European Journal of Cardiovascular Medicine

Acute Myocardial Infarction (AMI) is a critical event in cardiovascular diseases and a leading cause of morbidity and mortality globally. The interruption of blood flow to the heart, resulting in ischemia, triggers a cascade of biochemical and electrophysiological changes in cardiac tissue. These alterations increase the likelihood of arrhythmias—abnormal heart rhythms—during the acute phase of AMI, which can range from benign conditions to life-threatening events like ventricular fibrillation and tachycardia. The occurrence and severity of arrhythmias in AMI reflect the extent of myocardial injury and are closely associated with poor short- and long-term outcomes (1). The underlying mechanisms of post-AMI arrhythmias are complex, involving ischemia, reentry circuits, enhanced automaticity, and triggered activity. Management strategies have evolved significantly, encompassing pharmacological treatments, percutaneous coronary interventions, and the use of devices like pacemakers and defibrillators. However, despite advancements, arrhythmias in the context of AMI continue to pose significant challenges in clinical practice (2).This study aims to explore the incidence, outcomes, and prognostic implications of arrhythmias in AMI patients. By analyzing the relationship between arrhythmias and clinical parameters, treatment strategies, and outcomes, the research hopes to improve prognostication and refine therapeutic approaches, ultimately enhancing patient care for those affected by AMI.

AIMS AND OBJECTIVES

This prospective study aims to investigate the incidence and outcomes of various arrhythmias in patients with acute myocardial infarction (AMI) admitted to the intensive coronary care unit of SVRRGGH, Tirupati. The study will explore the correlation between different types of arrhythmias and the location and extent of myocardial infarction. Additionally, it will assess factors such as age, sex, and the site of infarction in relation to the occurrence of arrhythmias, and evaluate their impact on patient outcomes. The research will further analyze the effect of arrhythmias on mortality and morbidity in patients experiencing acute MI, with the goal of providing deeper insights into their prognostic implications.

This hospital-based, prospective observational study was conducted at SVRRGGH, Tirupati, over a one-year period. It included patients admitted to the Department of General Medicine and Cardiology with acute myocardial infarction (AMI). The sample size consisted of 100 patients, selected based on specific inclusion and exclusion criteria. Inclusion criteria included patients with acute or hyper-acute MI, clinical features and ECG evidence of AMI, arrhythmias pre- and post-thrombolysis, ST elevation, and elevated cardiac biomarkers. Exclusion criteria were patients with prior heart failure, age under 25, chronic lung diseases, pulmonary hypertension, structural heart diseases, electrolyte disturbances, pericarditis, early repolarization, intracranial hemorrhage, thyroid disorders, or previous cardiac surgeries. Upon admission, a comprehensive history, clinical examination, and ECG were performed. Blood tests including complete blood count, blood sugar, renal function, lipid profile, and cardiac biomarkers (CK-MB and troponin I) were carried out. A 12-lead ECG, including right-sided leads, was used to assess ischemic changes and determine arrhythmias. Coronary interventions, such as angioplasty, were noted, and 2D echocardiography was performed within the first 48 hours of hospitalization to evaluate cardiac function. The study aimed to analyze the incidence, patterns, and outcomes of arrhythmias in these patients.

In the study population, the majority of patients were aged between 41 and 70 years, followed by those in the 31–40 years, 71–80 years, and 20–30 years age groups, respectively. A significant gender disparity was observed, with 83% of the patients being male and 17% female. Chest pain was the predominant presenting symptom, reported by 82% of patients, while other symptoms such as dyspnea and palpitations were less common. Lifestyle factors revealed that 39% of patients were habitual alcohol users, followed by 28% who had a history of smoking. Additionally, 28% of the patients had hypertension, and 27% were diagnosed with Type 2 diabetes mellitus.

Regarding the distribution of myocardial infarctions (MIs), the most common type was Inferior Wall Myocardial Infarction (INFWMI), followed by Anterior Wall Myocardial Infarction (AWMI), Anterolateral Wall Myocardial Infarction (ALWMI), Anterosuperior Wall Myocardial Infarction (ASWMI), and Right Ventricular Myocardial Infarction (RVMI). No statistically significant differences were found between the various types of MI and alcohol consumption or smoking.

