7/6/23, 10:44 AM Vagal maneuvers - UpToDate Official reprint from UpToDate www.uptodate.com 2023 UpToDate, Inc. and/or its affiliates. All Rights Reserved. Vagal maneuvers : Daniel R Frisch, MD, Peter J Zimetbaum, MD : Brian Olshansky, MD : Susan B Yeon, MD, JD, FACC All topics are updated as new evidence becomes available and our peer review process is complete. Literature review current through: Jun 2023. This topic last updated: Feb 15, 2023. INTRODUCTION The autonomic nervous system is composed of the sympathetic and parasympathetic divisions. This system innervates and regulates most visceral functions including electrophysiological and hemodynamic cardiovascular responses. Various physical maneuvers can elicit autonomic responses (see 'Types of vagal maneuvers' below). Many of these maneuvers can be performed at the bedside or in an office setting with minimal risk. These maneuvers can be both diagnostic (eg, in confirming carotid sinus hypersensitivity) and therapeutic (eg, terminating supraventricular tachycardia [SVT]). Understanding the indications, techniques, and complications of various vagal maneuvers is necessary to safe and effective clinical application. Vagal maneuvers to evaluate and treat cardiac arrhythmias and conduction abnormalities are reviewed here. The evaluation of carotid sinus hypersensitivity and SVT are presented separately. (See "Carotid sinus hypersensitivity and carotid sinus syndrome" and "Narrow QRS complex tachycardias: Clinical manifestations, diagnosis, and evaluation".) CARDIAC RESPONSES TO VAGAL STIMULATION In the heart, parasympathetic (vagal) stimulation causes local release of acetylcholine, with the following effects: https://www.uptodate.com/contents/vagal-maneuvers/print 1/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate In the sinus node, there is slowing of the rate of impulse formation. (See "Sinus node dysfunction: Epidemiology, etiology, and natural history", section on 'Autonomic nervous system and the SA node'.) In the atrioventricular (AV) node, conduction velocity slows and the refractory period lengthens [1,2]. In atrial tissue, there is no change in conduction velocity, while the refractory period shortens [1]. The electrophysiologic properties of the His-Purkinje system do not change significantly. In ventricular myocardium, vagal nerve stimulation has been shown to decrease ventricular inotropy [3]. The effects on the sinus node are often more manifest with right vagus activation and the effects on the AV node by left vagus activation. Manual pressure on the carotid sinus can elicit an intense activation of the vagus nerve on that side. The intensity of the response is directly related to the ambient blood pressure, the sensitivity of the vagus nerve, the underlying sympathetic activation, and the expertise of applying manual pressure to the correct spot. The direct role of acute increases in vagus nerve activation in stopping supraventricular tachycardias is supported by the following observations: Successful arrhythmia termination with vagal maneuvers is associated with a greater degree of bradycardic response to vagal maneuvers while in sinus rhythm [4]. Arrhythmia termination is often preceded by gradual slowing of the tachycardia, suggesting progressive prolongation of AV conduction during the maneuver [2,5,6]. CLINICAL USES Vagal maneuvers can be performed in a variety of clinical settings for diagnostic and/or therapeutic purposes ( table 1): Vagal maneuvers are a safe and easily performed diagnostic test as well as an effective first-line therapeutic intervention for patients with SVT. The 2015 American College of Cardiology/American Heart Association/Heart Rhythm Society guidelines recommend vagal maneuvers (Class IA LOE B-R) for acute treatment of SVT of unknown mechanism, for treatment of AV reentrant tachycardia, and for treatment of AV nodal reentrant tachycardia [7]. (See "Narrow QRS complex tachycardias: Clinical manifestations, diagnosis, and https://www.uptodate.com/contents/vagal-maneuvers/print 2/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate evaluation" and "Atrioventricular nodal reentrant tachycardia" and "Atrioventricular reentrant tachycardia (AVRT) associated with an accessory pathway".) Vagal maneuvers, in particular carotid sinus massage, can be helpful in determining the location of the conduction abnormality in a patient with 2:1 AV block (eg, within the AV node or in the His-Purkinje system). Increased vagal tone slows conduction through the AV node but has little effect on conduction properties of the His-Purkinje system. (See "Second-degree atrioventricular block: Mobitz type I (Wenckebach block)" and "Second- degree atrioventricular block: Mobitz type II".) Carotid sinus massage is employed in the evaluation of potential