Final answer:
With a septal wall AMI, you would expect an 85-year-old male to exhibit a third degree heart block on the ECG, characterized by an absence of coordination between P waves and QRS complexes, often resulting in bradycardia.
Step-by-step explanation:
If your patient is an 85-year-old male experiencing a septal wall acute myocardial infarction (AMI), you would expect to see a third degree heart block on the ECG. In a third-degree block, there is a complete absence of correlation between atrial activity (the P waves) and ventricular activity (the QRS complexes). This block can occur as a result of an AMI and indicates that the electrical impulses generated by the sinoatrial (SA) node are not being transmitted to the ventricles. The most critical aspect of a third-degree block is that even though some impulses do not reach the AV node while others do, the P waves are not followed by the QRS complex, leading to a separate atrial and ventricular rhythm.
A third-degree block, also known as a complete heart block, often results in bradycardia, where the heart rate (pulse) decreases because the ventricles may rely on a secondary, slower pacemaker. If an AV block is complete, the AV node or other pacemaking cells within the ventricles will initiate contractions at 40-60 beats per minute, adequate to maintain consciousness but likely lower than the normal sinus rhythm established by the SA node.