Nul said that allowed the nurse and patient to get to know each other.

CNN: Study: Heart patients helped by phone calls

Azerbaijan's President Ilham Aliyev has ordered an inquiry into why his country gave Russia "nul points" at Saturday's Eurovision Song Contest.

BBC: Eurovision: Azerbaijan probes Russian 'nul points'

Dr. Daniel Nul, who presented the findings of the study at a briefing held at the annual Scientific Sessions of the American Heart Association, said phone intervention also leads to a smaller -- 5 percent -- reduction in mortality.

CNN: Study: Heart patients helped by phone calls

But, Nul said, the cost of this intervention is lower than the cost of patients being hospitalized, a significant point because much of the cost associated with congestive heart failure stems from patients needing to be hospitalized after they suffer setbacks.

CNN: Study: Heart patients helped by phone calls