I would think it is very possible that they can target the heart, being of the shark family, I would think that they are equipped with the Lateral Line Sensing Systems of that genus:
http://www.elasmodiver.com/shark_senses.htm
Vision:
Many sharks depend heavily on their vision whilst hunting although there are occasions where the eyes play little or no role at all such as when a hammerhead is searching for a stingray which is completely buried. In the majority of species, the eyes are well developed, large, and complex structures. Some species are also able to sense light and dark through a thin area of skin on top of the head which leads directly to the pineal gland in the brain. As there is no lens to focus the light there is no shape perception but the shark may be able to use the differing light levels to time its vertical migration throughout the day.
When sharks are close to prey it appears that their electrical sense takes over from sight or smell. This would explain why sharks which have been chummed to a fishing or shark diving boat will sometimes attack the propellers and other metal objects rather than the bait which has been put in the water in front of them. Photographers (and I can testify to this) may have the unnerving experience of having a shark maul their underwater camera strobes which emit strong electrical fields. Sharks will also respond more aggressively to the erratic electrical signals emitted by a wounded animal. This may explain why shark attack victims are repeatedly bitten whilst rescuers swimming next to them often remain completely unscathed.
http://www.physorg.com/news10587.html
Using molecular tests, scientists found two independent genetic markers of neural crest cells in the animal’s electricity-sensing organs. Analysis shows these cells migrate from the brain and travel into the developing shark’s head, creating the framework for the electrosensory system — a previously unknown function of a much-studied group of cells, according to Renata Freitas, a doctoral candidate in the zoology department and first author of the paper.
http://www.elasmo-research.org/educ...ingray_city.htm
The venom is a fairly powerful nerve toxin which affects the heart in complex and dangerous ways.
From what I can find out possibly yes?
http://www.guppiesfishing.com/modul...rticle&sid=1817
Stingrays
(Potentially serious injury)
Stingrays, Skates and Rajiformes are cartilagenous fish related to sharks. As bottom feeders hiding in the sand, they may be stepped on by the people while wading in shallow water. Stingrays posses a long tail with a venemous barb at the end. If a ray is stepped on, it will flail its tail around vigorously. T he sharp barbed tail can result in considerable damage to the hapless reef walker. The venom in the barb affects the cardiovascular system (heart and blood vessels) and can even cause irregular heart rhythms and in some cases cause the heart to stop beating all together!
Symptoms of Stingray venom injury
· The barbed tail itself can do considerable damage and there may be significant bleeding (hemorrhage).
Pain at the site of injury is immediate and intensifies over 30-90 minutes. and will gradually subside over the next 6-48 hours depending on the amount of venom delivered.
· The venom from the barbed tail affects the cardiovascular system (heart and blood vessels), causing both peripheral vasoconstriction (blanched white extremities) or dilatation (beefy red extremities).
· The venom may also cause arrhythmias (irregular heartbeats) or even asystole (the heart may stop beating altogether).
· The venom can act on respiratory centers in the brain and cause a slowing of respiration.
· Convulsion may develop from the venom's effect on other brain center.
Treatment of Skin injuries from Stingrays.
1. SEEK PROMPT MEDICAL ATTENTION! --The venom of stingrays can affect both repiration and heart rate. Intravenous medication may be necessary to maintain heart rate, and if respiration is slow enough, mechanical ventilation may be required!
2. The wound should be well irrigated with saline solution.
3. Stingray venom is destroyed by heat, and it is advisable to soak the affected extremity in hot water (120°F) for 30 minutes to 1 hour.
4. Intravenous calcium gluconate may be required to prevent muscle spasms.
5. Local infiltration of the wound with lidocaine may be required for pain relief, as well as meperidine or some other narcotic analgesic.
6. Surgical debridment (removal of dead tissue) may be necessary if the wound is severe. The patient should be given tetanous toxoid and antibiotics to prevent secondary infection.
