Assessment of Heart Failure Signs and Symptoms in DMD
HF management has been well study with guidelines from multiple medical
associations supporting the use of these guidelines57-59. HF warning signs
and symptoms are common and direct care and frequently used as outcomes
measures in trials. These include shortness of breath, persistent cough
or wheezing, building up of fluid in the tissue (edema), fatigue, lack
of appetite, nausea, confusion or impaired thinking as well increase
heart rate. The utility of HF classifications including the NYHA
classification have been well published and shown to improve patient
outcomes 58,
60. Stages of HF established the extent
of risk and disease and are used to guide treatment changes clinically
and used to determine outcomes in therapeutic trials61-63. Neuromuscular
disease (NMD) such as DMD universally develop cardiomyopathy and
HF19. Due to skeletal
and respiratory muscle disease, HF signs and symptoms are frequently
masked and have limited utility. DMD-CM patients lack traditional HF
symptoms making NYHA classification challenging even in advances stages64,
65. Care guidelines frequently comment
on HF in DMD-CM but suggest lack of symptoms due to skeletal muscle
weakness and the use of supportive equipment. Many concluded that HF
signs and symptoms are frequently absent and when present are vague and
non-specific 66,
67. In the absence of reported symptoms,
HF scoring systems, such as the NYHA functional classification, are
often falsely reassuring, even in the setting of marked ventricular
dysfunction. In a study by the Pediatric Cardiomyopathy Registry Study
Group only 30% DMD patients have any HF symptoms at diagnosis but the
group was not able to determine if these symptoms were all cardiac or
from skeletal muscle weakness. The team concluded that DMD patients have
a higher mortality than non-DMD cardiomyopathy patients and recommended
imaging rather relying on HF symptoms to track and manage DMD patients68.