Dual-chamber pacing in the treatment of neurally mediated tilt-positive cardioinhibitory syncope : pacemaker versus no therapy: a multicenter randomized study. The Vasovagal Syncope International Study (VASIS) Investigators

Endocardial ablation of epicardial ganglionated plexi: history, open questions and future prospects of cardioneuroablation

Neurocardiogenic syncope is the most common cause of transient loss of consciousness and considerably reduces quality of life. Pharmacological and pacing therapy may not be fully efficacious and complications related to implanted hardware must be considered. In this context, cardioneuroablation (CNA) has been proposed to attenuate the vagal reflex with elimination of cardioinhibition. It has been shown that CNA is able to eliminate recurrences of syncope in over 90% of cases and no major complications are reported in the current literature. Despite these encouraging findings, CNA is only mentioned in current guidelines as a possible alternative treatment and has no real indication class. The diversity of mapping techniques, the absence of direct denervation control, the lack of a precise endpoint, the possible placebo effect, the short follow-up, and the question of the learning curve represent the major limitations of this promising procedure. The aim of this review was to look over the existing literature, analysing the novelties, the limitations, the unresolved issues and the outcome of CNA.

Cardioneuroablation for severe neurocardiogenic syncope

INTRODUCTION AND OBJECTIVES

Cardioneuroablation (CNA), a technique based on radiofrequency ablation of cardiac vagal ganglia, was developed to treat recurrent vasovagal syncope (VVS) with a predominant cardioinhibitory component, as an alternative to pacemaker implantation. The aim of our study was to evaluate the safety and success rate of CNA guided by extracardiac vagal stimulation in patients with highly symptomatic cardioinhibitory VVS.

METHODS

Prospective study of patients who underwent anatomically guided CNA at two cardiology centers. All patients had a history of recurrent syncope with a predominant cardioinhibitory component and refractory to conventional measures. Acute success was determined by the absence or significant reduction of cardiac parasympathetic response to extracardiac vagal stimulation. The primary endpoint was the recurrence of syncope during follow-up.

RESULTS

In total, 19 patients (13 males; mean age 37.8±12.9 years) were included. Ablation was acutely successful in all patients. One patient had a convulsive episode after the procedure, which was deemed unrelated to the ablation, requiring admission to intensive care but without sequelae. No other complications occurred. At a mean follow-up of 21.0±13.2 months (range 3-42 months), 17 patients remained free of syncope. The remaining two patients had recurrence of syncope and, despite undergoing a new ablation procedure, required pacemaker implantation during follow-up.

CONCLUSION

Cardioneuroablation, confirmed by extracardiac vagal stimulation, appears to be an effective and safe treatment option for highly symptomatic patients with refractory VVS with a predominant cardioinhibitory component, providing a new potential approach as an alternative to pacemaker implantation.

Transcatheter Leadless Pacemaker for the Treatment of Vasovagal Syncope

Vasovagal syncope (VVS) is largely a benign condition focused on patient education, lifestyle modification, and avoidance of triggers. However, a subset of patients may benefit from permanent pacemaker placement. Commonly, patients with VVS are younger and those requiring pacing have symptoms associated with severe cardioinhibitory syncope. With the advent of leadless pacemaker systems, a lot of the risks associated with traditional transvenous pacemaker systems are mitigated. In this article, we provide a comprehensive review of the data available for the treatment of cardioinhibitory vasovagal syncope using leadless pacemaker systems.

Long-Term Outcome of Cardiac Denervation Procedures: The Anatomically Guided Septal Approach

BACKGROUND

Functional bradycardia is a challenging condition that affects a healthy population. Ganglionated plexus ablation has emerged as a therapeutic alternative to avoid a pacemaker.

OBJECTIVES

The purpose of this study is to evaluate long-term effects of anatomically guided cardiac denervation.

METHODS

This is a prospective longitudinal study that included 36 patients with symptomatic functional bradycardia. Electroanatomic reconstruction of both atria was carried out, and the main septal ganglionated plexi were anatomically located and targeted.

