Reproducibility of carotid sinus massage.

AIMS: The reproducibility of carotid sinus massage (CSM) is debated. The aim of this study was to assess the reproducibility according to the methodology and diagnostic criteria defined by the guidelines on syncope of the European Society of Cardiology. METHOD: Among 2800 patients with syncope who underwent CSM in the years 2005-2019, 109 patients (62 males; mean age 76 ± 10 years) had performed a second CSM after a median of 28 months. Carotid sinus hypersensitivity (CSH) was diagnosed when CSM elicited a pause of >3 s and/or a fall in systolic blood pressure >50 mm Hg without reproduction of spontaneous symptoms. Carotid sinus syndrome (CSS) was established when spontaneous symptoms were reproduced in the presence of bradycardia and/or hypotension. RESULTS: The reproducibility of CSM was 78% for 18 CSS patients, 41% for 29 CSH patients, and 77% for 62 negative patients. The corresponding interrater agreement was good for CSS (kappa = 0.66), moderate for negative CSM (kappa = 0.42), and poor for CSH (kappa = 0.30). Combining CSH and negative tests, their reproducibility rose to 90% with kappa = 0.66. CONCLUSION: CSS but not CSH has a good reproducibility. About half of patients with CSH had a negative response at the second test, thus suggesting a great overlap between them.

Baroreceptors in the carotid and hypertension-systematic review and meta-analysis of the effects of baroreflex activation therapy on blood pressure.

Activation of baroreceptors in the carotid modulates the autonomic nervous system. Baroreflex activation therapy (BAT), which activates baroreceptors in the carotid, has become available in the treatment of resistant hypertension. Besides this, a carotid implant modulating baroreceptors as well as pharmacological modulation of carotid bodies were quite recently presented. This review will underscore currently available and promising approaches that activate baroreceptors in the carotid, and thereby contribute to beneficial effects in patients with arterial hypertension, and discusses potential organoprotective BAT effects beyond blood pressure (BP) reduction. A systematic review and meta-analysis was conducted including observational studies or randomized controlled trials that investigated the effect of BAT on BP in resistant hypertension. Nine studies, seven observational and two randomized, with a total of 444 patients, were included in the evaluation. Analysing the longest follow-up visit from the different studies, there was a significant reduction of systolic BP after BAT of -36 mmHg [95% confidence interval (CI) -42 to -30 mmHg]. Separate meta-analysis of the short-term (1-6 months) and long-term effects (≥12 months) revealed a reduction of -21 mmHg (95% CI -26 to -17 mmHg) and -38 mmHg (95% CI -46 to -30 mmHg), respectively. There are promising data both in the experimental and the clinical application for BAT. Though the present meta-analysis suggests beneficial effects of BAT on BP, the results must be interpreted extremely carefully. Considering that evidence from controlled trials is very limited, it is evident that there is a strong need for further investigation.

Endovascular Baroreflex Amplification for Resistant Hypertension.

PURPOSE OF REVIEW: Most hypertension devices have been designed to interrupt or modify the sympathetic nervous system, which seems to be unbalanced in hypertension. Carotid baroreceptors play a pivotal role in maintaining adrenergic balance via a direct feedback interface and would be an exceptional target for intervention. The purpose of this review is to define the role of the baroreceptor in hypertension, to examine device-based therapies targeting the baroreflex and to explore future promises of endovascular baroreflex amplification (EBA). RECENT FINDINGS: In the last two decades, two therapeutic strategies targeting the carotid baroreceptor have evolved: baroreflex activation therapy (BAT) and EBA. Both therapies enhance baroreceptor activity, either directly by electrical stimulation or indirectly by changing the geometric shape of the carotid sinus and increasing pulsatile wall strain. By showing a significant, sympathetic inhibition-mediated effect on blood pressure, BAT has laid the foundation for baroreflex-targeting therapies for resistant hypertension. EBA is a less invasive therapy with promising first-in-man study results. Ongoing randomized sham-controlled trials are needed to better understand efficacy, durability, and long-term safety and define phenotypes that may most benefit from this treatment.