Table 1:

The study also explored the impact of thrombolysis on different types of MI, revealing a significant association between INFWMI and Ventricular Premature Contractions (VPCS) with thrombolysis. Notably, VPCS showed spontaneous resolution in 9 patients, demonstrating a statistically significant outcome. However, there were no significant associations (Table 1) between MI type and pharmacological treatments or electrical cardioversion. The study also found no significant correlation between MI types and mortality, although among those who expired, 3 had AWMI, 2 had INFWMI, and 1 had RVMI. These findings suggest that while certain trends were observed, further research is needed to better understand the complex interplay of factors influencing outcomes in AMI patients.

Cardiac arrhythmias represent a significant and frequent complication in individuals with acute myocardial infarction (AMI), profoundly influencing clinical outcomes and prognosis. This study aims to provide a comprehensive analysis of the incidence and implications of arrhythmias in AMI patients, contributing new insights to the understanding of their patterns and clinical relevance. The occurrence of arrhythmias post-AMI is well-documented, with several studies reporting varying rates of prevalence and identifying different types of arrhythmias. According to the China Acute MI (CAMI) registry, 8.35% of AMI patients experienced arrhythmias, including ventricular tachyarrhythmias, bradyarrhythmias, and atrial tachyarrhythmias, all of which were linked to worse outcomes during hospitalization. Similarly, a study found that 40.8% of AMI patients developed arrhythmias within the first hour of hospitalization, with the most common being ventricular premature complexes and sinus tachycardia (3). Our study builds upon this body of research by offering a detailed breakdown of arrhythmic events

following AMI, observing similar types of arrhythmias but with some variation in the prevalence rates. The incidence of ventricular tachycardia and sinus bradycardia, in particular, was higher in our cohort, which could be due to differences in patient characteristics, geographic factors, or diagnostic criteria. Additionally, the reduced occurrence of atrial fibrillation (AF) (2% in our study compared to a range of 6-21% in the literature) underscores the evolving nature of AMI treatment protocols or possible differences in the study populations and diagnostic methods(4).  A comparative analysis of our findings with those from studies by Xu et al. (2024) and Ranjith GK et al. (5) highlights the inherent variability in arrhythmia types and their incidence in AMI. Our study found a higher prevalence of ventricular premature complexes (9%) compared to Ranjith GK et al.'s (24%), suggesting that patient characteristics or the timing of arrhythmia detection might explain these discrepancies.

This study supports previous findings that older age is a key risk factor for the development of arrhythmias in AMI. However, a growing body of literature, such as the work of Krittanawong et al., highlights a rising incidence of AMI among younger individuals, particularly under 45, often linked to non-atherosclerotic causes. While our research aligns with studies like the Framingham Heart Study, which identified a significantly higher risk of AMI in older individuals, it also calls attention to the increasing frequency of AMI in younger populations, warranting greater attention to preventive strategies in this demographic.

Gender differences in AMI outcomes have long been documented, with males generally experiencing more frequent episodes of AMI and arrhythmias. This study corroborates those findings, as 83% of our cohort consisted of males. However, when examining the clinical outcomes, research by Kim et al. (6) and Fedele et al. (7) suggests that although men are more likely to suffer from AMI, women may face more severe complications when they do experience it. Women with AMI, particularly those under 70, tend to have worse outcomes, potentially due to distinct pathophysiological mechanisms. This further underscores the need for gender-specific approaches in managing AMI and arrhythmias. Moreover, research by the American College of Cardiology emphasizes that women with AMI often experience more advanced age, a higher prevalence of comorbidities, and worse renal function. They are also less likely to receive guideline-directed medical therapy, which results in poorer in-hospital outcomes and greater mortality rates. These findings highlight the importance of personalized care tailored to the unique needs of both male and female AMI patients, with a particular focus on improving outcomes for women.