RESULTS

Ablation endpoints were: 1) heart rate increment; 2) Wenckebach cycle length shortening; and 3) atrio-Hisian (AH) interval shortening. A sinus node denervation was obtained in all patients with an increment of 21.6% in the mean heart rate. All patients presented a negative atropine test after ablation. Twenty-eight (77.7%) patients presented immediate sings of atrioventricular node denervation, with a shortening of 15.6% of mean Wenckebach cycle length and 15.9% of the mean AH interval. All heart rate variability parameters showed a significant reduction after 12 months, enduring after 18 months. Thirty (83.3%) patients remained free of events after a mean follow-up of 52.1 ± 35.2 months. One patient (2.77%) presented acute sinus node artery occlusion during ablation with persistent sinus dysfunction and had a pacemaker implantation; 3 (8.3%) other patients evolved with sinus tachycardia, and 4 (11.1%) patients presented syncope recurrence during follow-up, 3 (8.3%) of them requiring a pacemaker implantation. No other tachyarrhythmia was observed.

CONCLUSIONS

The anatomically guided septal approach is an effective technique for syncope prevention, promoting long-lasting autonomic changes. No significant proarrhythmia effect has been observed during the long-term follow-up.

Prospective randomized study comparing permanent pacing with rate drop response and closed loop stimulation in patients with vasovagal syncope where permanent pacing is indicated and selected as the appropriate treatment option

BACKGROUND

Pacing for vasovagal syncope is established. Two pacing algorithms are available. The rate-drop-response (RDR-Medtronic) is triggered by falling heart rate acting with modified rate-hysteresis. The closed loop stimulation or system (CLS-Biotronik) is triggered by impedance changes in the right ventricle reflecting falling volume and rising contractility. These are very different physiologically. Both algorithms carry favorable reports in clinical use.

METHODS

A randomized-controlled superiority trial is proposed to compare the two algorithms for the control of vasovagal syncope in patients for whom pacing is indicated by current guidelines in North America and Europe. Available recent evidence may be seen as supporting superiority of CLS. No comparison between the two algorithms has been made. In this trial, patients will be centrally randomized to one or other algorithm on a 1:1 basis. Two-hundred-seventy-six patients in each group will be recruited. Sample size is determined using a confidence interval of 95%, a power of 90%, and a drop-out rate of 10% to detect an 11% difference between CLS and RDR. Recurrent symptom comparison will be made by an independent committee. The Co-primary endpoints will be recurrent syncope burden compared with that in 24-months preimplant, and occurrence of syncope in 24-months follow-up. Each outcome will be compared between the two algorithms. Secondary endpoints will be program and drug therapy changes over 24-months follow-up and quality of life by questionnaire at baseline,1 and 2 years.

RESULTS AND CONCLUSIONS

These are anticipated to clarify the device algorithm choice and, therefore, to improve patient care.

The effects of ALDH2 Glu487Lys polymorphism on vasovagal syncope patients undergoing head-up tilt test supplemented with sublingual nitroglycerin

Background and objective

Head-up tilt test (HUTT) is clinically advantageous for diagnosing patients with vasovagal syncope (VVS). Nitroglycerin is mainly used as a stimulant during HUTT, and mitochondrial aldehyde dehydrogenase 2 (ALDH2) is involved in the metabolism of nitroglycerin (NTG). ALDH2 Glu487Lys polymorphism (ALDH2 rs671) is the most common variant in the East Asian population. This study aimed to assess the effects of ALDH2 rs671 on VVS patients undergoing HUTT supplemented with sublingual NTG (HUTT-NTG). 

Methods

Patients with recurrent VVS (at least 2 times) who were admitted to the syncope center of our hospital were enrolled. All VVS patients have undergone HUTT. The polymorphism of Glu487Lys gene of ALDH2 was measured by the DNA Microarray Chip Method. The results of HUTT-NTG of VVS patients with different ALDH2 genotypes were compared and their hemodynamic characteristics were assessed.

