Pediatric Cardiology CHD RT Board Review (PDF)

Pediatric Cardiology Judith Fatima E. Garcia, MD FPPS Asst. Professor, Department of Child health, FEU-NRMF Asst. Professor, School of respiratory therapy, FEU-NRMF This blood vessel carries deoxygenated blood: A. pulmonary artery B. u...

Pediatric Cardiology Judith Fatima E. Garcia, MD FPPS Asst. Professor, Department of Child health, FEU-NRMF Asst. Professor, School of respiratory therapy, FEU-NRMF This blood vessel carries deoxygenated blood: A. pulmonary artery B. umbilical vein C. aorta D. coronary arteries  In utero, fetal gas exchange takes place in the : A. fetal lungs B. mother’s lungs C. placenta Anatomic adaptations in the circulatory system present in-utero, except : A. ductus venosum B. umbilical vein C. ligamentum arteriosum D. foramen ovale  Always Remember : blood flows from high pressure to low pressure areas The higher the resistance, the higher the pressure and vise versa blood flows easily through areas with low resistance while flow is restricted or almost none at all in areas with high resistance the higher the resistance, the more work has to happen in the area proximal to the point of resistance in the heart : too much volume causes dilatation of the chamber working against a higher pressure causes muscle hypertrophy Persistent Pulmonary Hypertension ( Persistent Fetal Circulation) This is present in an infant with persistent pulmonary hypertension A. Right to left shunt B. left to right shunt  PPHN occurs in post-term, term and near terms, occasionally prematures characterized by severe hypoxemia without evidence of parenchymal lung disease or structural heart defect pulmonary vessels remain constricted in response to hypoxemia, acidosis, hypothermia and sepsis often seen in asphyxia or meconium-stained AF may be also seen in : congenital pneumonia,hyperviscosity- polycythemia, congenital diaphragmatic hernia, pulmonary hypoplasia, hypoglycemia, cyanotic congenital heart defect, RDS  PPHN Pulmonary vessels constrict increases resistance to blood flow to lungs blood flows via pathway of least resistance Right atrium Foramen Ovale Right Ventricle Left Atrium Pulmonary Artery Left Ventricle Ductus Arteriosus Aorta Deoxygenated blood enters arterial hypoxemia circulation perpetuates vasoconstriction & right to left shunt  Pathophysiology of PPHM 1. Increased, abnormal muscularization of the pulmonary arterioles prior to birth ( remodelling ) right to left shunt through the ductus arteriosus 2. Vasospasm and delayed relaxation of the pulmonary vasculature may be triggered and aggravated by hypoxemia, acidosis sepsis, polycythemia, possible hypothermia and associated lung diseases 3. Underdeveloped ( hypoplastic ) pulmonary vasculature because of decreased lung size ( pulmonary hypoplasia and congenital diaphragmatic hernia )  Diagnosis of PPHN 2D echocardiography : elevated PAP and sites of right to left shunts rule out structural heart defects and transient myocardial dysfunction  Treatment of PPHN General Supportive Care Correction of hypotension, anaemia and acidosis Management of complications associated with asphyxia Assisted Ventilation : most important therapy muscle relaxant may assist vigorous assisted ventilation If still unsuccessful , give nitric oxide ECMO Physiologic Classification of Congenital Heart Disease Cyanosis occurs in the presence of a: A. Left to Right Shunt B. Right to Left Shunt Acyanotic Congenital Heart Diseases Acyanotic CHD with Increased Pulmonary Blood Flow  Atrial Septal Defect persistent communication between the LA and RA more common in females ( 2:1 ), most common congenital heart disease diagnosed in adults LA pressure > RA pressure = L to R shunt  Clinical Manifestations of ASD related to the magnitude of the left to right shunt increased volume of blood in right heart ( systemic venous + Shunted blood ) enlargement of RA, RV and pulmonary arteries Atrial Septal Defect Murmur/ PE EKG Chest X-ray  Clinical Manifestations of ASD most do not manifest congestive heart failure precordial bulge, RV lift, Gr 2-3/6 systolic ejection murmur at the midsternal border classic wide and fixed S2 split  Diagnostic Tests CXR : cardiomegaly, RA, RV and MPA dilatation, increased pulmonary arterial markings, RVH EKG : right axis deviation and RVH Echocardiogram  Management Spontaneous Closure may occur. Surgical closure ( 1 year old ) : autologous pericardium closure, ASD closure devices implanted during cardiac catheterization. Infective endocarditis has not been reported in isolated ASD cases  Ventricular Septal Defect most common cardiac malformation The ratio of