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Cardiovascular AND Tachycardia, ventricular, [keywords]
- Elimination of ventricular arrhythmias originating from the anterior interventricular vein with ablation in the right ventricular outflow tract. [Journal Article]
- Circ Arrhythm Electrophysiol 2014 Oct; 7(5):984-5.
- Editor's Perspective: In the Middle. [Journal Article]
- Circ Arrhythm Electrophysiol 2014 Oct; 7(5):982-3.
- End points for ablation of scar-related ventricular tachycardia. [Journal Article]
- Circ Arrhythm Electrophysiol 2014 Oct; 7(5):949-60.
- Human Induced Pluripotent Stem Cell Models of Inherited Cardiovascular Diseases. [JOURNAL ARTICLE]
- Curr Stem Cell Res Ther 2014 Oct 16.
Cardiovascular cells derived from patient specific induced Pluripotent Stem Cell (iPSC) harbor gene mutations associated with the pathogenesis of inherited cardiac diseases and congenital heart diseases (CHD). Numerous reports have demonstrated the utilization of human induced Pluripotent Stem Cell (hiPSC) to model cardiac diseases as a means of investigating their underlying mechanisms. So far, they have been shown to investigate the molecular mechanisms of many cardiac disorders, such as long-QT syndrome (LQT), catecholaminergic polymorphic ventricular tachycardia (CPVT), dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), LEOPARD syndrome (LS), arrhythmogenic cardiomyopathy (ACM), Friedreich ataxia (FRDA), Barth syndrome (BTHS), hypoplastic left heart syndrome (HLHS), Marfan syndrome (MFS) and other CHD. This article summarizes the growing body of research related to modeling various cardiac diseases using hiPSCs. Moreover, by reviewing the methods used in previous studies, we propose multiple novel applications of hiPSCs to investigate comprehensive cardiovascular disorders and facilitate drug discovery.
- Left ventricular systolic function and the pattern of late-gadolinium-enhancement independently and additively predict adverse cardiac events in muscular dystrophy patients. [JOURNAL ARTICLE]
- J Cardiovasc Magn Reson 2014 Sep 25; 16(1):81.
Cardiac involvement is a frequent finding in patients with Duchenne (DMD) and Becker (BMD) muscular dystrophies. With this study, we aimed at elucidating the relationship between the phenotypic expression of cardiac involvement and the occurrence of adverse cardiac events in DMD/BMD patients.Eighty-eight male DMD/BMD patients (age 29 ± 14 yrs) were prospectively enrolled. All patients underwent cardiovascular magnetic resonance (CMR) comprising cine- and late-gadolinium-enhancement (LGE)-CMR at study entry and were subsequently followed-up for adverse cardiac events. The primary endpoint was defined as all-cause/cardiac death or cardiac transplantation. Secondary endpoints were (1) hospitalization for heart failure and/or (2) occurrence of non-/sustained ventricular tachycardia (VT).During a mean follow-up time of 47 ± 18 months, the primary endpoint was observed in three (3%) and the secondary endpoint in 21 (24%) patients. On multivariable analysis, LV-EF (HR, 95% CI: 0.94, 0.89-0.97, p = 0.001) and the presence of "transmural" LGE (HR, 95% CI: 2.89, 1.09-7.68, p = 0.033) were the only independent predictors for secondary endpoints. A cut-off for LV-EF of 45% was associated with the highest hazard ratio (HR, 95% CI: 11.50, 4.49-29.43, p < 0.0001) in a Cox regression survival analysis. In the group of patients with a LV-EF (>45%), those patients already showing "transmural" LGE had a significantly lower event-free-survival (HR, 95% CI: 13.48, 1.89-96.12, p = 0.009) compared to those without.An impaired LV systolic function (LV-EF ≤45%) and a "transmural" pattern of myocardial fibrosis independently predict the occurrence of adverse cardiac events in DMD/BMD patients. Even in DMD/BMD patients with relatively preserved LV-EF (>45%), the simple and visually assessable parameter "transmural LGE" is of additive prognostic value.
- [A woman in her forties with cancer, syncope and spasms]. [English Abstract, Journal Article]
- Tidsskr Nor Laegeforen 2014 Oct 14; 134(19):1855-7.
A female in her forties with advanced incurable rectal cancer presented to our emergency department after loss of consciousness followed by brief myoclonic jerks in her legs.A cerebral MRI was normal. Her electrocardiogram showed a prolonged QTc interval of 596 milliseconds and hypokalemia was present. She had no family history of congenital long QT syndrome or of cardiovascular disease. She was not on any medication apart from having ingested 100 g caesium carbonate over the previous 11 days as an alternative cancer treatment. Caesium chloride is postulated to increase pH and thereby induce apoptosis in cancer cells. In treatment doses caesium competes with potassium for membrane transport proteins in the cardiac cell membrane and in the reabsorption tubuli of the kidneys. A result is hypokalemia shortly after depolarization during the cardiomyocytes' repolarisation phase or delayed post-depolarisation. Torsade de pointes ventricular arrhythmias, ventricular tachycardia, pump failure and death can follow. A few case reports of adverse effects from caesium ingestion have been published, as well as reports on how caesium is used in animal models to induce ventricular tachycardia, but the hazards of caesium ingestion and its long half-life are not well known in the medical care profession or among patients. As this patient's QTc interval normalised slowly to 413 milliseconds 60 days after stopping caesium ingestion, we consider caesium intoxication and convulsive syncope from a self-terminating ventricular tachycardia as the most probable aetiology. The main message from this case is that alternative medicine can have life-threatening side effects.
