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Increased ventilatory response to exercise in symptomatic and asymptomatic LMNA mutation carriers: a follow-up study
Laura Ollila1, Tiina Heliö1, Anssi Sovijärvi2
1Heart and Lung Centre, Helsinki University Central Hospital, Helsinki, Finland.
Insights
LMNA mutations can cause heart disease. Asymptomatic carriers show increased ventilatory response during exercise, suggesting a preclinical sign of lamin A/C (LMNA) cardiomyopathy.
Area of Science:
- Cardiology
- Genetics
- Pulmonary Medicine
Background:
- Mutations in the LMNA gene are a significant cause of cardiomyopathy, leading to arrhythmias, heart failure, and potentially heart transplantation.
- Screening of family members identifies an increasing number of asymptomatic LMNA mutation carriers.
- Cardiolaminopathy, caused by LMNA mutations, presents a spectrum of clinical manifestations.
Purpose of the Study:
- To investigate disease progression in asymptomatic LMNA mutation carriers.
- To compare disease progression in symptomatic cardiolaminopathy patients.
- To utilize serial spiroergometric testing in a prospective follow-up study.
Main Methods:
- 26 LMNA mutation carriers underwent annual spiroergometry, clinical assessment, lab tests, and echocardiography for up to 5 years.
- 23 control subjects had a single clinical assessment and spiroergometry.
- Mutation carriers were divided into asymptomatic (12) and symptomatic (14) groups.
Main Results:
- Symptomatic carriers exhibited a higher ventilatory equivalent for CO2 (V˙E/V˙CO2 slope) and lower end-tidal CO2 (FetCO2) compared to controls.
- Asymptomatic carriers also demonstrated an increased ventilatory response to exercise over the follow-up period.
- This increased response was evidenced by a rising V˙E/V˙CO2 slope and decreasing FetCO2.
Conclusions:
- An elevated ventilatory response during exercise may indicate a preclinical stage of dilated cardiomyopathy (DCM) in LMNA mutation carriers.
- Spiroergometry can detect early functional changes in individuals with LMNA mutations.
- This finding aids in identifying individuals at risk for developing symptomatic cardiolaminopathy.
Background:
LMNA mutations are an important cause of cardiomyopathy often leading to cardiac arrhythmias, heart failure and even heart transplantation. An increasing number of asymptomatic mutation carriers are identified, as family members of the index patients are screened. Our aim was to study the disease progression in asymptomatic LMNA mutation carriers and in patients with symptomatic cardiolaminopathy by repeated spiroergometric testing in a prospective clinical follow-up study.
Methods And Results:
We studied 26 LMNA mutation carriers once a year during 5 years up to 6 times by spiroergometry, clinical assessment, laboratory tests and echocardiography. The 23 control subjects underwent clinical assessment and spiroergometry once. Twelve of the mutation carriers were asymptomatic, and 14 had some clinical manifestations of the mutation ranging from clinically relevant rhythm disturbances to DCM and heart failure. Compared to controls, the symptomatic carriers showed a higher slope of the ventilatory equivalent for CO2 (V˙E/V˙CO2 slope) and a lower fraction of end-tidal CO2 (FetCO2 ). The asymptomatic mutation carriers also showed an increased ventilatory response to exercise during the follow-up as indicated by increased V˙E/V˙CO2 slope and decreased FetCO2 .
Conclusions:
The study suggests that an increased ventilatory response during exercise might reveal a preclinical manifestation of DCM in LMNA mutation carriers.
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