Final answer:
Increasing the ECG recording speed to 50 mm/sec stretches the EKG traces, affecting the interpretation of intervals. An increased frequency of QRS complexes indicates a higher heart rate and pulse. Abnormal patterns prior to QRS complexes suggest potential heart rhythm issues.
Step-by-step explanation:
When an ECG, also known as an EKG, is recorded at a speed of 50 mm/sec, the EKG traces will be stretched out, causing the waves and intervals on the graph to appear longer than they would at the standard speed of 25 mm/sec. This can make interpretation easier but also requires adjustment in the measurement of intervals and segments for accurate diagnosis. If the frequency between the QRS complexes has increased, as noted in the question, this implies that the heart rate is higher, resulting in an increased pulse. This finding on an ECG can be indicative of conditions like tachycardia or a response to physiological demands or stress. Abnormal patterns prior to the QRS complexes may suggest issues such as premature contractions or atrial fibrillation, depending on the specific appearance and origin of these patterns.