carotid sinus hypersensitivity as a cause of syncope. This maneuver should not be performed in patients with carotid artery disease, as discussed below. (See 'Contraindications' below and 'Carotid sinus massage' below.) The Valsalva maneuver can also be useful in the evaluation of cardiac murmurs. (See "Auscultation of cardiac murmurs in adults".) Historical case reports and small series have documented termination of atrial fibrillation and hemodynamically stable ventricular tachycardia initiated during cardiac electrophysiological studies by vagal maneuvers [8-10]. TYPES OF VAGAL MANEUVERS A wide variety of physical maneuvers can have intended or unintended influence on increasing vagal tone. These include: Carotid sinus massage (see 'Carotid sinus massage' below) Valsalva maneuver (standard or modified technique) (see 'Valsalva maneuver' below) Water immersion, especially cold water immersion (diving reflex) (see 'Diving reflex' below) Eyeball pressure (oculocardiac reflex) (see 'Oculocardiac reflex' below) Breath holding Rectal examination Coughing Deep respirations Gagging and/or vomiting Swallowing Intracardiac catheter placement Nasogastric tube placement https://www.uptodate.com/contents/vagal-maneuvers/print 3/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate Squatting Trendelenburg position Although only a small number of these maneuvers are used clinically for diagnostic or therapeutic purposes (eg, carotid sinus massage and the Valsalva maneuver), it is useful to be aware of the potential autonomic impact of the others. CHOICE OF MANEUVER The choice of a particular vagal maneuver is dependent on the clinical scenario and the patient's ability to successfully perform some of the maneuvers. Our approach to choosing a vagal maneuver for the most commonly encountered clinical scenarios is as follows: For diagnostic and/or therapeutic use in a patient with SVT, we typically start with the Valsalva maneuver and employ the modified Valsalva when possible, as the Valsalva maneuver appears to be more effective in terminating SVT than other vagal maneuvers. For diagnostic evaluation of a patient with suspected carotid sinus hypersensitivity, we use carotid sinus massage. For diagnostic evaluation of a cardiac murmur, we use the Valsalva maneuver. (See "Physiologic and pharmacologic maneuvers in the differential diagnosis of heart murmurs and sounds", section on 'Valsalva maneuver'.) Successful termination of SVT by vagal maneuvers has been noted in as many as 72 percent of cases, although likelihood of success diminishes as the duration of the arrhythmia increases [4- 6,11,12]. In the largest randomized trial of vagal maneuvers for the treatment of SVT, patients performing the modified Valsalva maneuver with supine repositioning and passive leg raise were significantly more likely to have restoration of sinus rhythm at one minute (43 versus 17 percent in the standard Valsalva group; adjusted odds ratio 3.7; 95% CI 2.3-5.8) [11]. The relative efficacy of four different vagal maneuvers (Valsalva maneuver, right carotid sinus massage, left carotid massage, and the diving reflex) was evaluated in a series of 35 patients with SVT inducible by programmed electrical stimulation [4]. The supine Valsalva maneuver was most successful in terminating SVT (54 percent), with significantly lower efficacy right and left carotid sinus massage (17 and 5 percent, respectively) and the diving reflex (17 percent). https://www.uptodate.com/contents/vagal-maneuvers/print 4/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate Another study evaluated the standard Valsalva maneuver, modified Valsalva maneuver, and carotid sinus massage and found that the success rate for SVT termination was 43.7 percent (14 of 32 cases) for the modified Valsalva maneuver, 24.2 percent (8 of 33) for the standard Valsalva maneuver, and 9.1 percent (3 of 33) for carotid sinus massage (p <0.05) [12]. VALSALVA MANEUVER For both diagnostic and therapeutic purposes, the Valsalva maneuver is commonly used in patients with suspected SVTs. Because of its greater efficacy in terminating SVT, we perform a modified Valsalva maneuver involving passive leg raising whenever feasible. (See "Atrioventricular nodal reentrant tachycardia", section on 'Vagal maneuvers' and "Treatment of arrhythmias associated with the Wolff-Parkinson-White syndrome", section on 'Acute treatment of symptomatic arrhythmias'.) A.M. Valsalva is credited with describing the maneuver that bears his name [13]. In the original 1704 reporting, the use of the maneuver, essentially a forceful expiration against a closed mouth and nose, was beneficial in rapid expulsion of pus from the middle ear. Subsequent investigation of the Valsalva maneuver has focused on its cardiovascular and autonomic nervous properties [14,15]. Currently, the Valsalva maneuver is primarily used in clinical practice in the diagnosis and treatment of SVTs and, occasionally, for the assessment of heart failure and left ventricular dysfunction [7]. Valsalva maneuver technique Various descriptions of the technique of performing a Valsalva maneuver exist ( figure 1). Most commonly, the patient is placed in a supine or semirecumbent position and instructed to exhale forcefully against a closed glottis after a normal inspiratory effort (ie, at tidal volume). Signs of adequacy include neck vein distension, increased tone in the abdominal wall muscles, and a flushed face. The patient should maintain the strain for 10 to 15 seconds and then release it and resume normal breathing. A modified Valsalva maneuver, which involves the standard strain (40 mmHg pressure for 15 seconds in the semirecumbent position) followed by supine repositioning with 15 seconds of passive leg raise at a 45 degree angle, has been shown to be more successful in restoring sinus rhythm for patients with SVT [11]. While some descriptions have required patients to blow into a manometer to generate a certain amount of pressure (eg, 40 mmHg), this is not generally required. https://www.uptodate.com/contents/vagal-maneuvers/print 5/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate In the largest randomized trial of vagal maneuvers for the treatment of SVT, patients performing the modified Valsalva maneuver with supine repositioning and passive leg raise were significantly more likely to have restoration of sinus rhythm at one minute (43 versus 17 percent in the standard Valsalva group; adjusted odds ratio 3.7; 95% CI 2.3-5.8) [11]. When feasible, the modified Valsalva maneuver should be performed given the greater likelihood of successful restoration of sinus rhythm. (See "Atrioventricular nodal reentrant tachycardia", section on 'Vagal maneuvers'.) Valsalva maneuver monitoring When the Valsalva maneuver is performed in a medical environment (eg, hospital, clinic, etc), all patients should have vital signs monitored before and after the maneuver, with some variation in monitoring during the maneuver depending upon the indication (ie, paroxysmal SVT versus heart failure). Patients who are performing the Valsalva maneuver for either diagnostic and/or therapeutic purposes in the setting of SVT should have continuous heart rate monitoring. Ideally, the continuous monitoring is performed with 12-lead electrocardiography, yielding the most information about the heart rhythm and tachycardia, but if this is not available or practical then continuous single-lead telemetry monitoring should be performed. Although seldom used in current practice, alterations in the systemic arterial blood pressure response to the Valsalva maneuver have been described in patients with heart failure and/or left ventricular dysfunction [16]. Patients who are performing the Valsalva maneuver for diagnostic purposes in this setting should have continuous blood pressure monitoring along with continuous heart rate monitoring (single-lead telemetry is adequate here) during the maneuver. When noninvasively monitoring blood pressure responses using a blood pressure cuff, the cuff should be inflated to approximately 15 mmHg above the patient's resting systolic blood pressure, and the examiner should auscultate the brachial artery throughout the maneuver and for 15 to 30 seconds afterward. Blood pressure responses following a Valsalva maneuver The expected blood pressure response in normal subjects is divided into four phases ( figure 2) [14]. Phases 1 and 2 occur during the active strain phase of the Valsalva maneuver, while phases 3 and 4 occur after the strain phase has been completed. The normal pattern of systolic blood pressure has been named the "sinusoidal" response. Phase 1 is characterized by a >15 mmHg rise in the patient's systolic blood pressure that occurs at the onset of straining and typically lasts less than five seconds. Phase 1 occurs because of increased intrathoracic pressure. https://www.uptodate.com/contents/vagal-maneuvers/print 6/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate Phase 2 is typified by a return of the systolic blood pressure to baseline (below the 15 mmHg increase) during the remainder of the straining phase. Phase 2 occurs due to decreased venous return (leading to a decrease in stroke volume) and an increase in systemic vascular resistance. Relative tachycardia may occur during this phase [17]. Phase 3 occurs after release of the strain and is distinguished by an abrupt fall in systolic blood pressure below baseline. Phase 3 occurs due to an acute decrease in intrathoracic pressure. Phase 4 follows and is identified by a secondary rise in systolic blood pressure >15 mmHg above baseline. Phase 