Method of pacing does not affect the recurrence of syncope in carotid sinus syndrome

Introduction: Pacemaker therapy is effective in reducing recurrent syncope in patients with symptomatic carotid sinus hypersensitivity (CSH), yet the optimal pacing modality for this syndrome is not known. The objective of this study is to prospectively investigate the impact of three pacing methods (DDDR vs DDDR with sudden bradycardia response [SBR] vs VVI) on recurrent syncope and quality of life. Methods: Twenty‐one patients with symptomatic CSH (syncope or near syncope) were randomized to VVI, DDDR, or DDDR with SBR on a double‐blinded basis in a sequential crossover fashion with 6 months in each mode. The primary endpoints were recurrent events and quality of life (assessed by SF‐36). The mean number of events and SF‐36 scores were compared. Results: At baseline, over the preceding 6 months, there were a total of 29 syncopal events and 258 presyncopal events among 21 patients. Following pacing in any mode, the total number of these syncopal events reduced to two in two patients (P < 0.001) and 17 presyncopal events (P < 0.001) in 12 patients. The mean number of events was not significantly different between the three pacing methods. SF‐36 scores revealed some minor benefits of DDDR pacing versus baseline in the categories, but no pacing method was found to be superior. Conclusions: The study was unable to confirm the initial study hypothesis of a superiority of one pacing modality over another. Quality of life measures allude to potential benefit from DDDR pacing alone. (PACE 2012;xx;1–7)     

Dual AV Nodal Pathways—Vagal Influences on AV Nodal Conduction

This 52-year-old male presented with syncope and demonstrated two distinct PR intervals on the electrocar-diogram. Electrophysiologic studies showed dual A V nodal path ways. Right-sided carotid sinus massage induced prolonged periods of sinus arrest with no change in AH interval. Left-sided carotid sinus massage produced long AH intervals (slow pathway conduction) with some slowing of sinus rate. Whenever sinus rhythm with slow pathway conduction was observed (long AH) a 20-30 mmHg drop systolic pressure was seen. Following implantation of an AV sequential pacemaker, the patient has been asymptomatic.     

Hypersensitive carotid sinus syndrome due to neurofibromatosis-1 and manifested by repeated episodes of syncope

A 28-year-old patient with neurofibromatosis-1 presented with syncope. The exam demonstrated a mass adjacent and inferior to the right occiput that extended to the posterior lateral right-sided neck. Initial invasive and noninvasive testing was negative. Imaging of her head and neck demonstrated a large neurofibroma enveloping her right carotid sinus without vessel occlusion or evidence of malignancy. An event recorder documented asystole. A pacemaker was implanted to avoid the surgical morbidity of removing the neck mass. The patient has since been free of syncope. We believe neurofibromatosis-1 should be included in the differential of syncope.     

Deglutition Syncope Associated with Carotid Sinus Hypersensitivity

A 78-year-old patient complained of syncope, near syncope, and dizziness when eating; complete atrioventricular block, with ventricular asystole for 3.6 seconds, was recorded on continuous electrocardiographic monitoring. Left and right carotid sinus masssage produces sinus arrest and ventricular asystole lasting 6.4 and 4.8 seconds, respectively. These phenomena were prevented by atropine administration. The symptoms were completely relieved by permanent pacing, but the patient died 6 months later because of large cell undifferentiated carcinoma of the lower third of the esophagus.     

The Heart Rate Response to Carotid Artery Massage in a Sample of Healthy Elderly People

Carotid artery massage was carried out in a cross-section of 95 healthy elderly subjects (51 men and 44 woman, mean age of 74 years) to assess the heart rate response and associated symptoms. These subjects were drawn from a larger group of randomly selected healthy elderly people living in Southampton. They had no history of myocardial infarction or stroke and were not taking any drugs that might enhance the carotid sinus reflex. A continuous distribution of response to carotid artery massage was seen with a median percent change in RR interval of 11.6% (IQR 22.9%); 66% had a percent change in RR interval of < 20%, 90% had a change of < 50%, and 9.5% a change of > 100%. Carotid sinus hypersensitivity (sinus arrest > 3 s) was found in 4 previously asymptomatic subjects; a prevalence of 4.2% (95% CI 1.2%–10.4%), and this was associated with dizziness in 2 of these 4 subjects. Dizziness also occurred in one other subject who had a change in RR interval of 178%, The definition of an abnormal carotid sinus reflex is arbitrary given the continuous RR interval response to carotid artery massage. In diagnosing carotid sinus syndrome, the RR interval response to carotid artery massage alone is not sufficient, as this maneuver must also reproduce the patient's presenting symptoms.     

