Developments in Cardiology from Day 2 of ACC.23

What did we learn from the second day of the American College of Cardiology's (ACC) 72nd Scientific Session & Expo? Here are some of the latest developments.

Heart Attack Deaths Drop Over Past Two Decades

A hopeful trend was highlighted in a study presented at this year’s American College of Cardiology conference, showing heart attack-related deaths in the U.S. dropped over the past 20 years. While there is a noticeable difference between the number of heart attack-related deaths for White and Black individuals, the study found the gap is shrinking.

Researchers explored this data in a session titled “Trends in Acute Myocardial Infarction Age-Adjusted Mortality Rates by Race in the USA: 1999-2020.” Based on data from the Centers for Disease Control and Prevention, researchers noted heart attack-related deaths fell by 4 percent a year from 1999-2020.

Heart attack-related deaths per 100,000 people were reported as follows:

• 87 overall in 1999
• 38 overall in 2020
• 104 Black individuals in 1999
• 46 Black individuals in 2020

According to the study, 17 more Black individuals per 100,000 died from heart attack-related causes than White individuals in 1999. This number remarkably shrank to only 8 more Black individuals per 100,000 in 2020.

Experts continue to try to pinpoint what caused the decline. Improved diagnostic tools, new treatment options, and a greater emphasis on healthy lifestyles certainly contributed to the 20-year decline. Notably, there were more heart attack-related deaths reported in 2020, but researchers believe this to be related to the COVID-19 pandemic. Despite that slight increase, the study clearly illustrated new prevention strategies and advanced treatment options are not only lowering the number of heart attack-related deaths but closing the gap in healthcare racial disparities.

Insights from the RAPID-HF Trial

Heart failure with preserved ejection fraction, or HFpEF, accounts for less than 50 percent of all heart failure patients. Because of this, there are only a few effective treatments for this condition.

­In a session titled “Rate-Adaptive Atrial Pacing for Heart Failure with Preserved Ejection Fraction: The RAPID-HF Trial,” researchers predicted that the implementation of a rate-adaptive atrial pacemaker to augment exertional HR will improve exercise performance in patients with HFpEF and chronotropic incompetence.

The RAPID-HF trial was a single-center, double-blind, RCT that aimed to test the effects of rate-adaptive atrial pacing in patients with HFpEF. The primary endpoint was a VO₂ at the anaerobic threshold. Some Of the secondary endpoints included peak VO_2, ventilatory efficiency, patient-reported health status by the KCCQ-OSS, and safety.

To assess this, researchers evaluated patients on a pacing off/pacing on basis. They evaluated sinus rhythm and chronotropic incompetence.

Based on the results, the researchers were able to learn the following:

• With rate-adaptive atrial pacing, there were no beneficial improvements in heart rate during exercise performance or health status.
• The lack of a clear benefit may have to do with the decrease in stroke volume during exercise preventing gains in cardiac output
• Any adverse events were likely related to the implantation of the pacemaker and were infrequent

The trial’s key results don't support the use of rate-adaptive atrial pacing to treat patients with HFpEF and chronotropic incompetence.