4 occurs because of a reflex sympathetic response to the decrease in systolic blood pressure encountered during phase 3. Relative bradycardia may occur during this phase. In addition to the normal sinusoidal response to Valsalva, two abnormal response patterns have been described in patients not taking beta-blocking agents [17,18]. The "absent overshoot" response is characterized by an absence of the expected rise in systolic blood pressure during phase 4. This response is associated with a moderately decreased left ventricular ejection fraction. The "square wave" response is characterized by the presence of Korotkoff sounds during the entire straining phase (indicating a sustained rise in blood pressure following phase 1) and an absence of the expected rise in systolic blood pressure during phase 4. This response is associated with a severely decreased ejection fraction. Patients taking beta-blockers typically show a blunted blood pressure response to the Valsalva maneuver. Heart rate responses for patients with SVT For a patient with SVT in whom the Valsalva maneuver is performed for both diagnostic and/or therapeutic purposes, the potential heart rate and rhythm responses are similar to those that can be seen following any vagal maneuver or the administration of adenosine. Potential outcomes include slowing of sinoatrial nodal activity, block at the AV node "unmasking" atrial activity, termination of the SVT, or no response (generally indicating inadequate performance of the technique). These responses are discussed in detail separately. (See "Narrow QRS complex tachycardias: Clinical manifestations, diagnosis, and evaluation", section on 'Possible outcomes following vagal maneuvers or adenosine administration'.) https://www.uptodate.com/contents/vagal-maneuvers/print 7/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate CAROTID SINUS MASSAGE The cerebrovascular and cardiovascular effects of carotid artery compression were documented at least as early as the 18th century [19]. Early theories suggested that pressure on the carotid sinus directly stimulated the vagus nerve. However, later work demonstrated that distinct afferent nerve fibers are present in the carotid sinus and that these fibers join the glossopharyngeal nerve (cranial nerve IX) to directly stimulate medullary centers [19]. Carotid sinus massage (CSM) is commonly used in a variety of settings, most commonly in the evaluation of SVTs as well as the evaluation of patients with suspected reflex syncope or carotid sinus hypersensitivity [1,4,20,21]. Use of CSM in the diagnosis of syncope and carotid sinus hypersensitivity is discussed separately. (See "Reflex syncope in adults and adolescents: Clinical presentation and diagnostic evaluation" and "Carotid sinus hypersensitivity and carotid sinus syndrome".) Carotid sinus massage technique Carotid sinus massage is performed as follows [22]: Patients are first screened for contraindications to carotid sinus massage. In those without known carotid disease, auscultation for carotid bruits should be performed first to avoid inadvertent carotid artery injury. (See 'Contraindications' below.) The patient is placed in the supine position with the neck extended (ie, raising the chin away from the chest) to maximize access to the carotid artery. The carotid sinus is usually located inferior to the angle of the mandible at the level of the thyroid cartilage near the arterial impulse ( figure 3). Pressure is applied to one carotid sinus for 5 to 10 seconds. Although pulsatile pressure via vigorous circular motion may be more effective, steady pressure is recommended because it may be more reproducible [6]. If the expected response is not obtained, the procedure is repeated on the other side after a one- to two-minute delay. (See 'Responses to carotid sinus massage' below.) Carotid sinus massage monitoring When carotid sinus massage is performed in a medical environment (eg, hospital, clinic, etc), all patients should have vital signs monitored before and after the maneuver, with some variation in monitoring during carotid sinus massage depending upon the indication (ie, paroxysmal SVT versus carotid sinus hypersensitivity) [22]. Patients undergoing carotid sinus massage for either diagnostic and/or therapeutic purposes in the setting of SVT should have continuous heart rate monitoring. Ideally, the https://www.uptodate.com/contents/vagal-maneuvers/print 8/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate continuous monitoring is performed with 12-lead electrocardiography, yielding the most information about the heart rhythm and tachycardia, but if this is not available or practical then continuous single-lead telemetry monitoring should be performed. Patients undergoing carotid sinus massage for diagnostic purposes