Reversibility of atrioventricular block according to coronary artery disease: results of a retrospective study

The impact of smoking on third-degree atrioventricular block outcomes: A propensity-matched analysis

Background

Third-degree atrioventricular (AV) blocks are rare but cause significant symptoms and require immediate intervention. Coronary artery disease (CAD) is felt to be the most common etiology. Although smoking is a prominent risk factor for CAD, there is a paucity of data assessing the direct effect of smoking on third-degree AV block.

Methods

We performed a retrospective cohort study on adult-weighted admissions in 2019-2020 with a primary diagnosis of third-degree AV block and a history of smoking using the National Inpatient Sample (NIS) database. In-hospital mortality, rates of pacemaker insertion, cardiogenic shock, cardiac arrest, acute kidney injury (AKI), stroke, tracheal intubation, mechanical ventilation, mechanical circulatory support, vasopressor use, length of stay (LOS), and total hospitalization costs were analyzed using regression analysis. We performed a secondary analysis using propensity score matching to confirm the results.

Results

A total of 77,650 admissions met inclusion criteria (33,625 females [43.3 %], 58,315. Caucasians [75 %], 7030 African American [9 %], 6155 Hispanic [7.9 %]; mean [SD] age 75.4.[10.2] years) before propensity matching. A total of 29,380 (37.8 %) patients with AV block were smokers.A total of 5560 patients with and without a history of smoking were matched for the analysis. Smokers had.decreased odds of mortality (aOR, 0.59; CI, 0.44-0.78; p < 0.001), cardiogenic shock, cardiac arrest, tracheal intubation, mechanical ventilation, shorter LOS, and lower total hospital costs in both the multivariable regression and propensity-matched analyses.

Conclusion

Third-degree AV block had lower in-hospital mortality, cardiogenic shock, cardiac arrest, LOS, and total hospitalization cost in patients with smoking history.

Management of Arrhythmias in the Cardiovascular Intensive Care Unit

Arrhythmias in the cardiovascular intensive care unit (CVICU) can be difficult to manage because of the complex hemodynamic and respiratory states of critically ill patients. Treating physicians must be educated to prevent, diagnose, and treat a multitude of tachyarrhythmias and bradyarrhythmias. In this review article, the authors outline a pragmatic approach to patient assessment, arrhythmia diagnosis, and management of the most common arrhythmias seen in the CVICU.

Resolution of Marked Bradycardia Following Angioplasty

Bradycardia, a condition commonly managed conservatively and, subsequently, with pacemaker implantation presents a unique challenge when coexisting with coronary artery disease (CAD). This case report delves into an unusual scenario where bradycardia and its related symptoms resolved following coronary angioplasty. Our goal is to contribute valuable data to the argument for a comprehensive evaluation of bradycardic patients for underlying CAD prior to considering pacemaker implantation. This approach aims to prevent unnecessary pacemaker implantations and offers insights into the optimal management of patients presenting with both arrhythmia and CAD. The unusual resolution of bradycardia in this case underscores the importance of considering CAD as a possible underlying factor in bradycardic patients, prompting a reevaluation of conventional treatment protocols. By documenting this exceptional case, the authors advocate a more nuanced and individualized treatment strategy in the management of bradycardia, emphasizing the need to assess and address CAD as part of the diagnostic workup.

Hibernation of the Conduction System and Atrioventricular Block Reversibility Following Revascularization in Patients without Acute Coronary Syndrome

Although myocardial infarction (MI) is a reversible cause of atrioventricular (AV) block, the association of ischemia other than MI with AV block is unclear. The purpose of this study is to investigate this relationship. Among patients nominated for pacemaker implantation due to AV block in two centers from 2017-2020, 120 patients with significant coronary artery disease (CAD) in angiography were included in the study. Patients were divided into two equal groups based on their CAD treatment approach: drug therapy and revascularization. Coronary lesions were divided into three types based on location: left anterior descending artery (type 1), dominant coronary with AV node branch (type 2), and a combination of both (type 3). After coronary disease treatment, all patients were followed up with for 14 months, and AV block reversibility was assessed. There were 7 cases of block reversibility in the revascularization group (11.7%) and 1 case in the medical group (1.7%), which differed significantly (P = .02). A history of acute coronary syndrome, smoking, opium use, chronic kidney disease, hypertension, age, sex, and chronic obstructive pulmonary disease were not significantly associated with reversible block. Also, the type of coronary obstruction had no significant relationship with block reversibility (P = .3, .5, and .8 for type 1, type 2, and type 3, respectively). Hibernation due to ischemia can be a reversible cause of an AV blockage. Therefore, it is recommended that significant coronary artery lesions be revascularized before pacemaker implantation.

Reversible Causes of Atrioventricular Block

Atrioventricular blocks may be caused by a variety of potentially reversible conditions, such as ischemic heart disease, electrolyte imbalances, medications, and infectious diseases. Such causes must be always ruled out to avoid unnecessary pacemaker implantation. Patient management and reversibility rates depend on the underlying cause. Careful patient history taking, monitoring of vital signs, electrocardiogram, and arterial blood gas analysis are crucial elements of the diagnostic workflow during the acute phase. Atrioventricular block recurrence after the reversal of the underlying cause may pose an indication for pacemaker implantation, because reversible conditions may actually unmask a preexistent conduction disorder.

Reversible Causes of Atrioventricular Block

Atrioventricular blocks may be caused by a variety of potentially reversible conditions, such as ischemic heart disease, electrolyte imbalances, medications, and infectious diseases. Such causes must be always ruled out to avoid unnecessary pacemaker implantation. Patient management and reversibility rates depend on the underlying cause. Careful patient history taking, monitoring of vital signs, electrocardiogram, and arterial blood gas analysis are crucial elements of the diagnostic workflow during the acute phase. Atrioventricular block recurrence after the reversal of the underlying cause may pose an indication for pacemaker implantation, because reversible conditions may actually unmask a preexistent conduction disorder.

