Question: Is Calcium/Calmodulin dependent protein kinase II (CaMKII) involved in cardiac arrhythmias and heart failure?

Context:
In human hypertrophy, both CaMKII and PKA functionally regulate RyR2 and may induce SR Ca(2+) leak. In the transition from hypertrophy to HF, the diastolic Ca(2+) leak increases and disturbed Ca(2+) cycling occurs. This is associated with an increase in CaMKII- but not PKA-dependent RyR2 phosphorylation. CaMKII inhibition may thus reflect a promising therapeutic target for the treatment of arrhythmias and contractile dysfunction.
Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is an enzyme with important regulatory functions in the heart and brain, and its chronic activation can be pathological. CaMKII activation is seen in heart failure, and can directly induce pathological changes in ion channels, Ca(2+) handling and gene transcription.
In the recent years, Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) was suggested to be associated with cardiac hypertrophy and heart failure but also with arrhythmias both in animal models as well as in the human heart.
Calcium-calmodulin-dependent protein kinase II (CaMKII) has emerged as a central mediator of cardiac stress responses which may serve several critical roles in the regulation of cardiac rhythm, cardiac contractility and growth. Sustained and excessive activation of CaMKII during cardiac disease has, however, been linked to arrhythmias, and maladaptive cardiac remodeling, eventually leading to heart failure (HF) and sudden cardiac death. 
Overexpression of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in transgenic mice results in heart failure and arrhythmias.
From recent studies, it appears evident that Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) plays a central role in the arrhythmogenic processes in heart failure by sensing intracellular Ca(2+) and redox stress, affecting individual ion channels and thereby leading to electrical instability in the heart. 
CaMKII activation is proarrhythmic in heart failure where myocardium is stretched.
The Ca-calmodulin dependent kinase II (CaMKII) seems to be involved in the development of heart failure and arrhythmias and may therefore be a promising target for the development of antiarrhythmic therapies.
Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is up-regulated in heart failure and has been shown to cause I(Na) gating changes that mimic those induced by a point mutation in humans that is associated with combined long QT and Brugada syndromes.
CaMKII-dependent phosphorylation of Na(V)1.5 at multiple sites (including Thr-594 and Ser-516) appears to be required to evoke loss-of-function changes in gating that could contribute to acquired Brugada syndrome-like effects in heart failure.
Because CaMKII expression and activity are increased in cardiac hypertrophy, heart failure, and during arrhythmias both in animal models as well as in the human heart a clinical significance of CaMKII is implied.
The multifunctional Ca(2+)- and calmodulin-dependent protein kinase II (CaMKII) is now recognized to play a central role in pathological events in the cardiovascular system. CaMKII has diverse downstream targets that promote vascular disease, heart failure, and arrhythmias, so improved understanding of CaMKII signaling has the potential to lead to new therapies for cardiovascular disease.
In our opinion, the multifunctional Ca and calmodulin-dependent protein kinase II (CaMKII) has emerged as a molecule to watch, in part because a solid body of accumulated data essentially satisfy Koch's postulates, showing that the CaMKII pathway is a core mechanism for promoting myocardial hypertrophy and heart failure. Multiple groups have now confirmed the following: (1) that CaMKII activity is increased in hypertrophied and failing myocardium from animal models and patients; (2) CaMKII overexpression causes myocardial hypertrophy and HF and (3) CaMKII inhibition (by drugs, inhibitory peptides and gene deletion) improves myocardial hypertrophy and HF
 In contrast, inhibiting the CaMKII pathway appears to reduce arrhythmias and improve myocardial responses to pathological stimuli. 
In this review, we discuss the important role of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in the regulation of RyR2-mediated Ca(2+) release. In particular, we examine how pathological activation of CaMKII can lead to an increased risk of sudden arrhythmic death. Finally, we discuss how reduction of CaMKII-mediated RyR2 hyperactivity might reduce the risk of arrhythmias and may serve as a rationale for future pharmacotherapeutic approaches.
Transgenic (TG) Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) δ(C) mice develop systolic heart failure (HF). CaMKII regulates intracellular Ca(2+) handling proteins as well as sarcolemmal Na(+) channels. We hypothesized that CaMKII also contributes to diastolic dysfunction and arrhythmias via augmentation of the late Na(+) current (late I(Na)) in early HF (8-week-old TG mice).
Thus, late I(Na) inhibition appears to be a promising option for diastolic dysfunction and arrhythmias in HF where CaMKII is found to be increased.
We tested the hypothesis that increased RyR2 phosphorylation by Ca(2+)/calmodulin-dependent protein kinase II is both necessary and sufficient to promote lethal ventricular arrhythmias.
CONCLUSIONS: our results suggest that Ca(2+)/calmodulin-dependent protein kinase II phosphorylation of RyR2 Ca(2+) release channels at S2814 plays an important role in arrhythmogenesis and sudden cardiac death in mice with heart failure.
Excessive activation of calmodulin kinase II (CaMKII) causes arrhythmias and heart failure, but the cellular mechanisms for CaMKII-targeted proteins causing disordered cell membrane excitability and myocardial dysfunction remain uncertain.
