True or False: The underlying cause of primary pulseless electrical activity (PEA) can be related to inadequate volume or impaired myocardial contractility.

The statement is true because primary pulseless electrical activity (PEA) is defined as a condition where there is electrical activity on the electrocardiogram, but the heart is not effectively pumping blood, resulting in no detectable pulse. The underlying mechanisms that can lead to this phenomenon indeed include inadequate circulatory volume, such as from severe dehydration or hemorrhage, and impaired myocardial contractility due to various reasons like ischemia or cardiomyopathy.

Inadequate volume results in decreased venous return to the heart, limiting the amount of blood that is available to be pumped out. Meanwhile, impaired myocardial contractility affects the heart's ability to contract effectively, even if the heart is receiving adequate volume. This combination of factors contributes to the state of PEA, highlighting the critical need to assess and address volume status and heart function when presented with this condition.