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Reviews in Cardiovascular Medicine Dec 2021Inappropriate sinus tachycardia (IST) has been defined as a resting heart rate of >100 beats per minute and an average 24-hour heart rate >90 bpm with distressing... (Review)
Review
Inappropriate sinus tachycardia (IST) has been defined as a resting heart rate of >100 beats per minute and an average 24-hour heart rate >90 bpm with distressing symptoms resulting from the persistent tachycardia. IST is prevalent in 1% of the middle-aged population, mostly females. Rarely can elderly patients also present with IST. Possible mechanisms of IST include intrinsic sinus node abnormality, beta-adrenergic receptor stimulating autoantibody, beta-adrenergic receptor supersensitivity, muscarinic receptor autoantibody, or hyposensitivity, impaired baroreflex control, depressed efferent parasympathetic/vagal function, nociceptive stimulation, central autonomic overactivity, aberrant neurohumoral modulation, etc. Symptoms associated with IST are palpitations, chest pain, fatigue, shortness of breath, presyncope, and syncope. Despite these distressing symptoms, IST has not been associated with tachycardia-associated cardiomyopathy or increased major cardiovascular events. Various treatment options for patients with IST are ivabradine, beta-adrenergic blockers, calcium channel blockers, psychiatric evaluation, and exercise training. Although, endocardial radiofrequency ablation targeting the sinus node has been used as a treatment modality for otherwise treatment-refractory IST, the results have been dismal. The other modalities used for refractory IST treatment are endocardial modification of the sinus node using radiofrequency energy, combined endo and epicardial ablation of the sinus node, thoracoscopic epicardial ablation of the sinus node, sinus node sparing thoracoscopic and endocardial hybrid ablation. The goal of this review is to provide the readership with the pathophysiological basis of IST and its management options.
Topics: Adrenergic beta-Antagonists; Aged; Catheter Ablation; Female; Heart Rate; Humans; Male; Middle Aged; Sinoatrial Node; Tachycardia, Sinus
PubMed: 34957774
DOI: 10.31083/j.rcm2204139 -
Circulation. Arrhythmia and... Sep 2022Sinus tachycardia (ST) is ubiquitous, but its presence outside of normal physiological triggers in otherwise healthy individuals remains a commonly encountered... (Review)
Review
Sinus tachycardia (ST) is ubiquitous, but its presence outside of normal physiological triggers in otherwise healthy individuals remains a commonly encountered phenomenon in medical practice. In many cases, ST can be readily explained by a current medical condition that precipitates an increase in the sinus rate, but ST at rest without physiological triggers may also represent a spectrum of normal. In other cases, ST may not have an easily explainable cause but may represent serious underlying pathology and can be associated with intolerable symptoms. The classification of ST, consideration of possible etiologies, as well as the decisions of when and how to intervene can be difficult. ST can be classified as secondary to a specific, usually treatable, medical condition (eg, pulmonary embolism, anemia, infection, or hyperthyroidism) or be related to several incompletely defined conditions (eg, inappropriate ST, postural tachycardia syndrome, mast cell disorder, or post-COVID syndrome). While cardiologists and cardiac electrophysiologists often evaluate patients with symptoms associated with persistent or paroxysmal ST, an optimal approach remains uncertain. Due to the many possible conditions associated with ST, and an overlap in medical specialists who see these patients, the inclusion of experts in different fields is essential for a more comprehensive understanding. This article is unique in that it was composed by international experts in Neurology, Psychology, Autonomic Medicine, Allergy and Immunology, Exercise Physiology, Pulmonology and Critical Care Medicine, Endocrinology, Cardiology, and Cardiac Electrophysiology in the hope that it will facilitate a more complete understanding and thereby result in the better care of patients with ST.
Topics: COVID-19; Humans; Postural Orthostatic Tachycardia Syndrome; Tachycardia, Sinus
PubMed: 36074973
DOI: 10.1161/CIRCEP.121.007960 -
Europace : European Pacing,... Feb 2019Inappropriate sinus tachycardia (IST) is a clinical syndrome, oftentimes debilitating, defined by fast sinus rates (>100 b.p.m. at rest or >90 b.p.m. on average over... (Review)
Review
Inappropriate sinus tachycardia (IST) is a clinical syndrome, oftentimes debilitating, defined by fast sinus rates (>100 b.p.m. at rest or >90 b.p.m. on average over 24 h and not due to underlying causes) associated with symptoms that may include palpitations, as described in some guidelines and consensus documents. While heart rates may vary by patient, especially based upon gender and age, some individuals experience sinus tachycardia or persistent fast sinus rates with no symptoms; these individuals would not necessarily be considered to have the syndrome of IST. Various explanations for IST have been considered but a definitive common mechanism is not yet known; the true aetiology may be multifactorial. A thorough evaluation of secondary causes of tachycardia is required in the work-up of all cases and if found, must be treated before a diagnosis of IST can be made. Finally, effective treatments vary but can include ivabradine, beta-blockers, or calcium channel antagonists; ablation is seldom advised.