the pulmonary flow to the systemic flow ( QpQs ) estimates the volume of the left to right shunt ( > 1.5:1) 2 factors that determine the volume of the shunt size of the VSD pulmonary vascular resistance Ventricular Septal Defect Murmur/ PE EKG Chest X-ray  Clinical Manifestations of VSD small VSD : insignificant or small shunt - Asymptomatic moderate - large shunts: congestive heart failure, precordial bulge, Harrison’s groove, displaced apex beat failure to thrive Cardiac catheterization is reserved for cases with severe pulmonary hypertension and associated lesions not seen on 2D echo ( PAP and PVR ) Eisenmenger Syndrome : RV and PA pressure becomes equal or higher than the LV pressure causing reversed shunting from right to left resulting to cyanosis  Management of VSD Most VSDs specially the small ones close spontaneously during the 1st 2 years of life. ( highest during the 1st year ) Subpulmonic VSD should be closed surgically because of the risk for aortic insufficiency. Surgery also indicated for QpQs > 2:1, or less if with pulmonary hypertension Medical management for congestive heart failure  Patent Ductus Arteriosus ( PDA ) normal closure influenced by the increased in partial pressure of oxygen and the disappearance of the circulating prostaglandins ( esp PGE ) communication between the aorta and PA one of the more common CHDs, female: male ratio 2:1 maternal rubella causes PDA incidence increased by prematurity, perinatal asphyxia and high altitude  Patent Ductus Arteriosus ( PDA ) magnitude of the left to right shunt is dependent on the size of the ductus and the pulmonary vascular resistance large PDA and normal PP : shunt is high Pulmonary vascular disease and Eisenmenger syndrome occurs earlier because the lungs are exposed to the systemic pressure of the aorta Patent Ductus Arteriosus ( PDA ) Murmur/ PE EKG Chest X-ray  Clinical Manifestations of PDA Small PDA : tolerated well, no symptoms Medium to large PDA : congestive heart failure, failure to thrive, repeated pulmonary infections pulmonary vascular disease and Eisenmenger syndrome  Management of PDA Prematures : symptomatic PDA IV or oral indomethacin ( SE: bleeding and renal failure) ibuprofen, mefenamic acid and paracetamol Definitive Treatment : Surgical Ligation or transaction via thoracotomy Cardiac catheterization and occlusion device - now the Tx of choice surgery now reserved for prematures, large PDA ( > 12mm ), those with recalcitrant infective endarteritis Prognosis excellent Acyanotic CHD with Normal or Decreased Pulmonary Blood Flow  Coarctation of the Aorta ( CoA) localized narrowing of the aorta, 7%-8% of all CHD classified by its relation to the insertion of the ductus arteriosus most common associated with a PDA; more often in males ( 2:1); seen in 35% of Turner syndrome  Pathophysiology Neonate with PDA blood from RV enters descending aorta via the PDA lower oxygen saturation in the lower extremities, normal in upper extremities; pulses may be equal as long as RV pressure maintain near systemic pressure heart failure and pulmonary hypertension when ductus closes infant becomes acutely unwell  Pathophysiology blood flows from LV to the arch and thru the narrowing of the aorta ( TOLERATED UNTIL LATE CHILDHOOD ) LVH and increased LV pressure same as in vessel before constriction. Beyond constriction, BP and pulses are lower Collaterals develop over time  Clinical Manifestations of CoA most children are asymptomatic; though a frequent cause of heart failure in neonates if isolated : absent or diminished femoral pulses with systemic hypertension if with VSD or PDA : CHF, pulmonary edema, pulmonary hypertension and increased blood flow headache, epistaxis, cerebral haemorrhage SEM left upper sternal border and back  Diagnostics in CoA CXR : normal heart size ( 45%), slight to moderate enlargement (50%); notching of the ribs, E sign infants : enlarged heart with increased PVM EKG : normal or LVH; RVH may be seen in infants Cardiac Cath : elevated LVP and aortic pressure proximal to constriction  Management of CoA Infants with severe CoA : immediate surgery If well : elective surgery Surgical repair with use of prosthesis for aortoplasty, wide excision of the coarctated segment, and end-to-end anastomoses graft to connect the ascending and descending aorta bypassing the coarctation  Prognosis in CoA Infantile type : very poor Most do well during the 1st 2 decades but possible complications include IE, aortic rupture, hypertensive encephalitis, intracranial haemorrhage Cyanotic Congenital Heart Diseases Cyanotic Congenital Heart Diseases  Differential Diagnosis of Cyanotic CHD