>> I WORKED AT CHOP FOR 15 YEARS IN THE ECHO LAB,
AND WE WERE JUST FOOLING AROUND,
SCANNING THE BABY.
AND THE FETAL HEART TECHNICIAN,
SHE ACTUALLY CAUGHT THIS LESION WHEN I WAS 15 WEEKS
PREGNANT.
AND IN MY FAMILY HISTORY, THERE'S SOME HEART DISEASE,
SO THEY WANTED TO WATCH.
AND ABOUT AT 20 WEEKS, THEY TOLD ME THEY SUSPECTED
THAT HE WAS TETRALOGY.
I WAS OKAY.
OF COURSE, I WAS CONCERNED AND NERVOUS,
BUT I KNEW WHERE I WAS AND THAT HE WOULD BE TAKEN CARE OF.
>> ALL OF HEART SURGERY IS 50 YEARS OLD,
AND WE'VE COME FROM A SITUATION OF BEING ABLE TO
TREAT NOTHING TO BEING ABLE TO AT LEAST DEAL WITH MOST,
IF NOT THE VAST MAJORITY OF, CONGENITAL HEART DEFECTS IN
A WAY THAT ALLOWS CHILDREN TO GROW INTO ADULTHOOD.
>> WE LIVE IN AN ERA WHERE THERE ARE VERY FEW THINGS
THAT WE REALLY CAN'T TAKE CARE OF.
>> TETRALOGY OF FALLOT WAS ONE OF THE FIRST SIGNIFICANT
CONGENITAL HEART DEFECTS TO BE ADDRESSED SURGICALLY.
>> THE FIRST SUCCESSFUL OPERATION WAS DONE
IN THE MID-1940S AT JOHNS HOPKINS.
>> SO THERE ARE MANY PEOPLE OUT THERE NOW WITH TETRALOGY
OF FALLOT WHO ARE IN THEIR 30S,
40S, 50S, HAD CHILDREN OF THEIR OWN,
WHO ARE DOING FINE, WHO HAVE HAD REPAIRS OF THAT
PARTICULAR HEART DEFECT.
>> TETRALOGY OF FALLOT IS A FORM OF CONGENITAL HEART
DISEASE INITIALLY DESCRIBED BY ETIENNE FALLOT,
WHO WAS A FRENCH PATHOLOGIST IN THE MID-1800S.
HE IDENTIFIED FOUR SPECIFIC ASSOCIATED FEATURES WITH
THIS PARTICULAR FORM OF CONGENITAL HEART DISEASE.
>> THE MOST IMPORTANT FEATURES ARE THAT THERE'S
A VENTRICULAR SEPTAL DEFECT, OR A HOLE BETWEEN THE TWO
PUMPING CHAMBERS OF THE HEART,
AND BLOCKAGE OF BLOOD FLOW GETTING OUT TO THE LUNGS.
IN SOME CHILDREN THERE'S ALMOST NO BLOCKAGE AND THEY
CAN ACTUALLY HAVE TOO MUCH BLOOD FLOW TO THE LUNGS.
IN OTHER CHILDREN THE BLOCKAGE CAN BE SO SEVERE
THAT THERE'S NOT ENOUGH BLOOD FLOW AND THEY'RE VERY
SICK AFTER BIRTH.
AND SOMETIMES THERE'S A COMPLETE BLOCKAGE,
OR WHAT'S CALLED PULMONARY ATRESIA.
>> IN ORDER TO UNDERSTAND AND TO COMPREHEND ANY
OF THE DIFFERENT FORMS OF HEART DISEASE THAT EXIST,
IT'S VERY IMPORTANT TO MAKE SURE WE UNDERSTAND WHAT
THE HEALTHY OR THE NORMAL HEART LOOKS LIKE.
THE NORMAL HEART HAS TWO SIDES,
A RIGHT SIDE AND A LEFT SIDE,
AND FOUR CHAMBERS, THE TOP RECEIVING CHAMBERS,
OR ATRIUM, AND THE LOWER CHAMBERS,
WHICH ARE THICK-WALLED PUMPING CHAMBERS
CALLED VENTRICLES.
RED BLOOD CELL WILL COME FROM EITHER THE SUPERIOR
VENA CAVA OR THE INFERIOR VENA CAVA AND ENTER
INTO THE RIGHT ATRIUM.
THE BLOOD THEN FLOWS ACROSS THE TRICUSPID VALVE
TO THE RIGHT VENTRICLE.
THE RIGHT VENTRICLE THEN SQUEEZES AND EJECTS THAT
BLOOD CELL INTO A VESSEL CALLED THE PULMONARY ARTERY.
THE PULMONARY ARTERY SPLITS INTO TWO VESSELS,
EACH GOING TO THE LUNGS.
AS THAT RED BLOOD CELL MAKES ITS WAY THROUGH THE LUNG,
IT RETURNS THROUGH THE PULMONARY VEINS
TO THE LEFT ATRIUM.
THAT BLOOD IS NOW OXYGENATED.
