There is nothing in the medical journals that supports a strike, blow or non penetrating trauma to any of these dim mak "death points" causing immediate or delayed state of being deceased. Nothing. Other than the concept of commotio cordis, whereby a blow to the sternum, during a certain and very brief part of the relaxation phase of the ventricles of the heart, can cause a dysrhythmia known as ventricular fibrillation. Ventricular fibrillation causes cardiac arrest, and if patients are not successfully resuscitated soon after the event, death will occur. "Delayed death", in terms of hours, is generally not possible, unless the blow to the sternum and the underlying heart was serious enough to cause cardiac contusion, a focus of heart damage that itself gives rise to an arrythmia that leads to ventricular fibrillation. The blow to the chest must occur during a certain phase of cardiac relaxation, and that phase is a very brief part of the cardiac cycle. It must be of a certain energy, usually five joules or more, and over a certain part of the heart, generally in the sternal area. Non penetrating trauma to these other so called "dim mak death points", from a current medical and scientific viewpoint, are just not possible, with the exception of rib fracture and possible resultant tension pneumothorax.
This is an important concept, one which should be well understood given the propensity for martial arts enthusiasts to spar. Contact sports can lead to dangerous conditions, and one of the critical concepts one should take from this, is that there is a danger to central chest strikes. The risk of causing a serious adverse event is low, but considering that the result can be death, should give all to believe that proper sparring equipment be used during contact martial arts training, and, more importantly, that central chest strikes can be very dangerous.