based on Pulmonary Blood Flow CYANOSIS Increased PBF Decreased PBF RVH BVH RVH LVH TGA Truncus TVA TAVPR arteriosus PVA with IVS TOF DORV DORV with PS HLHS Ebstein’s Anomaly PVA with ASD Cyanotic CHD with Increased Pulmonary Blood Flow  Transposition of the Great Arteries ( TGA / TGV ) one of the most common serious CHD occurs predominantly in males; IDM venous return to the heart is normal BUT aorta arises from the RV while the pulmonary artery arises from the LV systemic and pulmonary circulation running parallel NOT serial needs ASD or PFO, VSD, and PDA to survive RV high systolic pressure equal to aorta. LV systolic pressure equal to PAP  Clinical Features of TGA TGA with intact or nearly intact septum looks normal and well-developed at birth but rapidly progressive cyanosis noted in a few hours becomes severely hypoxemic and acidotic, may die  Clinical Features of TGA TGA with large PDA, combined PDA and VSD or large VSD mild cyanosis with signs of heart failure continuous murmur of PDA with bounding pulses to systolic murmur of VSD if with significant PS : severe cyanosis and SEM  Diagnostics in TGA CXR : increased PVM, enlarged heart due to increased volume, “ egg on side” appearance EKG : RAD, RVH ; those with large VSD - BVH Cardiac Catheterization: elevated RVP, oxygen saturation higher on PA than aorta egg on side  Management of TGA Initial treatment : IV prostaglandin E1 to maintain PDA Balloon atrial septostomy and palliation ( Rashkind Balloon thru PFO ) Definitive surgery : atrial switch procedure ( Senning or Mustard ) or arterial switch procedure ( Jatene ) *  Prognosis of TGA without surgery ; 51% die within the 1st month, 90% within the first year those with VSD or large PDA : early pulmonary vascular disease arterial switch : midterm survival good ; normal adolescence and adulthood expected  Total Anomalous Pulmonary Venous Return usually isolated, accounts for only 1% of CHD all the pulmonary veins enter the RA directly or through the systemic veins complete mixing of systemic and pulmonary venous return in the RA blood in the LA and LV comes from the right to left shunting across the PFO or ASD survival requires an interatrial communication severe obstruction to the venous blood to LA is a true cardiac emergency  Clinical Manifestations of TAPVR without venous obstruction : same as ASD RA, RV, and PA are dilated because of the increased volume if with adequate left to right shunt ( ASD / PFO ), mild cyanosis and PAP is normal. Pulmonary vascular disease occurs much later mild fatigue on feeding, tachypnea, clubbing  Clinical Manifestations of TAPVR with venous obstruction : severe pulmonary hypertension and congestion marked cyanosis from day 1 of life, respiratory distress and acidosis rales, peripheral edema and hepatomegaly  Diagnostics in TAPVR CXR: cardiac shadow : snowman or figure of 8 those without significant pulmonary hypertension - hyper vascular lungs, RAE, RVE and MPAE those with significant pulmonary hypertension near normal sized heart with marked venous congestion of lungs ( ground glass appearance ) EKG : RAH, RVH snow man sign / figure of 8  Management of TAPVR Surgery : definitive management large anastomoses between the pulmonary venous confluence and the LA with closure of the atrial defect. Closure of the communication between the PV and the RA  Prognosis of TAPVR residual stenosis after surgery : poor prognostic sign necessitating re-operation prognosis depends on the degree of pulmonary hypertension without : may survive through 2nd decade without significant symptoms with : die within the first few weeks or month if not operated upon on diagnosis  Hypoplastic Left Heart Syndrome ( HLHS) rare defect ( 1.4%-3.8%) but a major cause of mortality in the first few weeks of life more common in males left heart lesions which lead to the RV being the systemic ventricle and the systemic output is via the PDA  Pathophysiology of HLHS Varying degrees of underdevelopment of the mitral valve, aortic valve and proximal aorta hypoplasia of the LV severe stenosis or atresia of the AV and MV with intact ventricular septum Interatrial communication necessary for entry of pulmonary venous return from LA to RA complete mixing of all venous blood in RA RV takes over the role of systemic ventricle and systemic circulation is dependent on flow to descending aorta from the PDA. Retrograde flow to ascending aorta from coronaries  Clinical Manifestations of HLHS infants are severely ill after birth with signs of heart failure and low cardiac output Cyanosis may be milk with greyish pallor and poor pulses when the DA starts to constrict