed-thus, emphasizing the importance of good patient education.
- Multivalvular Replacement and Ventricular Arrhythmias in a Female Child With Congenital Polyvalvular Disease. [JOURNAL ARTICLE]
- World J Pediatr Congenit Heart Surg 2014 Jun 23; 5(3):463-466.
We report the clinical course of a female child with a normal karyotype and chromosomal microarray who presented as an infant with clinical findings consistent with congenital polyvalvular disease (CPVD). This clinical entity describes patients with multiple congenitally dysplastic valves, often showing nodular or cystic malformation in at least two cardiac valves. This patient then developed medically refractory multifocal ventricular arrhythmia and required radiofrequency ablation at seven months of age. She had good tachycardia control but became symptomatic with right heart failure related to progressive tricuspid, pulmonary, and mitral valve dysfunction necessitating multivalvular replacement at 21 months of age.
- Cardiac ablation of Rheb1 reduces sodium currents in infant mice. [Journal Article]
- Int J Clin Exp Med 2014; 7(4):947-54.
The Ras homolog enriched in brain gene (Rheb) is a center player within the insulin/Rheb/Mammalian Target of Rapamycin (mTOR) pathway, and plays a critical role in regulating cellular growth. Rheb-/- embryos have been reported to die around midgestation, due to the defects of the development of the cardiovascular system. Recent studies from ours and another group consistently showed that Rheb1 was indispensable for the cardiac hypertrophic growth after early postnatal period. Besides that, we also found that Rheb1 a-MHC-Cre (cKO) mice exhibited ventricular tachycardia. However, the precise mechanism by which Rheb1 knockout causes ventricular arrhythmia in these mice is still unclear.Mouse cardiomyocytes were isolated using 10 days suckling Rheb1 cKO and wide type mice using Collagenase Type II. Sodium currents and L-type calcium currents were recorded using the whole-cell patch clamping technique.The sodium current density of ventricular cardiomyocytes from Rheb1 cKO mice was decreased by about 60%. Significant left shift but no slope altered was observed in activation curve with V1/2 values of -35.35 ± 1.12 mV for Rheb1 cKO group and -40.72 ± 1.18 mV for the controls. In addition, the area of window current, which refers the overlap of normalized activation and inactivation, was larger in Rheb1 cKO mice. Moreover, the sodium current, in general, was recovered much slower in Rheb1 cKO mice than that of the controls. However, L-type calcium currents were preserved in Rheb1 cKO mice.Sodium currents are decreased in Rheb1 cKO mice, which might be responsible for the phenotype of arrhythima in Rheb1 cKO mice. Understanding the molecular composition of sodium ion channel complexes in the heart of these Rheb1 cKO mice will be critical to develop innovative and effective therapies for the treatment of cardiac arrhythmia.
- Cardioverter-defibrillator implantation to treat cardiac fibroma-induced ventricular tachycardia in a 70-year-old woman. [Journal Article]
- Tex Heart Inst J 2014 Jun; 41(3):329-31.
Benign cardiac fibroma is rarely reported in adults. Its clinical symptoms are related to outflow obstruction or dysrhythmias. We present the case of a 70-year-old woman who had a syncopal episode from ventricular tachycardia caused by cardiac fibroma. Because of unfavorable tumor anatomy, the patient was not a candidate for surgical excision, and she declined orthotopic heart transplantation. To prevent sudden cardiac death, we placed an implantable cardioverter-defibrillator, and the patient remained well throughout the 2-year follow-up period. To our knowledge, this is the first report of implantable cardioverter-defibrillator therapy to treat an adult patient's unresectable cardiac fibroma.
- Feasibility and efficacy of a remote real-time wireless ECG monitoring and stimulation system for management of ventricular arrhythmia in rabbits with myocardial infarction. [JOURNAL ARTICLE]
- Exp Ther Med 2014 Jul; 8(1):201-206.
The purpose of this study was to explore the feasibility of continuous remote monitoring, and the induction and termination of malignant ventricular arrhythmias (VAs) by a novel implantable electronic cardiovascular device (IECD) system in rabbits with myocardial infarction (MI). The IECD was implanted and MI was induced by ligation of the left anterior descending coronary artery in 20 adult rabbits. Internet-based remote electrocardiogram (ECG) monitoring and ventricular stimulation were conducted in remote locations with internet access. The voltage amplitudes of the stimulation signals were recorded synchronously by remote and surface ECG. Programmed stimulation with regular stimuli and regular stimuli with an added extra stimulus were performed prior to and following the MI surgery to induce and terminate VAs. IECD implantation and MI surgery, as well as qualified remote and bidirectional signal communications between the implanted IECD and extracorporeal system, were successfully achieved in 18 rabbits. The voltage of the stimulation signals recorded by the remote and surface ECGs showed a good correlation with the stimulation current (remote ECG, r=0.972 and surface ECG, r=0.988; P<0.001). Sustained ventricular tachycardia (VT) was induced in five rabbits (5/20, 25%) prior to MI induction and in 12 rabbits (12/16, 75%) following MI induction. Of the 17 induced VTs, 16 were successfully terminated by remote ventricular stimulation. The novel IECD system provides qualified remote wireless ECG monitoring and possesses the potential to induce and terminate VAs by remote ventricular pacing in this rabbit model of MI. Thus, this model of MI may be used to test the efficacy of novel drugs and devices for the management of VAs.
