Arrhythmia-Ventricular Fibrillation and Pulseless Ventricular Tachycardia

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Two life-threatening cardiac rhythms that can lead to ineffective ventricular contractions are ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT). VF (Figure 24) prevents the ventricular walls from pumping, as it causes a rapid quivering, and this motion doesn’t synchronize with atrial contractions. VT (Figure 25), on the other hand, causes the ventricles to contract more than 100 times per minute. Pulseless VT is the emergency condition of VT, which is when ventricular contraction occurs so rapidly that the heart has no time to refill, which results in a pulse that can’t be detected. Tissues no longer receive adequate blood flow in individuals suffering from these conditions. ACLS deals with VF and VT similarly, despite the two having individual ECG rhythms and being different pathological phenomena. The BLS Survey begins the resuscitation for VF and pulseless VT.

An AED assesses whether a shock is required by analyzing the heart’s rhythm. It is programmed only to direct the user into shocking VF and VT rhythms. The machine cannot determine, however, if there is a pulse with the patient, which is why using an AED on someone with a palpable pulse is discouraged. A manual defibrillator and a cardiac monitor will usually be used to conduct ACLS responses to VF and pulseless VT when in a hospital. Therefore, it is the ACLS provider’s responsibility to analyze and read the rhythm. Only for VF and pulseless VT should shocks be delivered; similarly, blood pressure drugs and antiarrhythmic drugs can also be used.

Rules for Ventricular Fibrillation (RF)

ACLS Rhythm - Ventricular Fibrillation

Figure 24

Regularity There is no regularity shape of the QRS complex because all electrical activity is disorganized.
Rate The rate appears rapid but the disorganized electrical activity prevents the heart from pumping.
P Wave There are no P waves present.
PR Interval There are no PR Interval present.
QRS Complex The ventricle complex varies

Table 5

Rules for Ventricular Tachycardia

(Regular/Rapid Wide Complex Tachycardia)

ACLS Rhythm - Ventricular Tachycardia

Figure 25

Regularity R-R intervals are usually, but not always, regular. RATE
Rate The atrial rate cannot be determined. Ventricular rate is usually between 150 and 250 beats per minute.
P Wave QRS complexes are not preceded by P waves. There are occasionally P waves in the strip, but they are not associated with the ventricular rhythm.
PR Interval PR interval is not measured since this is a ventricular rhythm.
QRS Complex QRS complex measures more than 0.12 seconds. The QRS will usually be wide and bizarre. It is usually difficult to see a separation between the QRS complex and the T wave.

Table 6

Rules for Torsades De Pointes

(Irregular Wide Complex Tachycardia)

ACLS Rhythm - Torsades de pointes

Figure 26

Regularity There is no regularity.
Rate The atrial rate cannot be determined. Ventricular rate is usually between 150 and 250 beats per minute.
P Wave There are no P waves present.
PR Interval There are no PR intervals present.
QRS Complex The ventricle complex varies.

Table 7

Take Note

The AED isn’t equipped to detect whether an individual has a pulse; VF and pulseless VT are shockable rhythms.

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