Results

A total of 199 VVS patients were enrolled, including 101 patients in the ALDH2*1/*1 group and 98 patients in the ALDH2*2 group. Among patients undergoing HUTT-NTG, 70.3% of patients in the ALDH2*1/*1 group and 68.4% of patients in the ALDH2*2 group were positive, and the difference between the two groups was not statistically significant (P = 0.77). The proportions of VASIS I, VASIS II, and VASIS III were 40.6%, 8.9%, and 20.8% in the ALDH2*1/*1 group, respectively, and the corresponding proportions in the ALDH2*2 group were 36.7%, 11.2%, and 20.4%, respectively. There was no statistically significant difference between the two groups (P = 0.91). The hemodynamic characteristics of different genotypes in VVS patients undergoing HUTT-NTG were compared, and no statistically significant difference was found. The median time of syncopal episode occurred after NTG administration in the ALDH2*1/*1 group was 6 min (interquartile range [IQR]: 5.0–9.0), and it was 6.0 min in the ALDH2*2 group (IQR: 4.25–8.0, P = 0.64).

Conclusion

ALDH2 Glu487Lys polymorphism did not affect the outcome of VVS patients undergoing HUTT-NTG, and no significant change in the hemodynamic characteristics of different genotypes was found.

Why is the Tilt Table Test Still Useful to Define who Should or Should Not Get A Pacemaker with Vasovagal Syncope?

The the tilt table test (TTT )has been used identify appropriate candidates for pacing in the majority of randomized trials. However, in recent years, it has been claimed-based largely on International Study on Syncope of Uncertain Etiology (ISSUE) studies-that the TTT demonstrates only a weak correlation with the mechanism documented by implantable loop recorder (ILR) at the time of syncope and thus confounds the correct diagnosis. Thus, cardiac pacing was supported in patients with recurrent vasovagal syncope (VVS) in whom clinically relevant asystole had been documented by ILR. In the present Editorial, we tried to discuss potential role of TTT in diagnostic workflow of VVS based on current data.

Likelihood of injury due to vasovagal syncope: a systematic review and meta-analysis

AIMS

Vasovagal syncope (VVS) is the most common type of syncope and is usually considered a benign disorder. The potential for injury is worrisome but the likelihood is unknown. We aimed to determine the proportion of patients injured due to VVS.

METHODS AND RESULTS

A systematic search of studies published until August 2020 was performed in multiple medical and nursing databases. Included studies had data on the proportion of patients with injury due to VVS prior to study enrolment. Random effects methods were used. Twenty-three studies having 3593 patients met inclusion criteria. Patients were diagnosed clinically with VVS, and 82% had >2 syncopal episodes before enrolment. Tilt test was positive in 60% and 14 studies reported comorbidities (32.6% hypertensive). The weighted mean injury rate was 33.5% [95% confidence interval (CI): 27.3-40.5%]. The likelihood of injury correlated with population age (r = 0.4, P = 0.05), but not with sex, positive tilt test, or hypertension. The injury rates were 25.7% (95% CI: 19.1-32.8%) in studies with younger patients (mean age ≤50 years, n = 1803) and 43.4% (95% CI: 34.9-52.3%) in studies with older patients (P = 0.002). Nine studies reported major injuries; with a weighted mean rate of major injuries of 13.9% (95% CI: 9.5-19.8%).

CONCLUSION

Injuries due to syncope are frequent, occurring in 33% of patients with VVS. The risk of major injuries is substantial. Older patients are at higher risk. Clinicians should be aware of the risk of injuries when providing care and advice to patients with VVS.

Cardiac pacing in severe recurrent reflex syncope and tilt-induced asystole

Aim

The benefit of cardiac pacing in patients with severe recurrent reflex syncope and asystole induced by tilt testing has not been established. The usefulness of tilt-table test to select candidates for cardiac pacing is controversial.