in the setting of suspected carotid sinus hypersensitivity should have frequent blood pressure monitoring along with continuous heart rate monitoring (single-lead telemetry is adequate here) during the massage. (See "Carotid sinus hypersensitivity and carotid sinus syndrome".) Responses to carotid sinus massage Changes in heart rate or rhythm, as well as blood pressure, occur following carotid sinus massage. The expected responses vary somewhat depending upon the indication (ie, paroxysmal SVT versus carotid sinus hypersensitivity) [8]. For a patient with SVT in whom carotid sinus massage is performed for both diagnostic and/or therapeutic purposes, the potential heart rate and rhythm responses are similar to those that can be seen following any vagal maneuver or the administration of adenosine. Potential outcomes include slowing of sinoatrial nodal activity, block at the AV node "unmasking" atrial activity, termination of the SVT, or no response (generally indicating inadequate performance of the technique). These responses are discussed in detail separately. (See "Narrow QRS complex tachycardias: Clinical manifestations, diagnosis, and evaluation", section on 'Possible outcomes following vagal maneuvers or adenosine administration'.) Criteria for abnormal responses suggestive of carotid sinus hypersensitivity (and carotid sinus syndrome if clinical symptoms are reproduced) are discussed separately. (See "Carotid sinus hypersensitivity and carotid sinus syndrome", section on 'Diagnostic evaluation'.) Contraindications Injury to the carotid artery, with its attendant consequences, can occur with direct pressure on the carotid artery. Carotid sinus massage should be avoided in patients with known carotid artery stenosis, prior transient ischemia attack, or stroke within the past three months and in patients with carotid bruits (unless carotid Doppler studies have excluded significant stenosis) [21-23]. As noted above, in those without known carotid disease, auscultation for carotid bruits should be performed first to avoid inadvertent carotid artery injury. Additional exclusion criteria have been used in some studies including recent myocardial infarction, history of ventricular arrhythmia, immobility, blindness, and cognitive impairment [20,24]. (See 'Complications' below.) For patients in whom carotid sinus massage is needed as part of an evaluation (ie, in the evaluation of carotid sinus hypersensitivity), there are few data on screening for carotid disease with any means other than auscultation for carotid bruits (eg, carotid ultrasound, etc). (See "Screening for asymptomatic carotid artery stenosis".) https://www.uptodate.com/contents/vagal-maneuvers/print 9/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate For patients with SVT in whom there is concern about increased risk of stroke due to carotid sinus massage, alternative vagal maneuvers (eg, Valsalva maneuver) should be utilized. (See 'Valsalva maneuver' above.) DIVING REFLEX The diving reflex was first described in chickens and ducks and has also been observed as an oxygen-conserving maneuver in diving mammals. In humans, the diving reflex has been studied as a tool to assess the autonomic nervous system [25,26]. Similar to other vagal maneuvers, the diving reflex can potentially terminate paroxysmal SVT. The diving reflex is commonly used to terminate SVT in infants, but it is rarely used in older children or adults. A variety of techniques to elicit a diving reflex have been tried [25-27]. Infants In infants, the vagal maneuver most commonly used is application of a bag filled with ice and cold water over the face for 15 to 30 seconds. This successfully terminates SVT in 60 to 90 percent of cases. (See "Management of supraventricular tachycardia (SVT) in children", section on 'Vagal maneuvers'.) Adults and older children Most commonly, the patient is seated in front of a basin of water (at a temperature of 10 to 20 C) and is attached to continuous electrocardiographic monitoring (ideally, continuous 12-lead electrocardiography, but if this is not available or practical then continuous single-lead telemetry monitoring). The patient takes a moderate breath, holds it, and then submerges his or her face in water for 20 to 30 seconds. A bradycardic response usually occurs within 10 to 30 seconds of breath holding. If the inspiration is too deep, increased intrathoracic pressure may attenuate the bradycardic response. Contact of the area innervated by the ophthalmic division of the trigeminal nerve seems to be particularly important in eliciting a response. The expected response in normal subjects results from a combination of facial immersion and breath holding. The expected effect is parasympathetic-mediated bradycardia and sympathetic-mediated peripheral