Final answer:
A wide-QRS complex indicates that the ventricles of the heart are affected, and if there is an increased frequency between these complexes, it generally leads to an increase in heart rate. Disturbances such as a third-degree block may result in a reduced pulse due to the disassociated activity between the atria and ventricles.
Step-by-step explanation:
When analyzing an ECG, the QRS complex is crucial in determining the electrical activity and health of the heart's ventricles. A wide-QRS complex typically suggests a disturbance in the ventricular conduction system, such as ventricular tachycardia or a bundle branch block. An increased frequency between the QRS complexes, especially if coupled with an irregular or abnormal pattern prior to the QRS complex, may indicate conditions like atrial fibrillation. This can lead to an increase in heart rate (pulse), as the ventricles are responding more frequently to irregular atrial impulses.
In instances of heart blocks such as in a third-degree block, where there is no correlation between the P waves and the QRS complexes, a reduction in pulse may occur as the ventricles contract independently from the atria. Similarly, the P waves in second-degree blocks may not always lead to ventricular contraction (observed as a QRS complex), leading to an irregular heart rate.
Overall, abnormalities in the electrical conduction pattern, particularly before and during the QRS complex, have significant implications for heart rate and rhythms, requiring careful evaluation by medical professionals.