No abstract

Pacemakers can be directly involved in initiating or sustaining different forms of arrhythmia. These can cause symptoms such as dyspnea, palpitations, and decompensated heart failure. Early detection of these arrhythmias and optimal pacemaker programming is pivotal. The aim of this review article is to summarize the different types of pacemaker‐mediated arrhythmias, their predisposing factors, and mechanisms of prevention or termination.

Junctional Ectopic Tachycardia (JET) is a tachyarrhythmia arising from the atrioventricular node and His bundle area. It is also called junctional tachycardia, focal junctional tachycardia, or junctional nonreentrant tachycardia. Heart rate in JET should be more than 95 th percentile of heart rate for age (typically more than 100 beats per minute in adults); otherwise, it is called accelerated junctional rhythm. 1-3 JET is more common in children and may be congenital or acquired in postoperative settings. JET is a rare arrhythmia in adults and the pathogenesis is not completely understood. Moreover, because its clinical and electrocardiographic presentation varies, the diagnosis is challenging, and it can be easily mistaken for more common arrhythmias like atrioventricular nodal reentrant tachycardia (AVNRT). 1,4-5 2 | CLINI C AL FE ATURE S This arrhythmia can be categorized as primary JET, without a clear predisposing factor, or secondary JET, which occurs in a clinical condition. Primary JET occurs as congenital form or as sporadic cases in children and adults. Congenital JET occurs within the first 6 months of age, usually presents at birth, and is associated with high morbidity and mortality. It is an arrhythmia with mean ventricular rates of 200 to 250 beats/min and is associated with a high incidence of ventricular systolic dysfunction and clinical heart failure. Prenatal cases may present with hydrops. 1 When it occurs after the age of 6 months, the clinical course is not malignant. Indeed, a similar clinical course to other supraventricular tachycardias has been reported in adults and the main symptom in these patients is palpitations with exacerbation during physical

We sought to determine the anatomic characteristics of coronary arteries arising from an anomalous location (CAAL) detected on coronary computed tomography angiography (CTA) and assess the impact of high-risk anatomic characteristics on patient management and outcomes. We reviewed 9,774 consecutive CTA studies performed in adults between 2008-2013 and identified 114 with CAAL. CTA examinations were analysed to determine CAAL type, CAAL course (pre-pulmonary, interarterial, septal or retroaortic) and whether additional high-risk anatomic characteristics were present (luminal compression, intramural course, slit-like ostium and acute takeoff angle). Patients were contacted at mean 27.1-months to determine safety outcomes. The prevalence of CAAL was 1.14 % (114 of 9,974), with 36 (32 %) having anomalous right coronary artery from left coronary sinus, 71 (62 %) having anomalous left coronary artery from right coronary sinus and 7 (6 %) having a coronary artery arising outside coronary sinuses. Fifty-six patients (49 %) had ≥1 high-risk anatomic characteristic on CTA. Ten patients (9 %) underwent surgical intervention. Patients with high-risk anatomic features more frequently underwent functional testing (46 vs. 12 %, P = 0.01) and surgical intervention (14 vs. 3 %; P = 0.04) compared to patients without high-risk features. Patients undergoing surgery were more likely to have obstructive coronary disease on CTA than patients managed conservatively (50 vs. 13 %, P = 0.01). There was no cardiac death or ACS at follow-up (100 % complete). High-risk anatomic features on CTA in patients with CAAL more frequently lead to surgical management. Regardless of CAAL type, presence of high-risk anatomic characteristics or management strategy, the medium-term outcome of adults with CAAL is excellent.