Hypertension and diabetes were prevalent comorbidities in our cohort, present in 28% and 27% of patients, respectively. These findings align with existing research demonstrating that these conditions exacerbate the frequency and severity of arrhythmias in AMI patients. The effects of hypertension and diabetes on arrhythmic development have been well documented in studies such as those by Dinicolantio et al. and Gupta et al., who have shown that diabetes can lead to atypical symptoms and more severe outcomes in AMI patients, including arrhythmias. Furthermore, acute hyperglycemia post-AMI has been associated with increased left ventricular dysfunction and larger areas of myocardial injury, which may contribute to a heightened risk of arrhythmias (8). Our findings are consistent with these studies, as they emphasize the importance of managing hypertension and diabetes in AMI patients to prevent complications like arrhythmias. Patients with these comorbidities are more susceptible to developing life-threatening arrhythmias such as ventricular tachycardia, necessitating close monitoring and individualized treatment plans. Smoking is a well-established risk factor for cardiovascular diseases and arrhythmias. In our study, 33% of patients with AMI and arrhythmias reported a history of smoking. Research by D'Alessandro et al. (2012) and Irfan et al. further supports these findings, indicating that nicotine significantly contributes to the development of arrhythmias, particularly by increasing the vulnerability of cardiac tissue to catecholamines. Smoking is associated with a twofold increase in the incidence of AF, and its effects on the electrical activity of the heart, such as disturbances in the QT interval, are well-documented (9, 10). Our findings are consistent with these studies, as the types of arrhythmias observed in smokers, such as ventricular tachycardia and premature ventricular complexes, align with those seen in the literature. Moreover, the impact of smoking on arrhythmogenesis emphasizes the need for smoking cessation programs and public health initiatives to reduce the incidence of smoking-related cardiovascular events, particularly in high-risk populations. Alcohol consumption has been closely linked to an increased risk of developing abnormal heart rhythms, such as atrial fibrillation (AF) and ventricular arrhythmias. The effects of alcohol on cardiac electrophysiology include slowing conduction rates, reducing effective refractory periods, and causing heart rate instability, all of which contribute to arrhythmogenesis. This association is significant for both public health and clinical practice, highlighting the need for awareness and regulation of alcohol intake to prevent arrhythmias.

Research supports the link between alcohol use and arrhythmias. For instance, Ga-In Yu et al. (2023) found that alcohol consumers have a higher risk of experiencing prolonged atrial high-rate episodes (AHRE), with a hazard ratio of 2.83, indicating nearly three times the risk compared to non-drinkers (11). Similarly, Kilcoyne and Assaassa (2023) discuss how alcohol disrupts ventricular conduction, contributing to arrhythmias like ventricular tachycardia and fibrillation (12). Brunner et al. (2023) also note a 75% increase in arrhythmia risk for every gram of alcohol consumed per kilogram of blood, further substantiating alcohol's role in arrhythmogenesis (13). Moreover, studies such as those by Gregory et al. (2023) have shown that even modest alcohol intake can increase the likelihood of AF episodes, emphasizing alcohol's immediate effect on heart rhythm. In patients with acute myocardial infarction (AMI), arrhythmias like ventricular premature complexes and left bundle branch blocks were notably more prevalent in those with alcohol consumption histories, reinforcing alcohol's impact on heart rhythm disturbances.

In conclusion, this study highlights the significant prevalence of arrhythmias following acute myocardial infarction (AMI), particularly in elderly males, and underscores the role of lifestyle factors and comorbidities in exacerbating these conditions. The findings reveal a clear association between the location of the heart attack and the type of arrhythmias that arise, providing important insights into arrhythmic patterns. While many arrhythmias resolve spontaneously, the study stresses the need for timely medical intervention in cases where they persist or worsen. These observations not only enhance our understanding of post-AMI complications but also highlight the importance of tailored treatment strategies to improve patient outcomes. Furthermore, the study advocates for further research to refine management techniques and develop more effective prevention strategies for AMI-related arrhythmias, ultimately contributing to advancements in cardiovascular care and improving the quality of life for patients.

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