Inherited and Acquired Vulnerability to Ventricular Arrhythmias: Cardiac Na+ and K+ Channels

2005 ◽  
Vol 85 (1) ◽  
pp. 33-47 ◽  
Author(s):  
Colleen E. Clancy ◽  
Robert S. Kass

Mutations in cardiac Na+ and K+ channels can disrupt the precise balance of ionic currents that underlies normal cardiac excitation and relaxation. Disruption of this equilibrium can result in arrhythmogenic phenotypes leading to syncope, seizures, and sudden cardiac death. Congenital defects result in an unpredictable expression of phenotypes with variable penetrance, even within single families. Additionally, phenotypically opposite and overlapping cardiac arrhythmogenic syndromes can stem from one mutation. A number of these defects have been characterized experimentally with the aim of understanding mechanisms of mutation-induced arrhythmia. Improving understanding of abnormalities may provide a basis for the development of therapeutic approaches.

2012 ◽  
pp. 74-83
Author(s):  
Anh Tien Hoang ◽  
Nhat Quang Nguyen

Background: Decades of research now link TWA with inducible and spontaneous clinical ventricular arrhythmias. This bench-to-bedside foundation makes TWA, NT-ProBNP a very plausible index of susceptibility to ventricular arrythmia, and motivates the need to define optimal combination of TWA and NT-ProBNP in predicting ventricular arrythmia in myocardial infarction patients. We research this study with 2 targets: 1. To evaluate the role of TWA in predicting sudden cardiac death in myocardial infarction patients. 2. To evaluate the role of NT-ProBNP in predicting sudden cardiac death in myocardial infarction patients 3. Evaluate the role of the combined NT-ProBNP and TWA in predicting sudden cardiac death in myocardial infarction patients. Methods: Prospective study with follow up the mortality in 2 years: 71 chronic myocardial infarction patients admitted to hospital from 5/2009 to 5/20011 and 50 healthy person was done treadmill test to caculate TWA; ECG, echocardiography, NT-ProBNP. Results: Cut-off point of NT-ProBNP in predicting sudden cardiac death is 3168 pg/ml; AUC = 0,86 (95% CI: 0,72 - 0,91); Cut-off point of TWA in predicting sudden cardiac death is 107 µV; AUC = 0,81 (95% CI: 0,69 - 0,87); NT-ProBNP can predict sudden cardiac death with OR= 7,26 (p<0,01); TWA can predict sudden cardiac death with OR= 8,45 (p<0,01). The combined NT-ProBNP and TWA in predicting ventricular arrythmia in heart failure patients: OR= 17,91 (p<0,001). Conclusions: The combined NT-ProBNP and TWA have the best predict value of sudden cardiac death in myocardial infarction patients, compare to NT-ProBNP or TWA alone


2021 ◽  
pp. 263246362110124
Author(s):  
Manjappa Mahadevappa ◽  
Vikram Patil ◽  
K.S. Poornima ◽  
Sowmya Velamala ◽  
B.V. Guruprasad

Tuberous sclerosis complex is an autosomal dominant condition with variable penetrance. It is characterized by tuberose deposits in various organ systems. Although clinical features predominate neurocutaneous manifestations, cardiac, kidney, and lung involvement are common. Cardiac involvement is marked by the presence of multiple rhabdomyomas and in some cases arrhythmias. In the absence of symptoms, rhabdomyomas require no specific treatment. However, cardiac arrhythmias are unpredictable and may be the cause of sudden cardiac death in some cases. Although treatment is mainly symptomatic, drugs like rapamycin have shown promise in the regression of astrocytomas and angiofibromas. Here, we are reporting two cases of tuberous sclerosis of which one succumbed to arrhythmias and the other to possible sudden cardiac death.


2021 ◽  
Vol 4 (57) ◽  
pp. 8-11
Author(s):  
Szymon Warwas ◽  
Marta Jagosz ◽  
Beata Średniawa ◽  
Michał Mazurek ◽  
Ewa Jędrzejczyk-Patej

The most common cause of death among dialysis patients with end-stage kidney disease are cardiovascular diseases. It is estimated that 18-27% of all deaths in dialysis patients are sudden cardiac deaths due to arrhythmias and conduction disturbances. The most common arrhythmias in dialysis patients, often leading to sudden death, are not ventricular arrhythmias but bradyarrhythmias. The article below discusses the most common arrhythmias in dialysis patients and methods of preventing sudden cardiac death in this group of patients.


Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Mengjun Wang ◽  
Valerio Zaca ◽  
Alice Jiang ◽  
Itamar Ilsar ◽  
Matthew Ebinger ◽  
...  

