Explanation:
In third-degree atrioventricular block (AVB), also known as complete heart block, the atrial electrical impulses fail to conduct to the ventricles. This results in an independent rhythm between the atria and ventricles, leading to the characteristic dissociation between P waves and QRS complexes on an ECG.
Explanation:
In a complete heart block, there is a dissociation between the atrial and ventricular rates, resulting in regular P-P intervals (atrial rate) and regular R-R intervals (ventricular rate), but occurring at different rates due to the interruption in the electrical conduction between the atria and ventricles.
Explanation:
Semilunar valves, including the aortic and pulmonary valves, prevent the back flow of blood from the aorta and pulmonary arteries into the ventricles during diastole by closing when the ventricles relax, thus maintaining one-way blood flow through the heart.
Explanation:
The left ventricle contains the most muscle mass of the heart because it is responsible for pumping oxygenated blood throughout the entire body, requiring significant muscular force.
Explanation:
If a dual chamber pacemaker's ventricular lead senses a non-cardiac signal, it may incorrectly interpret it as a heartbeat, leading to a failure to deliver the appropriate pacing stimulus to the ventricle. This can result in a failure to ventricular pace, meaning the ventricle does not receive the necessary pacing impulse, potentially leading to symptoms related to bradycardia or other rhythm disturbances.
Explanation:
Atrial flutter is characterized by a rapid, regular atrial depolarization originating from a single reentrant circuit within the atria. This single reentry focus leads to the characteristic sawtooth pattern on an ECG.
Explanation:
Junctional tachycardia is a type of arrhythmia where the heart rate is typically between 100 to 140 beats per minute (bpm), with rates exceeding the normal range for the junctional pacemaker. Therefore, a rate of 130 bpm could be considered within the range of junctional tachycardia.
Explanation:
A junctional escape rhythm is characterized by a regular rhythm, narrow QRS complexes, and rates typically between 40 to 60 bpm. In this rhythm, the electrical impulses originate from the atrioventricular junction (AV node or His-Purkinje system) as a backup pacemaker when the normal pacemaker fails to function.
Explanation:
A PVC (Premature Ventricular Contraction) that occurs during the relative refractory period, where the ventricles are still in a vulnerable state, is referred to as the R-on-T phenomenon. It's called so because the PVC occurs on the peak of the T wave of the preceding beat, potentially leading to dangerous arrhythmias like ventricular tachycardia or ventricular fibrillation.
Explanation:
The conduction system of the heart terminates with the Purkinje network, which consists of specialized fibers responsible for rapidly conducting the electrical impulses to the myocardium, triggering ventricular contraction.
Explanation:
In a paced atrial rhythm, regular spikes are seen representing the pacing of the atria by the pacemaker. This is characterized by consistent atrial pacing spikes followed by atrial depolarization.
