NBME CBSE TEST EXAM REAL EXAM 226 QUESTIONS AND
ANSWERS LATEST 2026 (usmle step 1)MEDICAL EXAMINATION
Bulbus cordis - CORRECT ANSWERS Smooth parts (outflow tract) of left and right
ventricles
endocardial cushions - CORRECT ANSWERS Atrial septum, membranous interventricular
septum; AV and semilunar valves
neural crest
left horn of the sinus venosus - CORRECT ANSWERS coronary sinus
posterior, sub cardinal, and supra cardinal veins - CORRECT ANSWERS IVC
Right common cardinal vein and right anterior cardinal vein - CORRECT ANSWERS SVC
Right horn of sinus venosus - CORRECT ANSWERS Smooth part of right atrium (sinus
venarum)
Patent foramen ovale - CORRECT ANSWERS failure of septum primum and septum
secundum to fuse after birth
Transposition of the great vessels
Tetralogy of Fallot
Persistent truncus arteriosus - CORRECT ANSWERS Conotruncal abnormalities
associated with failure of neural crest cells to migrate
ductus venosus - CORRECT ANSWERS connects the umbilical vein to the inferior vena
cava, bypassing the liver
becomes ligamentum venosum
,phrenic nerve - CORRECT ANSWERS innervates the diaphragm and pericardium
,S3 heart sound - CORRECT ANSWERS Increased ventricular filling pressure (e.g., mitral
regurgitation, HF), common in dilated ventricles
normal in kids and pregnant women
S4 heart sound - CORRECT ANSWERS atrial kick late diastole, right before S1
best heard at apex in LLD position
High atrial pressure.
Stiff/hypertrophic ventricle (aortic stenosis, restrictive cardiomyopathy)
Always abnormal
atria contract - CORRECT ANSWERS a wave of JVP
c wave - CORRECT ANSWERS RV contraction (closed tricuspid valve bulging into atrium)
wave of JVP
x descent - CORRECT ANSWERS JVP wave corresponding to downward displacement of
closed tricuspid valve during rapid ventricular ejection phase
reduced or absent in tricuspid regurge
V wave - CORRECT ANSWERS JVP wave corresponding to inc'd RA pressure due to filling
against closed tricuspid valve
y descent - CORRECT ANSWERS JVP wave corresponding to RA emptying into RV
absent in cardiac tamponade
, plusus parvus et tardus - CORRECT ANSWERS pulses are weak with delayed peak
Aortic stenosis
PR interval - CORRECT ANSWERS 0.12-0.20 seconds
120 milliseconds
QT interval length - CORRECT ANSWERS 9 - 11 squares = .36 to .44 seconds
Hypokalemia - CORRECT ANSWERS U wave present on ECG
Mg sulfate - CORRECT ANSWERS for torsades de pointe, hypokalemia (can lengthen QT
and cause torsades), and pre-eclampsia (prevent seizures)
Romano-Ward syndrome - CORRECT ANSWERS -Congenital long QT syndrome
-Autosomal dominant, pure cardiac phenotype (no deafness).
Jervell and Lange-Nielsen syndrome - CORRECT ANSWERS -Congenital long QT
syndrome
-Autosomal recessive, sensorineural deafness
Brugada syndrome - CORRECT ANSWERS -Autosomal dominant disorder affecting Na
channels most common in Asian males.
-ECG pattern of pseudo-right bundle branch block and ST elevations in V1-V3 (anterior
ventricular septum)
-inc risk of ventricular tachyarrhythmias and sudden cardiac deatgh
Prevent SCD with implantable cardioverter-defibrillator (ICD).
ANSWERS LATEST 2026 (usmle step 1)MEDICAL EXAMINATION
Bulbus cordis - CORRECT ANSWERS Smooth parts (outflow tract) of left and right
ventricles
endocardial cushions - CORRECT ANSWERS Atrial septum, membranous interventricular
septum; AV and semilunar valves
neural crest
left horn of the sinus venosus - CORRECT ANSWERS coronary sinus
posterior, sub cardinal, and supra cardinal veins - CORRECT ANSWERS IVC
Right common cardinal vein and right anterior cardinal vein - CORRECT ANSWERS SVC
Right horn of sinus venosus - CORRECT ANSWERS Smooth part of right atrium (sinus
venarum)
Patent foramen ovale - CORRECT ANSWERS failure of septum primum and septum
secundum to fuse after birth
Transposition of the great vessels
Tetralogy of Fallot
Persistent truncus arteriosus - CORRECT ANSWERS Conotruncal abnormalities
associated with failure of neural crest cells to migrate
ductus venosus - CORRECT ANSWERS connects the umbilical vein to the inferior vena
cava, bypassing the liver
becomes ligamentum venosum
,phrenic nerve - CORRECT ANSWERS innervates the diaphragm and pericardium
,S3 heart sound - CORRECT ANSWERS Increased ventricular filling pressure (e.g., mitral
regurgitation, HF), common in dilated ventricles
normal in kids and pregnant women
S4 heart sound - CORRECT ANSWERS atrial kick late diastole, right before S1
best heard at apex in LLD position
High atrial pressure.
Stiff/hypertrophic ventricle (aortic stenosis, restrictive cardiomyopathy)
Always abnormal
atria contract - CORRECT ANSWERS a wave of JVP
c wave - CORRECT ANSWERS RV contraction (closed tricuspid valve bulging into atrium)
wave of JVP
x descent - CORRECT ANSWERS JVP wave corresponding to downward displacement of
closed tricuspid valve during rapid ventricular ejection phase
reduced or absent in tricuspid regurge
V wave - CORRECT ANSWERS JVP wave corresponding to inc'd RA pressure due to filling
against closed tricuspid valve
y descent - CORRECT ANSWERS JVP wave corresponding to RA emptying into RV
absent in cardiac tamponade
, plusus parvus et tardus - CORRECT ANSWERS pulses are weak with delayed peak
Aortic stenosis
PR interval - CORRECT ANSWERS 0.12-0.20 seconds
120 milliseconds
QT interval length - CORRECT ANSWERS 9 - 11 squares = .36 to .44 seconds
Hypokalemia - CORRECT ANSWERS U wave present on ECG
Mg sulfate - CORRECT ANSWERS for torsades de pointe, hypokalemia (can lengthen QT
and cause torsades), and pre-eclampsia (prevent seizures)
Romano-Ward syndrome - CORRECT ANSWERS -Congenital long QT syndrome
-Autosomal dominant, pure cardiac phenotype (no deafness).
Jervell and Lange-Nielsen syndrome - CORRECT ANSWERS -Congenital long QT
syndrome
-Autosomal recessive, sensorineural deafness
Brugada syndrome - CORRECT ANSWERS -Autosomal dominant disorder affecting Na
channels most common in Asian males.
-ECG pattern of pseudo-right bundle branch block and ST elevations in V1-V3 (anterior
ventricular septum)
-inc risk of ventricular tachyarrhythmias and sudden cardiac deatgh
Prevent SCD with implantable cardioverter-defibrillator (ICD).
