what does this indicate about the anatomical locale as the source of the electrical disturbance in Sabrina’s heart?

Case Study 1

Sabrina is a 67-year-old woman with a history of cardiac abnormalities. You perform a resting ECG test to evaluate her heart’s electrical activity. You notice that her PR interval is 0.25 s. Considering that this measure is often between 0.12 s and 0.20 s, what does this indicate about the anatomical locale as the source of the electrical disturbance in Sabrina’s heart?

Case Study 2

Ralf is a 72-year-old retired air force captain who has come into your facility and revealed that he has suffered a myocardial infarction in the last 4 months. What might you suspect you would see in his resting ECG? Are there other indicators in his resting ECG strip that you can relate to his myocardial infarction?