Heart rate variability patterns in anterior st-segment elevation myocardial infarction versus inferior st-segment elevation myocardial infarction patients treated by primary percutaneous coronary intervention

Abstract

Introduction: Heart rate variability (HRV) has been known as a measurable parameter of the cardiac autonomic function. The cardiac autonomic innervation is heterogeneous and hence leads to different patterns of autonomic modulation. The normal pattern of autonomic modulation is altered in the case of myocardial infarction, the pattern of alteration is not uniform, and it depends on the infarcted wall or region of the heart. Primary percutaneous coronary intervention (PCI) is the gold standard therapy for revascularization of ST-segment elevation myocardial infarction (STEMI) cases, but still conflicting and nonconclusive data are available on the modifications that happen to the cardiac autonomic function after a successful primary PCI with restoration of the Thrombolysis in Myocardial Infarction III flow in the infarct-related artery (IRA). Aim of The Work: Studying and comparing the pattern of autonomic modulation between anterior STEMI patients and inferior STEMI patients. Methods and Results: A total of 93 consecutive patients (56 males and 37 females) presented by STEMI and treated by primary PCI at our cath lab at Ainshams university hospitals (a 24/7 tertiary referral center for primary PCI) during the period between February 2016 and March 2017; 48 had an anterior wall STEMI (ANT) and 45 had an inferior wall STEMI (INF). Mean duration for hospital stay was 4 ± 2 days. Electrocardiogram and respiration were recorded within the day of admission (DA) and at day of discharge (DD). Cardiac autonomic modulation was evaluated using symbolic analysis (SA) of HRV. The first recording for HRV by SA (DA recording) was performed after 18 ± 6 h from primary PCI as soon as the IRA has been opened and the patient stabilized in the cardiac care unit (CCU) for 12 h at least. The second recording for HRV by SA (DD recording) was performed at the DD (duration of admission was 4 ± 2 days). SA recordings showed a significantly predominant of vagal modulation in anterior STEMI patients compared to inferior STEMI at DA, as indicated by 2LV% (10% [7–15] vs. 6% [2–9], P = 0.03). Moreover, at DA, inferior STEMI patients had a significantly higher 0V%, index of sympathetic modulation, compared to anterior STEMI patients (33% [18–47] vs. 19% [12–29], P = 0.02). The second recordings on the DD (DD recording) showed nonsignificant difference between the anterior STEMI and the inferior STEMI groups. Conclusion: After revascularization by primary PCI for STEMI patients, the group presenting by inferior STEMI were characterized by a sympathetic predominance, while those presenting by anterior STEMI were characterized by a predominant vagal modulation. This difference in the sympathetic modulation between the two groups disappeared at the time of discharge from the hospital.