Increase in Isovolumic Relaxation Time May Increase Risk for Incident Heart Failure

Increased heart failure (HF) among patients aged less than 65 years is associated with an increase in isovolumic relaxation time (IVRT), with cardiac time intervals also increasing significantly with age, according to study findings published in the International Journal of Cardiology.

IVRT, isovolumic contraction time (IVCT), left ventricular ejection time (LVET), and the myocardial performance index (MPI; defined as IVCT+IVRT/LVET) represent the cardiac time intervals. Investigators assessed whether normal aging includes longitudinal changes in cardiac time intervals among a heart-healthy population.

Secondary aims included identification of risk factors for cardiac time interval acceleration and to determine whether an increased risk for incident HF is associated with longitudinal changes in these time intervals.

Investigators conducted a longitudinal cross-sectional analysis of the 4^th and 5^th Copenhagen City Heart Study (CCHS4 and CCHS5, respectively; ClinicalTrials.gov Identifier: NCT02993172 ), designed as a prospective cohort study to identify cardiovascular risk factors among participants from the general population in Denmark. Patients from the original study who underwent echocardiographic examination with color tissue Doppler imaging were included in the analysis.  

Incident HF was the primary endpoint and all-cause death the competing event, with study examinations performed 10.5 years apart. Multivariable linear regression was used to assess the impact of clinical and nonclinical factors on changes in cardiac time intervals.

Investigators found a significant increase over time in IVRT (12±22 ms), IVCT (5±15 ms), LVET (2±29 ms), and consequently MPI (0.05±0.12).

An increase in IVRT was associated with male sex (P =.044), smoking (P =0.006), diastolic blood pressure (P =0.030), and age (P <.001). Impact of age on change in IVRT was marked until about 60 years.

An IVRT decrease was accelerated by higher levels of hemoglobin A1c (P =.039). Increase in IVCT was not accelerated by any of the clinical factors explored in this study.  

An accelerated decrease in LVET was associated with systolic blood pressure (P =.043) and male sex (P =.020).

Among participants aged less than 65 years, an increased risk for subsequent HF was associated with increasing IVRT over a 10-year period (per 10 ms increase, P =.034).

Smoking (P =.011), higher diastolic blood pressure (P =.020), male sex (P =.021), and more advanced age (P =.001) were noted as accelerators of an increase in MPI.

Study limitations included use of different ultrasound machines and postprocessing software versions to perform echocardiographic examinations during CCHS4 and CCHS5, lack of antihypertensive medication data, and low numbers of cardiac events.

“It is of clinical importance to identify the risk factors that accelerate changes of the cardiac time intervals. This could potentially guide risk factor modification and improve the understanding of the aging heart assessed by the cardiac time intervals,” study authors stated.

Disclosure: At least one study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.