NBME CBSE|VERIFIED QUESTIONS AND CORRECT DETAILED ANSWERS|RATED
AND GRADED A+ NEW UPDATE| 2026/2027
Bulbus cordis - ANSWER✔ Smooth parts (outflow tract) of left and right ventricles
endocardial cushions - ANSWER✔ Atrial septum, membranous interventricular septum; AV and
semilunar valves
neural crest
left horn of the sinus venosus - ANSWER✔ coronary sinus
posterior, sub cardinal, and supra cardinal veins - ANSWER✔ IVC
Right common cardinal vein and right anterior cardinal vein - ANSWER✔ SVC
Right horn of sinus venosus - ANSWER✔ Smooth part of right atrium (sinus venarum)
Patent foramen ovale - ANSWER✔ failure of septum primum and septum secundum to fuse after
birth
Transposition of the great vessels
Tetralogy of Fallot
Persistent truncus arteriosus - ANSWER✔ Conotruncal abnormalities associated with failure of neural
crest cells to migrate
ductus venosus - ANSWER✔ connects the umbilical vein to the inferior vena cava, bypassing the liver
becomes ligamentum venosum
,phrenic nerve - ANSWER✔ innervates the diaphragm and pericardium
S3 heart sound - ANSWER✔ Increased ventricular filling pressure (e.g., mitral regurgitation, HF),
common in dilated ventricles
normal in kids and pregnant women
S4 heart sound - ANSWER✔ 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 - ANSWER✔ a wave of JVP
c wave - ANSWER✔ RV contraction (closed tricuspid valve bulging into atrium) wave of JVP
x descent - ANSWER✔ JVP wave corresponding to downward displacement of closed tricuspid valve
during rapid ventricular ejection phase
reduced or absent in tricuspid regurge
V wave - ANSWER✔ JVP wave corresponding to inc'd RA pressure due to filling against closed
tricuspid valve
,y descent - ANSWER✔ JVP wave corresponding to RA emptying into RV
absent in cardiac tamponade
plusus parvus et tardus - ANSWER✔ pulses are weak with delayed peak
Aortic stenosis
PR interval - ANSWER✔ 0.12-0.20 seconds
120 milliseconds
QT interval length - ANSWER✔ 9 - 11 squares = .36 to .44 seconds
Hypokalemia - ANSWER✔ U wave present on ECG
Mg sulfate - ANSWER✔ for torsades de pointe, hypokalemia (can lengthen QT and cause torsades),
and pre-eclampsia (prevent seizures)
Romano-Ward syndrome - ANSWER✔ -Congenital long QT syndrome
-Autosomal dominant, pure cardiac phenotype (no deafness).
Jervell and Lange-Nielsen syndrome - ANSWER✔ -Congenital long QT syndrome
-Autosomal recessive, sensorineural deafness
Brugada syndrome - ANSWER✔ -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).
Wolff-Parkinson-White Syndrome - ANSWER✔ Most common type of ventriuclar pre-excitation
sydnrome. Abnormal fast accessory conduction pathway from atria to venricle bypasses the rate-
slowing AV node causing a delta wave and widening QRS with shortened PR interval. Could lead to a
reentrant circuit and suprvaventicular tachy.
First degree AV block - ANSWER✔ - PRI >5 boxes/.20 sec (200 msec)
- Fixed but prolonged PRI
(consistent but long)
- normally get bradycardia here
second degree AV block mobitz type 2 - ANSWER✔ -PR interval is constant
-atrial conduction to ventricle is intermittent: dropped QRS without increasing PR interval length
-disease below AV node in His bundle
may progress to 3rd degree/complete AV block
Second Degree AV Block Mobitz Type 1 (wenckebach) - ANSWER✔ Progressive lengthening of pr
interval leading to dropped QRS
third degree AV block - ANSWER✔ The atria and Ventricles are totally dissociated.
-So, the QRSs and the P waves have no relation to each other.
