Pacemaker therapy in patients with neurally mediated syncope and documented asystole: Third International Study on Syncope of Uncertain Etiology (ISSUE-3): a randomized trial

BACKGROUND

The efficacy of cardiac pacing for prevention of syncopal recurrences in patients with neurally mediated syncope is controversial. We wanted to determine whether pacing therapy reduces syncopal recurrences in patients with severe asystolic neurally mediated syncope.

METHODS AND RESULTS

Double-blind, randomized placebo-controlled study conducted in 29 centers in the Third International Study on Syncope of Uncertain Etiology (ISSUE-3) trial. Patients were ≥40 years, had experienced ≥3 syncopal episodes in the previous 2 years. Initially, 511 patients, received an implantable loop recorder; 89 of these had documentation of syncope with ≥3 s asystole or ≥6 s asystole without syncope within 12 ± 10 months and met criteria for pacemaker implantation; 77 of 89 patients were randomly assigned to dual-chamber pacing with rate drop response or to sensing only. The data were analyzed on intention-to-treat principle. There was syncope recurrence during follow-up in 27 patients, 19 of whom had been assigned to pacemaker OFF and 8 to pacemaker ON. The 2-year estimated syncope recurrence rate was 57% (95% CI, 40-74) with pacemaker OFF and 25% (95% CI, 13-45) with pacemaker ON (log rank: P=0.039 at the threshold of statistical significance of 0.04). The risk of recurrence was reduced by 57% (95% CI, 4-81). Five patients had procedural complications: lead dislodgment in 4 requiring correction and subclavian vein thrombosis in 1 patient.

CONCLUSIONS

Dual-chamber permanent pacing is effective in reducing recurrence of syncope in patients ≥40 years with severe asystolic neurally mediated syncope. The observed 32% absolute and 57% relative reduction in syncope recurrence support this invasive treatment for the relatively benign neurally mediated syncope.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00359203.

Cardiac resynchronization therapy in patients undergoing atrioventricular junction ablation for permanent atrial fibrillation: a randomized trial

AIMS

On the basis of the current knowledge, cardiac resynchronization therapy (CRT) cannot be recommended as a first-line treatment for patients with severely symptomatic permanent atrial fibrillation undergoing atrioventricular (AV) junction ablation. We examined whether CRT was superior to conventional right ventricular (RV) pacing in reducing heart failure (HF) events.

METHODS AND RESULTS

In this prospective, multi-centre study, we randomly assigned 186 patients, in whom AV junction ablation and CRT device implantation had been successfully performed, to receive optimized echo-guided CRT (97 patients) or RV apical pacing (89 patients). The data were analysed according to the intention-to-treat principle. During a median follow-up of 20 months (interquartile range 11-24), the primary composite endpoint of death from HF, hospitalization due to HF, or worsening HF occurred in 11 (11%) patients in the CRT group and 23 (26%) patients in the RV group [CRT vs. RV group: sub-hazard ratio (SHR) 0.37 ( 95% CI 0.18-0.73), P = 0.005]. In the CRT group, compared with the RV group, fewer patients had worsening HF [SHR 0.27 (95% CI 0.12-0.58), P = 0.001] and hospitalizations for HF [SHR 0.20 (95% CI 0.06-0.72), P = 0.013]. Total mortality was similar in both groups [hazard ratio (HR) 1.57 (95% CI 0.58-4.27), P = 0.372]. The beneficial effects of CRT were consistent in patients who had ejection fraction ≤35%, New York Heart Association Class ≥III and QRS width ≥120 and in those who did not. At multi-variable Cox regression, only CRT mode remained an independent predictor of absence of clinical failure during the follow-up [HR = 0.23 (95% CI 0.08-0.66), P = 0.007].

CONCLUSIONS

In patients undergoing 'Ablate and Pace' therapy for severely symptomatic permanent atrial fibrillation, CRT is superior to RV apical pacing in reducing the clinical manifestations of HF. (ClinicalTrials.gov number: NCT00111527).

Diagnosis, management, and outcomes of patients with syncope and bundle branch block

Aims

Although patients with syncope and bundle branch block (BBB) are at high risk of developing atrio-ventricular block, syncope may be due to other aetiologies. We performed a prospective, observational study of the clinical outcomes of patients with syncope and BBB following a systematic diagnostic approach.

Methods and results

Patients with ≥1 syncope in the last 6 months, with QRS duration ≥120 ms, were prospectively studied following a three-phase diagnostic strategy: Phase I, initial evaluation; Phase II, electrophysiological study (EPS); and Phase III, insertion of an implantable loop recorder (ILR). Overall, 323 patients (left ventricular ejection fraction 56 ± 12%) were studied. The aetiological diagnosis was established in 267 (82.7%) patients (102 at initial evaluation, 113 upon EPS, and 52 upon ILR) with the following aetiologies: bradyarrhythmia (202), carotid sinus syndrome (20), ventricular tachycardia (18), neurally mediated (9), orthostatic hypotension (4), drug-induced (3), secondary to cardiopulmonary disease (2), supraventricular tachycardia (1), bradycardia–tachycardia (1), and non-arrhythmic (7). A pacemaker was implanted in 220 (68.1%), an implantable cardioverter defibrillator in 19 (5.8%), and radiofrequency catheter ablation was performed in 3 patients. Twenty patients (6%) had died at an average follow-up of 19.2 ± 8.2 months.

