Michael Madsen's manager previously said, 'What we understand is Michael had a cardiac arrest and was found unresponsive in his Malibu home' on July 3. The 'Kill Bill' actor was 67.

Michael Madsen’s doctor is confirming the actor’s cause of death, less than a week after the “Reservoir Dogs” star died. He was 67.

Madsen died from cardiac arrest, his manager Ron Smith told NBC News. Cardiac arrest occurs when the heart stops functioning. It can lead to death without immediate treatment, according to Mayo Clinic.