Atrioventricular block after acute myocardial infarction and its association with other clinical parameters in Pakistani patients: an institutional perspective

OBJECTIVES

Conduction defects complicating acute myocardial infarction are frequently associated with increased morbidity and mortality. As frequency of this complication has not been widely studied in our population, therefore in this study we aimed to evaluate the frequency of complete atrioventricular block in patients with acute ST segment elevation myocardial infarction and its association with other clinical parameters.

RESULTS

The mean age of the patients was 50.55 ± 6.72 years at the time of MI. There were 147 (82.1%) males and 32 (17.9%) females. There were 83 (46.4%) patients having hypertension, 61 (34.1%) diabetes mellitus, 75 (41.9%) smokers, 75 (41.9%) patients having positive family history, 11 (6.1%) having dyslipidemia, and 73 (40.8%) obese patients in this study. The Frequency of complete atrioventricular (AV) block in acute ST segment elevation myocardial infarction was found to be 7.3%, and no association with any other clinical factor was found which could predict this condition according to results of our study. Therefore, protocols should be designed in our routine clinical practice to deal with such a life threatening condition.

Prevalence and characterization of coronary artery disease in patients with symptomatic bradyarrhythmias requiring pacemaker implantation

Background

This study was conducted to assess the prevalence and characterization of CAD in high risk patients requiring pacemaker implantation for symptomatic bradyarrhythmias.

Methods

This study included 100 patients with symptomatic sinus node dysfunction or atrioventricular block, who were at high risk of CAD or had previously documented atherosclerotic vascular disease (ASCVD). Coronary angiography was performed before pacemaker implantation. CAD was defined as the presence of any degree of narrowing in at least one major coronary artery or its first order branch. Obstructive CAD was defined as ≥50% diameter stenosis. CAD was categorized as single vessel disease (SVD), double vessel disease (DVD), or triple vessel disease (TVD); and obstructive CAD in the arteries supplying the conduction system was sub-classified according to Mosseri's classification.

Results

Out of 100 patients (mean age 64.6 ± 10.7 years), 45 (45%) had CAD. 29% patients had obstructive CAD while 16% had non-obstructive CAD. 53.3% patients had SVD, 15.6% had DVD and 31.1% had TVD. Among patients with obstructive CAD; Type I, II, III and IV coronary anatomies were present in 6.9%, 34.5%, 10.3% and 48.3% patients respectively. Presence of CAD significantly correlated with dyslipidemia (p = 0.047), history of smoking (p = 0.025), and family history of CAD (p = 0.002).

Conclusion

Angiographic CAD is observed in a substantial proportion of patients with symptomatic bradyarrhythmias and risk factors for CAD. It could be argued that such patients should undergo a coronary work-up before pacemaker implantation. Treatment of concomitant CAD is likely to improve the long term prognosis of these patients.

Reversibility of High-Grade Atrioventricular Block with Revascularization in Coronary Artery Disease without Infarction: A Literature Review

Complete atrioventricular (AV) block is known to be reversible in some cases of acute inferior wall myocardial infarction (MI). The reversibility of high-grade AV block in non-MI coronary artery disease (CAD), however, is rarely described in the literature. Herein we perform a literature review to assess what is known about the reversibility of high-grade AV block after right coronary artery revascularization in CAD patients who present without an acute MI. To illustrate this phenomenon we describe a case of 2 : 1 AV block associated with unstable angina, in which revascularization resulted in immediate and durable restoration of 1 : 1 AV conduction, thereby obviating the need for permanent pacemaker implantation. The literature review suggests two possible explanations: a vagally mediated response or a mechanism dependent on conduction system ischemia. Due to the limited understanding of AV block reversibility following revascularization in non-acute MI presentations, it remains difficult to reliably predict which patients presenting with high-grade AV block in the absence of MI may have the potential to avoid permanent pacemaker implantation via coronary revascularization. We thus offer this review as a potential starting point for the approach to such patients.

Primary percutaneous coronary intervention ameliorates complete atrioventricular block complicating acute inferior myocardial infarction

Objective

Complete atrioventricular block (CAVB) in acute inferior ST-segment elevation myocardial infarction (STEMI) is associated with poor clinical outcomes after noninvasive treatment. This study was designed to determine the effect of primary percutaneous coronary intervention (PCI) in patients with CAVB complicating acute inferior STEMI, at a single center.

Methods

We enrolled 138 consecutive patients diagnosed with STEMI involving the inferior wall; of these, 27 patients had CAVB. All patients received primary PCI. The clinical characteristics, procedural data, and clinical outcomes were compared in patients with versus without CAVB.

Results

Baseline clinical characteristics were similar between patients with and without CAVB. Patients with CAVB were more likely to present with cardiogenic shock, and CAVB was caused primarily by right coronary artery occlusion. Door-to-balloon time was similar between those two groups. After primary PCI, CAVB was reversed in all patients. The peak creatinine phosphokinase level, left ventricular ejection fraction and in-hospital mortality rate were similar between the two groups. After a median follow up of 318 days, major adverse cardiac events did not differ between the groups (8.1% in patients without CAVB; 11.1% in patients with CAVB) (P=0.702).

Conclusion

We conclude that primary PCI can ameliorate CAVB-complicated acute inferior STEMI, with an acceptable rate of major adverse cardiac events, and suggest that primary PCI should be the preferred reperfusion therapy in patients with CAVB complicating acute inferior myocardial infarction.