Life expectancy for an individual suffering from an untreated stiff heart is less than two years, according to WebMD. Cardiac amyloidosis, or stiff heart, cannot be cured, and an individual suffering from this ailment must receive a heart transplant.
Amyloidosis occurs when a protein abnormally accumulates in an individuals organs and tissues, reports WebMD. This accumulation can lead to fatal organ failure. If amyloidosis occurs in the heart, the cardiac walls thicken and stiffen. This impacts the rhythm and strength of the heart. According to WebMD, the symptoms of cardiac amyloidosis are cardiac arrhythmia, shortness of breath and the signs of heart failure.