- Impact of intra-aortic balloon pumping on hypotension and outcomes in acute right ventricular infarction. [JOURNAL ARTICLE]
- Coron Artery Dis 2014 Jun 16.
This study investigated the immediate hemodynamic effects of intra-aortic balloon pump (IABP) support and clinical outcomes in patients with acute right ventricular infarction (RVI) complicated by hypotension.IABP improves hypotension in patients with acute myocardial infarction and left ventricular shock, but the effects have not been well studied in acute RVI with predominant right ventricular shock.We retrospectively analyzed hemodynamics and clinical outcomes in 32 patients with acute inferior ST elevation myocardial infarction complicated by RVI, in whom hypotension requiring IABP placement developed despite intact left ventricular ejection fraction.Pre-IABP hypotension was present in all (100%) patients, and in every case IABP augmentation increased mean arterial pressure (55.9±7.4 to 76.8±14.7 mmHg, P<0.0001). Adverse clinical events included respiratory distress requiring intubation in 46.9%, cardiopulmonary resuscitation in 25%, episodes of ventricular tachycardia/fibrillation in 56.3%, and transvenous pacemaker placement in 56.3% of patients. There were six inhospital deaths (18.8%). Pre-IABP hemodynamics were similar in those patients who survived to discharge compared with those who died. However, in those patients who died, there was significantly lower augmentation of peak systolic blood pressure during IABP support compared with survivors (2.7±17 vs. 27±22 mmHg, P<0.015).IABP support results in immediate hemodynamic improvement in patients with acute RVI complicated by shock. The majority of these shock patients survived and the magnitude of mean arterial pressure and peak systolic blood pressure augmentation may impart prognostic value.
- 125 Cardiovascular Magnetic Resonance is Valuable in the Investigation of Aborted Sudden Cardiac Death. [JOURNAL ARTICLE]
- Heart 2014 Jun; 100(Suppl 3):A71-A72.
Aborted sudden cardiac death (SCD) is an infrequent indication for cardiovascular magnetic resonance (CMR). Patients who survive an arrhythmic cardiac arrest usually receive an implantable cardioverter-defibrillator (ICD). It is important to determine a precise diagnosis in these patients as it has implications for ongoing healthcare, both for themselves and family members. It is presently unknown if CMR is useful for this purpose.At a large tertiary cardiac centre, electronic records from June 2006 to June 2013 were investigated to identify all patients who had ICD implantation. These records were cross referenced with all patients who had been investigated by CMR. Electronic records and medical notes were systematically reviewed to establish the details of the cardiac arrest, other cardiac investigations and aetiology. Aborted SCD was defined as ventricular fibrillation (VF) or hemodynamically unstable ventricular tachycardia (VT) requiring electrical or chemical cardioversion.152 patients had an ICD implanted and a prior CMR scan. Of these, 62 patients had the CMR to specifically investigate aborted SCD.The scan was abandoned in one because of claustrophobia and detailed records were available on 56 patients. Of these, the rhythm was primary VF in 29, torsade de pointes in 4 and haemodynamically unstable VT treated by electrical or chemical cardioversion 23. All patients underwent investigation by ECG, transthoracic echocardiography and coronary angiography. CMR was able to establish the diagnosis in 39 (70%) patients and angiography in 20 (36%). The final diagnosis was unclear after ECG, echocardiography and angiography in 22 patients.CMR revealed a diagnosis in 8 of these (2 ischaemic subendocardial scar, 2 myocarditis,1 ARVC, 1 DCM, 1 cardiac sarcoid and 1 LV non-compaction). Of the remaining patients the diagnosis was 12 primary VF (diagnosed by the clinical team), 1 ARVC(diagnosed on non-imaging criteria) and in 1 patient the diagnosis was unclear. There were no cases when CMR yielded the diagnosis if the ECG, echocardiogram and angiography were completely normal.In this series of patients who suffered aborted SCD CMR was able to establish the diagnosis in 39/56 of all patients and 8/22 patients in whom the diagnosis was unclear after routine investigation with ECG, echocardiography and angiography. The high diagnostic yield of CMR, even in patients where routine investigations did not yield a diagnosis, supports its more widespread use in aborted SCD. heartjnl;100/Suppl_3/A71-b/F1F1F1 Abstract 125 Figure 1 CMR findings of 3 patients who suffered aborted SCD in whom the diagnosis was unknown after ECG, echocardiography and angiography. (A) lateral subepicardial late gadolinium enhancement (myocarditis), (B) Lateral subendocardial late gadolinium enhancement (myocardial infarction) and (C) Two layered myocardium with prominent trabeculation (LV non-compaction).
- Variations of electroanatomic substrates and markers of successful ablation in idiopathic left ventricular tachycardia: role of electroanatomic substrates and potential mechanism of tachycardia. [JOURNAL ARTICLE]
- J Cardiovasc Med (Hagerstown) 2014 Jun 11.
