Cardiac Emergencies in Infants Michael Luceri, DO October 7, 2017
I have no financial obligations or conflicts of interest to disclose.
Objectives Understand the scope of congenital heart disease Recognize the presentation of a critically ill neonate Categorize the disease to facilitate its treatment
Background Congenital heart defect (CHD) A gross structural abnormality of the heart or intrathoracic great vessels that is actually or potentially of functional significance Mitchell, et al (Circulation, 1971) 8-10/1000 live births, ~1% About half require an intervention Recent increased detection
Total CHD Birth Prevalence Over Time Time course of reported total congenital heart disease (CHD) birth prevalence from 1930 until 2010. The blue line shows the time trend, and the squares represent the calculated birth prevalence values for each time period. Birth Prevalence of Congenital Heart Disease Worldwide: A Systematic Review and Meta-Analysis J Am Coll Cardiol. 2011;58(21):2241-2247. doi:10.1016/j.jacc.2011.08.025
Congenital Heart Defects Recent increased detection Improvements in echocardiography Doppler Fetal echocardiography Transesophageal echocardiography 3D echocardiography Advanced non-invasive imaging CT MRI No increase in disease severity!!!
Birth Prevalence of CHD Subtypes Over Time Time course of birth prevalence of the 8 most common CHD subtypes from 1945 until 2010. AoS = aortic stenosis; ASD = atrial septal defect; Coarc = coarctation; PDA = patent ductus arteriosus; PS = pulmonary stenosis; TGA = transposition of the great arteries; TOF = tetralogy of Fallot; VSD = ventricular septal defect. Birth Prevalence of Congenital Heart Disease Worldwide: A Systematic Review and Meta-Analysis J Am Coll Cardiol. 2011;58(21):2241-2247. doi:10.1016/j.jacc.2011.08.025
Birth Prevalence of CHD Subtypes Reported birth prevalence of the 8 most common CHD subtypes per continent. Distribution of subtypes within total CHD is mentioned as percentages above bars. *Reported PS and TOF birth prevalence in Asia was significantly higher than in Europe (p < 0.001) and North America (p < 0.001). Reported Coarc birth prevalence in Asia was significantly lower than in Europe (p < 0.001). Reported TGA and AoS birth prevalence in Asia was significantly lower than in Europe (p < 0.001), North America (p < 0.001) and Oceania (p < 0.001). No data on TOF and AoS birth prevalence in Africa were available. Abbreviations as in Figure 4. Birth Prevalence of Congenital Heart Disease Worldwide: A Systematic Review and Meta-Analysis J Am Coll Cardiol. 2011;58(21):2241-2247. doi:10.1016/j.jacc.2011.08.025
Circulation Fetal circulation Fetal lungs collapsed, alveoli filled with fluid High pulmonary vascular resistance (PVR), thus minimal pulmonary blood flow (Qp) Ohm s Law: V = I R (Voltage = Flow Resistance) In hemodynamics: Pressure (gradient) = Flow Resistance Flow = Pressure/Resistance Oxygenation from placenta via umbilical vein PFO & PDA shunt R L
Normal Heart
Normal Heart w/pda
Circulation Neonatal circulation Hormones of labor cease production of lung liquid i.e. Epinephrine, vasopressin, cortisol, etc. First breath and lung expansion Remaining liquid absorbed PVR decreases Qp increases Functional closure of PFO & PDA Now pulmonary & systemic circulation in series!
Circulation Certain lesions can interrupt serial blood flow: i.e. TOF, aortic stenosis, coarctation Transposition of the great arteries (TGA) Newborn then depends on the presence of a shunt Balloon atrial septostomy
Balloon Atrial Septostomy First interventional procedure: Rashkind Septostomy (1966) No animal studies Prone to material embolization
Circulation Certain lesions can interrupt serial blood flow: i.e. TOF, aortic stenosis, coarctation Transposition of the great arteries (TGA) Newborn then depends on the presence of a shunt Balloon atrial septostomy Prostagladins!!! Very forgiving, almost foolproof! When in doubt, try it out! Usually 0.01 mcg/kg/min works, can go up to 0.1 mcg/kg/min Watch for fever (14%), apnea (12%), and flushing (10%)
Presentation Varies dependent upon cardiac lesion, though can include: Cyanosis Peripheral/Acrocyanosis: common and benign Central: always pathologic Incomplete oxygenation in the lung Abnormal hemoglobin Intracardiac shunting Hyperoxia Test: Measure pre-ductal (RUE) P A O 2 in room air Measure again after 5-10 minutes of 100% FiO 2 Strongly consider cyanotic heart disease if P A O 2 is <150 mmhg Caveat #1: PPHN may also have P A O 2 <150 mmhg! Caveat #2: Hyperoxia can close a PDA that might be needed!
