What is venticular left prominence?

Question

What is venticular left prominence?

Answer 1

Electrical forces generated during left ventricular activation ordinarily produce the normal QRS complex. With an increase in the thickness of left ventricular myocardium (left ventricular hypertrophy) as seen with systemic hypertension and left ventricular outflow obstruction, electrical preponderance of left ventricle over right ventricle is further accentuated. The mean vector of the left ventricle becomes more posterior and leftward, increasing QRS complex voltage and ventricular activation time.

Secondary ST and T wave abnormalities are not uncommon in the later stages of left ventricular hypertrophy. On voltage criteria alone, standards have been established for different leads. Left ventricular hypertrophy may be diagnosed in the extremity leads if the sum of the R wave in lead I and the S wave in lead III equals or exceeds 25mm. An R wave of 11 mm in aVL or 20 mm in aVF is considered high voltage and adequate for diagnosis of left ventricular hypertrophy in extremity leads. For precordial leads, an S wave in V1 exceeding 24 mm, an R wave in V5 or V6 exceeding 26 mm, or a sum of R wave in V5 or V6 and S wave in V2 of more than 35 mm are generally considered sufficient for diagnosis of left ventricular hypertrophy. The presence of ST depression and T wave inversion in the presence of adequate voltage criteria improves the diagnostic accuracy of left ventricular hypertrophy by ECG. Additional ECG clues to diagnosis of left ventricular hypertrophy are left axis deviation, increased QRS duration and the presence of left atrial enlargement. Due to the increased voltage of QRS complexes, many or all leads may have to be recorded at half the usual standardization scale of mV.