vasoconstriction, ideally resulting in termination of the SVT. Although its role is limited, this maneuver may be preferred in patients who should not be performing a Valsalva maneuver (eg, pregnant women with SVT). OCULOCARDIAC REFLEX https://www.uptodate.com/contents/vagal-maneuvers/print 10/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate As a clinical tool, the oculocardiac reflex is poorly defined and rarely used. It has been used to terminate supraventricular tachycardias and in the diagnostic evaluation of syncope [28-30]. However, due to limited utility, risk of injury to the eyes and other associated risks, and the availability of alternative maneuvers, we do not perform this test in clinical practice. The oculocardiac reflex involves a decrease in heart rate and/or blood pressure in response to eyeball pressure. The reflex is thought to originate from the ophthalmic portion of the trigeminal nerve. Afferent stimuli move through the reticular formation and nuclei of the vagus nerve output and proceed via an efferent link through the vagus nerve to cardiovascular structures [28]. This oculocardiac reflex is most often recognized in the context of ophthalmic surgery. Pressure or traction on the orbital contents, globe, or extra-ocular muscles can produce unwanted and sometimes dangerous consequences, which on rare occasions can include lethal arrhythmias [28]. COMPLICATIONS In appropriately selected patients, vagal maneuvers are generally safe. However, there are potential complications to performing vagal maneuvers ( table 2): Cardiac In general, the potential cardiac complications following a vagal maneuver are simply exaggerations of the expected response from the procedure. Patients may develop prolonged sinus pauses/asystole, AV block, and/or hypotension, all of which are transient and typically resolve within seconds to minutes. Less commonly, tachyarrhythmias such as atrial fibrillation can be provoked following a vagal maneuver. Neurologic Neurologic complications are rare (less than 1 percent) and are usually related to stroke or transient ischemia attack following carotid sinus massage [20,24,31]. (See 'Contraindications' above.) Miscellaneous In addition to the potential cardiac and neurologic complications, there are some maneuver-specific potential complications, including the following: Valsalva maneuver Rupture of the round window of the ear, induction of labor in pregnant women Diving reflex (ice-water immersion) Aspiration, drowning, induction of labor in pregnant women Oculocardiac reflex Ocular injury https://www.uptodate.com/contents/vagal-maneuvers/print 11/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate INFORMATION FOR PATIENTS UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." th th The Basics patient education pieces are written in plain language, at the 5 to 6 grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more th th sophisticated, and more detailed. These articles are written at the 10 to 12 grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon. Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.) Basics topics (see "Patient education: Vagal maneuvers and their responses (The Basics)") SUMMARY AND RECOMMENDATIONS Role of autonomic nervous system The autonomic nervous system is composed of the sympathetic and parasympathetic divisions. Various physical maneuvers can elicit autonomic responses, including a wide variety that can have intended or unintended influence on increasing vagal tone. (See 'Introduction' above.) Cardiac response to vagal stimulation In the heart, parasympathetic (vagal) stimulation causes local release of acetylcholine, which results in slowing of sinus node impulse formation and slowed conduction with lengthening of the refractory period in the atrioventricular (AV) node. (See 'Cardiac responses to vagal stimulation' above.) Clinical uses Vagal maneuvers can be performed in a variety of clinical settings for diagnostic and/or therapeutic purposes ( table 1), including the evaluation and/or treatment of patients with supraventricular tachycardia (SVT), AV block, syncope, and cardiac murmurs. (See 'Clinical uses' above.) Choice of vagal maneuver The choice of a particular vagal maneuver is dependent on the clinical scenario and the patient's ability to successfully perform the maneuvers. Our approach to choosing a vagal maneuver for the most commonly encountered clinical scenarios is as follows (see 'Choice of maneuver' above): https://www.uptodate.com/contents/vagal-maneuvers/print 12/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate For diagnostic and/or therapeutic use in a patient with SVT, we typically start with the Valsalva maneuver and employ the modified Valsalva when possible, as the Valsalva maneuver appears to be more effective in terminating