Tachycardia

2015-10-19T14:56:43Z

080346591: Summary of the three types of tachycardia and their causes

Tachycardia is the terms describing a faster than normal heart rate. A heart rate higher than 100 beats per minute is considered to be tachycardia, however, this can vary from person-to-person as their normal may differ ([http://www.heart.org/HEARTORG/Conditions/Arrhythmia/AboutArrhythmia/Tachycardia-Fast-Heart-Rate_UCM_302018_Article.jsp#.ViUCtFI1iUk http://www.heart.org/HEARTORG/Conditions/Arrhythmia/AboutArrhythmia/Tachycardia-Fast-Heart-Rate_UCM_302018_Article.jsp#.ViUCtFI1iUk]).

'''There are three types of tachycardia:'''

'''1. Atrial or Supraventricular Tachycardia:'''

Atrial or Supraventricular tachycardia (SVT) is a fast heart rate that starts in the [[Atria|atria]] of the heart. Other forms are called paroxysmal atrial tachycardia (PAT) or paroxysmal supraventricular tachycardia (PSVT). Electrical signals in the atria fire abnormally, which interferes with electrical signals coming from the sinoatrial (SA) node. A series of early beats in the atria speeds up the heart rate. The rapid heartbeat does not allow enough time for the heart to fill before it contracts so blood flow to the rest of the body is compromised ([http://www.nhs.uk/Conditions/Supraventricular-tachycardia/Pages/Symptoms.aspx http://www.nhs.uk/Conditions/Supraventricular-tachycardia/Pages/Symptoms.aspx]). 

'''2. Sinus Tachycardia:''' This is a fast but steady heart rate usually related to anxiety, emotional stress, exercise or certain drugs. It is not considered dangerous unless and doctors may prefer to treat the underlying cause such as anxiety and depression ([http://www.nottingham.ac.uk/nursing/practice/resources/cardiology/function/sinus_tachycardia.php http://www.nottingham.ac.uk/nursing/practice/resources/cardiology/function/sinus_tachycardia.php]).

'''3. Ventricular Tachycardia:'''

Ventricular tachycardia is a fast heart rate that starts in the [[Ventricles|ventricles]]. It can be a life-threatening heart rhythm and requires rapid diagnosis and treatment.

Electrical signals in the ventricles fire abnormally, which interferes with electrical signals coming from the sinoatrial (SA) node. The rapid heartbeat does not allow enough time for the heart to fill before it contracts so blood does not get pumped throughout the body. This is considered the more dangerous type due to its potential to escalate into cardiac arrest, heart failure or fibrillation ([https://www.nlm.nih.gov/medlineplus/ency/article/000187.htm https://www.nlm.nih.gov/medlineplus/ency/article/000187.htm]).

Antisense strand

2014-11-28T00:02:15Z

080346591: The strand to which RNA polymerase binds to transcribe into mRNA

[[DNA]] is a double stranded molecule which uses four base [[Nucleotides]] to code genetic material. In order to use the genetic code in DNA, it must undergo [[Transcription]] from DNA to [[MRNA]]. The mRNA then undergoes [[Translation]] to form a [[Polypeptide]]; which is folded in a specific way to produce a functional protein. The enzyme responsible for transcription is called [[RNA polymerase]]. It must bind to one of the strands of DNA in order to use the sequence to produce a complimentary single stranded RNA molecule. The strand that the enzyme binds to is called the antisense (or template) strand. It is the strand that runs in the 3'-5' direction.

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Tachycardia

Antisense strand