Troponin-T Levels Predict New AF in Large Cohort Study

Pam Harrison

February 03, 2015

Baseline and serial measures of high-sensitivity cardiac troponin T (hs-TnT) predict incident atrial fibrillation (AF) independently of traditional risk factors, suggests a new analysis from the Cardiovascular Health Study (CHS)[1].

"Our study shows that circulating troponin levels from either myocyte damage or protein turnover occurs upstream and predisposes to AF in older adults," Dr Ayman Hussein (Cleveland Clinic Foundation, OH) told heartwire by email. "And it highlights a key element in cardiac structural remodeling that leads to AF."

Hussein is lead author of the study, published online January 17, 2015 in Heart Rhythm.

The study population consisted of 4262 participants in CHS without AF who had hs-TnT levels at enrollment. About one-third of patients had hs-TnT levels less than 3.00 ng/L, and the remaining had levels 3.00 ng/L or higher.

During a median follow-up of 11.2 years, 32% of participants developed new-onset AF, the group reported. "Participants with higher hs-TnT levels at baseline were more likely to have incident AF during follow-up."

In covariate-adjusted analyses, the hazard ratio (HR) for AF among patients in the third tertile of hs-TnT was 75% greater than patients with undetectable levels at baseline.

The HR for AF attenuated somewhat to HR 1.38 (95% CI 1.16–1.65) but remained significant in the third tertile after further adjustment for baseline natriuretic peptides and C-reactive protein. With that adjustment, the HR for the second tertile lost significance.

Hazard ratio (95% CI) for AF by baseline hs-TnT tertile (reference, <3.00 ng/L)

hs-TnT tertile (ng/L) HR (95% CI)
1 (3.00–6.23) 1.08 (0.93–1.27)
2 (6.24–10.97) 1.27 (1.09–1.49)
3 (>10.97) 1.75 (1.48–2.08)
Adjusted for age, race, sex, body mass index, prevalent MI or CAD, prevalent heart failure, smoking status, systolic blood pressure, fasting glucose level, antihypertensive drugs, antiarrhythmic agents, digoxin use, and incident heart failure

"As of today, no clinical trial data exist to support any intervention based on circulating troponin levels as a risk marker of AF," Hussein cautioned. However, he said, the same biomarker has been associated with incident heat failure and mortality in multiple studies.

Hussein pointed out the significant demonstrated association between hs-TnT and risk of CV mortality and sudden cardiac death beyond that of traditional risk factors. The current study, he said, "helps [us] better understand the mechanisms that lead to AF in older adults, and we depend on understanding such mechanisms to be able to initiate upstream therapies [in the future]."

Hussein had no relevant financial interests to declare. Disclosures for the other authors are listed in the report.

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