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.     

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.     

Diagnostic Value of Carotid Sinus Hypersensitivity

VOLKMANN, H., ET AL.: Diagnostic Value of Carotid Sinus Hypersensitivity. In order to evaluate the diagnostic value of carotid sinus hypersensitivity (CSH) we have investigated 163 asymptomatic patients (88 male, 75 female, mean age 57.9 ± 22.7 years) and 210 symptomatic patients (108 males, 102 females, mean age 61.1 ± 28.1 years) with syncopes or dizziness. Thirty two of the 163 asymptomatic patients (20%) and 87 of the 210 symptomatic patients (41%) showed CSH (asystole ≥ 3 sec during carotid sinus pressure). Male patients had a higher number of CSH than female (28% vs 10% in the asymptomatic group, 48% vs 34% in the symptomatic group). Electrophysiological investigations were performed in all 210 symptomatic patients. Normal electrophysiological results had 94 of the 210 patients. Thirty seven of these 94 patients showed CSH (39%). Prolonged sinus node recovery time (SNRT) and/or prolonged sinoatrial conduction time (SACT) were evaluated in 38 patients. Seventeen of the 38 patients had CSH (45%]. Disorders of atrioventricular (AV) conduction were evaluated in 43 patients. Seventeen of the 43 patients showed CSH (40%). Thirty-five patients had both AV conduction disorders and prolonged SNRT or SACT. Sixteen of these 35 patients showed CSH (46%). In conclusion, no significant difference was found between patients with and without pathological electrophysiological results. The CSH is without value for predicting sinus node dysfunction and AV conduction disorder.     

Carotid Sinus Hypersensitivity is Common in Patients Presenting with Hip Fracture and Unexplained Falls

Background: We tried to determine the prevalence of carotid sinus hypersensitivity (CSH) in patients with hip fractures with and without a clear history of an accidental fall.
Methods: We studied 51 patients hospitalized for a hip fracture and 51 matched controls from our outpatients department. All patients were subjected to a carotid sinus massage in the supine and upright position . Patients were categorized in accidental (Group A) and unexplained (Group B) fallers.
Results: Six of 33 (18.2%) patients in Group A and 12 of 18 (66.7%) patients in Group B ( P < 0.001) had a positive response to the carotid sinus massage. Nine controls (17.6%) also demonstrated CSH. Patients in Group B were older (A: 75.5 ± 8.5 years vs B: 80.1 ± 5.9 years, P = 0.029) and were more likely to have a history of unexplained falls or syncope in the past (A: 0% vs B: 66.7%, P < 0.0001) than individuals in group A. Vasodepressor/mixed forms accounted for the majority of CSH responses in Group B (75%). When compared with the control group, CSH was still more common in Group B (B: 66.7% vs control: 17.6%, P < 0.0001) but not in Group A (A: 18.2% vs control: 17.6%, P = 1.000).
Conclusions: The prevalence of CSH is increased in elderly patients with hip fractures, only in those who present with an unexplained fall and report a history of syncope or unexplained falls in the past. The vasodepressor/mixed forms account for the majority of CSH responses in the group of unexplained fallers.     

Mixed Carotid Sinus Hypersensitivity: Successful Therapy with Pacing, Ephedrine, and Propranolol

Three forms of carotid sinus hypersensitivity are recognized clinically (cardio-inhibitory, vasodepressor, and mixed). The cardio-inhibitory form has been managed successfully with pacemaker therapy. The vasodepressor element has been difficult to manage clinically whether in its pure form or in combination with the cardio-inhibitory type. We review the various pharmacologic methods previously reported and present our experience with a new pharmacologic alternative, which is the combined use of ephedrine and propranolol to induce unopposed alpha stimulation.     

