Abstract
Inappropriate sinus tachycardia is an ill-defined clinical syndrome with diverse clinical manifestations. Clinical symptoms can range from intermittent palpitations to multisystem complaints. Although there is a general consensus that when the heartbeat exceeds 100 beats per minute at rest or with minimal physiologic challenge, it is considered “inappropriate,” this quantitative differentiation is quite arbitrary, while validation of the reproducibility of the heart rate/activity correlation can be challenging. Once the clinical diagnosis of inappropriate sinus tachycardia is expected, other supraventricular tachyarrhythmias and medical conditions causing sinus tachycardia should be excluded.
The underlying mechanism of inappropriate sinus tachycardia is not well understood. “Intracardiac” mechanisms such as enhanced intrinsic automaticity, enhanced sympathetic tone, increased sympathetic receptor sensitivity, and blunted parasympathetic tone have been proposed. Evidences for “extracardiac” mechanisms such as length-dependent autonomic neuropathy, excessive venous pooling, beta-receptor hypersensitivity, alpha-receptor hyposensitivity, altered sympathovagal balance, and brainstem dysregulation have also been reported. Currently, our ability to differentiate primary (intracardiac) from secondary (extracardiac) mechanisms of inappropriate sinus tachycardia is limited.
It has been reported that ablative therapy of sinus node is effective in treating patients with symptomatic inappropriate sinus tachycardia. Acute success of sinus node modification/ablation can be accomplished in 70%–100% of the various study populations. Although long-term successful outcome may be accomplished in a few patients, symptoms of palpitations and autonomic characteristics frequently persist. Identification and differentiation of patients who are suitable for ablative therapy versus medical therapy should be one of the central clinical research issues in this patient population.
This brief review first considers the clinical and electrophysiologic diagnosis of inappropriate tachycardia and then summarizes the mechanisms of inappropriate sinus tachycardia and related syndromes such as postural orthostatic tachycardia syndrome. Techniques of mapping and ablation of sinus node are discussed briefly. A critical review of the acute and long-term clinical outcomes following sinus node ablation and modification is updated. In conclusion, the precise role of sinus node modification in patients with inappropriate sinus tachycardia remains to be determined. Sinus node modification could be considered in patients with inappropriate sinus tachycardia with persistently increased heart rate in the absence of any autonomic abnormalities. Autonomic laboratory testing should be performed to exclude any evidence of autonomic dysregulation. Clinical research on the pathophysiology of inappropriate sinus tachycardia should be pursued vigorously.
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References
Bauernfeind RA, Amat-Y-Leon F, Dhingra RC, Kehoe R, Wyndham C, Rosen KM. Chronic nonparoxysmal sinus tachycardia in otherwise healthy persons. Ann Intern Med1979;91:702–710.
Karch MR, Shinbane JS, Kalman JM, Lee RJ, Lesh MD. Role of radiofrequency catheter ablation and intracardiac echocardiography in the treatment of inappropriate sinus tachycardia. Cardiac Electrophysiol Rev 1997;1:425–429.
Krahn AD, Yee R, Klein GJ, Morillo C. Inappropriate sinus tachycardia: Evaluation and therapy. J Cardiovasc Electrophysiol 1995;6:1124–1128.
Lee RJ, Kalman JM, Fitzpatrick AP, Epstein LM, Fisher WG, Olgin JE, Lesh MD, Scheinman MM. Radiofrequency catheter modification of the sinus node for “inappropriate” sinus tachycardia. Circulation 1995;92:2919–2928.
Morillo CA, Klein GJ, Thakur RK, Li H, Zardini M, Yee R. Mechanism of “inappropriate” sinus tachycardia: Role of sympathovagal balance. Circulation 1994;90:873–877.
Yee R, Guiraudon GM, Gardner MJ, Gulamhusein SS, Klein GJ. Refractory paroxysmal sinus tachycardia: Management by subtotal right atrial exclusion. J Am Coll Cardiol 1984;3:400–404.