Topics: Ablation Techniques; Adult; Age Factors; Animals; Anti-Arrhythmia Agents; Female; Heart Rate; Humans; Male; Middle Aged; Risk Factors; Sex Factors; Sinoatrial Node; Syndrome; Tachycardia, Sinus; Time Factors; Treatment Outcome
PubMed: 29931244
DOI: 10.1093/europace/euy128 -
Journal of the American College of... Jun 2022Inappropriate sinus tachycardia (IST) is a clinical syndrome that generally affects young patients and is associated with distressing symptoms. Although the most common... (Review)
Review
Inappropriate sinus tachycardia (IST) is a clinical syndrome that generally affects young patients and is associated with distressing symptoms. Although the most common symptom is palpitations, it can be accompanied by a myriad of symptoms, including anxiety, dizziness, presyncope, and syncope. The pathogenesis of IST is not well understood and considered multifactorial, with autonomic dysfunction being the central abnormality. IST is a diagnosis of exclusion. Management presents a clinical challenge. The overall efficacy of lifestyle modifications and medical therapy may be limited. Recent advances in catheter and surgical sinus node sparing ablation techniques have led to improvement in outcomes. In addition, increased focus has led to development of multimodality team-based interventions to improve outcomes in this group of patients. In this review, we discuss the mechanistic basis of IST, review current approaches to diagnosis, and outline contemporary therapeutic approaches.
Topics: Catheter Ablation; Heart Rate; Humans; Sinoatrial Node; Syndrome; Tachycardia, Sinus
PubMed: 35710196
DOI: 10.1016/j.jacc.2022.04.019 -
Heart Rhythm Jun 2015
2015 heart rhythm society expert consensus statement on the diagnosis and treatment of postural tachycardia syndrome, inappropriate sinus tachycardia, and vasovagal syncope.
Topics: Child; Female; Humans; Male; Middle Aged; Postural Orthostatic Tachycardia Syndrome; Societies, Medical; Syncope, Vasovagal; Tachycardia, Sinus
PubMed: 25980576
DOI: 10.1016/j.hrthm.2015.03.029 -
Europace : European Pacing,... Oct 2022Inappropriate sinus tachycardia (IST) is a syndrome characterized by an elevated sinus rate unassociated with known physiological, pathological, or pharmacological... (Review)
Review
AIMS
Inappropriate sinus tachycardia (IST) is a syndrome characterized by an elevated sinus rate unassociated with known physiological, pathological, or pharmacological causes. Despite published consensus documents, IST definitions appear to vary in the literature. In this study, we reviewed IST publications to evaluate IST definition variability and ascertain the degree to which consensus definitions are being adopted.
METHODS AND RESULTS
English-language articles in PubMed, Ovid MEDLINE, Ovid Embase, and Google Scholar published from 1 January 1970 to 1 June 2021 with the title terms 'inappropriate sinus tachycardia,' 'non-paroxysmal sinus tachycardia,' or 'permanent sinus tachycardia' were searched. In each, the IST definition used, qualifying characteristics, and publications cited to support each definition were recorded. We identified 138 publications meeting the search criteria. Inappropriate sinus tachycardia definitions were provided in 114 of 138 articles (83%). A majority of definitions (92/114, 81%) used distinct heart rate (HR) thresholds. Among these, the most common threshold was ≥100 beats per minute (BPM) (75/92, 82%), mainly measured at rest (54/92, 59%). Most definitions (47/92, 51%) included a second criterion to qualify for IST; these were most often an HR threshold of 90 BPM measured over 24 h by ambulatory electrocardiogram (37/47, 79%). Diagnosis of exclusion was a common criterion (75/92, 82%) but symptom status was not (41/92, 45%). The 2015 Heart Rhythm Society IST consensus was commonly cited but adopted in only 37% of definitions published after 2015.
CONCLUSIONS
Inappropriate sinus tachycardia definitions in current literature are inconsistent, and professional society consensus IST definitions have, to date, had limited impact.