dyspnea, tachycardia and hepatomegaly, systolic murmur of TR Neonates will deteriorate rapidly to shock due to combination of PDA constriction, lowering of PVR and inadequate interatrial communication  Diagnostics in HLHS CXR : enlarged heart with increased PVM EKG : RVH with tall T waves due to RAE 2D ECHO : all the abnormalities seen  Management and Prognosis of HLHS rare to survive beyond the first week without intervention IV Prostaglandin E1 to keep the PDA open Surgery : heart transplantation or 3 stage operation Norwood, Sano, or hybrid procedure, cavopulmonary connection, and complete Fontan ) fetal aortic ballon valvuloplasty in midgestation Cyanotic CHD with Decreased Pulmonary Blood Flow  Tetralogy of Fallot accounts for at least 15% of all CHD and 30% of all cyanotic CHD ANATOMIC DEFECTS : 1. pulmonary stenosis 2. overriding of the aorta 3. VSD 4. RVH PHYSIOLOGIC DEFECTS : combination of VSD and PS. systemic Right ventricular pressure, and a shunt at the ventricular level predominantly or exclusively right to left  Clinical Manifestation of TOF onset of cyanosis is related to the severity of the PS rarely present at birth except when there is pulmonary atresia; usually manifest at 3-6 months Cyanosis appears or exaggerated with exercise, straining, crying, or manuevers that lover systemic vascular resistance favouring right to left shunt across the VSD Clubbing and polycythemia due to chronic systemic arterial desaturation  Clinical Manifestation of TOF growth and developmental retardation directly proportional to severity of cyanosis exercise intolerance or dyspnea on exertion at 6 months and correlates with degree of PS Squatting : assumes this position to alleviate cyanosis; increases SVR and decreases venous return to right side, favouring more blood flow to lungs and deceased right to left shunt across VSD  Clinical Manifestation of TOF precordial bulge, prominent RV heave along left sternal border, S1 normal, S2 single and loud ( aortic component only ) SEM at 3rd-4th ICS along left sternal border  Clinical Manifestation of TOF HYPOXIC SPELLS or TET Spells hyperpnea, restlessness, increasing cyanosis and later syncope or sometimes convulsions lasts for few minutes to hours, common in the morning upon waking up and after crying due to a further decreased in PBF resulting from lowering of the SVR or spasm of the RV outflow tract SEM disappears as blood flow to PA is almost cut off  Tet Spells SVR ( crying and defacation) RVOT obstruction infundibular spasm tachycardia R to L Shunting PBF pO2 Systemic Venous Return pH Systemic Vascular resistance pCO2 Hyperpnea or Hyperventilation  Diagnostics in TOF CXR : “ couer en sabot” / boot-shaped heart, PVM may be normal in mild PS, decreased in most cases, right sided aortic arch EKG: RVH, tall and peaked P wave, T waves upright on right chest leads  Management of Tet Spells RVOT obstruction SVR ( crying and defacation) infundibular spasm Propanolol tachycardia R to L Shunting Knee chest position PBF O2 pO2 NaHCO3 Systemic Venous Return pH Systemic Vascular resistance pCO2 MSo4 Vasoconstrictors Hyperpnea or Hyperventilation  Management of TOF Medical : Correct anemia Very high hematocrits may lead to hyperviscosity symptoms and thromboembolism : Phlebotomy Avoid dehydration IE prophylaxis; increased risk for brain abscess  Management of TOF Surgical Palliative Procedures : increasing the PBF modified Blalock-Thomas-Taussig shunt Complete Repair : open heart surgery  Pulmonary Atresia with Intact Ventricular Septum seen in < 1% of CHD; PA-dependent condition that presents as a neonatal emergency either a membranous imperforate PV or a long segment muscular atresia of the RV outflow tract hypoplastic RV with thick ventricular walls; TV size follows RV cavity size Pathophysiology of PA with intact ventricular septum RV pressure is usually suprasystemic because there is no VSD, associated PFO or ASD and PDA needed to survive RA pressure is elevated, obligatory right to left shunting at the atrial level. Systemic and pulmonary venous return combine in the LV and ejected into the aorta Pulmonary circulation and degree of cyanosis dependent on the size of the PDA  Clinical Manifestations of PA with IVS severe and progressive cyanosis as PDA constricts infant becomes tachypneic and acidotic S2 is single, no heart murmur in majority of patients Systolic murmur of TR or continuous murmur of PDA  Diagnostics in PA with IVS CXR: diminished PVM; cardiac size variable - normal when RV is small and LV not very dilated, may be big with prominent RA, dilated RV and LV EKG : LAD if with hypoplastic RV, tall P waves ( atrial enlargement ), LVH.  