Question

Identify what colors corresponds to each lead placement P wave: 1. Indicates? 2. Normal interval: 3. Abnormal P waves indicates what disease process? QRS wave: 1. Indicates? 2. Normal interval: 3. Abnormal QRS waves indicates what disease process? T wave: 1. Indicates? 2. Normal interval: 3. Abnormal T waves indicates what disease process?

Answer 1

P wave

1. Indicates - Atrial depolarization (the P wave occurs when the sinus node, also known as sinoatrial node, creates an action potential that depolerize the atria. The P wave should be upright in lead 2 if the action potential is originating from the SAP node.

2.Normal interval - 0.12-2.0 seconds (80 milliseconds) .

3.*Left atrial enlargement

*Cardiovascular disease

*Right atrial enlargement

*Arrhythmia

*Atrial fibrillation

QRS wave

1. The QRS complex represents the electrical impulse as it spreads through the ventricles and indicates ventricular repolerization.

2.Normal interval - 0.8 and 0.10 seconds (80 and 100 milliseconds).

3.Tall QRS complex are usually caused by hypertrophy of one or both ventricles, or by an abnormal pacemaker or aberrantly conducted beat. Low voltage or abnormaly small QRS complex may be seen in obese patients, hyperthyroid patients and pleural effusion.

T wave

1. T wave indicates ventricular repolarization. It is typically much wider than the ventricular depolarization.

2.Normal interval - 160 milliseconds.

3. *Hyperkalemia - Hyperkalemia is a common cause of tall and peak T wave.

*Ischaemia - Myocardial ischemia is a common cause of inverted T wave.

*Left ventricular hypertrophy

*wellens syndrome

*Q wave and non Q wave MI (evolving anteroseptal MI)

*subacute or old pericarditis

*myocarditis

*Myocardial contusion (from trauma)

*CNS disease causing long QT inteval (especially subarrachnoid haemorrhage)

*Mitral valve prolapse

*Digoxin effect