Topics: Electrocardiography, Ambulatory; Heart Rate; Humans; Tachycardia, Sinus
PubMed: 35851637
DOI: 10.1093/europace/euac057 -
Journal of the American College of... Feb 2013Inappropriate sinus tachycardia (IST) is a syndrome in which the sinus heart rate is inexplicably faster than expected and associated symptoms are present. The heart... (Review)
Review
Inappropriate sinus tachycardia (IST) is a syndrome in which the sinus heart rate is inexplicably faster than expected and associated symptoms are present. The heart rate at rest, even in a supine position, can exceed 100 beats/min; minimal activity accelerates the rate rapidly and substantially. Patients with IST may require restriction from physical activity. Mechanisms responsible for IST are understood incompletely. It is important to distinguish IST from so-called appropriate sinus tachycardia and from postural orthostatic tachycardia syndrome, with which overlap may occur. Because the long-term outcome seems to be benign, treatment may be unnecessary or may be as simple as physical training. However, for patients with intolerable symptoms, therapeutic measures are warranted. Even at high doses, β-adrenergic blockers, the first-line therapy, often are ineffective; the same is true for most other medical therapies. In rare instances, catheter- or surgically- based right atrial or sinus node modification may be helpful, but even this is fraught with limited efficacy and potential complications. Overtreatment, in an attempt to reduce symptoms, can be difficult to avoid, but is discouraged.
Topics: Adrenergic beta-Antagonists; Biological Clocks; Catheter Ablation; Depression, Chemical; Disease Management; Electrocardiography; Electrophysiologic Techniques, Cardiac; Heart Rate; Humans; Neurotransmitter Agents; Sinoatrial Node; Tachycardia, Sinus; Vagus Nerve
PubMed: 23265330
DOI: 10.1016/j.jacc.2012.07.074 -
Ugeskrift For Laeger Aug 2018Sinus tachycardia may have a definite aetiology, but in the remaining cases inappropriate sinus tachycardia (IST) may be considered. IST is primarily treated in order to... (Review)
Review
Sinus tachycardia may have a definite aetiology, but in the remaining cases inappropriate sinus tachycardia (IST) may be considered. IST is primarily treated in order to improve symptoms. During pregnancy, tachycardia-induced cardiomyopathy is rare; however, it needs urgent attention and treatment due to the risk of fast progression. In Denmark, performing an electrocardiogram is recommended in any pregnant woman, who has palpitations or a persisting heart rate > 100 beats per minute.
Topics: Adrenal Gland Neoplasms; Cardiomyopathies; Critical Pathways; Denmark; Diagnosis, Differential; Electrocardiography; Female; Humans; Pheochromocytoma; Pregnancy; Pregnancy Complications, Cardiovascular; Pulmonary Embolism; Tachycardia, Sinus; Thyrotoxicosis
PubMed: 30152314
DOI: No ID Found -
Deutsche Medizinische Wochenschrift... Apr 2015Inappropriate sinus tachycardia is characterized by an unexplained increase of the resting sinus rate (> 100 bpm) with excess increase in response to moderate activity... (Review)
Review
Inappropriate sinus tachycardia is characterized by an unexplained increase of the resting sinus rate (> 100 bpm) with excess increase in response to moderate activity (mean heart rate > 90 bpm/24 h). Affected patients may suffer from heart race, palpitations, fatigue, weakness and dizziness. The mechanisms underlying inappropriate sinus tachycardia and its long term prognosis are poorly understood. Thus, diagnosis and treatment are empiric and require the initial exclusion of potential causes of secondary sinus tachycardia. Therapeutic approaches include physical training, beta blockers or ivabradine. Radiofrequency catheter ablation should be restricted to patients with refractory and longstanding symptoms.
Topics: Adrenergic beta-Antagonists; Benzazepines; Catheter Ablation; Combined Modality Therapy; Diagnosis, Differential; Electrocardiography; Exercise Therapy; Humans; Ivabradine; Tachycardia, Sinus
PubMed: 25945910
DOI: 10.1055/s-0041-101620 -
American Journal of Therapeutics 2017Inappropriate Sinus Tachycardia (IST) is a chronic medical condition with a wide variety of clinical presentations making it, sometimes, very insidious at the time of... (Review)
Review
Inappropriate Sinus Tachycardia (IST) is a chronic medical condition with a wide variety of clinical presentations making it, sometimes, very insidious at the time of the diagnosis. Several therapeutic options, including, pharmacotherapy, cardiac rehabilitation, and modification or ablation of the sinus node, have been proposed for the management of IST, but because of the complexity and lack of understanding of pathophysiology, it can be difficult to manage, despite the numerous treatment options currently available. The purpose of this review is to analyze the treatment for IST, focusing on the role of newer therapy and the potential benefits in the management of this cardiac rhythm disturbance.
Topics: Cardiovascular Agents; Catheter Ablation; Chronic Disease; Heart Rate; Humans; Sinoatrial Node; Syndrome; Tachycardia, Sinus
PubMed: 26381365
DOI: 10.1097/MJT.0000000000000335