They may engage in 'expressive panting', by making a distinct 'ha-ha-ha-ha' sound as an invitation to play or to indicate a desire for nearby food. They sometimes whine.The PWD's biddability, high intelligence, and tendency to vocalise and then seek out its human master when specific alarms occur make it an ideal hearing-ear or deaf-assistance dog. PWDs can be readily trained to bark loudly when a telephone rings, and then to find and alert a hard-of-hearing or deaf master. Juvenile dilated cardiomyopathy is a fatal condition caused by an autosomal recessive gene. Affected puppies die suddenly or with very little warning usually between the ages of six weeks to seven months old. The signs and symptoms include a 12- to 48-hour onset of loss of appetite, decreased energy level, vomiting, and difficulty breathing.