The QRS complex on an ECG indicates ventricular excitation and contraction. It represents depolarization of the ventricles as they prepare to contract and pump blood out to the rest of the body.
The R wave of the ECG is most closely associated with the depolarization of the ventricles during the cardiac contraction cycle, specifically with the QRS complex. This represents the initiation of ventricular contraction.
Just as ventricular volume reaches approximately 130 mL, the QRS complex on the ECG tracing occurs. This complex represents ventricular depolarization, which precedes ventricular contraction. At this point, the ventricles are filled with blood, leading to the onset of systole. The increase in ventricular volume correlates with the end of diastole, just before the heart pumps blood into the circulation.
Premature Atrial Contraction (PAC) occurs when the heart's upper chambers contract too early, causing an abnormal heartbeat on an ECG. Premature Ventricular Contraction (PVC) happens when the heart's lower chambers contract prematurely, also leading to an abnormal rhythm on an ECG. The key difference is the origin of the early contraction within the heart's chambers.
The portion of the ECG that indicates ventricular repolarization or recovery is the t wave. It is the wave found after the QRS complex (Ventricular depolarizaton) in a normal ECG
Okay so an EKG show the electrical impulse that travels through the heart. What I mean is EKG don't show contraction. However the QRS complex represent ventricular depolarization, which signals ventricular contraction
On an ECG, PVC (premature ventricular contraction) is an early heartbeat originating from the ventricles, while PAC (premature atrial contraction) is an early heartbeat originating from the atria. Both can indicate potential heart rhythm abnormalities.
The normal time of ventricular contraction depends on the heart rate. The QT segment represents the ventricular contraction on an ECG exam. The corrected QT segment is 0.45 seconds for men and 0.46 seconds for women.
The lub sound occurs around the peak of the R wave in an ECG because it is associated with closure of the mitral and tricuspid valves, which happens at the beginning of ventricular contraction. This coincides with the R wave, which represents ventricular depolarization and the onset of ventricular systole.
The QRS complex on an ECG represents ventricular depolarisation. This wave should have the greatest amplitude.
On an ECG the heart rate will match both ventricular rate and atrial rate if the heart is normal. If people have atrial fibrilation then the ventricular rate will be used on the ECG to work out the rate of the ventricular contraction and vice-versa with ventricular fibrilation. Usually both atrial and ventricular rates match so if the atria contracts at 70 BPM the ventricles will beat at 70 BPM. It is possible for the ECG machine to work out atrial or ventricular rate if needs be. Usually, however, if the ECG machine just displays heart rate then both ventricular and atrial rates match.
P wave - represents atrial depolarization (contraction) QRS complex - ventricular depolarization T wave - ventricular repolarization (relaxation) atrial repolarization is "buried" within the QRS Complex