Pacing for Carotid Sinus Syndrome and Sick Sinus Syndrome

BRIGNOLE, M., ET AL: Pacing for Carotid Sinus Syndrome and Sick Sinus Syndrome. The real incidence of pacemaker implants for carotid sinus syndrome (CSS) and the relation between CSS and sick sinus syndrome (SSS) is not precisely known. Patients who needed pacing therapy because of atrial bradyarrhythmias were investigated by means of carotid sinus massage, dynamic ECG, and invasive electrophysiological sinus node evaluation. Of 298 consecutive patients receiving a pacemaker implant, 36 (12%) had a severe cardioinhibitory carotid sinus reflex with reproducible spontaneous symptoms (CSS), 33 (11%) had sinus bradycardia < 50 beat/min or an abnormal electrophysiological evaluation (SSS) and 24 (8%) had both (CSS + SSS). The annual incidence was 40, 37, and 26, respectively, implants per year/million of inhabitants (total incidence 325). Patients affected by CSS, if compared with those affected by SSS, showed: a higher prevalence of syncope (97% vs 42%); more syncopal, episodes per patient (2.9 ± 2 vs 1.8 ± 0.9); a lower prevalence of associated cardiac diseases (53% vs 100%); cardiac enlargement (36% vs 88%); heart failure (6% vs 36%) and paroxysmal atrial fibrillation (0% vs 42%); and a more frequent indication for VVI pacing (75% vs 3%). In patients with CSS + SSS, intermediate characteristics were present. In conclusion, CSS is as frequent an indication to cardiac pacing as SSS; clinical differences justify a distinction between them, even if they are associated in 26% of cases.     

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.     

Prevalence of Cardioinhibitory Carotid Sinus Hypersensitivity in Patients 50 Years or over Presenting to the Accident and Emergency Department with "Unexplained" or "Recurrent" Falls

To study the prevalence of Cardioinhibitory Carotid Sinus Hypersensitivity (CICSH) in patients 50 years or over presenting to casualty with "unexplained" or "recurrent" falls. The prospective study was from October 1, 1995 to April 30, 1996 in the Inner City Accident and Emergency Departments, Newcastle Upon Tyne, U.K. Ten thousand four hundred forty-three patients 50 years and over presented, of which 4,051 (39%) were fallers. Fallers were excluded if they lived over 15 miles from the hospital (81), were registered blind (17), were unable to speak English (22), were unable to previously walk (27), if there was a history of only one accidental fall (1,659) or were cognitively impaired (776: Mini Mental State Examination < 24 [30]) or if there was a clear attributable medical diagnosis for the fall (871). Five hundred ninety-eight "unexplained" or "recurrent" fallers (defined as three or more falls in the previous 12 months) were assessed for carotid sinus massage (CSM). One hundred forty-five patients declined CSM (24%), 70 (12%) had relative contraindications to CSM and 13 already had pacemakers in situ (2%). Two hundred seventy-nine underwent CSM, of whom 65 had CICSH (23%), which might be amenable to treatment with pacemakers. The prevalence of CICSH (a potentially treatable condition) in "unexplained" or "recurrent" fallers who present to the accident and emergency department is 23%. A randomized control study to assess benefit from pacemaker intervention in these patients is underway.     

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.     

Assessment of VVI Diagnostic Pacing Mode in Patients with Cardioinhibitory Carotid Sinus Syndrome

In this study, we used Holter pacemakers in a group of 13 patients affected by severe carotid sinus syndrome in order to evaluate its evolution. All the patients had one to three syncopal episodes and frequent other symptoms such as fainting, dizziness, lightheadedness and pre-syncope interferring with their daily activity so that pacemaker therapy was considered necessary. Patient selection criteria were: presence of the isolated cardioinhibitory type, absence of associated sinus dysfunction and absence of symptomatic WI pacemaker effect. All the patients received a Micropacer 1 device; among special functions, bradycardia events counter was activated and programmed so that each sequence of three consecutives beats at a cycle length 1.5 sec (i.e., 4.5 sec total interval) could he recognized and stored in its memory. The follow-up lasted 13±7 months. Brady events occurred in eight out of 13 patients (62%), during this period. Syncope and major symptoms disappeared in ail the patients; mild dizziness recurred rarely in two patients and were not linked to brady-events recording. In conclusion, disappearance of severe symptoms observed after pacemaker implant in cardioinhibitory carotid sinus syndrome seems to depend from pacing therapy, in most cases, yet from the benign natural course of the disease in some other cases.     

Validation of a Method for Choice of Pacing Mode in Carotid Sinus Syndrome With or Without Sinus Bradycardia