SVT than other vagal maneuvers. (See 'Valsalva maneuver' above.) For diagnostic evaluation of a patient with suspected carotid sinus hypersensitivity, we use carotid sinus massage. (See 'Carotid sinus massage' above.) For diagnostic evaluation of a cardiac murmur, we use the Valsalva maneuver. Contraindications and complications In appropriately selected patients, vagal maneuvers are generally safe. However, there are potential contraindications and complications to performing vagal maneuvers. While noncardiac side effects are rare ( table 2), interventions that alter cardiac conduction properties can result in adverse events, including sinus pauses, AV block, and, rarely, tachyarrhythmias. (See 'Contraindications' above and 'Complications' above.) Use of UpToDate is subject to the Terms of Use. REFERENCES 1. Kirchhof CJ, Gorgels AP, Wellens HJ. Carotid sinus massage as a diagnostic and therapeutic tool for atrial flutter-fibrillation. Pacing Clin Electrophysiol 1998; 21:1319. 2. Klein HO, Hoffman BF. Cessation of paroxysmal supraventricular tachycardias by parasympathomimetic interventions. Ann Intern Med 1974; 81:48. 3. Yamakawa K, So EL, Rajendran PS, et al. Electrophysiological effects of right and left vagal nerve stimulation on the ventricular myocardium. Am J Physiol Heart Circ Physiol 2014; 307:H722. 4. Mehta D, Wafa S, Ward DE, Camm AJ. Relative efficacy of various physical manoeuvres in the termination of junctional tachycardia. Lancet 1988; 1:1181. 5. Josephson ME, Seides SE, Batsford WB, et al. The effects of carotid sinus pressure in re- entrant paroxysmal supraventricular tachycardia. Am Heart J 1974; 88:694. 6. Waxman MB, Wald RW, Sharma AD, et al. Vagal techniques for termination of paroxysmal supraventricular tachycardia. Am J Cardiol 1980; 46:655. 7. Page RL, Joglar JA, Caldwell MA, et al. 2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia: A Report of the American College of https://www.uptodate.com/contents/vagal-maneuvers/print 13/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation 2016; 133:e506. 8. Schweitzer P, Teichholz LE. Carotid sinus massage. Its diagnostic and therapeutic value in arrhythmias. Am J Med 1985; 78:645. 9. Hess DS, Hanlon T, Scheinman M, et al. Termination of ventricular tachycardia by carotid sinus massage. Circulation 1982; 65:627. 10. Wei JY, Greene HL, Weisfeldt ML. Cough-facilitated conversion of ventricular tachycardia. Am J Cardiol 1980; 45:174. 11. Appelboam A, Reuben A, Mann C, et al. Postural modification to the standard Valsalva manoeuvre for emergency treatment of supraventricular tachycardias (REVERT): a randomised controlled trial. Lancet 2015; 386:1747. 12. Ceylan E, Ozpolat C, Onur O, et al. Initial and Sustained Response Effects of 3 Vagal Maneuvers in Supraventricular Tachycardia: A Randomized, Clinical Trial. J Emerg Med 2019; 57:299. 13. DERBES VJ, KERR A Jr. Valsalva's maneuver and Weber's experiment. N Engl J Med 1955; 253:822. 14. IRVIN CW Jr. Valsalva maneuver as a diagnostic aid. J Am Med Assoc 1959; 170:787. 15. Smith G, Morgans A, Boyle M. Use of the Valsalva manoeuvre in the prehospital setting: a review of the literature. Emerg Med J 2009; 26:8. 16. Zema MJ. Diagnosing Heart Failure by the Valsalva Maneuver: Isn't it Finally Time? JACC Heart Fail 2018; 6:969. 17. Zema MJ, Restivo B, Sos T, et al. Left ventricular dysfunction bedside Valsalva manoeuvre. Br Heart J 1980; 44:560. 18. Zema MJ, Masters AP, Margouleff D. Dyspnea: the heart or the lungs? Differentiation at bedside by use of the simple Valsalva maneuver. Chest 1984; 85:59. 19. LOWN B, LEVINE SA. The carotid sinus. Clinical value of its stimulation. Circulation 1961; 23:766. 20. Richardson DA, Bexton R, Shaw FE, et al. Complications of carotid sinus massage a prospective series of older patients. Age Ageing 2000; 29:413. 21. Brignole M, Moya A, de Lange FJ, et al. 2018 ESC Guidelines for the diagnosis and management of syncope. Eur Heart J 2018; 39:1883. 22. Pasquier M, Clair M, Pruvot E, et al. Carotid Sinus Massage. N Engl J Med 2017; 377:e21. 23. Shen WK, Sheldon RS, Benditt DG, et al. 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of https://www.uptodate.com/contents/vagal-maneuvers/print 14/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate Cardiology/American Heart Association Task Force on Clinical Practice Guidelines, and the Heart Rhythm Society. J Am Coll Cardiol 2017. 24. Davies AJ, Kenny RA. Frequency of neurologic complications following carotid sinus massage. Am J Cardiol 1998; 81:1256. 25. Reyners AK, Tio RA, Vlutters FG, et al. Re-evaluation of the cold face test in humans. Eur J Appl Physiol 2000; 82:487. 26. Duprez D, De Buyzere M, Trouerbach J, et al. Continuous monitoring of haemodynamic parameters in humans during the early phase of simulated diving with and without breathholding. Eur J Appl Physiol 2000; 81:411. 