The Impact of a Dedicated "Syncope and Falls" Clinic on Pacing Practice in Northeastern England

This study examined whether the increased demand for pacemaker implants for carotid sinus syndrome (CSS) at the Regional Pacing Service in northeastern England was related to the establishment of a dedicated "syncope and falls" clinic or to the publication of NASPE and BPEG guidelines for pacing symptomatic bradycardia. To this end, pacemaker rates for various indications at this institution were compared with those of a comparable region (Liverpool), as well as with BPEG's national pacemaker database. Findings indicate a distinct impact of the Newcastle syncope and falls clinic on recognition and pacemaker treatment of CSS.     

Cardiovascular Syncope Is the Most Common Cause of Drop Attacks in the Elderly

Drop attacks are defined as a sudden loss of postural tone without loss of consciousness. The mechanism is often unknown. This report examines findings in consecutive elderly patients with drop attacks referred to a dedicated "syncope and falls" center. Thirty-five patients were included. A diagnosis was established in 25 (71 %); cardioinhibitory cartoid sinus syndrome (CSS) or mixed CSS in 15, vasodepressor CSS in 3, orthostatic hypotension in 5, vasovagal syncope in 1, and gait imbalance in 1. In 21%, more than one pathological diagnosis was present. In conclusion, absence of a history of syncope is unreliable in elderly patients, and these individuals should be routinely investigated for hemodynamic changes during carotid massage and standing.     

Clinical Experience with Thera DR Rate-Drop Response Pacing Algorithm in Carotid Sinus Syndrome and Vasovagal Syncope

This study examined the effectiveness of cardiac pacing using the Thera DR rate-drop response algorithm for prevention of recurrent symptoms in patients with carotid sinus syndrome (CSS) or vasovagal syncope. The algorithm comprises both diagnostic and treatment elements. The diagnostic element consists of a programmable "window" used to identify heart rate changes compatible with an evolving neurally mediated syncopal episode. The treatment arm consists of pacing at a selectable rate and for a programmable duration. Forty-three patients (mean age 53 ± 20.4 years) with CSS alone (n = 8), CSS in conjunction with vasovagal syncope (n = 4), or vasovagal syncope alone (n = 31) were included. Thirty-nine had recurrent syncope, while the remaining four reported multiple presyncopal events. Prior to pacing, 40 ± 152 syncopal episodes (range from 1 to approximately 1,000 syncopal events) over the preceding 56 ± 84.5 months. Postpacing follow-up duration was 204 ± 172 days. Three patients have been lost to follow-up and in one patient the algorithm was disabled. Among the remaining 39 individuals, 31 (80%) indicated absence or diminished frequency of symptoms, or less severe symptoms. Twenty-three patients (23/29, or 59%) were asymptomatic with respect to syncope or presyncope. Sixteen patients had symptom recurrences. Of these, seven experienced syncope (7/39, or 18%) and 9 (29%) had presyncope: the majority of patients with recurrences (6/7 syncope and 7/9 presyncope) were individuals with a history of vasovagal syncope. Consequently, although symptoms were observed during postpacing follow-up, they appeared to be of reduced frequency and severity. Thus, our findings suggest that a transient period of high rate pacing triggered by the Thera DR rate-drop response algorithm was beneficial in a large proportion of highly symptomatic patients with CSS or vasovagal syncope.     

The Use of Serotonin Reuptake Inhibitors for the Treatment of Recurrent Syncope Due to Carotid Sinus Hypersensitivity Unresponsive to Dual Chamber Cardiac Pacing

Carotid sinus hypersensitivity can be a cause of recurrent unexplained syncope in the older patient. Dual chamber cardiac pacing may relieve the bradycardia, but may not affect the vasodilatory component of this disorder. We report on two patients with carotid sinus hypersensitivity with a predominant vasodilatory component who experienced recurrent syncope following permanent pacemaker implantation. Both patients were treated with serotonin reuptake inhibitors and after 4–6 weeks of therapy had complete resolution of symptoms. We conclude that serotonin reuptake inhibitors may be useful in the treatment of recurrent syncope due to carotid sinus hypersensitivity resistant to dual chamber cardiac pacing.     