Conclusion

In patients with syncope, BBB, and mean left ventricular ejection fraction of 56 ± 12%, a systematic diagnostic approach achieves a high rate of aetiological diagnosis and allows to select specific treatment.

Scanning probe nanoimprint lithography

The present paper reports on a novel lithographic approach at the nanoscale level, which is based on scanning probe microscopy (SPM) and nanoimprint lithography (NIL). The experimental set-up consists of an atomic force microscope (AFM) operated via software specifically developed for the purpose. In particular, this software allows one to apply a predefined external load for a given lapse of time while monitoring in real-time the relative distance between the tip and the sample as well as the normal and lateral force during the embossing process. Additionally, we have employed AFM tips sculptured by means of focused ion beam in order to create indenting tools of the desired shape. Anti-sticking layers can also be used to functionalize the tips if one needs to investigate the effects of different treatments on the indentation and de-molding processes. The lithographic capabilities of this set-up are demonstrated on a polystyrene NIL-patterned sample, where imprinted features have been obtained upon using different normal load values for increasing time intervals, and on a thermoplastic polymer film, where the imprint process has been monitored in real-time.

A simplified biventricular defibrillator with fixed long detection intervals reduces implantable cardioverter defibrillator (ICD) interventions and heart failure hospitalizations in patients with non-ischaemic cardiomyopathy implanted for primary prevention: the RELEVANT [Role of long dEtection window programming in patients with LEft VentriculAr dysfunction, Non-ischemic eTiology in primary prevention treated with a biventricular ICD] study

Aims

To investigate the efficacy and safety of a cardiac resynchronization therapy with cardioverter–defibrillator (CRT-D) device with simplified ventricular tachycardia management in patients with non-ischaemic heart failure (HF) and primary prevention implantable cardioverter defibrillator (ICD) indication.

Methods and results

Prospective, controlled, parallel, multicentre, non-randomized study enrolling 324 primary prevention non-ischaemic HF patients implanted with CRT-D devices from 2004 to 2007: Protect group, 164 patients implanted with a Medtronic Insync III Protect device and Control group, 160 patients utilizing other Medtronic CRT-D devices.

Efficacy was assessed by computing appropriate and inappropriate detections and therapies during follow-up; safety compared hospitalizations and syncopal events between groups. Ninety per cent of both ventricular and supraventricular tachyarrhythmias terminated within the 13–29 beat detection interval with the Protect algorithm. The Protect group showed a significantly better event-free survival to first delivered therapy for total (P = 0.0001), appropriately treated (P = 0.002), and inappropriately treated episodes (P = 0.017). The total number of delivered shocks was significantly lower in the Protect group (22 vs. 59, P < 0.0001). In the Protect group, a significantly reduced HF hospitalization (hazard ratio 0.38, 95% CI 0.15–0.98, P = 0.044) was observed without any increase of syncope or death.

Conclusion

A simplified CRT-D device with fixed long detection reduced overall ICD therapy burden and HF hospitalizations without entailing any additional adverse events in primary prevention non-ischaemic HF patients.

Radiofrequency catheter ablation of atrioventricular nodal re-entry tachycardia: selective approach to the slow pathway via the cephalic veins

Inferior venous access to the right heart is not possible in some patients due to vena caval obstruction. Here we describe a case of a patient with atrioventricular nodal re-entry tachycardia where radiofrequency ablation from the inferior vena cava was impossible because of the presence of important stenosis of the distal part of the vein. Catheter ablation of the slow pathway could be performed successfully using a superior approach via the cephalic veins.

Reproducibility of electrocardiographic findings in patients with suspected reflex neurally-mediated syncope

The reproducibility of electrocardiographic (ECG) recordings in syncopal recurrences and the diagnostic role of nonsyncopal arrhythmias are not well known. The objective of this study was to analyse the reproducibility of the ECG findings recorded with implantable loop recorders in 41 patients with suspected neurally-mediated syncope who were included in the International Study on Syncope of Uncertain Origin-2 study and that had > or =2 events recorded by implantable loop recorders. In these patients, the electrocardiogram obtained with the first documented syncope (index syncope) was compared with other recorded events. Twenty-two patients had > or =2 syncopes, and their electrocardiograms were reproducible in 21 (95%): 15 with sinus rhythm, 5 with asystole, and 1 with ventricular tachycardia; 1 had asystole at first syncope and sinus rhythm at recurrent syncope. In 32 patients with nonsyncopal episodes, an arrhythmia was documented in 9, and all of them had the same arrhythmia during the index syncope (100% reproducibility); conversely, when sinus rhythm was documented (23 patients) during nonsyncopal episodes, an arrhythmia was still documented in 6 during the index syncope (70% reproducibility; p = 0.0004). In conclusion, the ECG findings during the first syncope are highly reproducible in subsequent syncopes. The presence of an arrhythmia during nonsyncopal episodes is also highly predictive of the mechanism of syncope, but the presence of sinus rhythm does not rule out the possibility of arrhythmia during syncope. Therefore the finding of an arrhythmia during a nonsyncopal episode allows the etiologic diagnosis of syncope, and eventually to anticipate treatment, without waiting for syncope.