Methods and results

We randomly assigned patients aged 40 years or older who had at least two episodes of unpredictable severe reflex syncope during the last year and a tilt-induced syncope with an asystolic pause longer than 3 s, to receive either an active (pacing ON; 63 patients) or an inactive (pacing OFF; 64 patients) dual-chamber pacemaker with closed loop stimulation (CLS). The primary endpoint was the time to first recurrence of syncope. Patients and independent outcome assessors were blinded to the assigned treatment. After a median follow-up of 11.2 months, syncope occurred in significantly fewer patients in the pacing group than in the control group [10 (16%) vs. 34 (53%); hazard ratio, 0.23; P = 0.00005]. The estimated syncope recurrence rate at 1 year was 19% (pacing) and 53% (control) and at 2 years, 22% (pacing) and 68% (control). A combined endpoint of syncope or presyncope occurred in significantly fewer patients in the pacing group [23 (37%) vs. 40 (63%); hazard ratio, 0.44; P = 0.002]. Minor device-related adverse events were reported in five patients (4%).

Conclusion

In patients aged 40 years or older, affected by severe recurrent reflex syncope and tilt-induced asystole, dual-chamber pacemaker with CLS is highly effective in reducing the recurrences of syncope. Our findings support the inclusion of tilt testing as a useful method to select candidates for cardiac pacing.

Study registration

ClinicalTrials.gov identifier NCT02324920, Eudamed number CIV-05-013546.

Permanent pacemaker implantation in unexplained syncope patients with borderline sinus bradycardia and electrophysiology study-proven sinus node disease

BACKGROUND

Significant sinus bradycardia (SB) in the context of sinus node dysfunction (SND) has been associated with neurological symptoms. The objective was to evaluate the effect of permanent pacing on the incidence of syncope in patients with rather mild degrees of SB, unexplained syncope, and "positive" invasive electrophysiologic testing.

METHODS

This was an observational study based on a prospective registry of 122 consecutive mild SB patients (61.90 ± 18.28 years, 61.5% male, 57.88 ± 7.73 bpm) presenting with recurrent unexplained pre and syncope attacks admitted to our hospital for invasive electrophysiology study (EPS). Τhe implantation of a permanent antibradycardia pacemaker (ABP) was offered to all patients according to the results of the EPS. Eighty patients received the ABP, while 42 denied.

RESULTS

The mean of reported syncope episodes was 2.23 ± 1.29 (or presyncope 2.36 ± 1.20) in the last 12 months before they were referred for a combined EP guided diagnostic and therapeutic approach. Over a mean follow-up of approximately 4 years (50.39 ± 32.40 months), the primary outcome event (syncope) occurred in 18 of 122 patients (14.8%), 6 of 80 (7.5%) in the ABP group as compared to 12 of 42 (28.6%) in the no pacemaker group (P = .002).

CONCLUSIONS

Among patients with mild degree of SB and a history of unexplained syncope, a set of positivity criteria for the presence of EPS defined SND after differentiating reflex syncope, identifies a subset of patients who will benefit from permanent pacing.

Permanent pacing for recurrent vasovagal syncope: New answers or just more questions?

Vasovagal syncope (VVS) is a clinical condition related to bradycardia (cardioinhibitory response) and/or hypotension (vasodepressor response), likely mediated by parasympathetic overactivity and sympathetic withdrawal. Although clinical presentation is usually related to a self-limited event, frequent episodes or events without prodrome might be debilitating. There are limited medical therapies proven effective in randomized clinical trials. In patients not responsive to standard therapy, permanent pacemaker therapy may be suggested. However, the role of cardiac pacing for the prevention of syncope recurrences remains controversial due to difficulties to exclude potential role of the vasodepressor component during the episode.

New insights in diagnostics and therapies in syncope: a novel approach to non-cardiac syncope

This article aims to give advice on how to identify and manage patients with syncope who are at risk of severe outcomes, that is, at risk of trauma, potentially life-threatening episodes or frequent recurrences reducing quality of life. The first step of syncope diagnostic assessment is to identify patients with cardiac syncope, and once established, these patients must receive the adequate mechanism-specific treatment. If cardiac syncope is unlikely, reflex (neurally mediated) syncope and orthostatic hypotension are the most frequent causes of transient loss of consciousness. For these presentations, efficacy of therapy is largely determined by the mechanism of syncope rather than its aetiology or clinical features. The identified mechanism of syncope should be carefully assessed and assigned either to hypotensive or bradycardic phenotype, which will determine the choice of therapy (counteracting hypotension or counteracting bradycardia). The results of recent trials indicate that 'mechanism-specific therapy' is highly effective in preventing recurrences. Established mechanism-specific treatment strategies include withdrawal of hypotensive drugs, applying fludrocortisone and midodrine for the hypotensive phenotype and cardiac pacing in the bradycardic phenotype.

