TOPLINE: 

Patients with hypertrophic cardiomyopathy (HCM) had a higher long-term risk for out-of-hospital cardiac arrest than matched individuals without the condition, with older age at diagnosis of HCM and recent or ongoing heart failure associated with a higher risk. 

METHODOLOGY:

• Researchers conducted a cohort study and a nested case-control study using data from multiple Danish registers from June 2001 through December 2022 to estimate the long-term risk for out-of-hospital cardiac arrest after a first-time diagnosis of HCM and to identify associated factors.
• For the cohort study, they identified 5901 adults with incident HCM (median age, 65 years; 55.5% men) and matched them with 23,339 control individuals without the condition.
• The nested case-control study included 250 patients with HCM who experienced out-of-hospital cardiac arrest (median age, 68 years; 66.8% men), matched with 1000 patients with HCM who did not experience out-of-hospital cardiac arrest.
• The primary outcome was the first out-of-hospital cardiac arrest during which resuscitation was attempted.
• Researchers followed up for a median duration of 21.6 years. Patients and control individuals were followed up until out‑of‑hospital cardiac arrest, death, turning older than 85, emigration, or end of study, and analyses were adjusted for competing risks.

TAKEAWAY:

• Patients with HCM had a higher 10-year risk for out-of-hospital cardiac arrest than control individuals: 2.8% vs 1.5% among those aged 18-60 and 4.3% vs 3.3% among those 61-85 years.
• Each 10-year increase in age at diagnosis of HCM was associated with a 41% increased risk for out-of-hospital cardiac arrest (P < .001).
• Recent heart failure (< 1 year) was associated with a 3.63-fold increased risk for out-of-hospital cardiac arrest (P = .003), and longer-term heart failure (≥ 1 year) was associated with a 2.82-fold increased risk (P < .001).
• Other factors associated with a higher risk for out-of-hospital cardiac arrest included longer-term atrial fibrillation, longer-term chronic kidney disease, liver disease, and initiation of beta‑blocker treatment within 90 days.

IN PRACTICE:

“The nested case-control study demonstrated that patients with HCM who experienced an OHCA [out-of-hospital cardiac arrest] had a higher occurrence of HCM-related conditions such as heart failure, atrial fibrillation, and stroke, compared with patients with HCM who had not experienced an OHCA,” the researchers of the study wrote.

SOURCE:

The study was led by Rasmus Bork Dinesen, MD, of Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark. It was published online on April 29 in JAMA Network Open.

LIMITATIONS: 

The registers lacked information on cardiac MRI, echocardiography, genetic testing, or ECG data. Researchers relied on diagnostic codes to identify HCM, which may have misclassified other heart conditions. They included only out-of-hospital cardiac arrests where resuscitation was attempted and had no data on causes of arrest.

DISCLOSURES:

The study received support from the Novo Nordisk Foundation and the Birthe and John Meyer Family Foundation. One author reported receiving grant support from Rigshospitalets Forskningspulje and another from Novo Nordisk A/S. One author reported receiving consulting fees from Cytokinetics Incorporated and Boston Scientific Corporation.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.