A palpable pulse that presents with a chaotic rhythm and no predictable pattern is called:

A palpable pulse that presents with a chaotic rhythm and no predictable pattern is called irregularly irregular pulse. An irregularly irregular pulse is a pulse in which the heart beats are spaced very irregularly with no fixed or discernable pattern. Causes of irregularly irregular rhythms include atrial fibrillation, premature atrial contractions and premature ventricular contractions. When this pulse is confirmed using electrocardiography (ECG), it shows 'saw tooth' pattern, and irregularly irregular normal QRS complexes.

A pulse with unpredictable pattern is termed as an irregularly irregular pulse. This kind of pulse coincides with an irregularly irregular heart rhythm seen in those with severe arrhythmias such as 3rd degree AV block. In contrast, there is a pulse that is irregular but has a predictable pattern termed as regularly irregular.