What happens if there is no QRS complex?

Second-degree AV nodal block – the conduction velocity is slowed to the point where some impulses from the atria cannot pass through the AV node. This results in P waves that are not followed by QRS complexes. There are two subtypes of second-degree AV blocks: Mobitz Type I and Mobitz Type II.

How is it possible to have P waves that are not followed by QRS complexes?

When transmission of the depolarizing impulse from the sinus node through the AV conduction system of the heart is interrupted intermittently, P wave of atrial contraction is no longer followed by a QRS complex of ventricular contraction in the interrupted beat.

What happens during QRS complex quizlet?

The QRS complex is a recording of ventricular depolarization. This depolarization begins just prior to the ventricular contraction it initiates. As the ventricles contract, the increase in ventricular pressure closes the atrioventricular valves, beginning isovolumetric contraction.

What happens in the Pqrst complex?

An ECG complex consists of a PQRST complex. The sinoatrial node (SA) is the pacemaker of the heart and produces the P wave. The QRS wave is produced by the atrioventricular node (AV). The P wave in an ECG complex indicates atrial depolarization.

What does it mean when there is no P wave?

Absence of P Waves A lack of visible P waves preceding QRS complexes suggests a lack of sinus beats; this may occur with sinus dysfunction or in the presence of fibrillation or flutter waves. The P wave may also be hidden within the QRS complex.

Where does the QRS complex end?

It ends at the point where the last wave of the complex transitions into the ST segment. QRS complex is larger than the P wave because ventricular depolarization involves a considerably larger muscle mass than atrial depolarization. Amplitude of a normal QRS is 5 to 30 mm and the duration is 0.06 to 0.12 seconds.

What two events are happening in the QRS complex?

The QRS complex refers to the combination of the Q, R, and S waves, and indicates ventricular depolarization and contraction (ventricular systole). The Q and S waves are downward waves while the R wave, an upward wave, is the most prominent feature of an ECG.