Management of PA with IVS Prostaglandin E1 infusion as soon as diagnosis is suspected If RV is tripartite and with imperforate valve and good sized branched PA : cardiac catheterization where PV is punctured and dilated with a balloon catheter and balloon atrial septostomy to enlarge the communication Open heart Surgery  Prognosis of PA without VSD without appropriate treatment : 50% die by the end of the 1st month, 85% by 6 months  Tricuspid Valve Atresia tricuspid valve either imperforate or absent so no connection between the RA and the RV Interatrial communication is mandatory for the systemic venous return to flow into LA and mix with the pulmonary venous return LV receives desaturated blood then some blood goes to the RV via VSD and into the PA, associated with different degrees of PS  Pathophysiology of TVA RAP is elevated and forces systemic venous blood into LA where there is complete mixing. Systemic arterial saturation depends on the presence of the shunt and the magnitude of the PBF Absence of an adequate sized VSD will lead to hypoplastic RV  Clinical Manifestations of TVA Cyanosis is the dominant finding especially when PBF is limited by severe PS or atresia If PBF is high : cyanosis minimal but with CHF when PVR drops to normal If small ASD or PFO : hepatomegaly and low cardiac output  Clinical Manifestations of TVA LV heave and thrill at lower left sternal border single 1st heart sound, S2 intensity depends on PA abnormality usually no murmur but if with VSD (+) loud holosystolic murmur. SEM at upper left sternal border if with PS; may have continuous murmur of PDA.  Diagnostics of TVA CXR: usually normal sized heart; mild to moderate cardiomegaly in those with increased PBF; RAE with decreased PVM in those with pulmonary obstruction EKG: LAD, LVH and biatrial hypertrophy is diagnostic  Management of TVA IV infusion of Prostaglandin E1 to maintain PDA Balloon atrial septostomy if interatrial defect is inadequate Palliative Surgery : Modified Blalock-Tomas-Taussig shunt or Glenn shunt if PBF is low; pulmonary artery banding if PBF is high Definitive Surgery : Fontan Operation  Prognosis of TVA Untreated patients die within the first 6 months from severe cyanosis or CHF Those with large septal defects and mild PS survive longer  Tachyarrhythmias heart rate is faster than what it should be relative to the patient’s activity  Tachyarrhythmias A. Supraventricular Tachycardia ( SVT ) B. Junctional Tachycardia C. Junctional Ectopic Tachycardia  Supraventricular Tachycardia Neonates : sustained HR > 220 beats/minutes Children: sustained HR > 180beats/minutes tall and narrow QRS complexes, P waves may absent since they merge with the T wave  Supraventricular Tachycardia Look for signs of shock perfusion, pulses, metabolic acidosis, blood pressure, respiratory compromised, altered level of consciousness  Supraventricular Tachycardia Causes ECTOPIC atrial form : a pacemaker other than the sinus node assumes the rhythm of the heart and has a faster intrinsic rate that the sinus node REENTRY : two routes of conduction from the atria to the ventricles 1. normal AV node -His-Purkinje system 2. accessory pathway seen in Wolff-Parkinson-White Syndrome  Supraventricular Tachycardia Treatment for Hemodynamically Stable Patients 1. Vagal manuevers Neonates Simulate gag, suction the nasopharynx, apply crushed to the nose and forehead area for 15 seconds or less if SVT stops Children and Adults Valsalva manuever Carotid Massage Swallowing cold water or immerse  Supraventricular Tachycardia Treatment for Hemodynamically Stable Patients 2. Intravenous Adenosine restores normal sinus rhythm by slowing AV nodal conduction and re-entry pathways Dose neonates : 100 mcg/kg rapid IV push for 1-2 seconds then normal saline flush. If no response in 2 minutes, increase by 50 mcg/kg increments every 2 minutes until a maximum dose of 250 mcg/kg is reached  Supraventricular Tachycardia Treatment for Hemodynamically Stable Patients 2. Intravenous Adenosine Dose children and adolescents : 1st dose : 0.1 mg/kg rapid bolus ( max 6 mg ) 2nd dose: 0.2 mg.kg rapid bolus ( max 12 mg) 3. If adenosine ineffective : synchronised cardioversion  Supraventricular Tachycardia Treatment for Hemodynamically Unstable Patients or Non- Responsive to Adenosine 3. Synchronized Cardioversion neonates : 0.5 joules / kg Older children and adolescents : 0.5 - 1 J/kg if not effective, increase to 2 J/kg Supraventricular Tachycardia Prevention 1. beta blockers : safest choice 2. calcium channel blockers 3. amiodarone 4. ablation of the atrial focus or the reentry circuit