IT'S PICKED UP OXYGEN, THEN GOES ACROSS THE MITRAL VALVE
INTO THE LEFT VENTRICLE, WHICH DOES MOST OF THE WORK
IN TERMS OF DELIVERY OF BLOOD FLOW TO THE BODY.
THAT BLOOD CELL IS NOW EJECTED INTO THE AORTA
TO SOME ORGAN OR MUSCLE OR SKIN IN THE HUMAN BODY.
NOW, THERE ARE SOME SIGNIFICANT DIFFERENCES
BETWEEN THE HEART IN THE NEWBORN AND THE HEART
IN THE FETUS.
>> THE HEART ACTUALLY IS-- ASSUMES ITS ALMOST
COMPLETE ANATOMY OFTEN BEFORE A WOMAN WOULD EVEN
KNOW SHE WAS PREGNANT.
>> THE HEART IS ACTUALLY FUNCTIONING AND PUMPING
BLOOD TO THE BABY THROUGHOUT MOST OF FETAL LIFE.
>> BECAUSE THE LUNGS ARE COLLAPSED IN THE FETUS
AND IT'S REALLY THE PLACENTA THROUGH WHICH MUCH
OF THE OXYGENATION TAKES PLACE THROUGH THE MOTHER,
THERE ARE VARIOUS BYPASS PATHWAYS WITHIN THE FETAL
HEART THAT DIRECT BLOOD AWAY FROM THE LUNG.
THE FIRST IS A STRUCTURE CALLED THE FORAMEN OVALE.
THAT'S COMMUNICATION BETWEEN THE TWO TOP CHAMBERS
OF THE HEART THAT ALLOWS FOR BLOOD TO GO FROM
THE RIGHT ATRIUM TO THE LEFT ATRIUM.
IN FACT, BECAUSE THERE IS VERY LITTLE BLOOD THAT'S
RETURNING FROM THE LUNG WHICH WOULD NORMALLY GO TO
THE LEFT SIDE, THE MAJORITY OF BLOOD THAT FILLS THE LEFT
ATRIUM AND LEFT VENTRICLE IS COMING ACROSS THE FORAMEN
OVALE FROM THE RIGHT SIDE.
BECAUSE THE LUNGS ARE COLLAPSED,
THERE'S HIGH PRESSURE, HIGH RESISTANCE IN THE LUNGS.
AS BLOOD IS EJECTED OUT THE RIGHT VENTRICLE AND ENTERS
INTO THE MAIN PULMONARY ARTERY,
VERY LITTLE GOES DOWN INTO THE LUNGS THEMSELVES.
THE MAJORITY GOES INTO A STRUCTURE CALLED THE DUCTUS
ARTERIOSUS, WHICH IS THE SECOND IMPORTANT
COMMUNICATION BETWEEN THE PULMONARY ARTERY
AND THE DESCENDING AORTA.
THE THIRD STRUCTURE THAT'S IMPORTANT THAT CONNECTS
THE UMBILICAL VEIN TO THE FETAL CIRCULATION IS A SITE,
A JUNCTION, CALLED THE DUCTUS VENOSUS.
THAT ACTS AS SOMEWHAT OF A RESISTER,
IF YOU WILL, IN TERMS OF CONTROLLING THE RETURN
OF BLOOD FROM THE PLACENTA TO THE FETAL CIRCULATION.
BIRTH IS A WONDERFUL PROCESS AND AN AMAZING PROCESS,
AND THERE'S A DRAMATIC CHANGE THAT TAKES PLACE
IN WHAT WE CALL THE FETAL TRANSITION,
THIS TRANSITION OF THE CIRCULATION FROM FETAL LIFE
TO NEONATAL LIFE.
AS SOON AS THE CORD IS CLAMPED,
THE DUCTUS VENOSUS CEASES TO CARRY BLOOD TO THE HEART,
AND IT BEGINS TO CONSTRICT WITHIN THE FIRST FEW HOURS
OR DAYS OF LIFE.
THE VERY FIRST THING THAT HAPPENS WHEN A FETUS IS BORN
IS IT TAKES ITS FIRST BREATH,
THE LUNGS EXPAND, AND SO THE RESISTANCE OR PRESSURE
IN THE LUNGS DROP, AND THAT PROMOTES BLOOD FLOW
INTO THE LUNG ITSELF.
THE DUCTUS ARTERIOSUS BEGINS TO CONSTRICT
AND IS TYPICALLY FULLY CLOSED WITHIN 24 TO 48 HOURS
OF LIFE, AND BLOOD IS NOW THEN FULLY DIRECTED INTO THE LUNG.
AS THE BLOOD RETURNS TO THE LEFT SIDE OF THE HEART,
AFTER TRAVERSING THE PULMONARY CIRCULATION
AND PICKING UP OXYGEN, THE PRESSURE IN THE LEFT ATRIUM
RISES JUST A BIT, AND THE TRAP DOOR OF THE FORAMEN
OVALE, WHICH WAS OPEN BEFORE BIRTH,
NOW BEGINS TO CLOSE, USUALLY WITHIN THE FIRST FEW DAYS
OF LIFE.