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Supraventricular rhythms
Published in Andrew R Houghton, Making Sense of the ECG, 2019
The rapid atrial rate gives a characteristic ‘sawtooth’ appearance to the baseline of the ECG, made up of flutter or ‘F’ waves. This can be made more apparent by carotid sinus massage or by giving adenosine. This will not terminate the atrial flutter, but will increase the degree of AV block, making the baseline easier to see by reducing the number of QRS complexes. Carotid sinus massage should be performed with the patient supine and with the neck slightly extended. Do not perform carotid sinus massage if carotid bruits are present, or if there is a history of cerebral thromboembolism. Massage the carotid artery on one side of the neck, medial to the sternomastoid muscle, for 5 s. The technique can be repeated, if necessary, on the opposite side after waiting for 1 minute. The ECG must be monitored continuously throughout the procedure.
Neck Holds
Published in Darrell L. Ross, Gary M. Vilke, Guidelines for Investigating Officer-Involved Shootings, Arrest-Related Deaths, and Deaths in Custody, 2018
Patients with a significant medical history of atherosclerotic disease may be at risk for disruption of atherosclerotic material or plaque when a neck hold is used. This disruption of plaque could potentially result in a stroke from blockage of blood flow in the carotid arteries. Such cases have been reported in the medical field with the use of carotid sinus massage. Carotid sinus massage involves placing pressure directly over the carotid artery at the level of the carotid sinus and massaging the area, which has the effect of increasing neurologic discharge to slow down the heart rate. Munro and colleagues (1994) reported seven episodes of the neurological symptoms consistent with brain ischemia in older patients with the use of carotid sinus massage in 500 patients. The neurological findings of Munro et al. included weakness in five and visual field defects in two. Of these cases, five spontaneously resolved, one had persistent residual weakness on the same side as a pre-existing stroke, and another had permanent visual field loss (Munro et al., 1994). Richardson et al. (2000) had similar findings in 1,000 patients over 50 years of age, with nine patients reporting neurological complications possibly attributable to the carotid sinus massage, eight of which spontaneously resolved and one had persistent hand weakness. There were no sudden cardiac arrests or deaths reported in any of these case series.
Supraventricular rhythms
Published in Andrew R Houghton, David Gray, Making Sense of the ECG, 2014
An episode of AVRT can be terminated by blocking the AV node, thereby breaking the re-entry circuit. The Valsalva manoeuvre increases vagal inhibition of AV nodal conduction, thus slowing AV nodal conduction and terminating the tachycardia. Alternatively, you can perform carotid sinus massage (while monitoring the ECG) with the same aim, as long as the patient does not have carotid bruits or any history of cerebrovascular events. The technique of carotid sinus massage is described on page 66.
Non-Sustained Polymorphic Ventricular Tachycardia Induced by Modified Valsalva in a Pregnant Patient with Supraventricular Tachycardia
Published in Prehospital Emergency Care, 2023
Corey Lapalme, Sean Kaw, Ian Drennan, Sheldon Cheskes
The occurrence of ventricular dysrhythmia associated with Valsalva maneuver has not been well explored in the literature. Besides the two cases of polymorphic VT mentioned above, there is also a reported case of transient ventricular standstill induced by Valsalva (11).Additionally the related procedure of carotid sinus massage has also been associated with cases of ventricular dysrhythmias, with a reported case of pause-dependent ventricular tachycardia resultant from carotid sinus massage (12), as well as a case of ventricular fibrillation induced by carotid sinus massage that was not preceded by pause or bradycardia (13). It is also noteworthy that Appelboam et al. (2) reported 4 occurrences of ventricular dysrhythmias during the REVERT trial, but the nature of these events was not further explained in that article.
Long term use of donepezil and QTc prolongation
Published in Clinical Toxicology, 2021
Jason Kho, Adam Ioannou, Amit K. J. Mandal, Andrew Cox, Ashraf Nasim, Sofia Metaxa, Constantinos G. Missouris
A possible explanation is that male patients have a greater sensitivity to the increase in cardiac acetylcholine concentrations caused by donepezil, which results in a greater prolongation of the QT interval [4]. Naturally, there is an increase in vagal tone and acetylcholine release when patients undergo a carotid sinus massage. Male patients exhibit increased sensitivity to carotid sinus massage and have an increased prevalence of carotid sinus disease, which could theoretically be due to an underlying oversensitivity to acetylcholine [21–23]. Further evidence of this is that male patients are less responsive to muscarinic receptor antagonists such as atropine [24]. This mechanism may explain why male patients exhibit a greater prolongation of the corrected QT interval compared to females, but our results would require confirmation in a larger study.
How can we better manage hypotensive syndromes in older adults?
Published in Expert Review of Cardiovascular Therapy, 2022
Head turning is an important trigger for hypotension in the elderly with carotid sinus hypersensitivity (CSH). The CSS syndrome is rare and it occurs approximately in 1% of patients with documented syncope, mainly in older men. Carotid sinus massage is used to confirm CSH. In addition to hydration and salt tablets, adding fludrocortisone or midodrine can be considered in the management [1]. The treatment of the vasodepressive type of CSS is difficult.