Transgenic (TG) Ca/calmodulin-dependent protein kinase II (CaMKII)delta(C) mice have heart failure and isoproterenol (ISO)-inducible arrhythmias. We hypothesized that CaMKII contributes to arrhythmias and underlying cellular events and that inhibition of CaMKII reduces cardiac arrhythmogenesis in vitro and in vivo.
We conclude that CaMKII contributes to cardiac arrhythmogenesis in TG CaMKIIdelta(C) mice having heart failure and suggest the increased SR Ca leak as an important mechanism. Moreover, CaMKII inhibition reduces cardiac arrhythmias in vitro and in vivo and may therefore indicate a potential role for future antiarrhythmic therapies warranting further studies.
Ca2+/calmodulin dependent protein kinase II (CaMKII) can phosphorylate RyR2 and modulate its activity. This phosphorylation positively modulates cardiac inotropic function but in extreme situations such as heart failure, elevated CaMKII activity can adversely increase Ca2+ release from the SR and lead to arrhythmogenesis. 
Calcium/calmodulin-dependent kinase II (CaMKII) is a multifunctional serine/threonine kinase expressed abundantly in the heart. CaMKII targets numerous proteins involved in excitation-contraction coupling and excitability, and its activation may simultaneously contribute to heart failure and cardiac arrhythmias.
Under stress conditions, excessive CaMKII activity promotes heart failure and arrhythmias, in part through actions at Ca(2+) homeostatic proteins.
Ca-calmodulin-dependent protein kinase II (CaMKII) was recently shown to alter Na(+) channel gating and recapitulate a human Na(+) channel genetic mutation that causes an unusual combined arrhythmogenic phenotype in patients: simultaneous long QT syndrome and Brugada syndrome. CaMKII is upregulated in heart failure where arrhythmias are common, and CaMKII inhibition can reduce arrhythmias. Thus, CaMKII-dependent channel modulation may contribute to acquired arrhythmic disease. 
In heart failure (HF), Ca(2+)/calmodulin kinase II (CaMKII) expression is increased. Altered Na(+) channel gating is linked to and may promote ventricular tachyarrhythmias (VTs) in HF. Calmodulin regulates Na(+) channel gating, in part perhaps via CaMKII.
Thus, CaMKII-dependent regulation of Na(+) channel function may contribute to arrhythmogenesis in HF.
Recent findings that CaMKII expression in the heart changes during hypertrophy, heart failure, myocardial ischemia, and infarction suggest that CaMKII may be a viable therapeutic target for patients suffering from common forms of heart disease.
 Overexpression of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in transgenic mice results in heart failure and arrhythmias.
Transgenic (TG) Ca/calmodulin-dependent protein kinase II (CaMKII)delta(C) mice have heart failure and isoproterenol (ISO)-inducible arrhythmias.
BACKGROUND: Transgenic (TG) Ca/calmodulin-dependent protein kinase II (CaMKII)delta(C) mice have heart failure and isoproterenol (ISO)-inducible arrhythmias.
CaMKII targets numerous proteins involved in excitation-contraction coupling and excitability, and its activation may simultaneously contribute to heart failure and cardiac arrhythmias.
Calcium/calmodulin-dependent protein kinase II contributes to cardiac arrhythmogenesis in heart failure.
From recent studies, it appears evident that Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) plays a central role in the arrhythmogenic processes in heart failure by sensing intracellular Ca(2+) and redox stress, affecting individual ion channels and thereby leading to electrical instability in the heart.
Ryanodine receptor phosphorylation, calcium/calmodulin-dependent protein kinase II, and life-threatening ventricular arrhythmias.
CaMKII targets numerous proteins involved in excitation-contraction coupling and excitability, and its activation may simultaneously contribute to heart failure and cardiac arrhythmias
The Ca-calmodulin dependent kinase II (CaMKII) seems to be involved in the development of heart failure and arrhythmias and may therefore be a promising target for the development of antiarrhythmic therapies
Calcium-calmodulin kinase II mediates digitalis-induced arrhythmias.
Transgenic (TG) Ca/calmodulin-dependent protein kinase II (CaMKII)delta(C) mice have heart failure and isoproterenol (ISO)-inducible arrhythmias

Answer: Calcium/calmodulin-dependent kinase II (CaMKII) is a multifunctional serine/threonine kinase expressed abundantly in the heart. CaMKII targets numerous proteins involved in excitation-contraction coupling and excitability, and its activation may simultaneously contribute to heart failure and cardiac arrhythmias.  
Calcium/calmodulin-dependent kinase II (CaMKII) is a multifunctional serine/threonine kinase expressed abundantly in the heart. CaMKII targets numerous proteins involved in excitation-contraction coupling and excitability, and its activation may simultaneously contribute to heart failure and cardiac arrhythmias.
Overexpression of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in transgenic mice results in heart failure and arrhythmias.The Ca-calmodulin dependent kinase II (CaMKII) seems to be involved in the development of heart failure and arrhythmias and may therefore be a promising target for the development of antiarrhythmic therapies.
Exact answer: yes