The Role of Rate Hysteresis Pacing in the Hypersensitive Carotid Sinus Syndrome

The ability of rate hysteresis programming with the escape interval longer than the automatic interval lo reduce the hypotensive response to carotid sinus massage at the onset of ventricular pacing was studied in six patients paced for carotid sinus syndrome. Rate hysteresis significantly reduced this hypotensive response and abolished spontaneous symptoms in two patients and symptoms reproduced by carotid sinus massage in four patients.     

The Role of Rate Hysteresis Pacing in the Hypersensitive Carotid Sinus Syndrome

The ability of rate hysteresis programming with the escape interval longer than the automatic interval lo reduce the hypotensive response to carotid sinus massage at the onset of ventricular pacing was studied in six patients paced for carotid sinus syndrome. Rate hysteresis significantly reduced this hypotensive response and abolished spontaneous symptoms in two patients and symptoms reproduced by carotid sinus massage in four patients.     

Methods Other Than Tilt Testing for Diagnosing Neurocardiogenic (Neurally Mediated) Syncope

The recording of spontaneous episodes of bradycardic neurocardiogenic syncope (NCS) has shown that: a prolonged ventricular asystole seems necessary to cause syncope; asystole is preceded by other bradyarrhythmias in the vast majority of cases; some warning symptoms precede the loss of consciousness in most cases; conventional dual-chamber pacing is efficacious both in patients with a positive response to carotid sinus massage (CSM) and eyeball compression test (EBC) and in those with a positive response to tilt-testing (TT). CSM, EBC, and TT are established tools for diagnosing NCS, when the recording of spontaneous syncope is lacking. When combined together, they are probably able to correctly identify most patients affected by NCS. Nevertheless, whether the type of reflex induced by the cardiovascular reflexivity maneuvers correlates with that of the spontaneous syncope is largely unknown. Our knowledge suggests that the correlation may be unsatisfactory, owing to the following: the variability of the mechanism of spontaneous syncope from patient to patient and also, in the same patient, from one episode to another; the discordance of the type of response when 2 or 3 tests are positive in the same patient, the response being more frequently asystolic with CSM and EBC and more frequently vasodepressor with TT; the different timing between hypotension induced by CSM (in which it follows the bradycardia) and that induced by TT (in which it usually precedes the bradycardia) and the uncertainty about the timing of hypotension during the spontaneous syncope; the good reproducibility of the spontaneous event by CSM and EBC, but not by TT, when cardiac asystole is the manifestation of NCS: and the fairly high rate of false-positive results of cardiovascular reflexivity maneuvers. Hypotension is the main reason for the failure of pacemaker therapy in all the forms of neurocardiogenic syncope (NCS), whether diagnosed by CSM, EBC, or TT. Thus, the need arises to correctly identify the magnitude of the hypotensive reflexes of spontaneous events.     

Cardiac Arrest Caused by Trigeminal Neuralgia

A 67-year-old man with a 12-year history of trigeminal neuralgia experienced multiple fainting episodes preceded by right facial pain. One episode resulted in cardiac arrest with successful resuscitation. Pacemaker insertion prevented further episodes of syncope despite the occurrence of pain. The fainting episodes and cardiac arrest are believed to be unusual manifestations of trigeminal neuralgia.     

Carotid Sinus Hypersensitivity: Diagnosis of Vasodepressor Type in the Presence of Cardioinhibitory Type

The diagnosis of carotid sinus syncope may sometimes be difficult because its symptoms are not specific, especially in the older age group where carotid sinus hypersensitivity and syncope are not uncommon events. Of major diagnostic importance is the screening of the vasodepressor type of carotid sinus syncope in the presence of the cardioinhihitory type, as this diagnosis has important therapeutic applications. This work is based on the electrophysiological studies performed on seven men with a mean age of 61.9 years who had syncope of unknown cause and hypersensitive carotid sinus reflex. The studies revealed no evidence of sinus node dysfunction or high degree atrioventricular block that would explain the neurological symptoms. The studies also included carotid sinus stimulation with simultaneous interarterial pressure recordings with and without atrial or A-V sequential pacing. The pacing assured the maintenance of normal heart rate during carotid sinus stimulation. The results of these studies revealed that five patients suffered from cardioinhibitory type and two from a combined form of cardioinhibitory and vasodepressor type (mixed form) of carotid sinus syncope. A permanent cardiac pacemaker was implanted in the five patients with the isolated cardioinhibitory type and in one patient with the mixed type of carotid sinus syncope.     