Heart failure (HF) is associated with a high incidence of ventricular tachycardia (VT) and fibrillation (VF). Patients with HF in whom these lethal arrhythmias can be induced by electrophysiological (EP) testing carry a high risk of sudden cardiac death. We showed that chronic electrical carotid baroreflex activation therapy (BAT) with the Rheos® System (CVRx, Inc.) improves LV function, attenuates LV remodeling and restores autonomic sympathetic-parasympathetic balance in dogs with HF. This study examined the effects of long-term therapy with BAT on the induction of VT or VF in dogs with coronary microembolization-induced HF (LV ejection fraction ~20%). Eleven dogs with HF underwent EP testing at baseline prior to therapy and after 3 and 6 months of therapy with BAT and again 6 weeks after withdrawal of BAT therapy (n = 7) or no therapy at all (Control, n = 4). Programmed ventricular stimulation was performed from the right ventricular apex and included delivery of up to 4 extrastimuli at progressively shorter coupling intervals (in steps of 10 msec). The extrastimuli were delivered following 8 ventricular paced beats with a drive cycle length between 600 and 200 msec. If a sustained monomorphic VT or VF could not be induced, isoproterenol infusion was initiated to increase the sinus rate by ~30% and the EP stimulation protocol was repeated. At baseline, a sustained VT or VF was induced in all 11 dogs (100%). After 3 and 6 months of follow-up, all Control dogs (100%) were induced into sustained VT or VF. After 3 months of BAT, only 3 of 7 dogs (43%) were induced into sustained VT or VF. After 6 months of BAT, only 2 of 7 dogs (29%) were induced into sustained VT or VF. Finally after withdrawal of BAT therapy, all dogs (100%) were again induced into systained VT or VF. In addition to improving LV function and attenuating LV remodeling, long-term monotherapy with BAT markedly increases the threshold for lethal ventricular arrhythmias in dogs with chronic HF. This is a marked improvement over inducibility of lethal arrhythmias seen in historical untreated controls. This benefit of BAT supports the continued exploration of this device as a therapeutic modality for treating patients with chronic HF and increased risk of sudden cardiac death.


Author(s):  

Dilated cardiomyopathy (DCM) is a disease characterised as left ventricular (LV) or biventricular dilatation with impaired systolic function. Regardless of underlying cause patients with DCM have a propensity to ventricular arrhythmias and sudden cardiac death. Implantable Cardioverter Defibrillator (ICD) implantation for these patients results in significant reduction of sudden cardiac death [1-3]. ICD devices may be limited by right ventricle (RV) sensing dysfunction with low RV sensing amplitude. We present a clinical case of patient with DCM, implanted ICD and low R wave sensing on RV lead.


2009 ◽  
Vol 30 (21) ◽  
pp. 2599-2605 ◽  
Author(s):  
Juan R. Gimeno ◽  
Maite Tomé-Esteban ◽  
Carla Lofiego ◽  
José Hurtado ◽  
Antonios Pantazis ◽  
...  

2012 ◽  
Vol 23 (12) ◽  
pp. 1929-1939 ◽  
Author(s):  
Isaac R. Whitman ◽  
Harold I. Feldman ◽  
Rajat Deo

2019 ◽  
Vol 28 (1) ◽  
pp. 146-154 ◽  
Author(s):  
Benjamin Moore ◽  
Christopher Semsarian ◽  
Kim H. Chan ◽  
Raymond W. Sy

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Nathalie Strutz-eebohm ◽  
Katja Steinke ◽  
Ulrike Henrion ◽  
Matthias Rohbeck ◽  
Karin Klingel ◽  
...  

In patients as well as in mouse models, enteroviral infections, especially Coxsackie group B viruses (CVB1-6), frequently induce ventricular arrhythmias and sudden cardiac death. The cardiac action potential requires proper function of cardiac ion channels. CVB3 alters Kv7.1 channel trafficking potentially leading to changes in action potentials and increasing likelihood of arrhythmias. Genetic variants of cardiac ion channels can cause changes in channel trafficking that may preserve from CVB3 modulations and present an evolutionary advantage. Here, we show that a common polymorphic Kv7.1 channel variant uses alternative trafficking pathways and may thus exert a benefit during CVB3 infections. Genetic and pharmacological disruption of a CVB3-stimulated Serum- and Glucocorticoid inducible Kinase 1 (SGK1) pathways blunts Kv7.1 channel dysfunctions. Our results suggest that escape from CVB3-induced SGK1-stimulation by genetic variation in Kv7.1 may be protective and inhibition of SGK1 may present a pharmacological approach to reduce the pro-arrhythmic risk associated with acute coxsackievirus infections.


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