Question

what is happening in the heart during nonperfusing ventricular tachycardia. Be sure to address what is happening in the conduction system, how that affects the cardiac cycle (particularly stroke volume) and why that results in poor tissue perfusion. Why is this life-threatening? What does defibrillation do to treat it?

Answer 1

Ventricular tachycardia is a life threatening condition in which an abnormally rapid rhythm originates in the ventricle and causes the heart to beat inefficiently . What happens in it is that irritable ventricular focus takes over as a pacemaker site, OR may result from multiple ventricular foci attempting to become the pacemaker site

# Cause of V-Tach.

1. Myocardial Ischemia

2. Digitalis Toxicity

3. Myocardial Trauma

4. Hypoxia

5. Electrolyte Imbalance

The characteristics of V-Tach :-

- Complexes look similar to PVCs

- May see P Waves before complexes but uncommon

- Usually has a rate between 100 - 250bpm

# Complications with VT?

- Can decrease cardiac output

- Increase cardiac workload

- Decrease coronary perfusion

- Can quickly deteriorate into V-Fib

# Defibrillation is the treatment of choice for ventricular fibrillation or pulseless ventricular tachycardia.

Most effective when completed within 2 minutes of dysrhythmia onset.

Passage of discharged electrical shock through the heart to depolarize cells of myocardium. Allows SA node to resume pacemaker role.

How defibrillator works :-

When you discharge the paddles, a NONsynchronized electric charge (measured in joules) is delivered to the myocardium.

All cells are depolarize simultaneously and all electrical activity is temporarily stopped.

Usually the SA node is the first to recover and assume control.

Spontaneous repolarization of all cells results in atrioventricular synchrony.