Is DDD Superior to VVI Pacing in Mixed Carotid Sinus Syndrome? An Acute and Medium-Term Study

The aim of this study was to evaluate fhe importance of atrial synchronism for pacing therapy of patients with mixed carotid sinus syndrome. In 23 patients (21 m, two f: mean age 69 ± 8 years) affected by symptomatic mixed carotid sinus syndrome we performed: (1) Research of ventriculo-atrial conduction, orthostatic hypotension and pacemaker effect; and [2] Carotid sinus massage in the standing position during VVI and DVI temporary pacing. Next, ail patients received a permanent DDD pacemaker and entered a 2 month two period single-blind, randomized, cross-over study on DVI/DDD versus VVI mode. During the DVI/DDD period, no syncope occurred in any patients, minor symptoms persisted in 11 (48%) of them; during VVI period syncopes recurred in three patients, symptoms requiring the withdrawal of VVI pacing and premature DVI/DDD reprogramming in eight patients, minor symptoms in 17 (74%). A comparison between 14 patients, who preferred DVI/DDD period (Group A), and the remaining nine patients who noted no preference between DVI/DDD and VVI period (Group B) was performed on the basis of the preimplant evaluation. Group A patients had a greater pacemaker effect (-34 ± 16 mmHg vs -16 ± 14 mmHg) and a higher prevalence of symptomatic pacemaker effect (50% vs 0%), of ventriculo-atrial conduction (78% vs 44%) and of orthostatic hypotension (50% vs 11%), while the entity of the systolic pressure fall caused by carotid sinus massage was similar in the two groups either during VVI mode (Group A-51 ± 16 mmHg vs Group B-56 ± 27 mmHg) or DVI mode (Group A-38 ± 17 mmHg vs Group 3–45 ± 17 mmHg). Thus, we conclude that vasodepressor reflex of carotid sinus syndrome is not prevented by DVI/DDD pacing even if the loss of atrial synchronism resulting from WI pacing, by adding an important pacemaker effect, causes a more severe hemodynamic consequence. DVI/DDD pacing is more effective than VVI in 61% of patients. When pacemaker effect, ventriculoatrial conduction and orthostatic hypotension are present, VVI failure is possible, therefore DVI/DDD stimulation is indicated; on the contrary the evaluation of the vasodepressor reflex during WJ or DVI temporary pacing is of little value in the choice of the mode of pacing.     

Carotid Sinus Hypersensitivity and Syndrome in Patients with Chronic Atrial Fibrillation

Carotid sinus hypersensitivity (CSH) has been studied in subjects in sinus rhythm, but it has never been studied in patients with chronic atrial fibrillation (AF). After a finding of CSH in a patient with chronic AF and syncope, we studied the effects of carotid sinus stimulation in a group of patients with AF. Ten patients with chronic AF and normal ventricular rates who complained of dizziness or loss of consciousness underwent right and left carotid sinus massage (CSM) during ECG monitoring. A control group of ten patients with AF but without neurological symptoms was likewise investigated. CSH was present in eight symptomatic patients (5 patients presented right CSH, 1 left and 2 bilateral CSH), but only in three of the control patients. The mean duration of asystole induced by right CSM was 5.94 ± 2.10 seconds; the mean asystolic interval induced by left CSM lasted 8.58 ± 1.42 seconds. Six patients in the symptomatic group had a recurrence of spontaneous symptomatology during CSM, so that a diagnosis of carotid sinus syndrome was established. All symptomatic patients (8 patients with CSH, 2 patients with ventricular standstills but without CSH) received a permanent ventricular pacemaker. Following pacing, all patients, except for one with a significant drop of systolic blood pressure during CSM. became completely asymptomatic. In elder patients with chronic AF, CSH can induce prolonged ventricular asystole, which may be responsible for neurological symptoms such as dizziness, presyncope, or syncope, as observed in patients in sinus rhythm with carotid sinus syndrome. Abnormal sensitivity of the carotid sinus could, therefore, be one of the causes of increased morbidity and mortality in patients with chronic AF. Permanent ventricular pacing may help reduce these complications.     

