Two for the Price of One - ECG Case #2

Here is a nifty ECG case with two unrelated — but interesting — findings on one ECG tracing. One, a life-threatening diagnosis, and the other, a rare incidental finding leading to heart failure in this patient.

An 81-year-old, previously healthy male presents with recurrent syncope. He has also noted increasing dyspnea and lower extremity edema for the past year; it has been mild, and thus he never sought medical attention. Here is his ECG:

ApicalHCM-CHB-RBBB

ECG Finding #1 - Life Threatening

The rhythm is sinus (upright P waves in lead II), but with third-degree atrioventricular (AV) block, also known as complete heart block. Look at the rhythm strip at the bottom in V1. You can march out the P waves and see they are not at the same rate as the QRS complexes.

Here is what you should know about third-degree AV block:

  • The P waves are not able to conduct at all through the AV node to the ventricles.
  • P waves (atrial depolarization) are at a different rate than the QRS complexes (ventricular depolarization). This is called "AV dissociation."
  • The QRS rate is usually quite slow and originates at the AV junction (junctional escape, narrow QRS, rate 40-60) or in the ventricles (ventricular escape, wide QRS, rate 20-40).
  • Symptoms of bradycardia are usually present, including syncope, weakness, dyspnea and heart failure.
  • A permanent pacemaker (PPM) is the treatment of choice.

Here is another example of third-degree AV block:

3rdDegreeAVBlockECGCriteria

Here are even more examples:

ECG Finding #2 - Rare Cause of Heart Failure

This patient was found to have "Apical Hypertrophic Cardiomyopathy" — also known as "Yamaguchi syndrome" — a variant of hypertrophic cardiomyopathy. This can lead to slowly progressing diastolic congestive heart failure. 

The ECG findings of apical hypertrophic cardiomyopathy include giant T-wave inversions in the precordial leads. Here is another ECG example of apical hypertrophic cardiomyopathy, with the arrow pointing at the giant T-wave inversions:

ApicalHOCMECG

Here is our patient's echocardiogram showing abnormal left ventricular hypertrophy only towards the cardiac apex (top of the image):

Some points to know about apical hypertrophic cardiomyopathy:

  • Treat with verapamil or diltiazem (dihydropyridine calcium channel blockers) or beta-blockers to lower heart rate, allowing for more diastolic filling time.
  • There are no data to support disopyramide in this disease, as there is in typical hypertrophic obstructive cardiomyopathy (HOCM).
  • Surgical apical myomectomy is reserved for refractory cases.

I have only had one patient undergo apical myomectomy. That patient developed severe systolic dysfunction and severe mitral valve regurgitation requiring surgical repair about 2 years later!

- by Steven Lome, DO, RVT