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Brain & Heart Atropine can reducing reperfusion vagal reflex in STEMI

wall infarction . Experimental evidence has suggested two adjacent leads of ≥0.25 mV in men below the age of
[1]
that this cardiac reflex may result from the activation of 40 years and/or ≥0.2 mV in men over the age of 40 years, or
inhibitory cardiac receptors with vagal afferents located ≥0.15 mV in women in leads V2 – V3 and/or ≥0.1 mV in
predominantly in the inferior or posterior wall of the other leads (in the absence of left ventricular hypertrophy
left ventricle . Atropine has been recommended as the [LVH] or left bundle branch block [LBBB]). The patients
[2]
treatment of choice for hypotension and/or premature were randomly selected and divided into an experimental
ventricular depolarizations in patients with acute group and a control group depending on whether they
myocardial infarction and bradycardia because atropine received atropine preconditioning. The experimental
can counteract vagal tension . group was further divided into two subgroups: a low-dose
[3]
Inferior ST-elevation myocardial infarction (STEMI) is group (0.5 – 1 mg atropine) and a high-dose group (2 mg
predominantly caused by acute thrombotic occlusion of the atropine). The exclusion criteria included (1) lack of clinical
right coronary artery or the left circumflex artery. During data; (2) prior implantation of permanent or temporary
emergency percutaneous coronary intervention (PCI) pacemakers before STEMI; (3) a history of bradycardia,
for inferior STEMI, severe reperfusion reactions such as hypotension, ventricular tachycardia, or ventricular
bradycardia, hypotension, ventricular tachycardia, nausea, fibrillation with a definitive cause (unrelated to the disease
and vomiting often occur . The traditional approach is to under study); (4) prior PCI or coronary artery bypass graft
[4]
provide hypervolemic treatment and drug therapy, such as (CABG) for myocardial infarction; and (5) unwillingness
dopamine, norepinephrine, or atropine, when reperfusion to participate in the study.
reactions occur, as well as early or immediate temporary Atropine preconditioning was defined as the
pacemaker treatment, which conversely increases the risk administration of 0.5–2 mg atropine through the coronary
of operative complications . artery immediately before the passage of the guidewire. In
[5]
Studies have suggested that the use of atropine during the low-dose group, 0.5–1 mg atropine was injected into the
PCI for acute inferior myocardial infarction can reduce the coronary artery when the guidewire was passed through;
risk of reperfusion arrhythmia and hypotension, alleviate in the high-dose group, 2 mg atropine was injected prior
myocardial cell injury, improve cardiac function, shorten to reperfusion. The choice of treatment with atropine
the treatment time, and reduce the risk of mortality [3,6] . and the choice of dose were left to the physician based on
However, evidence concerning the prevalence of the patient’s signs and symptoms before administration.
reperfusion vagal reflex-related events after atropine The management of the patients was in accordance with
preconditioning and the recommended dosage remains the European Society of Cardiology Guidelines for the
elusive. Therefore, the aim of this study was to evaluate management of STEMI .
[6]
the potential of atropine at different doses in reducing
reperfusion vagal reflex-related events during emergency 2.3. Data collection
PCI for acute STEMI. The medical records of all the study participants were
collected from the electronic medical record system of
2. Methods the hospital and recorded according to a standardized

2.1. Study design protocol. The patients’ age, sex, previous medical history,
site of infarction, time of chest pain, door-to-balloon time,
In this retrospective case–control study, anonymized and atropine dosage were analyzed.
clinical data from October 2015 to October 2020 were
collected from Xianyang Central Hospital. This study was 2.4. Outcomes measures
conducted according to the principles of the Declaration
of Helsinki and approved by the Ethical Committee of The primary end point of this study was the difference
Xianyang Central Hospital (Approval No. 20200059). in prevalence of reperfusion vagal reflex-related events
Informed consent was obtained from the patients and their (bradycardia, hypotension, ventricular tachycardia, and
families. ventricular fibrillation) and that of temporary pacemaker
application between the experimental group and the
2.2. Study participants control group. The secondary end point of this study
was to determine a recommended dosage for patients
The medical records of consecutive patients receiving preconditioned with atropine.
emergency PCI for acute inferior STEMI were retrospectively
reviewed. The inclusion criteria were patients with acute In this study, hypotension was defined as a systolic
inferior STEMI who received emergency PCI. STEMI was blood pressure (BP) of <90 mmHg or a 30% decrease from
defined as ST-segment elevation at the J point in at least the baseline value ; bradycardia was defined as a heart
[7]

Volume 1 Issue 1 (2023) 2 https://doi.org/10.36922/bh.193