ANTI-ARRHYTHMICS
BY
DR AG. WILLIAM
Department of Pharmacology
College of Pharmacy
Gregory University Uturu, Abia State.
© July. 2024
,INTRODUCTION TO THE ARRHYTHMIAS
Arrhythmias refers to a range of Cardiac Rhythm Disorders due to:
- Abnormalities of Impulse Generation: Site, Rate or Regularity
- Abnormalities of Impulse Conduction: Velocity or Regularity
Site of impulse generation can be no r m al sinu s node or ectopic fo cu s, which can
develop in any self-excitator y part of the heart.
Rate of impulse conduction can be accelerated, slowed or blocked.
Therefore, Cardiac Arrhythmias can take various forms such as bradycardia, tachycardia,
flutter and fibrillation.
- Bradycardia: A Slow heart rate of usually less than 60 beats per min
- Tachycardia: A Fast heart rate of usually greater than 100 beats per min
- Flutter: A very Rapid heart rate between 200 & 350 beats per min
- Fibrillation: The frequency is so high & irregular that rate is indeterminate.
, REVIEW OF CARDIAC ELECTROPHYSIOLOGY - 1
In contrast to skeletal muscles which contracts only when it receives a
stimulus, the heart contains specialised cells that exhibit automaticity; i.e.
they can intrinsically generate rhythmic action potentials in the absence
of an external stimuli.
The electrical impulse that triggers a normal cardiac contraction
originates at regular intervals in the sinoatrial node, usually at a frequency
of 60-100 beats per minute.
This impulse spreads rapidly through the atria and enters the
atrioventricular node, which is normally the only conduction pathway
between the atria and ventricles.
Conduction through the atrioventricular node is slow, requiring about
0.15s. This delay provides time for atrial contraction to propel blood into
the ventricles.
BY
DR AG. WILLIAM
Department of Pharmacology
College of Pharmacy
Gregory University Uturu, Abia State.
© July. 2024
,INTRODUCTION TO THE ARRHYTHMIAS
Arrhythmias refers to a range of Cardiac Rhythm Disorders due to:
- Abnormalities of Impulse Generation: Site, Rate or Regularity
- Abnormalities of Impulse Conduction: Velocity or Regularity
Site of impulse generation can be no r m al sinu s node or ectopic fo cu s, which can
develop in any self-excitator y part of the heart.
Rate of impulse conduction can be accelerated, slowed or blocked.
Therefore, Cardiac Arrhythmias can take various forms such as bradycardia, tachycardia,
flutter and fibrillation.
- Bradycardia: A Slow heart rate of usually less than 60 beats per min
- Tachycardia: A Fast heart rate of usually greater than 100 beats per min
- Flutter: A very Rapid heart rate between 200 & 350 beats per min
- Fibrillation: The frequency is so high & irregular that rate is indeterminate.
, REVIEW OF CARDIAC ELECTROPHYSIOLOGY - 1
In contrast to skeletal muscles which contracts only when it receives a
stimulus, the heart contains specialised cells that exhibit automaticity; i.e.
they can intrinsically generate rhythmic action potentials in the absence
of an external stimuli.
The electrical impulse that triggers a normal cardiac contraction
originates at regular intervals in the sinoatrial node, usually at a frequency
of 60-100 beats per minute.
This impulse spreads rapidly through the atria and enters the
atrioventricular node, which is normally the only conduction pathway
between the atria and ventricles.
Conduction through the atrioventricular node is slow, requiring about
0.15s. This delay provides time for atrial contraction to propel blood into
the ventricles.
