Skip to main content

ELECTROCARDIOGRAPH

  Electrocardiograph (ECG) 



  1. You are probably familiar with this scene from a typical hospital television show:
  2. A patient is hooked up to a monitoring machine that shows voltage traces on a screen and makes the sound “... pip... pip... pip..... peeeeeeeeeeeeeeeeeeeeee” as the patient goes into cardiac arrest. 
  3. This type of machine (electro-cardiograph) is used to obtain an electrocardiogram (ECG). ECG is a graphical representation of the electrical activity of the heart during a cardiac cycle. 

  4. To obtain a standard ECG, a patient is connected to the machine with three electrical leads (one to each wrist and to the left ankle) that continuously monitor the heart activity. 
  5. For a detailed evaluation of the heart’s function, multiple leads are attached to the chest region. 
  6. Here, we will talk only about a standard ECG. 
  7. Each peak in the ECG is identified with a letter from P to T that corresponds to a specific electrical activity of the heart. 

  8. The P-wave represents the electrical excitation (or depolarisation) of the atria, which leads to the contraction of both the atria. 
  9. The QRS complex represents the depolarisation of the ventricles, which initiates the ventricular contraction. 
  10. The contraction starts shortly after Q and marks the beginning of the systole. 
  11. The T-wave represents the return of the ventricles from excited to normal state (repolarisation). 
  12. The end of the T-wave marks the end of systole. 
  13. Obviously, by counting the number of QRS complexes that occur in a given time period, one can determine the heart beat rate of an individual. 
  14. Since the ECGs obtained from different individuals have roughly the same shape for a given lead configuration, any deviation from this shape indicates a possible abnormality or disease. Hence, it is of a great clinical significance.

Labels:

Comments

Post a Comment

Popular posts from this blog

AIR POLLUTION

AIR POLLUTION   We are dependent on air for our respiratory needs.  Air pollutants cause injury to all living organisms.  They reduce growth and yield of crops and cause premature death of plants.  Air pollutants also deleteriously affect the respiratory system of humans and of animals.  Harmful effects depend on the concentration of pollutants, duration of exposure and the organism.  Smokestacks of thermal power plants, smelters and other industries release particulate and gaseous air pollutants together with harmless gases, such as nitrogen, oxygen, etc.  These pollutants must be separated/ filtered out before releasing the harmless gases into the atmosphere.  Electrostatic precipitator There are several ways of removing particulate matter; the most widely used of which is the electrostatic precipitator, which can remove over 99 per cent particulate matter present in the exhaust from a thermal power plant.  It has electrode wires that are m...
Post a Comment
Read more

HUMAN CIRCULATORY SYSTEM

😎 Human Circulatory System 😎 Human circulatory framework, additionally called the blood vascular framework comprises of a strong chambered heart, an organization of shut fanning veins and blood, the liquid which is circled.  Heart, the mesodermal determined organ, is arranged in the thoracic hole, in the middle of the two lungs, marginally inclined to one side. It has the size of a held clench hand. It is ensured by a twofold walled membranous sack, pericardium, encasing the pericardial liquid.  Our heart has four chambers, two moderately little upper chambers called atria and two bigger lower chambers called ventricles.  A slight, solid divider called the interatrial septum isolates the privilege and the left atria, while a thick-walled, the between ventricular septum, isolates the left and the correct ventricles.  The chamber and the ventricle of a similar side are likewise isolated by a thick stringy tissue called the atrio-ventricular septum.  Notwithstand...
3 comments
Read more

Digestive system

  DIGESTIVE SYSTEM 👉 This process of conversion of complex food substance to simple absorbable forms is known as DIGESTION.   👉 The alimentary canal opening the mouth and posterior/ending through the anus . MOUTH 👉 The mouth area is known as buccal cavity / oral cavity. 👉 The oral cavity has number of teeth and muscular tongue. 👉 Each tooth is embedded is a socket of jaw bone. This type of attachment is known as THECODONT. 👉 Majority mammals two set of teeth, set of milk/deciduous teeth replaced by a set of permanent/adult teeth . This is known as Diphyodont 👉 Adult human has 32 permanent teeth  which are 4 types Incisors (I), Canine (C), premolars (PM) and Molars (M). 👉 Dental formula 2123/2123 👉 The hard chewing surface of the teeth , made up enamel , helps in the mastication of food.  👉 The tongue is a freely movable muscular organ attached to the floor of the oral cavity by the frenulum .  👉 The upper surface of the tongue has small projec...
4 comments
Read more