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Cardiology Case: A Hole in One
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Here is a tricky case. Try to guess the diagnosis of this previously healthy 5-year-old boy who starts to complain of difficulty breathing over the past 2 weeks.
He used to be able to play with his friends and run quite well; however, now he has to stop and rest to catch his breath. He notes that his breathing is worse at night and when exposed to the cold. While the symptoms are not severe, they are certainly bothersome to him. His heart rate is 70 bpm, respiratory rate is 22, blood pressure is 120/80 mm Hg and his oxygen saturation is normal. On auscultation you hear diffuse expiratory wheezing in the lungs and a very loud V/VI holosystolic murmur that is loudest at the left lower sternal border, but you can hear it throughout the entire precordium. There is even a thrill associated with it. He has no edema and his jugular veins appear flat.
What could be causing his shortness of breath? Here is his ECG:
The ECG shows simple sinus tachycardia, nothing else exciting.
It helps to know two things: Common things happen commonly AND you have to know your auscultation.
When wheezing is heard in the lungs, people typically think of asthma, or in adults they think of chronic obstructive pulmonary disease (COPD). However, did you know that congestive heart failure can cause wheezing? This is called "cardiac asthma." It is estimated that about one-third of adults with severe decompensated congestive heart failure will have wheezing on exam.
If you know the murmur in this case, you have probably guessed that this boy has a very small ventricular septal defect (VSD), which is commonly referred to as a "hole in the heart." Small defects can cause VERY loud murmurs as the higher pressure in the left heart forcefully shoots blood through the VSD into the right heart. Think of putting your thumb over a garden hose: The more you obstruct the opening, the farther and faster the water will shoot! This is why small VSDs have a high velocity jet coursing from the left heart to the right heart causing a lot of turbulent flow and thus a loud murmur. Small VSDs, however, are harmless. The overall volume of blood is so small that it does not cause any symptoms or hemodynamic changes, just a really cool "thrilling" loud murmur.
Recall that a large VSD can cause significant strain on the heart. Eventually, as so much blood shunts from left to right forcing the right heart to handle quite a large volume of blood with each cardiac cycle, pulmonary hypertension starts to develop. As pulmonary hypertension becomes severe, the pressures in the right heart may exceed those of the left heart intermittently causing the shunt to reverse direction from right to left. When a left to right shunt causes pulmonary hypertension reversing it to a right to left shunt, this is called "Eisenmenger syndrome."
Here is a drawing of a VSD that is now right-to-left shunting (Eisenmenger syndrome):
Here is an ECG from a patient with Eisenmenger syndrome showing right ventricular hypertrophy with strain:
Common things being common, this boy does simply have asthma. Tricky, tricky. While it is true that you should always try to connect the dots and put all abnormal findings together to make one diagnosis, sometimes there are two things going on. One hint was that the boy was previously healthy without symptoms. Most congenital cardiac anomalies that are hemodynamically significant present quite early and do not suddenly appear.
Editor’s note: This Blog was originally published on learntheheart.com.
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