Pacing Therapies for Vasovagal Syncope

Vasovagal Syncope (VVS) is mediated by a cardiac autonomic reflex with resultant bradycardia and hypotension, precipitating syncope. While benign and mostly well controlled, recurrent VVS can be debilitating and warrants intervention. Non-pharmacological management of VVS have had variable success. In patients with recurrent cardioinhibitory VVS, permanent pacing can be effective. The utility of pacing to preempt the syncopal depends on the prominent temporal role of bradycardia during the vasovagal reflex. Current guidelines recommend pacing as a therapy to consider in older patients with recurrent VVS. Although younger patients can benefit, one should be cautious given the long-term risk of complications. Available data appears to favor a dual chamber pacemaker with closed loop stimulation algorithm to prevent recurrent cardioinhibitory VVS. Several aspects, including mechanistic understanding of VVS and appropriate patient selection, remain unclear, and require further study.

Recurrent seizures in a young woman: when video-EEG diagnoses a cardiac cause: a case report

Background

While transient loss of consciousness is a frequent presenting symptom, differential diagnosis between syncope and epilepsy can be challenging. Misdiagnosis of epilepsy leads to important psychosocial consequences and eliminates the opportunity to treat patient’s true condition.

Case summary

A 39-year-old woman presenting with recurrent seizures since her childhood was referred to neurological consultation. Electroencephalograms (EEGs) and magnetic resonance imaging previously performed were normal. A sleep-deprived video-EEG was performed and highlighted after 12 h of sleep deprivation a progressive dropping of the heart rate followed by a complete heart block without ventricular escape rhythm and asystole for about 30 s. Her EEG recording later showed diffuse slow waves traducing a global cerebral dysfunction and suffering. The diagnosis of vaso-vagal syncope with predominant cardioinhibitory response was made and a dual-chamber pacemaker with rate-drop response algorithm was implanted. After a 2 years of follow-up, the patient remained free of syncope.

Discussion

Patients presenting with loss of consciousness and convulsion are often diagnosed with epilepsy despite normal EEGs. In patients presenting with recurrent seizures with unclear diagnosis of epilepsy or in a situation of drug-resistant epilepsy, syncope diagnosis should always be considered and a risk stratification is necessary. The benefit of pacemaker implantation in patients with recurrent vaso-vagal syncope is still very controversial. Only patients presenting with spontaneous asystole should be considered for pacemaker implantation in case of recurrent vaso-vagal syncope.

Usefulness of post-procedural heart rate response to predict syncope recurrence or positive head up tilt table testing after cardioneuroablation

Aims

Previous reports have suggested that cardioneuroablation (CNA) can be effective in reducing syncopal recurrences in patients with vasovagal syncope (VVS). This study assessed the efficacy of CNA in preventing a positive response to head-up tilt testing (HUT).

Methods and results

This is a single-centre retrospective study reviewing prospectively collected data. Fifty-one consecutive patients with VVS were included in the study. After confirmation of >3 s asystole on HUT, all patients underwent CNA. Head-up tilt testing was repeated 1 month after CNA. The main outcome measures were recurrence of syncope episode and positive response on HUT. During a median follow-up period of 11 months (interquartile range 3–27 months), all but 3 (5.8%) of 51 patients were free of syncope. Repeated HUTs were negative in 44 (86.2%) patients. When patients with recurrent syncope were excluded, vasodepressor response was seen in three cases and cardioinhibitory response in one case, respectively. Cardioneuroablation caused significant and durable shortening of RR interval in all cases. This effect was significantly higher in patients without positive HUT responses.

Conclusion

This pilot study shows that CNA can effectively prevent recurrent syncopal episodes in patients with refractory VVS. Head-up tilt testing seems as a valuable diagnostic tool not only to select suitable candidates and but also to evaluate success of CNA.