27. Gooden BA. The diving response in clinical medicine. Aviat Space Environ Med 1982; 53:273. 28. Van Brocklin MD, Hirons RR, Yolton RL. The oculocardiac reflex: a review. J Am Optom Assoc 1982; 53:407. 29. Brignole M, Menozzi C, Gianfranchi L, et al. Carotid sinus massage, eyeball compression, and head-up tilt test in patients with syncope of uncertain origin and in healthy control subjects. Am Heart J 1991; 122:1644. 30. Allison CE, De Lange JJ, Koole FD, et al. A comparison of the incidence of the oculocardiac and oculorespiratory reflexes during sevoflurane or halothane anesthesia for strabismus surgery in children. Anesth Analg 2000; 90:306. 31. Puggioni E, Guiducci V, Brignole M, et al. Results and complications of the carotid sinus massage performed according to the "method of symptoms". Am J Cardiol 2002; 89:599. Topic 1034 Version 31.0 https://www.uptodate.com/contents/vagal-maneuvers/print 15/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate GRAPHICS Conditions in which vagal maneuvers may be useful diagnostically or therapeutically Tachyarrhythmias Narrow, regular supraventricular tachycardias Sinus tachycardia Conduction abnormalities 2:1 atrioventricular block Bundle branch blocks Preexcitation Other cardiovascular uses Carotid sinus hypersensitivity Pulmonary edema Courtesy of Peter J Zimetbaum, MD and Daniel Frisch, MD. Graphic 67134 Version 4.0 https://www.uptodate.com/contents/vagal-maneuvers/print 16/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate Valsalva maneuver The Valsalva maneuver is performed with the patient supine or in a semirecumbent position and instructed to exhale forcefully against a closed glottis after a normal inspiratory effort (ie, at tidal volume). Signs of adequacy include neck vein distension, increased tone in the abdominal wall muscles, and a flushed face. The patient should maintain the strain for 10 to 15 seconds and then release it and resume normal breathing. A modified Valsalva maneuver involves the standard strain (40 mmHg pressure for 15 seconds in the semirecumbent position at 45 degrees) immediately followed by lowering the trunk to a supine position with passive leg raise at a 45 degree angle for 15 seconds. The modified Valsalva maneuver has been shown to be more successful in restoring sinus rhythm for patients with supraventricular tachycardia. Modi ed from: Hunter C. Slow down, you re going too fast: SVT and The Modi ed Valsalva Maneuver. CPR Seattle 2019. Graphic 130499 Version 1.0 https://www.uptodate.com/contents/vagal-maneuvers/print 17/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate Normal blood pressure responses to the Valsalva maneuver Normal Valsalva response: Normal changes in systolic blood pressure during 10 seconds of straining (shaded). Phase 1 - systolic blood pressure rises with initiation of the maneuver. Phase 2 - systolic blood pressure returns to baseline after several seconds. Phase 3 - systolic blood pressure drops below normal after strain is released. Phase 4 - systolic blood pressure rises transiently before returning to baseline. Graphic 78776 Version 4.0 https://www.uptodate.com/contents/vagal-maneuvers/print 18/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate Anatomy of the carotid sinus The carotid sinus is located at the base of the internal carotid artery just superior to its bifurcation from the external carotid artery. Graphic 139405 Version 1.0 https://www.uptodate.com/contents/vagal-maneuvers/print 19/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate Potential complications of selected vagal maneuvers Vagal maneuver Potential complication Valsalva maneuver Rupture of the round window of the ear Carotid sinus massage Decreased cerebral perfusion, cerebral embolism Ice-water immersion Aspiration, drowning, pregnancy complications Eyeball compression Ocular injury Courtesy of Peter J Zimetbaum, MD and Daniel Frisch, MD. Graphic 79543 Version 5.0 https://www.uptodate.com/contents/vagal-maneuvers/print 20/21 7/6/23, 10:44 AM Vagal maneuvers - UpToDate Contributor Disclosures Daniel R Frisch, MD Other Financial Interest: Abbott [Arrhythmias speaking engagement]; St Jude Medical [Arrhythmias speaking engagement]. All of the relevant financial relationships listed have been mitigated. Peter J Zimetbaum, MD Consultant/Advisory Boards: Abbott Medical [Lead extraction]. All of the relevant financial relationships listed have been mitigated. Brian Olshansky, MD Other Financial Interest: AstraZeneca [Member of the DSMB for the DIALYZE trial]; Medtelligence [Cardiovascular disease]. All of the relevant financial relationships listed have been mitigated. Susan B Yeon, MD, JD, FACC No relevant financial relationship(s) with ineligible companies to disclose.