Final answer:
Without atrial stimulation, the ventricular beat rate would be determined by the next quickest part of the conduction system, with the AV node taking lead at 40-60 beats per minute, followed by slower rates from other components if the AV node is also nonfunctional.
Step-by-step explanation:
The ventricular beat rate without atrial stimulation, meaning in the absence of signals originating from the sinoatrial (SA) node, depends on the intrinsic rates of other parts of the cardiac conduction system. Without the SA node, the atrioventricular (AV) node would likely take over with an inherent firing rate of 40-60 beats per minute. If the AV node were also compromised, the atrioventricular bundle (or Bundle of His) would set the pace at approximately 30-40 beats per minute, followed by the bundle branches at 20-30 beats per minute, and finally, the Purkinje fibers at 15-20 beats per minute. These rates are notably slower than the normal sinus rhythm set by the SA node, which ranges from 80-100 beats per minute, and could result in bradycardia, a condition characterized by slower than normal heart rate.