Aortic depressor nerve stimulation does not impede the dynamic characteristics of the carotid sinus baroreflex in normotensive or spontaneously hypertensive rats.

Recent clinical trials in patients with drug-resistant hypertension indicate that electrical activation of the carotid sinus baroreflex can reduce arterial pressure (AP) for more than a year. To examine whether the electrical stimulation from one baroreflex system impedes normal short-term AP regulation via another unstimulated baroreflex system, we electrically stimulated the left aortic depressor nerve (ADN) while estimating the dynamic characteristics of the carotid sinus baroreflex in anesthetized normotensive Wistar-Kyoto (WKY; n = 8) rats and spontaneously hypertensive rats (SHR; n = 7). Isolated carotid sinus regions were perturbed for 20 min using a Gaussian white noise signal with a mean of 120 mmHg for WKY and 160 mmHg for SHR. Tonic ADN stimulation (2 Hz, 10 V, and 0.1-ms pulse width) decreased mean sympathetic nerve activity (73.4 ± 14.0 vs. 51.6 ± 11.3 arbitrary units in WKY, P = 0.012; and 248.7 ± 33.9 vs. 181.1 ± 16.6 arbitrary units in SHR, P = 0.018) and mean AP (90.8 ± 6.6 vs. 81.2 ± 5.4 mmHg in WKY, P = 0.004; and 128.6 ± 9.8 vs. 114.7 ± 10.3 mmHg in SHR, P = 0.009). The slope of dynamic gain in the neural arc transfer function from carotid sinus pressure to sympathetic nerve activity was not different between trials with and without the ADN stimulation (12.55 ± 0.93 vs. 13.03 ± 1.28 dB/decade in WKY, P = 0.542; and 17.37 ± 1.01 vs. 17.47 ± 1.64 dB/decade in SHR, P = 0.946). These results indicate that the tonic ADN stimulation does not significantly modify the dynamic characteristics of the carotid sinus baroreflex.

Resistant Hypertension.

Conservatively, ten million people in the USA alone may suffer from RH and may be similarly prevalent elsewhere. Given the strong linear correlation between hypertension and cardiovascular outcomes, better control is paramount. We favor a multi-pronged approach. It may not suffice to address this by pharmacologic means only. Careful attention to modifiable risk factors, particularly sodium intake, adhering to a proper diet (i.e. DASH), and avoiding agents, i.e. non-steroidals, that can elevate the blood pressure, is key. Frequent follow up to establish the right treatment regimen and home blood pressuring monitoring can have a strong impact on control. Finally, consideration of device therapy may be a more viable option in the future.

Swallow-induced syncope and carotid sinus hypersensitivity: Coincident or associated conditions?

Swallow induced syncope is a rare clinical condition which is thought to result from an abnormal vagal reflex leading to bradycardia and cerebral hypoperfusion. It mostly occurs in patients with organic or functional disorders of the esophagus, and often requires permanent pacemaker implantation, along with treatment of the underlying esophageal pathology. In the following case, we report of a 71-year-old male with achalasia post per oral endoscopic myectomy, who presented with syncope and documented AV-block while eating solid food. In addition, long sinus pauses were noted during carotid sinus massage, suggesting that the two distinct entities may be associated, and further supporting the mechanism of neurally mediated syncope in the pathophysiology of swallow-induced syncope.

[Baroreceptor activation therapy for therapy-resistant hypertension: indications and patient selection : Recommendations of the BAT consensus group 2017]. / Barorezeptorakivierungstherapie bei therapierefraktärer Hypertonie: Indikation und Patientenselektion : Empfehlungen der BAT-Konsensusgruppe 2017.