Visualization of bilateral carotid cavernous sinus fistulas with duplex sonography

Duplex sonography used as a primary diagnostic tool in the case of a 17-year-old boy with a traumatic head injury revealed bilateral carotid cavernous sinus fistulas, with bilateral dilated venous convolutions next to the carotid siphon and dilated superior ophthalmic veins. A bilateral craniectomy allowed visualization of the entire circle of Willis together with the dilated cavernous sinuses. Doppler spectral analysis of blood flow in the arterialized superior ophthalmic veins revealed an arterialized venous pattern with retrograde and increased blood flow. The same blood flow profile was found in the venous cavernous sinuses. These findings were confirmed by digital subtraction angiography. We planned to perform embolization of the patient's fistulas, but intracranial and subarachnoid hemorrhaging developed, and the patient died the day before the procedure was to have been performed. The entire pathologic state of carotid cavernous sinus fistulas, from their origin beside the carotid siphon to the superior ophthalmic veins, can be visualized with duplex sonography, particularly when patients have undergone craniectomy. We believe that patients with frontal or basilar skull fracture should undergo duplex sonographic examination to detect carotid cavernous sinus fistulas.     

Coexistence of tachycardia dependent (phase 3) left bundle branch block and Wolff-Parkinson-White conduction

A 53-year-old woman is described with tachycardia dependent block (Phase 3 block) within the left bundie branch and a right-sided accessory AV bypass tract Simple bedside autonomic maneuvers allowed an accurate assessment of these com-plex conduction disturbances     

Contribution of a Pacemaker Bradycardia Detection Algorithm in the Study of Patients with Carotid Sinus Syndrome

While carotid sinus syndrome (CSS) is often suspected as a cause of syncope in the elderly, whether it represents an indication for cardiac pacing may remain uncertain. Bradycardia algorithms included in pacemakers are now able to establish a precise relationship between spontaneous asystole and occurrence of symptoms and strengthen the indication for permanent pacing. This study included seven men and three women (70.5 +/- 7.3 years of age) who, over an average period of 54.1 +/- 17 months, had suffered from syncope (12.6 episodes/patient) and presyncope (11.2 episodes/patient) attributed to pure cardioinhibition (2 patients) or mixed CSS (8 patients). Other sources of symptoms were excluded by thorough clinical evaluations, including Holter monitoring, echocardiography, and electrophysiological testing. All patients received a CHORUS 6234 pacemaker, the memory of which includes a dedicated bradycardia detection algorithm capable of storing atrial and ventricular chains, and date and time of the last ten pauses and/or bradycardic events. After a initial period of 14.7 +/- 8 months, during which symptoms were suppressed, the bradycardia algorithm was activated. From then on, a cumulative increase in the number of patients presenting with diurnal pauses was measured (1 month, n = 0; 3 months, n = 6; 9 months, n = 7; 2 years, n = 8). Fourteen episodes of diurnal asystole were recorded. The mean duration of the longest episodes of spontaneous ventricular standstill was 6,319 +/- 1,615 ms and was due to sinoatrial block (n = 7), atrioventricular block (n = 5), and a combination of both (n = 2). In conclusion, activation of the CHORUS bradycardia algorithm allowed confirmation of the appropriateness of permanent pacing in a majority of patients suffering from CSS.     

Carotid Sinus Massage as a Diagnostic and Therapeutic Tool for Atrial Flutter-Fibrillation

Alterations in vagal tone can influence the atrial fibrillatory process by changing the atrial refractory period. We observed in a patient with paroxysmal atrial fibrillation (AF) that carotid sinus massage (CSM) changed a "coarse" type of fibrillation into a "fine" type, followed by termination of the arrhythmia. Although coincidental conversion of AF into sinus rhythm could not be excluded, we concluded that it is worthwhile to try CSM in every patient presenting with AF prior to other interventions to restore sinus rhythm.