The variation of the substrates of verapamil-sensitive idiopathic left ventricular tachycardia (ILVT) was not understood. The purpose of this study was to investigate the variation of electroanatomic substrate [slow conduction zone (SCZ) and left ventricular conduction system (LVCS)] in ILVT and control individuals and markers of successful ablation.Electroanatomical mapping was performed during sinus rhythm in 20 ILVT patients and 26 control individuals with paroxysmal supraventricular tachycardia. LVCS and SCZ were tagged in geometry and the anatomic aspects were investigated.According to the distribution of Purkinje potential, LVCS was distinguished into three types: left bundle branch (LBB) was divided into two discrete fascicles without interconnections; divided into three separate fascicles; and fanlike structure distribution over septum broadly. The length of LBB and its fascicles in patients with ILVT were slightly longer than those of controls (P > 0.05). In the ILVT group, the SCZ was located at the inferoposterior septum in 17, inferior apical septum in one and two SCZs were located at the posterior and mid-septal in the other two patients, which were greater in size and longer in length than those of six controls (P < 0.05). At the crossover junction area with diastolic potential and Purkinje potential, with the size of 1.5 ± 0.4 cm, concealed entertainment and ablation were obtained successfully in all patients with ILVT.The anatomy of the LVCS and SCZ is highly variable in patients with ILVT, and the crossover junction area with diastolic potential and Purkinje potential might be a marker of ablation.
- Novel Calmodulin (CALM2) Mutations Associated with Congenital Arrhythmia Susceptibility. [JOURNAL ARTICLE]
- Circ Cardiovasc Genet 2014 Jun 10.
-Genetic predisposition to life-threatening cardiac arrhythmias such as in congenital long-QT syndrome (LQTS) and catecholaminergic polymorphic ventricular tachycardia (CPVT) represent treatable causes of sudden cardiac death in young adults and children. Recently, mutations in calmodulin (CALM1, CALM2) have been associated with severe forms of LQTS and CPVT, with life-threatening arrhythmias occurring very early in life. Additional mutation-positive cases are needed to discern genotype-phenotype correlations associated with calmodulin mutations.-We employed conventional and next-generation sequencing approaches including exome analysis in genotype-negative LQTS probands. We identified five novel de novo missense mutations in CALM2 in three subjects with LQTS (p.N98S, p.N98I, p.D134H) and two subjects with clinical features of both LQTS and CPVT (p.D132E, p.Q136P). Age of onset of major symptoms (syncope or cardiac arrest) ranged from 1-9 years. Three of five probands had cardiac arrest and one of these subjects did not survive. Although all probands had LQTS, two subjects also exhibited electrocardiographic features consistent with CPVT. The clinical severity among subjects in this series was generally less than that originally reported for CALM1 and CALM2 associated with recurrent cardiac arrest during infancy. Four of five probands responded to β-blocker therapy whereas one subject with mutation p.Q136P died suddenly during exertion despite this treatment. Mutations affect conserved residues located within calcium binding loops III (p.N98S, p.N98I) or IV (p.D132E, p.D134H, p.Q136P) and caused reduced calcium binding affinity.-CALM2M mutations can be associated with LQTS and with overlapping features of LQTS and CPVT.
- Incidence and predictors of atrial fibrillation and its impact on long-term survival in patients with supraventricular arrhythmias. [JOURNAL ARTICLE]
- Europace 2014 Jun 6.
To determine the incidence and predictors of atrial fibrillation (AF) and its impact on survival in patients with other forms of supraventricular arrhythmias (SVAs) including atrial flutter (AFL), atrial tachycardia (AT), atrioventricular reentrant (AVRT), and AV nodal reentrant tachycardia (AVNRT). We hypothesized that SVA may increase risk of AF and concomitant AF may influence long-term survival.All patients who underwent catheter ablation for SVA from 2000 to 2010 were included in this study. The patients were identified retrospectively and the vital status determined prospectively. Observed survival in the study cohort was compared with survival rates in the age- and sex-matched general population. The study group included 1573 patients (mean age 50.5 ± 18 years, 47% female) with AVNRT (38.5%), AFL (29.6%), AVRT (22.6%) and AT (9.3%). The patients were followed for a mean of 35 months (median 23 months). Atrial fibrillation was documented in 424 patients (27%) with a higher incidence in males (35 vs. 18%). Atrial fibrillation was present in 19.6% of patients before the ablation and developed in 9.07% after ablation. Atrial fibrillation commonly occurred in patients with AFL (57.5%), AT (27.4%), AVRT (13.5%), and AVNRT (9.7%). Older age, prolonged PR interval, dilated left atrium, low left ventricular ejection fraction and presence of AFL were independent predictors for concomitant AF. Long-term survival was worse in the presence of AF.The incidence of AF is high in patients with other forms of SVA. The most common association is between AFL and AF. Long-term survival is decreased in those who have concomitant AF, although AF did not emerge as an independent predictor of mortality when adjusted for other covariates.