Baroreceptor activation therapy (BAT) has been available for several years for treatment of therapy-refractory hypertension (trHTN). This procedure is currently being carried out in a limited number of centers in Germany, also with the aim of offering a high level of expertise through sufficient experience; however, a growing number of patients who are treated with BAT experience problems that treating physicians are confronted with in routine medical practice. In order to address these problems, a consensus conference was held with experts in the field of trHTN in November 2016, which summarizes the current evidence and experience as well as the problem areas in handling BAT patients.

Diagnostic role of head-up tilt test in patients with cough syncope.

AIMS: The aim of this study was to describe the head-up tilt (HUT) test and carotid sinus massage (CSM) responses, and the occurrence of syncope with coughing during HUT in a large cohort of patients. METHODS AND RESULTS: A total of 5133 HUT were retrospectively analysed to identify patients with cough syncope. Head-up tilt followed by CSM were performed. Patients were made to cough on two separate occasions in an attempt to reproduce typical clinical symptoms on HUT. Patients with cough syncope were compared with 29 age-matched control patients with syncope unrelated to coughing. A total of 29 patients (26 male, age 49 ± 14 years) with cough syncope were identified. Coughing during HUT reproduced typical prodromal symptoms of syncope in 16 (55%) patients and complete loss of consciousness in 2 (7%) patients, with a mean systolic blood pressure reduction of 45 ± 26 mmHg, and a mean increase in heart rate of 13 ± 8 b.p.m. No syncope or symptoms after coughing were observed in the control group. The HUT result was positive in 13 (48%) patients with the majority of positive HUT responses being vasodepressor (70% of positive HUT). Carotid sinus massage was performed in 18 patients being positive with a vasodepressor response causing mild pre-syncopal symptoms in only 1 patient. CONCLUSION: Syncope during coughing is a result of hypotension, rather than bradycardia. Coughing during HUT is a useful test in patients suspected to have cough syncope but in whom the history is not conclusive.

Modified criteria for carotid sinus hypersensitivity are associated with increased mortality in a population-based study.

AIMS: Carotid sinus hypersensitivity (CSH) is arbitrarily defined as ≥3 s asystole or vasodepression of ≥50 mmHg in response to carotid sinus massage (CSM). Using this definition, 39% of older people meet the criteria for CSH. It has been suggested that current criteria are too sensitive. Krediet et al. [The history of diagnosing carotid sinus hypersensitivity: why are the current criteria too sensitive? Europace 2011;13:14-22] and Kerr et al. [Carotid sinus hypersensitivity in asymptomatic older persons: implications for diagnosis of syncope and falls. Arch Intern Med 2006;166:515-20] have proposed modified criteria. This population-based study aimed to compare the prevalence of CSH defined according to standard, Krediet and Kerr criteria, and to establish if CSH defined according these criteria is associated with all-cause mortality. METHODS AND RESULTS: A total of 272 community-dwelling people aged ≥65 were recruited at random. Carotid sinus massage was performed for 5 s in supine and head-up positions. Heart rate and blood pressure response were recorded using an electrocardiogram and photoplethysmography. Cox regression analysis was used to examine the association between each definition of CSH and all-cause mortality. The prevalence of CSH defined according to standard, Krediet, and Kerr criteria was 39, 52, and 10%, respectively. Seventy-one participants died over a mean follow-up of 8.6 years (SD 2.1). Carotid sinus hypersensitivity defined according to standard and Krediet criteria was not associated with survival. Carotid sinus hypersensitivity defined according to Kerr criteria was associated with all-cause mortality independent of age and sex [hazard ratio (HR) 2.023 (95% confidence interval (95% CI) 1.131-3.618) P = 0.018)]. This remained significant after adjusting for cardiovascular risk factors [HR 2.174 (1.075-3.900) P = 0.009]. CONCLUSION: Carotid sinus hypersensitivity defined according to Kerr criteria is associated with increased mortality. This raises an interesting question as to the suitability of the current criteria used to define CSH.

Safety and tolerability of Tilt Testing and Carotid Sinus Massage in the octogenarians.