PCWP - ANSWER✔ 4-12 mmHg
est of LA pressure
AND GRADED A+ NEW UPDATE| 2026/2027
Bulbus cordis - ANSWER✔ Smooth parts (outflow tract) of left and right ventricles
endocardial cushions - ANSWER✔ Atrial septum, membranous interventricular septum; AV and
semilunar valves
neural crest
left horn of the sinus venosus - ANSWER✔ coronary sinus
posterior, sub cardinal, and supra cardinal veins - ANSWER✔ IVC
Right common cardinal vein and right anterior cardinal vein - ANSWER✔ SVC
Right horn of sinus venosus - ANSWER✔ Smooth part of right atrium (sinus venarum)
Patent foramen ovale - ANSWER✔ failure of septum primum and septum secundum to fuse after
birth
Transposition of the great vessels
Tetralogy of Fallot
Persistent truncus arteriosus - ANSWER✔ Conotruncal abnormalities associated with failure of neural
crest cells to migrate
ductus venosus - ANSWER✔ connects the umbilical vein to the inferior vena cava, bypassing the liver
becomes ligamentum venosum
,phrenic nerve - ANSWER✔ innervates the diaphragm and pericardium
S3 heart sound - ANSWER✔ Increased ventricular filling pressure (e.g., mitral regurgitation, HF),
common in dilated ventricles
normal in kids and pregnant women
S4 heart sound - ANSWER✔ 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 - ANSWER✔ a wave of JVP
c wave - ANSWER✔ RV contraction (closed tricuspid valve bulging into atrium) wave of JVP
x descent - ANSWER✔ JVP wave corresponding to downward displacement of closed tricuspid valve
during rapid ventricular ejection phase
reduced or absent in tricuspid regurge
V wave - ANSWER✔ JVP wave corresponding to inc'd RA pressure due to filling against closed
tricuspid valve
,y descent - ANSWER✔ JVP wave corresponding to RA emptying into RV
absent in cardiac tamponade
plusus parvus et tardus - ANSWER✔ pulses are weak with delayed peak
Aortic stenosis
PR interval - ANSWER✔ 0.12-0.20 seconds
120 milliseconds
QT interval length - ANSWER✔ 9 - 11 squares = .36 to .44 seconds
Hypokalemia - ANSWER✔ U wave present on ECG
Mg sulfate - ANSWER✔ for torsades de pointe, hypokalemia (can lengthen QT and cause torsades),
and pre-eclampsia (prevent seizures)
Romano-Ward syndrome - ANSWER✔ -Congenital long QT syndrome
-Autosomal dominant, pure cardiac phenotype (no deafness).
Jervell and Lange-Nielsen syndrome - ANSWER✔ -Congenital long QT syndrome
-Autosomal recessive, sensorineural deafness
Brugada syndrome - ANSWER✔ -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).
Wolff-Parkinson-White Syndrome - ANSWER✔ Most common type of ventriuclar pre-excitation
sydnrome. Abnormal fast accessory conduction pathway from atria to venricle bypasses the rate-
slowing AV node causing a delta wave and widening QRS with shortened PR interval. Could lead to a
reentrant circuit and suprvaventicular tachy.
First degree AV block - ANSWER✔ - PRI >5 boxes/.20 sec (200 msec)
- Fixed but prolonged PRI
(consistent but long)
- normally get bradycardia here
second degree AV block mobitz type 2 - ANSWER✔ -PR interval is constant
-atrial conduction to ventricle is intermittent: dropped QRS without increasing PR interval length
-disease below AV node in His bundle
may progress to 3rd degree/complete AV block
Second Degree AV Block Mobitz Type 1 (wenckebach) - ANSWER✔ Progressive lengthening of pr
interval leading to dropped QRS
third degree AV block - ANSWER✔ The atria and Ventricles are totally dissociated.
-So, the QRSs and the P waves have no relation to each other.
PCWP - ANSWER✔ 4-12 mmHg
est of LA pressure
