 In addition to causing shortness of breath, pulmonary hypertension can cause excess fluid buildup in the legs, feet, and sometimes around the heart. When scleroderma affects the heart, heartbeats can become irregular. Heart failure may happen in some people. Digestive complications of the disease can include heartburn and difficulty swallowing. Scleroderma can cause bouts of cramping, bloating, constipation, or diarrhea.