Diastolic impairment drives new-onset atrial fibrillation during acute myocardial infarction

Abstract

Abstract Introduction Recent studies underscore that new-onset atrial fibrillation (NOAF) in acute myocardial infarction (AMI) remains a clinically relevant issue. Contemporary registries show that patients who develop NOAF frequently display markers of elevated filling pressures. However, evidence is far from uniform: while several analyses support diastolic impairment as a central mechanism, others report only modest associations.

Purpose The study aimed to assess the link between diastolic dysfunction and new-onset atrial fibrillation during acute myocardial infarction.

Methods This prospective study included 150 adults with AMI. Patients were randomly assigned to two groups: those who developed NOAF in the acute phase and those who maintained sinus rhythm. Individuals with prior atrial fibrillation, major non-cardiac comorbidities limiting life expectancy, cognitive impairment, or substance abuse were excluded. All participants underwent standardized clinical, laboratory, and echocardiographic assessment.

Results A total of 150 individuals were enrolled, with a mean age of 67.4 ± 10.6 years (95% CI: 66–69). Sex distribution was comparable between the two groups, with no statistically significant difference observed (p = 0.12).

In the total cohort, STEMI was the dominant presentation, identified in 104 patients (69.3%; 95% CI: 62–77%), whereas non-STEMI accounted for 46 cases (30.7%; 95% CI: 23–38%). Cardiogenic shock was documented in 10 patients overall (6.7%; 95% CI: 2.7–11%), and all these events occurred exclusively in the NOAF group (10/751; 13.3%; 95% CI: 5.6–21%). Analysis of diastolic parameters revealed a markedly impaired diastolic profile in patients who developed new-onset atrial fibrillation during acute myocardial infarction. Left atrial volume index ≥34 mL/m² was more frequent in the NOAF group (44.0% vs. 14.7%; p < 0.001). Early filling velocity (E) was similar between groups, whereas A-wave velocity showed a significant reduction in NOAF patients (p = 0.001), resulting in a higher E/A ratio (median 1.4 vs. 1.0; p = 0.007). Additional markers of elevated filling pressures were consistently worse in the NOAF group. Vp was significantly reduced (61.3 ± 26.1 mm/s vs. 75.3 ± 20.0 mm/s; p < 0.001), and the E/Vp ratio was significantly higher (1.2 ± 0.5 vs. 0.9 ± 0.4; p = 0.002), with E/Vp ≥1.5 present in 38.7% of NOAF patients (p < 0.001). Global grading of diastolic dysfunction demonstrated a significant shift toward more advanced dysfunction in the NOAF group (p = 0.004): grade III dysfunction was present in 21.3% of NOAF patients versus 13.3% in those maintaining sinus rhythm. Markers of increased right-sided pressure, including higher TR velocity (p = 0.025) and reduced IVC respiratory variation (p < 0.001).

Conclusions In this AMI cohort, patients with NOAF showed larger atria, impaired relaxation, and higher filling pressures, indicating diastolic dysfunction as a key substrate predisposing to NOAF during acute ischemia.