Pediatric Cardiac Acute Care Handbook, Study notes of Animal Anatomy and Physiology

Download Pediatric Cardiac Acute Care Handbook and more Study notes Animal Anatomy and Physiology in PDF only on Docsity!

Pediatric Cardiac Acute Care Handbook

Edition 2 (2018-2019)

Compiled by:

Alaina K. Kipps, MD, MS; Inger Olson, MD; Neha Purkey, MD; Charitha Reddy, MD

I. General Principles of Cardiology

a. Cardiac Anatomy…………………………………………………………………….

b. History and Physical……………………………………………………………….. 6

c. Cardiac Catheterization………………………………..………………………..1 0

d. Echocardiography…………………………………………………………………..1 4

II. Common Complaints in Cardiology

a. Murmurs……………………………………………………………………………….. 25

b. Chest Pain……………………………………………………………………………... 28

c. Syncope…………………………………………………………………………………. 30

d. Preventative Cardiology…………………………………………………………. 32

III. EKG Interpretation and Common Arrhythmias

a. EKG Reading……………………………………………………………………….…. 34

b. Arrhythmia Algorithm……………………………………………………………. 42

c. Common Arrhythmias………………………………………………………….... 45

IV. Congenital Heart Disease

a. Neonatal Presentation of CHD……………………………………………….. 64

V. Acyanotic Lesions

a. ASD…………………………………………………………………………………..…….. 68

b. VSD………………………………………………………………………………..……... 71

c. AVSD………………………………………………………………………………..…….. 74

d. PDA………………………………………………………………………………..………. 77

e. Ebstein Anomaly……………………………………………………………..…….. 81

f. Bicuspid Aortic Valve…….………………………………………………….…….. 84

g. Aortic Stenosis…………………………………………………………..…….…... 86

h. Pulmonary Stenosis……………………………………..............……………..8 9

i. Coarctation…………….………………………………..............…………...……. 92 j. Interrupted Aortic Arch……………………………..............………………. 95

Cardiac Anatomy: Learning the Language

• In congenital heart disease, the heart can be located anywhere in the chest, and the components of the heart can be arranged in a number of different ways.
• “Right” and “left” do not refer to the side of to the body, but to specific anatomic criteria that identify different components of the heart.

Cardiac Position

• Levocardia: heart is in the left chest, apex points leftward (normal position)
• Mesocardia: heart in the midline, apex points inferiorly
• Dextro cardia : heart in the right chest, apex points rightward
• Dextro position : heart in the right chest, with apex pointing leftward
• Dextro rotation : heart in the left chest, apex rotated rightward
• Ectopia cordis: heart partially or completely outside of the chest/sternum

The Main Chambers of the Heart

Netter’s Correlative Imaging: Cardiothoracic Anatomy

Right Atrium: receives the SVC, IVC and coronary sinus, limbus of fossa ovalis present

• Broad-based, triangular appendage with pectinate muscles that extend into the right atrial body
• Crista terminalis present

Left Atrium: receives the pulmonary veins (but this is not a defining feature)

• Narrow-based, thin, finger-like appendage with pectinate muscles that are confined to the appendage
• Visible attachments of septum primum to septum secundum

Right Ventricle:

• Coarse trabeculae with a prominent septal band, parietal band and moderator band
• Septo philic attachments of the tricuspid valve (attaches to the septum and free wall)
• Well-developed infundibulum (or conus) – the muscle underneath the semilunar valve, which results in lack of fibrous continuity between the tricuspid and semilunar valves
• The tricuspid valve always belongs to the right ventricle

Left Ventricle:

• Smooth septal surface with fine trabeculae
• Septo phobic attachments of the mitral valve (attaches only to the free wall)
• No infundibulum under the semilunar valve, so there is fibrous continuity between the mitral and semilunar valves

Right hand fits in the right ventricle = D-loop www.pedscards.com

3 rd^ letter, {X,X,__}: Great Arteries = the relative position of the semilunar valves to each other

• Solitus (S): normal anatomy with aortic valve posterior and to the right of the pulmonary valve
• Inversus (I): mirror image with aortic valve posterior and to the left of the pulmonary valve
• D-malposition (D): aortic valve is anterior and to the right of the pulmonary valve
• L-malposition (L): aortic valve is anterior and to the left of the pulmonary valve
• Anterior (A): aortic valve is directly anterior to the pulmonary valve
• Posterior (P): aortic valve is directly posterior to the pulmonary valve

www.pedscards.com

If the anatomy of a segment cannot be determined, then an “X” is used for that segment. The connecting segments and ventriculo-arterial connections are described separately.