- Central line placement may terminate ventricular tachycardia! [Journal Article]
- Avicenna J Med 2014 Oct; 4(4):105.
- Spontaneous coronary artery dissection: association with predisposing arteriopathies and precipitating stressors and cardiovascular outcomes. [Journal Article]
- Circ Cardiovasc Interv 2014 Oct; 7(5):645-55.
Nonatherosclerotic spontaneous coronary artery dissection (NA-SCAD) is underdiagnosed and an important cause of myocardial infarction in young women. The frequency of predisposing and precipitating conditions and cardiovascular outcomes remains poorly described.Patients with NA-SCAD prospectively evaluated (retrospectively or prospectively identified) at Vancouver General Hospital were included. Angiographic SCAD diagnosis was confirmed by 2 experienced interventional cardiologists and categorized as type 1 (multiple lumen), 2 (diffuse stenosis), or 3 (mimic atherosclerosis). Fibromuscular dysplasia screening of renal, iliac, and cerebrovascular arteries were performed with angiography or computed tomographic angiography/MR angiography. Baseline, predisposing and precipitating conditions, angiographic, revascularization, in-hospital, and long-term events were recorded. We prospectively evaluated 168 patients with NA-SCAD. Average age was 52.1±9.2 years, 92.3% were women (62.3% postmenopausal). All presented with myocardial infarction. ECG showed ST-segment elevation in 26.1%, and 3.6% had ventricular tachycardia/ventricular fibrillation arrest. Fibromuscular dysplasia was diagnosed in 72.0%. Precipitating emotional or physical stress was reported in 56.5%. Majority had type 2 angiographic SCAD (67.0%), only 29.1% had type 1, and 3.9% had type 3. The majority (134/168) were initially treated conservatively. Overall, 6 of 168 patients had coronary artery bypass surgery and 33 of 168 had percutaneous coronary intervention in-hospital. Of those treated conservatively (n=134), 3 required revascularization for SCAD extension, and all 79 who had repeat angiogram ≥26 days later had spontaneous healing. Two-year major adverse cardiac events were 16.9% (retrospectively identified group) and 10.4% (prospectively identified group). Recurrent SCAD occurred in 13.1%.Majority of patients with NA-SCAD had fibromuscular dysplasia and type 2 angiographic SCAD. Conservative therapy was associated with spontaneous healing. NA-SCAD survivors are at risk for recurrent cardiovascular events, including recurrent SCAD.
- Worsening thoracic impedance as a ventricular tachyarrhythmia risk. [Journal Article]
- Rev Cardiovasc Med 2014; 15(3):226-31.
The use of heart failure classification to identify patients with systolic dysfunction who are at risk for ventricular tachyarrhythmias (VAs), sudden cardiac death, and shocks from implantable cardioverter defibrillators (ICDs) is limited by its subjectivity. Measurement of thoracic impedance offers a more objective tool for assessing worsening of heart failure. We sought to look at the correlation between ventricular arrhythmia and heart failure as assessed objectively by thoracic impedance. We reviewed device interrogation data on thoracic impedance from ICD with Medtronic's OptiVol® feature (Medtronic Inc., Minneapolis, MN) at two medical centers. Data from the last two interrogations of the same device separated by at least 2 months were included. An OptiVol fluid index threshold of 60 represented early heart failure prior to appearance of symptoms. VAs included were ventricular fibrillation and/or ventricular tachycardia lasting more than 16 beats. Chi square distribution test was used in statistical data analysis. There were 24 VAs identified among the 322 interrogations reviewed (7.5%). Elevated OptiVol fluid index was seen in 71% (17/24), whereas normal OptiVol index was seen in the remaining 29% (7/24) of these interrogations with VA (P < .05). Our review shows that heart failure patients who have VA are approximately 2.5 times as likely to have worsening thoracic impedance as assessed objectively by the OptiVol fluid index. Careful monitoring of the OptiVol fluid index may identify a population at high risk of VA that merits more intense attention.
- Complex Excitation Dynamics Underlie Polymorphic Ventricular Tachycardia in a Transgenic Rabbit Model of LQT1. [JOURNAL ARTICLE]
- Heart Rhythm 2014 Oct 3.
Long QT syndrome type 1 (LQT1) is a congenital disease arising from a loss of function in the slowly activating delayed potassium current (IKs) that causes early afterdepolarizations (EADs) and polymorphic ventricular tachycardia (pVT).We investigated the mechanisms underlying pVT using a transgenic rabbit model of LQT1.Hearts were perfused retrogradely, and action potentials were recorded using a voltage-sensitive dye and CMOS cameras.Bolus injection of isoproterenol (140 nM) induced pVT initiated by focal excitations from the RV (n=16 out of 18 pVTs). After the pVT is initiated, complex focal excitations occur in both RV and LV that cause oscillations of the QRS complexes in the ECGs, consistent with the recent proposal of multiple shifting foci caused by EAD chaos. Moreover, the action potential upstroke in pVT showed a bimodal distribution, demonstrating the coexistence of two types of excitation that interact to produce complex pVT. Namely, Na(+) current (INa)-mediated fast conduction and L-type Ca(2+) current (ICa)-mediated slow conduction co-exist, manifesting as pVT. Addition of 2 μM TTX to reduce INa converted pVT into monomorphic VT. Reducing late INa in computer simulation converted pVT into a single dominant reentry, agreeing with experimental results.Our study demonstrates that pVT in LQT1 rabbits is initiated by focal excitations from the RV and is maintained by multiple shifting foci in both ventricles. Moreover, the wave conduction in pVT exhibits bi-excitability, i.e., fast wavefronts driven by INa and slow wavefronts driven by ICa co-exist during pVT.