Pacemakers give a BBB pattern and the pacing spike is usually visible. Pacemakers will only pace if the natural heart rate is too slow (usually <60bpm), so intermittent pacing is common. Left axis deviation occurs if lead I is positive and II is negative. Right axis deviation is negative in I and positive in II. Left axis deviation may occur in left ventricular hypertrophy (LVH), along with ST depression in lateral leads. Right axis deviation occurs in situations where there is right heart strain, such as pulmonary embolisms and atrial septal defect. An ECG lead is a graphical representation of the heart’s electrical activity which is calculated by analysing data from several ECG electrodes. The cardiac axis gives us an idea of the overall direction of electrical activity. ECG leads Normal cardiac axis Follow ACLS protocol for administration of atropine for symptoms of low cardiac output, dizziness, weakness, altered LOC, or low blood pressure.

Tall complexes imply ventricular hypertrophy (although can be due to body habitus e.g. tall slim people). There are numerous algorithms for measuring LVH, such as the Sokolow-Lyon index or the Cornell index. It is important to determine if a heart rate is regular or irregular. A regular heart rhythm has all of the aspects previously discussed. How do you know when you need to act immediately or can wait for expert consultation? Here are seven tips to help you gain confidence in interpreting what you see. 1. Assess Your Patient A narrow QRS complex occurs when the impulse is conducted down the bundle of His and the Purkinje fibre to the ventricles. This results in well organised synchronised ventricular depolarisation.When the electrical activity within the heart travels away from a lead, you get a negative deflection.

The deflection height represents the amount of electrical activity flowing in that direction (i.e. the higher the deflection, the greater the amount of electrical activity flowing towards the lead). The twelve leads show the electrical current through the heart from different planes. Think of each lead as a different snapshot of the heart you are trying to interpret. ECG is the abbreviated term for an electrocardiogram. It is used to record the electrical activity of the heart from different angles to both identify and locate pathology. Electrodes are placed on different parts of a patient’s limbs and chest to record the electrical activity. When it comes to heart function, the view (lead) you are looking at will determine which part of the heart you are trying to interpret. This is especially important when analyzing ST segment abnormalities. The location of the infarct determines what treatment should be used to improve oxygenation to the heart to minimize damage.The ST segment is an isoelectric line representing the time between depolarisation and repolarisation of the ventricles (i.e. ventricular contraction). T wave A 12-lead EKG is considered the gold standard; however, a 4-lead EKG can also diagnose different heart conditions. Rhythm can be difficult to assess especially in bradycardia or tachycardia. It may be helpful to use the ‘paper test’.

Don’t sweat all the complex details when you are first beginning to read and interpret EKGs. A normal heart rhythm contains a P wave, a QRS, and a T wave.³ Knowing the normal amplitude, deflection, and duration of each component is essential to accurate rhythm and EKG/ECG interpretation. High-takeoff is where there is widespread concave ST elevation, often with a slurring of the j-point (start of the ST segment). It is most prominent in leads V2-5, is usually in young health people and is benign. An ECG lead is a graphical representation of the heart’s electrical activity calculated by analysing data from several ECG electrodes. Chest leadsThe QRS may be small (or low voltage) in pericardial effusion, high BMI, emphysema, cardiomyopathy and cardiac amyloid. Benign early repolarisation occurs mostly under the age of 50 (over the age of 50, ischaemia is more common and should be suspected first). Isolated ventricular ectopic beats are common and do not usually need specific treatment. Patients often complain they keep 'missing a beat' followed by a heavy heartbeat. They usually notice this when resting and it is a good sign if it disappears during activity.

The lead with the most positive deflection is most aligned with the direction the heart’s electrical activity is travelling. As with all investigations the most important things are your findings on history, examination and basic observations. Having a good system will avoid making errors. A q-wave is an initial downward deflection in the QRS complex. These are normal in left-sided chest leads (V5, 6, lead I, aVL) as they represent septal depolarization from left to right. This is as long as they are <0.04secs long (1 small square) and <2mm deep. When confronted with an ECG it is best to start with the basics: rate, rhythm and axis. Then consider the PQRST complexes in all the leads with some basic questions in mind: After determining this, next decide if your rhythm is fast or slow, irregular or regular (more on this in the next section).The second part explains the theory underpinning the recording of an ECG to begin a basic interpretation of the 12 leads. A long QTc interval (known as “long QT”) is especially important to identify in patients with a history of collapse or transient loss of consciousness. A new opening chapter entitled ‘ The ECG made very easy ’ refines the simple essentials of using an ECG in clinical practice with minimum theory and maximum practicality.