The Andersonian Approach to Cardiac Anatomy A different approach to describing cardiac anatomy was championed by Dr. Bob Anderson. If the right atrium connects to the right ventricle, and the left atrium connects to the left ventricle, this is described as atrioventricular concordance. If the pulmonary artery arises from the right ventricle and the aorta arises from the left ventricle, this is described as ventriculoarterial concordance. If the right atrium

connects to the left ventricle, this is termed atrioventricular discordance. If the pulmonary artery arises from the left ventricle, this is termed ventriculoarterial discordance.

Questions

• What are the anatomic features of the tricuspid and mitral valves?
• What are the anatomic features of the semilunar valves?
• What is the anatomic relationship of the systemic arteries?
• Describe normal branching of the aortic arch.

Resources Anderson RH, Becker AE, Freedom RM, et al. Sequential segmental analysis of congenital heart disease. Pediatric Cardiology 1984; 5(4): 281-287. Edwards WD, Maleszewski JJ. Cardiac Anatomy and Examination of Cardiac Specimens. In: Allen HD, Driscoll DJ, Shaddy RE, Feltes TF, 8th, editors. Moss and Adams’ Heart Disease in Infants, Children, and Adolescents: Including the Fetus and Young Adult. Philadelphia: Lippincott Williams & Wilkins; 2013. p.1-31. Van Praagh R. Terminology of congenital heart disease: Glossary and commentary. Circulation 1977; 56:139-143.

the right ventricle to take longer to empty, and the pulmonary valve to take longer to close. To say the “S2 is normal” is to say you heard this variable splitting!! o A loud S2 is likely from early closure of the pulmonary valve and may suggest pulmonary artery hypertension.

• S3 gallop: “Kentucky” o Heard early in diastole during rapid filling o May be normal in older children and competitive athletes
• S4 gallop: “Tennessee” o Heard when the myocardium is poorly compliant, from rapid filling of the ventricle during atrial contraction (late in diastole) o Always pathologic in children, usually associated with CHF
• Ejection Clicks: early systolic, high-frequency sound associated with abnormal semilunar valves
• Midsystolic click: midsystolic, high-frequency sound associated with mitral valve prolapse

Adapted from: https://upload.wikimedia.org/wikipedia/commons/9/9a/Wiggers_Diagram.png

4th

• Murmurs: caused by turbulent blood flow creating audible sound waves in the range of 20Hz to 2000Hz o Described by:  Timing: - When in the cardiac cycle does the murmur occur? - What is the murmur’s relationship to S1 and S2?  Intensity or loudness: - Depends on the size of the orifice or vessel through which blood flows, the pressure difference or gradient across the site, and the blood flow or volume across the site - For systolic murmurs: o Grade 1: heard only with intense concentration o Grade 2: faint, but heard immediately o Grade 3: easily heard, of intermediate intensity o Grade 4: easily heard, associated with a thrill (a palpable vibration on the chest wall) o Grade 5: very loud with a thrill, audible with only the edge of the stethoscope on the chest wall o Grade 6: audible with the stethoscope off the chest wall  Duration of the murmur  Configuration: the dynamic shape of the murmur  Pitch: the frequency range of the murmur  Quality: the presence of harmonics or overtones  Location on the chest wall: - Point of maximal intensity: Where is the sound loudest? - Extent of radiation: Over what area is the sound audible? o Systolic Murmurs occur between S1 and S  Holosystolic murmurs: obscure S1 and terminate at S  Ejection murmurs: crescendo-decrescendo or diamond-shaped  Early systolic murmurs: start abruptly at S1, but taper and disappear before S - associated exclusively with small muscular VSDs  Mid- to late systolic murmurs: begin midway through systole, often heard with midsystolic clicks and the mitral regurgitation heard with mitral valve prolapse o Diastolic Murmurs occur between S2 and S  Early diastolic murmurs: decrescendo murmurs, arise from aortic or pulmonary valve regurgitation  Mid-diastolic murmurs: diamond shaped murmurs, associated with increased flow across a normal mitral or tricuspid valve, or normal flow across a stenotic mitral or tricuspid valve  Late diastolic murmurs: crescendo murmurs, created by stenotic or narrowed mitral or tricuspid valves, the noise is associated with atrial contraction  ALWAYS pathologic! o Continuous Murmurs occur throughout the cardiac cycle  Flow through vessels beyond the semilunar valves is not confined to systole or diastole  Murmur is heard from S1 and extends beyond S2 into diastole  These can be innocent (e.g. venous hum).

