DEAR MAYO CLINIC: I've noticed that sometimes my heart races or skips a beat. What causes this? Is there treatment for it? ANSWER: What you're experiencing may be an abnormal heart rhythm, also known ...

The correct diagnosis is sinus rhythm, nonconducted premature atrial complexes (PACs), and junctional escape complex (Figure 2). The rhythm is irregular, but the long intervals are all the same (↔) ...