OBJECTIVE: to evaluate the safety and tolerability of Tilt Testing (TT) and Carotid Sinus Massage (CSM) in octogenarians with unexplained syncope. METHODS: patients consecutively referred for transient loss of consciousness to the 'Syncope Units' of three hospitals were enrolled. TT and CSM were performed according to the European Society of Cardiology guidelines on syncope. Complications were evaluated in each group. An early interruption of TT was defined as 'intolerance' and considered as a non-diagnostic response. RESULTS: one thousand four hundred and one patients were enrolled (mean age 72 ± 16 years, male 40.8%). Six hundred and ninety-four patients (49.5%) were 80 years old or older (mean age 83 ± 3 years) and 707 (50.5%) were younger (mean age 60 ± 17 years). Complications after TT occurred in 4.5% of older patients and in 2.1% of the younger ones (P = 0.01). All complications were 'minor/moderate', as prolonged hypotension, observed in ∼3% of patients ≥80 years. Major complications such as sustained ventricular tachycardia, ventricular fibrillation, asystole requiring cardiac massage, transient ischaemic attack, stroke and death were not observed in any patient. The presence of orthostatic hypotension and the mean number of syncopal episodes were predictors of TT complications. Intolerance was reported in 2.4% of older patients and 1% of the younger ones (P = 0.08), mainly due to orthostatic intolerance. No complications occurred after CSM. CONCLUSIONS: TT and CSM appear to be safe and well tolerated in octogenarians, who should not be excluded by age from the diagnostic work-up of syncope.

A case of asystole from carotid sinus hypersensitivity during patient positioning for thyroidectomy.

BACKGROUND: We present a case of a patient with multinodular goiter disease who suffered asystole during head hyperextension for surgical positioning on the operational table. CASE PRESENTATION: Manipulation of carotid sinus may trigger bradycardia or even asystole even in patients without prior history of carotid sinus hypersensitivity. The time proximity between patient positioning and asystole, the late responsiveness to atropine, the immediate increase of heart rate after head elevation and the lack of any other trigger factor or prior history support the hypothesis of carotid sinus syndrome. CONCLUSIONS: Head hyperextension during surgical positioning is not only responsible for jeopardizing blood flow to spinal cord and brainstem but may trigger reflexes, as well, even in patients without prior neck pathology.

Electrical carotid sinus stimulation: chances and challenges in the management of treatment resistant arterial hypertension.

Treatment resistant arterial hypertension is associated with excess cardiovascular morbidity and mortality. Electrical carotid sinus stimulators engaging baroreflex afferent activity have been developed for such patients. Indeed, baroreflex mechanisms contribute to long-term blood pressure control by governing efferent sympathetic and parasympathetic activity. The first-generation carotid sinus stimulator applying bilateral bipolar stimulation reduced blood pressure in a controlled clinical trial but nevertheless failed to meet the primary efficacy endpoint. The second-generation device utilizes smaller unilateral unipolar electrodes, thus decreasing invasiveness of the implantation while saving battery. An uncontrolled clinical study suggested improvement in blood pressure with the second-generation device. We hope that these findings as well as preliminary observations suggesting cardiovascular and renal organ protection with electrical carotid sinus stimulation will be confirmed in properly controlled clinical trials. Meanwhile, we should find ways to better identify patients who are most likely to benefit from electrical carotid sinus stimulation.

Reconsidering the effectiveness and safety of carotid sinus massage as a therapeutic intervention in patients with supraventricular tachycardia.

