Cardiac rate is routinely assessed by the radial pulse. The examiner should stand in front of the patient and grasp both radial arteries. The second, third, and fourth fingers should overlie the radial artery, as shown in Figure 14-22. The examiner should count the pulse for 30 seconds and multiply the number of beats by 2 to obtain the beats per minute. This method is accurate for most regular rhythms. If the patient has an irregularly irregular rhythm, as is found in atrial fibrillation, a pulse deficit may be present. In atrial fibrillation, many impulses bombard the atrioventricular node and ventricles. Owing to the varying lengths of diastolic filling periods, some of the contractions may be very weak and unable to produce an adequate pulse wave despite ventricular contraction. A pulse deficit, which is the difference between the apical (precordial) and radial pulses, occurs. In such cases, only auscultation of the heart, not the radial pulse, provides an accurate assessment of the cardiac rate.