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Author(s):
Moinuddin Choudhury
,
Mark R Boyett
,
Gwilym M Morris
Added:
3 years ago
The sinoatrial or sinus node (SAN) is the heart’s natural pacemaker. Located in the superior right atrium, it automatically produces cyclical electrical activity to initiate each heartbeat in normal sinus rhythm. SAN dysfunction (SND) in humans, also known as ‘sick sinus syndrome’, can manifest as pathological bradycardia and asystolic pauses. As a result, SND can lead to symptoms of reduced…
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Author(s):
Dario DiFrancesco
Added:
3 years ago
HCN4 (hyperpolarisation-activated, cyclic nucleotide gated 4) channels, the pore-forming α–subunits of ‘funny’ channels originally described in pacemaker cells of the sinoatrial node (SAN),1 are responsible for the early phase of diastolic depolarisation in these cells and are key determinants of pacemaker generation and control of heart rate.2–5 HCN4 channels are selectively expressed in the SAN…
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Author(s):
Sharon A George
,
N Rokhaya Faye
,
Alejandro Murillo-Berlioz
,
et al
Added:
3 years ago
More than 100years have passed since the atrioventricular node (AVN) was first discovered by Sunao Tawara1 and described as a “Knoten” of tissue located at the proximal end of the Bundle of His (BoH).2 Despite the numerous advances in knowledge regarding the structure and function of the AVN, there are still several controversies that need to be addressed in both clinical and scientific settings…
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Author(s):
Penelope A Boyden
,
Wen Dun
,
Bruno D Stuyvers
Added:
3 years ago
Abnormalities in electrical rhythm were studied by Einthoven at the start of the 20th century. In the 1940s, studies by Bozler et al.1 described contractile signals that appeared to be ‘triggered’ heart beats. Today we use the term delayed afterdepolarisations (DADs) to refer to oscillations in voltage that follow a driven action potential.
In the mid-1970s, progress was made when Lederer and…
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Author(s):
Antonio Zaza
,
Carlotta Ronchi
,
Gabriella Malfatto
Added:
3 years ago
The incidence of ventricular arrhythmias is often related, within an individual, to the rate of their underlying sinus rhythm (heart rate). The direction of this relationship is generally considered to entail some prognostic significance: whereas ectopic activity suppressed by tachycardia is assumed to be benign, an arrhythmia enhanced by tachycardia is regarded with more concern. Is this…
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Author(s):
Cristina E Molina
,
Jordi Heijman
,
Dobromir Dobrev
Added:
3 years ago
Optimal cardiac function depends on appropriate rate and force of contraction, with specific cardiac regions having developed particular beat-to-beat properties depending on their individual functions. For example, isovolumetric contraction time is shorter in the right ventricle (RV) than in the left ventricle (LV). At the cellular level, cardiac function is regulated by regional cardiomyocyte…
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Author(s):
Daniele Muser
,
Simon A Castro
,
Jackson J Liang
,
et al
Added:
3 years ago
The role of catheter ablation (CA) in the management of ventricular tachycardia (VT) is becoming increasingly relevant, having repeatedly shown its superiority to medical therapy in reducing the arrhythmic burden, thus improving prognosis and quality of life in patients with structural heart disease presenting with VT.1–4 In such patients, recurrent VT and heart failure (HF) status are connected…
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Author(s):
Jean-Baptiste Gourraud
,
Jason G Andrade
,
Laurent Macle
,
et al
Added:
3 years ago
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia observed in clinical practice, occurring in approximately 2 % of the general population.1–3 A progressive increase in both the prevalence and incidence of AF has been demonstrated in recent years, defining AF as a major economic and public health issue.1
The identification of sites of AF initiation and/or maintenance within…
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Author(s):
Sunil Kapur
,
Moussa Mansour
Added:
3 years ago
Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting more than three million Americans.1 The management of AF revolves around the alleviation of symptoms related to an accelerated and irregular ventricular response, and the prevention of cardioembolism, notably stroke. In patients with AF, there is a fivefold increased incidence of embolic stroke.2 The prevention of systemic…
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Author(s):
Justine Bhar-Amato
,
William Davies
,
Sharad Agarwal
Added:
3 years ago
Ventricular tachyarrhythmias (VAs) most commonly occur early in ischaemia, and patients presenting with an acute MI and ventricular arrhythmias are a group that has a significantly increased risk of mortality.1,2 Thrombolysis primary percutaneous coronary intervention (PCI) and use of beta-blockers, while resulting in the modification of the natural history of an infarct, have also reduced the…
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