When Molly brought her 2-month-old daughter, Kara, to see me one morning, one look told me something was wrong. I’d known Molly since the birth of her son, Kevin, about three years ago, and she is usually fairly relaxed and cheerful, even with a crying baby in tow. But this day her face was drawn, and her eyes looked worried.
The first line of the nurse’s brief note read, “Fussy, not eating well, no vomiting,” so I asked about the fussiness. Molly said Kara had been very fussy, but only for the past day. Evaluating fussiness in a baby can be tricky. It can signify a cold, an ear infection, or even meningitis. I quickly reviewed Kara’s short medical history: She had been a healthy full-term baby, and she had been doing well. But a couple of days ago, something changed. Molly said that even though Kara seemed hungry, she would only take a few swallows from her bottle and then stop, as if she were out of breath.
Kara’s temperature was normal, her color was good, and she was crying vigorously. All are signs of good health in a baby. Yet somehow she didn’t look well. The examination didn’t yield many clues. Her heart rate was fast, but crying could cause that. I did note that her liver was enlarged. The lower edge of the organ was about four centimeters below the rib cage, when it should have been even with the ribs.
The enlarged liver worried me, so I sent her to the hospital for an abdominal ultrasound. An hour later, the radiologist called: “The liver is big, but it looks OK otherwise. There’s some free fluid in the abdomen, but there’s also a pericardial effusion.” Now I was really concerned. The heart is encased in a membrane called the pericardium, and a pericardial effusion means that fluid has accumulated within the sac. Maybe Kara had a viral infection that was affecting both her heart and her liver. Such an infection can cause serious heart problems very quickly. I arranged for her to be admitted to the pediatric unit and drove over to the hospital. Because I was concerned about a possible myocarditis—a heart infection—I told the admitting nurse to start an IV and to put Kara on a heart monitor.
When I got to the unit, the nurse had just connected Kara to the monitor. She came out of Kara’s room, looking puzzled. “Dr. Cohen, the monitor says her heart rate is 220.” A heart rate of 220? Of course! All of a sudden, the clues fell into place.
When I listened to Kara’s heart, the rate was well over 200 beats per minute. She wasn’t crying now, so that couldn’t be contributing to the fast rate. Kara’s liver was OK—the problem was with her heart! Kara needed to see a pediatric cardiologist. I turned to the nurse. “Get an EKG and a portable chest X-ray and see if Dr. Wolf can come over right away. Tell him I have a 2-month-old with SVT and CHF.”
The EKG confirmed that Kara had SVT—supraventricular tachycardia. Sometime in the past few days, a “short circuit” in her heart’s electrical conduction system had suddenly caused the sinoatrial node—a cluster of cardiac cells that function as the heart’s pacemaker—to fire off impulses at 200 to 220 beats per minute, about twice the normal rate for a 2-month-old. Babies can tolerate this fast heart rate for longer than adults, but not for more than a few days. Kara appeared to be experiencing congestive heart failure, or CHF.