Presentation Varies dependent upon cardiac lesion, though can include: Murmur Tachycardia Respiratory distress Tachypnea, retractions Poor feeding and/or inadequate weight gain Irritability or sweating with feeds Shock Gallop, HSM, poor capillary refill, pallor, weak pulses
Classification Transposition of the great arteries Obstructed systemic perfusion Obstructed pulmonary blood flow Single ventricle lesions Heart failure
Transposition of the Great Arteries (TGA) 5-7% of all CHD Male/female ratio ~3:1 Blood must mix via ASD, VSD, or PDA
Transposition of the Great Arteries (TGA) Presentation 1 day old term male infant with poor feeding & severe cyanosis PE: tachypneic, symmetric pulses, single S2, no murmur, no HSM Reverse differential cyanosis ECG: RVH (normal) CXR: normal cardiac size, increased pulmonary vascularity Hyperoxia Test: P A O 2 = 42 mmhg on 100% FiO 2 Treatment Cath: Emergent balloon atrial septostomy Surgical repair: Atrial vs Arterial Switch
Transposition of the Great Arteries (TGA) Mustard ( Atrial Switch )
Transposition of the Great Arteries (TGA) Jatene Procedure ( Arterial Switch )
Classification Transposition of the great arteries Obstructed systemic perfusion Obstructed pulmonary blood flow Single ventricle lesions Heart failure
Obstructed systemic perfusion Examples include: Coarctation of the aorta
Obstructed systemic perfusion Examples include: Critical aortic stenosis
Obstructed systemic perfusion Examples include: Interrupted aortic arch
Obstructed systemic perfusion Systemic flow is critically compromised when PDA closes If untreated, will lead to shock and eventually death Ductal-dependent PDA will allow for right to left shunting
Obstructed systemic perfusion Presentation 3 day old term infant acutely develops feeding and breathing difficulties PE: tachypneic, tachycardic, murmur, gallop, HSM, poor capillary refill and pulses Dusky appearance ECG: RVH CXR: cardiomegaly, increased pulmonary vascularity Hyperoxia Test: P A O 2 = 180 mmhg on 100% FiO 2 Treatment Rx: PGE1 infusion; inotropic support; NO Afterload Reduction! Eventual catheter-based and/or surgical intervention
Classification Transposition of the great arteries Obstructed systemic perfusion Obstructed pulmonary blood flow Single ventricle lesions Heart failure
Obstructed pulmonary blood flow Examples include: Tetralogy of Fallot
Obstructed pulmonary blood flow Examples include: Critical pulmonic stenosis
Obstructed pulmonary blood flow Acute and marked cyanosis May have adequate perfusion initially (especially if atrial level communication) Severe cyanosis can induce shock due to limited systemic O2 delivery that alters myocardial function Ductal-dependent PDA will allow for left to right shunting
Obstructed pulmonary blood flow Presentation 1 day old term infant initially feeds well and appears healthy, then acutely becomes cyanotic PE: tachypneic, increased work of breathing, tachycardic, murmur Severely cyanotic ECG: RVH CXR: decreased pulmonary vascularity Hyperoxia Test: P A O 2 = 30 mmhg on 100% FiO 2 Treatment Rx: PGE1 infusion; sedation, preload, B-blockers, phenylephrine, Avoid inotropes! Eventual catheter-based and/or surgical intervention
Classification Transposition of the great arteries Obstructed systemic perfusion Obstructed pulmonary blood flow Single ventricle lesions Heart failure
Single ventricle lesions Examples include: Tricuspid atresia
Single ventricle lesions Examples include: Hypoplastic left heart syndrome
Single ventricle lesions Initial presentation as glorified ductal-dependent lesions Tricuspid Atresia*: Ductal-dependent pulmonary circulation HLHS: Ductal-dependent systemic circulation Small/underdeveloped ventricle cannot serve as a functional pumping chamber Must undergo staged repair culminating in a Fontan circulation * Assuming normally related great vessels
Single ventricle lesions Presentation Rapid onset with ductal closure Often no murmur! Ductal-dependent systemic circulation Reduced cardiac output Metabolic acidosis Profound shock Respiratory failure Ductal-dependent pulmonary circulation Profound cyanosis ECG & CXR: Variable Hyperoxia Test: P A O 2 < 150 mmhg on 100% FiO 2
Single ventricle lesions Treatment Rx: PGE1 infusion! Manipulate SVR with systemic vasodilators i.e. Milrinone and Nipride Manipulate PVR with ventilatory strategies Hypoxic gas admixture (FiO 2 18%) Controlled respiratory acidosis Optimize hematocrit Eventual catheter-based and/or surgical intervention
Stage 1: Norwood Procedure with Blalock- Taussig (BT) Shunt or Sano (RV-PA) Conduit
Stage 2: Glenn Procedure SVC connected to pulmonary arteries
Stage 3: Fontan Procedure IVC connected to pulmonary arteries
Classification Transposition of the great arteries Obstructed systemic perfusion Obstructed pulmonary blood flow Single ventricle lesions Heart failure Volume overload
Heart failure: volume overload Examples include: Ventricular septal defect
Heart failure: volume overload Examples include: Atrioventricular septal defect
Heart failure: volume overload Examples include: Patent ductus arteriosus
Heart failure: volume overload Left to right shunting results in pulmonary overcirculation Wasted of ineffective blood flow Degree of shunting depends on PVR/SVR ratio
Heart failure: volume overload Presentation 3 month old infant with chronic feeding difficulties, failure to thrive, history of respiratory difficulties/pneumonia PE: tachypneic, retractions, single loud S2, murmur, HSM, symmetric pulses ECG: Biventricular hypertrophy CXR: cardiomegaly, hyperinflation, congestion, increased pulmonary vascularity
Heart failure: volume overload
Heart failure: volume overload Treatment Diuretics Inotropic support Optimize O 2 carrying capacity Manipulate PVR/SVR ratio Systemic vasodilators (i.e. ACE-inhibitors) Optimize hemoglobin to balance circulation Ventilatory strategies to increase PVR Eventual catheter-based and/or surgical intervention
Ventilatory strategies to manipulate Qp/Qs ratio Treatment PVR SVR Qp/Qs Ratio Reduce FiO 2 Increase Decrease Decrease Increase CO 2 Increase Decrease Decrease Reduce ph Increase Decrease Decrease PEEP Increase Decrease Decrease
Summary Congenital heart disease is relatively common Cardiac emergencies are rare Recognize symptoms early and keep a high index of suspicion Attempt to categorize the suspected lesion according to presentation and testing results When in doubt, start PGE1 infusion!
Questions? michael.luceri@nemours.org