A new method for selection of the pacing mode in 60 consecutive patients with severe cardie-inhibitory or mixed carotid sinus syndrome was prospectively validated. ODD pacing was preferred for 26 patients with: (1) the cardioinhibitory form and who had symptomatic pacemaker effect; (2) mixed type I form, (cardioinhibitory and vasodepressor) with symptomatic pacemaker effect, ventriculoatrial conduction or orthostatic hypotension; (3) mixed type II; or (4) severe bradycardia. VVI pacing was seiected in the remaining 34 patients without these symptoms. During a 32 ± 10 month follow-up period syncope and severe dizziness persisted in five patients in the VVI group (15%) and in three patients in the ODD group (12%). Symptomatic relief occurred in 87% (52/60) of patients. Minor symptoms persisted in 47% of the VVI group and 42% of the DDD group. No patient developed cardiac insufficiency or intolerance to pacing. During a 2-month duration a single-blind, randomized, cross-over study compared VVI and DDD pacing, 69% of the patients programmed from DDD to VVI suffered more frequent, severe, and intolerable symptoms. (1) Thirty four of 60 patients (57% of the entire group) in whom VVI pacing was satisfactory were identified prior to pacemaker implant. In the remainder, VVI pacing was contraindicated as it produced frequent side effects. (2) The preimplant predictive value that VVI pacing would be successful was 85% for those eventually receiving VVI pacemakers and the preimplant predictive value that VVI pacing would fail was 69% for those who underwent DDD implant.     

Ventricular and Dual Chamber Pacing for Treatment of Carotid Sinus Syndrome

Thirty-nine consecutive patients with recurrent syncope and either cardioinhibitory or mixed type carotid sinus syndrome were studied to determine the efficacy of ventricular (VVI) pacing in 16, and dual chamber (DDD/DVI) in 23 patients. Only those patients affected by the isolated vasodepressor form were excluded. Follow-up lasted 12 ± 5 months. Symptoms were totally eliminated in 67% of patients and ameliorated with persistence of minor symptoms in 33%. All patients underwent an initial 2-month follow-up in the VVI mode. Evaluation of the 19 patients who remained symptomatic and the 20 who became asymptomatic with VVI pacing demonstrated that factors observed prior to pacemaker implant were related to failure of the VVI mode. These included symptomatic pacemaker effect (42% vs 0%), mixed carotid sinus syndrome (95% vs 65%), orthostatic hypotension (47% vs 15%), or ventriculoatrial conduction (68% vs 38%). In the 23 patients with dual chamber pacing, random 2 month comparisons were performed between VVI and DVI/DDD pacing. The dual chamber mode was preferred by 14 patients, none preferred the VVI mode and nine noted no difference. Comparison of the two groups found that the factors linked to DVI/DDD preference were symptomatic pacemaker effect (50% vs 0%), ventriculoatrial conduction (78% vs 44%), or orthostatic hypotension (50% vs 11 %). VVI pacing is efficacious in a high proportion of patients affected by cardioinhibitory or mixed carotid sinus syndrome. The identification of causes of VVI pacing failure allows determination of those who will benefit from VVI pacing and those who should have DVI/DDD. VVI pacing is suggested for the cardioinhihitory type with no symptomatic pacemaker effect and for the mixed type with no symptomatic pacemaker effect or orthostatic hypotension or ventriculoatrial conduction. Dual chamber pacing should be used in all other instances.     

Electrophysiologic Findings in Carotid Sinus Massage

Thirty patients with carotid sinus syndrome were electrophysiologically studied. In 14 patients carotid sinus massage was performed during atrial and ventricular stimulation, and the conduction times were measured. The AH-time was prolonged by more than 120ms in 6 patients(20%); the HV-time was prolonged in 6 patients by more than 55 ms (20%); 5 patients had bundle branch block (16.7%); The sinus node recovery time was prolonged in 7 out of 27 patients (26%). Ten patients (33%) did not have additional electrophysiologic abnormalities. There was a predominance of carotid sinus syndrome on the right side. During carotid sinus massage there was a significant increase of the AH-time, but there were no significant changes of the HV-time or the width of the QRS-complexes. Twenty-one patients developed an atrial asystole and 9 patients an atrial bradycardia and an additional AV-block. There was a longer AH-time and a longer prolongation of the AH-time in the patients who developed an AV-block. Twelve out of 14 patients (85.7%) developed an AV-block during carotid sinus massage and atrial pacing. During ventricular pacing 5 of 14 patients (35.7%) revealed a complete retrograde block before carotid sinus massage and 5 of the remaining 9 patients developed a total retrograde block during carotid sinus massage. Consequently, in 71.4% of the patients with carotid sinus syndrome complete retrograde conduction block and atrial asystole can be expected during attacks of ventricular asystole and simultaneous ventricular pacing. In conclusion, there is a high incidence of additional disturbances of the sinus node function and AV-conduction in patients with carotid sinus syndrome. AAI pacemakers are contraindicateddue to the common development of additional A V-block during carotid sinus massage. Physiologic pacing might contribute to better hemodynamics, particularly in patients with the mixed type of carotid sinus syndrome.     

