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The preferred technique is the trans-oesophageal approach giving a view of 4 chambers. The normal thickness of a right ventricular free wall ranges from 2-5 millimetres, with a value above 5 mm considered to be hypertrophic. [10]
The electrical axis of the heart is the net direction in which the wave of depolarization travels. It is measured using an electrocardiogram (ECG).Normally, this begins at the sinoatrial node (SA node); from here the wave of depolarisation travels down to the apex of the heart.
Specifically, an increase in Q wave size, abnormalities in the P wave, as well as giant inverted T waves, are indicative of significant concentric hypertrophy. [13] Specific changes in repolarization and depolarization events are indicative of different underlying causes of hypertrophy and can assist in the appropriate management of the condition.
Normal T wave. In electrocardiography, the T wave represents the repolarization of the ventricles. The interval from the beginning of the QRS complex to the apex of the T wave is referred to as the absolute refractory period. The last half of the T wave is referred to as the relative refractory period or vulnerable period.
According to V. Gorshkov-Cantacuzene: "The U wave is the momentum carried by the blood in the coronary arteries and blood vessels". [4] [5] [6]The resistivity of stationary blood is expressed as () = | (+), where is a coefficient, and is the hematocrit; at that time, as during acceleration of the blood flow occurs a sharp decrease in the longitudinal resistance with small relaxation times.
It is normal to have a narrow QS and rSr' patterns in V 1, and this is also the case for qRs and R patterns in V 5 and V 6. The transition zone is where the QRS complex changes from predominantly negative to predominantly positive (R/S ratio becoming >1), and this usually occurs at V 3 or V 4 .
Schematic representation of normal ECG In electrocardiography , the ST segment connects the QRS complex and the T wave and has a duration of 0.005 to 0.150 sec (5 to 150 ms). It starts at the J point (junction between the QRS complex and ST segment) and ends at the beginning of the T wave.
The cardiac action potential has five phases. I to1 is active during phase 1, causing a fast repolarization of the action potential. The cardiac transient outward potassium current (referred to as I to1 or I to [1]) is one of the ion currents across the cell membrane of heart muscle cells.