block degree av atrioventricular second nd rd ventricular ecg type 
ventricular atrial tested tachycardia degree old fibrillation block lvef arrhythmias 
ventricular fibrillation atrial tachycardia arrhythmia contractions premature flutter uncontrolled controlled 
ventricular tachycardia fibrillation history pointes arrhythmia torsades arrhythmias sustained clinically 
ventricular atrial heart tachycardia degree fibrillation block lvef arrhythmias old