Introduction to Cardiac Cath

What information can be obtained in the cath lab?

• Measure pressures in the cardiac chambers
• Sample blood to measure oxygen saturations in each chamber
• Examine anatomy by injecting contrast
• Use the numbers obtained to calculate cardiac output, shunts and vascular resistance

Indications for Cath

• Confirm or complete the anatomic diagnosis
• Obtain hemodynamic information
• Clinical signs and symptoms do not fit with a patient’s diagnosis
• Clinical course is not progressing as expected
• Specific interventions

CALCULATIONS:

Oxygen Capacity: maximal amount of oxygen that can be taken up by hemoglobin in the blood O 2 capacity (mL/L) = 1.36 x Hgb (gm/dL) x 10

Oxygen Content: Amount of oxygen present in a blood sample (includes amount bound to hemoglobin and amount dissolved in plasma). At normal body temperature (37°C): O 2 content (mL/L) = O 2 bound to hemoglobin + O 2 dissolved in plasma = (O 2 capacity x O 2 saturation/100) + (0.03 x PO 2 )

In room air, amount of dissolved O 2 in the sample is ignored as it represents ~1.5% of total body oxygen, so we simplify to: O 2 content (mL/L) = (1.36 x Hgb x 10) x O 2 saturation/

Fick Equation: uses the speed of oxygen usage to estimate blood flow Uptake of a substance = Flow x [concentration of substance in – concentration of substance out]

QP = pulmonary blood flow QS = systemic blood flow = Cardiac Index

Q (^) P (L/min) = Oxygen consumption (mL/min) Pulmonary venous O 2 content – Pulmonary arterial O 2 content

Q (^) S (L/min) = Oxygen consumption (mL/min) Systemic arterial O 2 content – Mixed venous O 2 content

Qp:QS =* Systemic arterial O 2 saturation – Mixed venous O 2 saturation Pulmonary venous O 2 saturation – Pulmonary arterial O 2 saturation

*assuming samples were obtained in room air Oxygen consumption is an estimated value based on the patient’s age, gender and heart rate

Ohm’s Law:

R (^) P = pulmonary vascular resistance R (^) S = systemic vascular resistance

Resistance = Change in Pressure Flow

RP = Pressure in Pulmonary Artery – Pressure in Left Atrium QP

RS = Pressure in Aorta – Pressure in Right Atrium QS

Mean pressures are used for all calculations

Questions:

• What information is obtained during a pre-Glenn cath?
• What information is obtained during a cath in a patient with Tetralogy of Fallot, Pulmonary Atresia and MAPCAs?

Case A: 3 month old patient, intubated in 21% FiO2. Patient’s hemoglobin in 14.7g/dL. Assume the

oxygen consumption is 150mL/min and pulmonary venous saturations are 100%. Calculate the Q (^) P.

o Calculate Q (^) S. o What is the PVR? o What is the likely lesion and why?

Site Pressures (mm Hg) Oxygen Saturation SVC 60% RA mean 4 62% RV 80/3 63% PA 20/8, mean 12 63% PV mean 5 96% LV 80/5 75% Ao 82/45 75%

Case B: 1 day old patient, intubated in 50% FiO2. O 2 capacity is 200mL. Assume the oxygen consumption is 120mL/min/m 2 and pulmonary venous saturations are 100%. o Calculate the Q (^) P. o Calculate Q (^) S. o What is the Q (^) P:Q (^) S? o What is the likely lesion and why?

Site Pressures (mm Hg) Oxygen Saturation Oxygen Content (mL/L) SVC 40% 80 RA mean 6 62% 124 RV 75/5 65% 130 PA 60/40, mean 46 92% 184 PV mean 5 100% 200 LV 60/6 96% 192 Ao 75/55, mean 62 65% 130

References Taggart NW, Cabalka AK. Cardiac Catheterization and Angiography. In: Allen HD, Driscoll DJ, Shaddy RE, Feltes TF, 8 th, editors. Moss and Adams’ Heart Disease in Infants, Children, and Adolescents: Including the Fetus and Young Adult. Philadelphia: Lippincott Williams & Wilkins; 2013. p.258-287. Carrozza JP. Complications of diagnostic cardiac catheterization. Uptodate.com