Safety and efficacy of leadless pacemaker for cardioinhibitory vasovagal syncope

BACKGROUND

Single-chamber leadless pacemakers (LPs) have been shown to be an effective alternative to conventional transvenous pacemakers (CTPs), but their benefit in the context of cardioinhibitory vasovagal syncope (CI-VVS) is unknown.

OBJECTIVE

The purpose of this study was to evaluate the safety and efficacy of LP compared with dual-chamber CTP for CI-VVS.

METHODS

We conducted a multicenter, retrospective study comparing patients who received LP or dual-chamber CTP for drug-refractory CI-VVS. CI-VVS was diagnosed clinically and supported by cardiac monitoring and head-up tilt table testing. The primary efficacy endpoint was freedom from syncope during follow-up. Secondary endpoints included device efficacy and safety estimated by device-related major and minor adverse events (AEs).

RESULTS

Seventy-two patients (24 LP, 48 CTP; age 32 ± 5.5 years; 90% female; syncope frequency 7.6 ± 3.4 per year) were included. At 1 year, 91% of patients (22/24) in the LP group and 94% of patients (43/48) in the CTP group met the primary efficacy endpoint (P = .7). Device efficacy endpoint was met in 92% of the LP group and 98% of the CTP group (P = .2). Early major AEs occurred in 2 of 24 in the LP group and 3 of 48 in the CTP group (P = .4). Late major AEs occurred in 0 of 24 in the LP group and 2 of 48 in the CTP group (P = 1).

CONCLUSION

In patients with CI-VVS, single-chamber LP demonstrated equivalent efficacy in reducing syncopal events compared to dual-chamber CTP, with a similar safety profile.

Neuro-arrhythmology: a challenging field of action and research: a review from the Task Force of Neuro-arrhythmology of Italian Association of Arrhythmias and Cardiac Pacing

: There is a growing interest in the study of the mechanisms of heart and brain interactions with the aim to improve the management of high-impact cardiac rhythm disorders, first of all atrial fibrillation. However, there are several topics to which the scientific interests of cardiologists and neurologists converge constituting the basis for enhancing the development of neuro-arrhythmology. This multidisciplinary field should cover a wide spectrum of diseases, even beyond the classical framework corresponding to stroke and atrial fibrillation and include the complex issues of seizures as well as loss of consciousness and syncope. The implications of a more focused interaction between neurologists and cardiologists in the field of neuro-arrhythmology should include in perspective the institution of research networks specifically devoted to investigate 'from bench to bedside' the complex pathophysiological links of the abovementioned diseases, with involvement of scientists in the field of biochemistry, genetics, molecular medicine, physiology, pathology and bioengineering. An investment in the field could have important implications in the perspectives of a more personalized approach to patients and diseases, in the context of 'precision'medicine. Large datasets and electronic medical records, with the approach typical of 'big data' could enhance the possibility of new findings with potentially important clinical implications. Finally, the interaction between neurologists and cardiologists involved in arrythmia management should have some organizational implications, with new models of healthcare delivery based on multidisciplinary assistance, similarly to that applied in the case of syncope units.

Pacing in vasovagal syncope: Physiology, pacemaker sensors, and recent clinical trials-Precise patient selection and measurable benefit

The role of pacing in vasovagal syncope (VVS) is considered from a physiological basis. Most VVS patients lose consciousness due to hypotension before severe bradycardia/asystole occurs. Patients who benefit from dual-chamber pacing typically are older with highly symptomatic, late-onset, frequent and severe syncope with short/no prodrome and documented severe cardioinhibition. Tilt testing is of value in patients with recurrent unexplained syncope to identify important hypotensive susceptibility stemming from reduced venous return and stroke volume (SV). A negative tilt test in vasovagal patients with spontaneous asystole documented by an implantable/insertable loop recorder is associated with lower syncope recurrence rates after pacemaker implantation. Pacing may be more effective if triggered by sensor detection of a parameter changing earlier in the reflex than bradycardia when SV may still be relatively preserved. In this regard, detection of right ventricular impedance offers promise. Conservatism is recommended, limiting pacing in VVS to a small subset of symptomatic older patients with clearly documented cardioinhibition and paying particular attention to the timing of loss of consciousness in relation to asystole/bradycardia. Understanding VVS physiology permits application of well-timed, appropriate pacing that yields benefit for highly symptomatic patients.