Wising P. Familial, congenital sinus tachycardia. Acta Med Scand 1941;108:299–305.
Man KC, Knight B, Tse HF, Pelosi F, Michaud GF, Fleming M, Strickberger SA, Morady F. Radiofrequency catheter ablation of inappropriate sinus tachycardia guided by activation mapping. J Am Coll Cardiol 2000;35:451–457.
Shen WK, Low PA, Jahangir A, Munger TM, Friedman PA, Osborn MJ, Stanton MS, Packer DL, Rea RF, Hammill SC. Is sinus node modification appropriate for inappropriate sinus tachycardia with features of postural orthostatic tachycardia syndrome? Pacing Clin Electrophysiol2001;24:217–230.
Marrouche NF, Beheiry S, Tomassoni G, Cole C, Bash D, Dresing T, Saliba W, Abdul-Karim A, Tchou P, Schweikert R, Leonelli F, Natale A. Three-dimensional nonfluoroscopic mapping and ablation of inappropriate sinus tachycardia: Procedural strategies and long-term outcome. J Am Coll Cardiol 2002;39:1046–1054.
Castellanos A, Moleiro F, Chakko S, Acosta H, Huikuri H, Mitrani RD, Myerburg RJ. Heart rate variability in inappropriate sinus tachycardia. Am J Cardiol 1998;82:531–534.
Low PA, Novak V, Novak P, Sandroni P, Schondorf R, Opfer-Gehrking TL. Postural tachycardia syndrome (POTS). In: Low PA, ed. Clinical Autonomic Disorders: Evaluation and Management, 2nd ed. Philadelphia: Lippincott-Raven Publishers, 1997:681–697.
Schondorf R, Low PA. Idiopathic postural tachycardia syndromes. In: Low PA, ed. Clinical Autonomic Disorders: Evaluation and Management, Boston: Little, Brown and Company, 1993:641–652.
Singer W, Shen WK, Opfer-Gehrking TL, McPhee BR, Hilz MJ, Low PA. Evidence of an intrinsic sinus node abnormality in patients with postural tachycardia syndrome. Mayo Clin Proc 2002;77:246–252.
Leonelli F, Richey M, Beheiry S, Rajkovich K, Natale A. Tridimensional mapping: Guided modification of the sinus node. J Cardiovasc Electrophysiol 1998;9:1214–1217.
Schilling RJ, Peters NS, Davies DW. Simultaneous endocardial mapping in the human left ventricle using a noncontact catheter: Comparison of contact and reconstructed electrograms during sinus rhythm. Circulation 1998;98:887–898.
Kalman JM, Lee RJ, Fisher WG, Chin MC, Ursell P, Stillson CA, Lesh MD, Scheinman MM. Radiofrequency catheter modification of sinus pacemaker function guided by intracardiac echocardiography. Circulation 1995;92:3070–3081.
Lesh MD, Kalman JM, Karch MR. Use of intracardiac echocardiography during electrophysiologic evaluation and therapy of atrial arrhythmias. J Cardiovasc Electrophysiol 1998;9(Suppl):S40–S47.
Marchlinski FE, Ren JF, Schwartzman D, Callans DJ, Gottlieb CD. Accuracy of fluoroscopic localization of the Crista terminalis documented by intracardiac echocardiography. J Interv Card Electrophysiol 2000;4:415–421.
Shinbane JS, Lesh MD, Scheinman MM, Wood K, Evans GT Jr, Saxon LA, Barron H, Kalman JM, Lee RJ. Long-term follow-up after radiofrequency sinus node modification for inappropriate sinus tachycardia (abstract). J Am Coll Cardiol 1997;29(Suppl A):199A.
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Shen, WK. Modification and Ablation for Inappropriate Sinus Tachycardia: Current Status. Card Electrophysiol Rev 6, 349–355 (2002). https://doi.org/10.1023/A:1021167821190
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DOI: https://doi.org/10.1023/A:1021167821190