True or False: Pacemakers sense cardiac depolarization by measuring electrical potential changes in myocardial cells between the anode and cathode.

The statement is true because pacemakers are designed to monitor the electrical activity of the heart. They achieve this by sensing changes in electrical potential that occur during cardiac depolarization, which is a key phase in the cardiac cycle when the myocardial cells become activated and contract. The pacemaker's leads, which consist of anode and cathode, are placed in such a way that they can detect these electrical signals.

When the heart's cells depolarize, there is a measurable change in voltage due to the movement of ions across the cell membrane. The pacemaker captures these changes between the anode and cathode to determine whether the heart is beating adequately or whether it requires pacing. This dual ability—sensing and stimulating—is what allows the device to respond appropriately and maintain a proper heart rhythm, helping manage conditions such as bradycardia or heart block. The passage of time and further advancements in technology could introduce variations in device capabilities, but the fundamental principle of electrical sensing remains consistently true across both internal and external pacemakers.