A nurse is at the bedside of a patient complaining of severe fatigue with increasing dyspnea. The nurse quickly reviews the patient's electrocardiogram (EKG) and sees a normal P-to-P interval and normal R-to-R interval. However, the PR intervals appear to be completely unrelated to the QRS complexes and the QT intervals are long. What condition does the nurse suspect the patient is experiencing?
•Third-degree heart block (also known as complete heart block) occurs when there is no communication between the heart's ventricular and atrial conduction systems.
•The P-to-P interval and R-to-R interval are regular because the rhythm of each chamber is regular; they just don't communicate with the other chamber. The P-R intervals vary because the P waves are not "in sync" with QRS. Finally, the QT interval is prolonged, causing a
•In a second-degree heart block, there are more P waves than QRS complexes and some P waves are not conducted. There is not a complete miscommunication between the atria and ventricles in this rhythm.
•Ventricular fibrillation has an unobtainable rapid rate. The P-P and R-R intervals are also unobtainable, as is the PR interval.
•With junctional dysrhythmias, there are abnormal P waves (either absent or inverted) and the P-to-P and R-to-R intervals are not regular.