A three-month-old infant was taken to the consultation of his primary care pediatrician, because the mother reported that in the last days he had been tired and sudated a lot with the shots.
Pregnancy, delivery and neonatal period were normal, and there was no personal or family medical-surgical history of interest.
In the physical examination, the pediatrician found tachypnea with mild subcostal pull, oxygen saturation of 98% and a pansystolic murmur grade 3/6 audible in multiple foci of the left third intercostal space with maximum intensity.
After performing an electrocardiogram (ECG), the infant was referred to the hospital emergency department due to the suspected diagnosis.
1.
What is the interpretation of the ECG?
And the suspected diagnosis of the pediatrician? (review the ECG before reading again).
Sibling systematic reading, we observed a regular sinus rhythm (positive wave I and aVF) at 100 beats per minute, with no abnormalities in P wave or repolarization (segment ST).
The axis of the QRS complex is located around 60o (positive in I and in aVF, virtually isphasic with aVL), with a pattern of incomplete right bundle branch block (BIRD1: RS').
Attention is paid to QRS voltages in leads V5-V6.
At this point, it is important to thoroughly analyze all ECG details.
The habitual recording velocity consists of a 25 mm/second amplitude and a 10 mm/mV amplitude (the amplitude refers to the height and depth of the different waves).
In this case, velocity is the standard (composed on the right lower part of the ECG), but not amplitude.
Together with the place where the speed is indicated, "5 mm/mV" can be read, that is, each millivoltage (mV) is equivalent to 5 mm of the line, and not to 10 mm as usually
In other words, each millimeter measured with this fixation (5 mm/mV) shall be equal to twice the standard recording (10 mm/mV).
In the present case, we measured at V6 a 24 mm R wave, which in reality are 48 mm in view of reference values, and a 4 mm Q wave, which in fact constitute both ventricular hypertrophy limits 8 mm.
PR (0.11) and QTc (0.41) intervals are normal in duration, with no other pathological findings.
1.
The pediatrician urgently referred the patient with very good criteria, because he suffered congenital heart disease with left-right shunt and hemodynamic repercussions.
This presumption was confirmed when a broad muscular communication was diagnosed in the hospital by echocardiography.