Diagnostic and therapeutic approach to cardioinhibitory reflex syncope: A complex and controversial issue

Syncope is defined as a transient loss of consciousness due to global cerebral hypoperfusion and is one of the leading causes of emergency department admission. The initial approach should focus on excluding non-syncopal causes for loss of consciousness and risk stratification for cardiac cause, in order to ensure an appropriate etiological investigation and therapeutic approach. Vasovagal syncope (VVS), the most common type of syncope, should be assumed once other causes are excluded. Pathophysiologically, the vasovagal reflex is the result of a paradoxical autonomic response, leading to hypotension and/or bradycardia. VVS has not been shown to affect mortality, but morbidity may be considerable in those with recurrent syncopal episodes. The management of VVS includes both non-pharmacological and pharmacological measures that act on various levels of the reflex arc that triggers the syncopal episode. However, most are of uncertain benefit given the scarcity of high-quality supporting evidence. Pacemaker therapy may be considered in recurrent refractory cardioinhibitory reflex syncope, for which it is currently considered a robust intervention, as noted in the European guidelines. Non-randomized and unblinded studies have shown a potential benefit of pacing in recurrent VVS, but double-blinded randomized controlled trials have not consistently demonstrated positive results. We performed a comprehensive review of the current literature and recent advances in cardiac pacing and pacing algorithms in VVS, and discuss the diagnostic and therapeutic approach to the complex patient with recurrent VVS and reduced quality of life.

Impact of dual-chamber pacing with closed loop stimulation on quality of life in patients with recurrent reflex vasovagal syncope: results of the SPAIN study

Aims 

Reflex vasovagal syncope (VVS) is the most common cause of syncope and patients with recurrent episodes may severely impair quality of life (QoL). This pre-specified analysis evaluated whether the clinically significant reduction in syncope burden demonstrated by dual-chamber pacing with closed loop stimulation (DDD-CLS) reported in the SPAIN trial translates into improved QoL.

Methods and results

Patients aged ≥40 years with ≥5 VVS episodes and cardioinhibitory response induced by head-up tilt testing were included. Patients were randomized 1:1 to active DDD-CLS pacing algorithm for 12 months followed by sham DDI mode for the remaining 12 months (Group A) or vice versa (Group B). QoL was assessed using the Short Form-36 (SF-36) health survey, Physical Component Score (PCS), and Mental Component Score (MCS) before randomization (baseline) and at 12- and 24-month follow-up. Fifty-four patients were enrolled from 11 participating centres. No significant carryover effect was detected for any variable, and the only period effect was observed in the vitality subdomain (P = 0.033). Mean SF-36 scores were higher in the DDD-CLS group vs. the DDI group for the eight subdomains and significantly different in physical role, bodily pain, and vitality (P < 0.05). The analysis of component summary scores indicated that DDD-CLS benefited both mental and physical components with significant differences in PCS when compared with the DDI group.

Conclusion

Dual-chamber pacing with closed loop stimulation determined a significant and clinically relevant improvement in QoL across both mental and physical components in patients with recurrent VVS.

Registration

Closed Loop Stimulation for Neuromediated Syncope (SPAIN Study); NCT01621464.

ELectrophysiological mechanisms underlying the Inhibitory CArdiac syncope without asystolic significant pause: Therapeutic and prognostic implications. The ELICA randomized trial

BACKGROUND

The aim of this study was to investigate syncope recurrence in patients with a 2A cardioinhibitory response to the head up tilt testing (HUT).

METHODS

In this study, we enrolled 72 consecutive patients affected by syncope with cardioinhibitory response without asystolic significant pause to HUT (2A type). In these patients, we randomly performed electrophysiological study (ES). In case of sino-atrial node, atrio-ventricular node dysfunction, and sustained arrhythmias induction, the ES resulted positive. ES was positive in 9 patients (group A), then treated by catheter ablation, and/or by devices implants. Otherwise, ES resulted negative (group B), and these patients did not receive an interventional treatment. However, after ES, we evaluated syncope recurrence during 360 days follow-up.

