A German nurse has been sentenced to life in prison after confessing to killing everal patients with overdoses of heart medication simply because he found it challenging trying to revive them.

The Associated Press reports the 38-year-old man, only identified as Niels H., was found guilty of two counts of murder, two counts of attempted murder and another charge of causing serious bodily harm.

"The court concluded that the accused used the heart medication to bring about a life-threatening situation in five cases, so as to make himself appear particularly competent when he revived them," said Oldenburg regional court spokesperson Daniel Moennich said.

During court proceedings, Niels told the court he intentionally brought about cardiac episodes for some 90 patients because he enjoyed the feeling of being able to resuscitate them. In total, he estimated that as many as 30 patients died.

Several media outlets have reported the court found that Niels bore a "particular severity of guilt," meaning that he will be not be eligible for a commuted sentence before serving at least 15 years. He has also been legally stripped of his medical license.

"These people were pawns in a game for you -- a game that only you could win and all the others could only lose," presiding judge Sebastian Buehrmann told the defendant.

Niels H. was previously sentenced to 7 and a half years in prison for attempted murder in 2008 and police have now launched an investigation into as many as 200 deaths that occurred during his time working in Delmenhorst, Oldenburg area.

During proceedings, Niels apologized to the family of his victims, telling them, "usually the decision to do it was relatively spontaneous."

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