Ventricular Pacing as the Preferable Mode for Long-Term Pacing in Patients with Carotid Sinus Syncope of the Cardioinhibitory Type

This study was designed to determine the efficacy of long-term VVI pacing in patients having the isolated cardioinhibitory type of carotid sinus syncope. The study included 20 patients suffering from repeated syncopal attacks; all were proven by electrophysiological studies to have isolated forms of cardioinhibitory type carotid sinus syncope. Long-term pacing by the VVI mode was carried out in all patients by programming the pacemaker rate well below the patient's sinus rate. The follow-up period after pacemaker implantation, which ranged from 2 to 54 months (average, 20 months), revealed that none of the patients had any recurrence of syncopal attack. Repeated Holter monitoring showed that ten had permanent sinus rhythm without any artificial pacing activity, while in the other ten, pacemaker activity was recorded--predominant in two patients and rare in the other eight. During Holter monitoring, attacks of weakness were reported by four patients; however, they were not related to pacemaker activity. This report indicates the importance of electrophysiological studies in patients suffering from carotid sinus syncope. These studies make possible the diagnosis of the isolated form of cardioinhibitory type syncope for which VVI pacing offers complete relief of symptomatology, thus rendering AV sequential pacing superfluous.     

Use of Serotonin Re-Uptake Inhibitors as Primary Therapy for Carotid Sinus Hypersensitivity

Carotid sinus syndrome (CSS) is a well-recognized cause of unexplained syncope in older patients, and may lead to significant morbidity related to trauma suffered during falls. Dual chamber pacing has been demonstrated to be efficacious in relieving symptoms due to bradycardia, but not the accompanying vasodepressor response. We report three patients with recurrent syncope due to a mixed type of CSS, who were treated with serotonin re-uptake inhibitors (SSRIs) alone, and were symptom-free after 4–5 weeks of therapy. The patients have remained symptom-free after more than 13 months of treatment. We conclude that SSRIs may be potentially useful in the treatment of CSS, and that the central mechanisms involved in CSS may be similar to those that resalt in neurocardiogenic syncope.     

The Natural History of Sick Sinus Syndrome

A literature review has addressed the two major factors in disease progression in sick sinus syndrome: atrioventricular block and atrial fibrillation. An incidence of atrioventricular block of 8.4 percent in a follow-up period of 34.2 months is considered clinically significant and sufficient to justify use of a ventricular lead in pacemaker management. Atrial fibrillation occurs much more commonly [22.3%] in ventricular pacing than with atrial demand pacing (3.9%) in a 21/2 year observation period. Coincident with the reduction in arrhythmia achieved by atrial demand pacing is a significant reduction in systemic embolism (1.6% vs. 13%]. This is considered largely to be due to the improved rhythm control with AAI pacing but also possibly to the avoidance of retrograde atrioventricular conduction. The benefits of AAI pacing in terms of mortality in sick sinus syndrome have not yet been fully assessed. In the future, DDI pacing is recommended with, in some patients, the addition of another sensor to provide rate responsiveness on exercise.     

Carotid Sinus Syndrome: Acute Hemodynamic Evaluation of a Dual Chamber Pacing Mode

Cardiac pacing is the treatment of choice in patients with carotid sinus syndrome (CSS), Three different pacing modes were tested in 20 patients (16 males, 4 females; mean age 75 ± 9 years) with documented symptomatic CSS, Three carotid sinus massages (CSM) were performed in each supine patient successively paced in random order in: DDI—the reference pacing mode; DDD—automatic mode conversion (DDD/AMC) allowing automatic switching from AAI to DDD when AV block occurs; DDD/AMC plus a trial acceleration (DDD/AMC + ace); and OOO (CSM without pacing) to determine whether the vasodepressive effect was still present 10 minutes after the preceding CSM. Intraarterial blood pressure was continuously monitored. Results were expressed as the value of the mean systolic BP at TO + 3 s + 6 s … TO + 30 s divided by the value of the mean systolic blood pressure prior to onset of CSM. The drop in arterial blood pressure was more severe in the DDI mode than in DDD/AMC (P < 0,001) and DDD/AMC + acc (P < 0.0001) in 20 patients. In the OOO mode, the drop in arterial blood pressure was most marked and greater than in the DDI mode (P < 0.0001). The average time between start of the CSM and onset of the drop in blood pressure was the same in the three dual chamber modes. We conclude that the DDD/AMC mode significantly improves the vasodepressor response to CSM compared to the DDI mode. There is a current trend favoring DDD/AMC + acc over DDD/AMC.     

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.     

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)