RESULTS

There was a lower statistical significant syncope recurrence at follow-up, comparing group A to group B of patients [n of events 9 (40.9%) vs 8 (57.1%), P < .05]. At multivariate analysis, ES result was the only factor predicting syncope recurrence at follow-up (hazard ratio = 27.63, 95% confidence interval = 1.02-54.24, P < .005).

CONCLUSION

The positivity to ES study, and successful interventional therapies may reduce the burden of syncope recurrence at 360 days follow-up in 2A HUT subjects.Clinical trial number: NCT02861274.

Treatment of Neurocardiogenic Syncope: From Conservative to Cutting-edge

Neurocardiogenic syncope is the most frequent cause of syncope in the general population. Many years have been spent on determining an effective treatment for this condition. Conventional treatment usually follows a tiered approach for neurocardiogenic syncope, as follows: first, lifestyle modification, including increased fluid intake and the introduction of physical counterpressure maneuvers, is tried; then the use of targeted pharmacologic therapy, particularly agents that support blood pressure or that drive blood pressure is attempted; and, finally, pacemaker implantation in patients with a predominant cardioinhibitory component to their syncopal episodes is performed. More recently, autonomic modulation with cardiac ganglion ablation has emerged as a promising treatment modality for patients refractory to traditional approaches. In this review, we sought to summarize the existing therapies for neurocardiogenic syncope and explore the latest research on new modalities of treatment.

Pacing for Vasovagal Syncope

Vasovagal syncope (VVS) is due to a common autonomic reflex involving the cardiovascular system. It is associated with bradycardia (cardioinhibitory response) and/or hypotension (vasodepressor response), likely mediated by parasympathetic activation and sympathetic inhibition. While generally a situational, isolated and/or self-limited event, for some, VVS is recurrent, unpredictable and debilitating. Conservative, non-pharmacological management may help, but no specific medical therapy has been proven widely effective. Permanent pacing may have specific benefit, but its value has been debated. The temporal causative association of bradycardia with syncope in those with VVS may help identify which patient could benefit from pacing but the timing and type of pacing in lieu of blood pressure changes may be critical. The mode, rate, pacing algorithm and time to initiate dual-chamber pacing preferentially with respect to the vasovagal reflex may be important to prevent or ameliorate the faint but completely convincing data are not yet available. Based on available data, DDD pacing with the closed loop stimulation algorithm appears a viable, if not the best, alternative presently to prevent recurrent VVS episodes. While several knowledge gaps remain, permanent pacing appears to have a role in managing select patients with VVS.

Pacing in neurocardiogenic/vasovagal syncope

Pacing for neurocardiogenic or vasovagal syncope (VVS) has been practised for five decades, but the 1986 advent of tilt testing provided a means of diagnosis frequently revealing, in the early days, asystole caused by VVS. This was the basis for pacing these patients and the first studies created enthusiasm followed by randomised controlled trials, which were imperfectly designed, "confirming" benefit. When better trial design was employed, there was no obvious benefit. However, some cardiologists had seen patients experience a huge positive difference with pacing, so they set out to identify them. Two studies using ECG loop recorders to document heart rhythm during spontaneous attacks allowed better patient selection for pacing and appeared to achieve the aim. Further, it was noted in the second study, a randomised controlled trial (RCT) with good design, that tilt testing added a further dimension to the identification of the patient who would benefit. Thus, loop recorders are used to show asystole in spontaneous attacks and when tilt testing is negative, implying a lesser vasodepressor component, the patient will have the best outcome. From the available evidence, pacing should be dual-chamber in older patients (>40 years) with severe symptoms and in whom standard measures have demonstrably failed. The method of triggering pacing and its timing of introduction have not yet been resolved. Today's method is rate-hysteresis but there is another sensed event as an alternative: right ventricular impedance, which is now in RCT with substantial pilot evidence in its favour.