OBJECTIVE: The objectives of our investigation were to review the evidence for the efficacy and safety of carotid sinus massage in terminating supraventricular tachycardia and to determine if other potentially less harmful interventions have been established to be safer and more effective. METHODS: A search using PubMed, Ovid, and COCHRANE databases was performed using the terms supraventricular tachycardia, carotid sinus massage, SVT, and CSM. Articles not written in English were excluded. There was a paucity of randomized controlled trials comparing various supraventricular tachycardia (SVT) interventions. However, articles of highest quality were selected for review and inclusion. In addition, articles examining potential hazards of carotid sinus massage in case report format were reviewed, even when performed for other indications other than SVT, as the maneuver is identically performed. Selected articles were reviewed by both authors for relevance to the topic. RESULTS: Summarizing the findings of this review leads to these 3 fundamental conclusions. First, a therapeutic intervention should only be performed when the benefit of the procedure outweighs its risk. Carotid sinus massage exposes the patient to rare but potentially devastating iatrogenic harm. Second, a therapeutic intervention should be efficacious. The efficacy of carotid sinus massage in terminating supraventricular tachycardia appears to be modest at best. Third, other readily available, easily mastered, and potentially safer and more efficacious alternative interventions are available such as Valsalva maneuver and pharmacologic therapy. CONCLUSION: Based on the limited evidence available, we believe that carotid sinus massage should be reconsidered as a first-line therapeutic intervention in the termination of SVT.

Fainting Starting Parenteral Nutrition.

Complications such as mechanical accidents, infections, and thrombosis are commonly described in the presence of a central venous catheter. We present a case of a boy who had fainting episodes due to dislocation of a central venous catheter.

Clinical aspects and diagnostic relevance of neuroautonomic evaluation in patients with unexplained falls.

OBJECTIVE: To evaluate the diagnostic relevance of neuroautonomic evaluation in patients with unexplained falls compared to those with a syncope etiologically unexplained after initial evaluation. METHODS: It is an observational study, comparing 298 patients with unexplained fall with 989 patients with unexplained syncope. Each patient underwent supine and upright blood pressure measurement, tilt testing (TT) and carotid sinus massage (CSM). RESULTS: Patients with unexplained falls were older (75.3 ± 11.1 vs. 63.2 ± 19.2 years, p < 0.001), were more frequently hypertensive (66.1 vs. 47.2 %, p < 0.001) and more frequently prescribed antihypertensive drugs (62.4 vs. 48.7 %, p < 0.001) or benzodiazepines (15.7 vs. 10.6 %, p = 0.01), and in a greater proportion they experienced major traumatic injuries (77.5 vs. 29.6 %, p < 0.001) as a consequence of falls. The TT was less frequently positive in patients with unexplained falls (36 vs. 51.3 %, p < 0.001), whereas a Carotid Sinus Syndrome as suggested by CSM had a similar prevalence in the two groups (14.3 vs. 10.5 %, p = 0.074). Overall, either TT or CSM were positive in 61 % of patients with unexplained falls, and in 64 % of those with syncope (p = 0.346). After matching by age 298 patients with falls (75.3 ± 11.1 years) and 298 patients with unexplained syncope (75.4 ± 11.1 years), we found that the positivity prevalence of TT and CSM were similar in the two groups. CONCLUSIONS: The positivity prevalence of TT and CSM in patients with unexplained falls compared to patients with unexplained syncope is similar. Given its high diagnostic relevance, the neuroautonomic evaluation should be routinely performed in older patients with unexplained falls.

Carotid interventions and blood pressure.

Arterial baroreceptors are pressure sensors found in the carotid sinus near the bifurcation of the carotid artery and in the aortic arch. Carotid interventions, whether endovascular or surgical, affect this complicated control system and the post-interventional blood pressure behavior. Comparisons between the intervention techniques, however, are challenging due to the varying measurement methods, duration of observation, and patient populations. The question as to which interventional method is preferable, if undisturbed regulation of blood pressure is concerned, still remains unanswered. The fact that blood pressure events (i.e., hemodynamic instability, hypertension, unstable blood pressure) frequently occur both immediately after intervention and in the long term, mandates a particularly careful cardiopulmonary and blood pressure monitoring. Direct and indirect measurements of baroreceptor sensitivity can be helpful in identifying high-risk patients, although the association to hard clinical endpoints is rarely documented for methodological reasons.