Usefulness of echo-guided cardiac resynchronization pacing in patients undergoing "ablate and pace" therapy for permanent atrial fibrillation and effects of heart rate regularization and left ventricular resynchronization

An acute comparative study of right ventricular (RV) pacing and echocardiographically guided cardiac resynchronization pacing (CRP) was performed in patients who underwent "ablate and pace" therapy for permanent atrial fibrillation. It was hypothesized that optimized CRP guided by tissue Doppler echocardiography would exert an additive beneficial hemodynamic effect to that of rate regularization achieved through atrioventricular junction ablation. An acute intrapatient comparison of echocardiographic parameters was performed between baseline preablation values and RV pacing and CRP (performed <24 hours after ablation) in 50 patients. Optimized CRP configuration was defined as the modality of pacing corresponding to that of the shortest intra-left ventricular (LV) delay among simultaneous biventricular pacing, sequential biventricular pacing, and single-chamber pacing. The intra-LV delay was defined as the difference between the longest and the shortest activation time in the six basal segments of the left ventricle. Compared with preablation measures, the ejection fraction increased by 10.8% during RV pacing (19% in patients with intra-LV delays <47.5 ms and 3% in those with intra-LV delays >47.5 ms). Compared with RV pacing, CRP caused a 9.2% increase in the ejection fraction, a 6.8% decrease in LV systolic diameter, and a 17.3% decrease in mitral regurgitation area; LV dyssynchrony was reduced from 52 +/- 27 to 21 +/- 12 ms. Similar results were observed in patients with and without depressed systolic function and in patients with and without left bundle branch block. In conclusion, rate regularization achieved through atrioventricular junction ablation and RV pacing provides a favorable hemodynamic effect that is inversely related to the level of LV dyssynchrony. Minimizing LV dyssynchrony by means of optimized CRP yields an additional important benefit.

Clinical predictors of cardiac syncope at initial evaluation in patients referred urgently to a general hospital: the EGSYS score

OBJECTIVE

To develop, in patients referred for syncope to an emergency department (ED), a diagnostic score to identify those patients likely to have a cardiac cause.

DESIGN

Prospective cohort study.

SETTING

ED of 14 general hospitals.

PATIENTS

516 consecutive patients with unexplained syncope.

INTERVENTIONS

Subjects underwent a diagnostic evaluation on adherence to Guidelines of the European Society of Cardiology. The clinical features of syncope were analysed using a standard 52-item form. In a validation cohort of 260 patients the predictive value of symptoms/signs was evaluated, a point score was developed and then validated in a cohort of 256 other patients.

MAIN OUTCOME MEASUREMENTS

Diagnosis of cardiac syncope, mortality.

RESULTS

Abnormal ECG and/or heart disease, palpitations before syncope, syncope during effort or in supine position, absence of autonomic prodromes and absence of predisposing and/or precipitating factors were found to be predictors of cardiac syncope. To each variable a score from +4 to -1 was assigned to the magnitude of regression coefficient. A score >or=3 identified cardiac syncope with a sensitivity of 95%/92% and a specificity of 61%/69% in the derivation and validation cohorts, respectively. During follow-up (mean (SD) 614 (73) days) patients with score >or=3 had a higher total mortality than patients with a score <3 both in the derivation (17% vs 3%; p<0.001) and in the validation cohort (21% vs 2%; p<0.001).

CONCLUSIONS

A simple score derived from clinical history can be usefully employed for the triage and management of patients with syncope in an ED.

Cardioinhibitory carotid sinus hypersensitivity predicts an asystolic mechanism of spontaneous neurally mediated syncope

AIMS

We correlated the finding of cardioinhibitory carotid sinus hypersensitivity (CSH) with that observed during a spontaneous syncopal relapse by means of an implantable loop recorder (ILR).

METHODS AND RESULTS

We included 18 consecutive patients with suspected recurrent neurally mediated syncope and positive cardioinhibitory response during carotid sinus massage (max pause 5.5 +/- 1.6 s) who had subsequent documentation of a spontaneous syncope by means of an ILR. They were compared with a 2:1 age- and sex-matched group of 36 patients with a clinical diagnosis of recurrent neurally mediated syncope and negative response to carotid sinus massage, tilt testing and ATP test. Asystole >3 s was observed at the time of the spontaneous syncope in 16 (89%) of CSH patients and in 18 (50%) of the control group (P = 0.007). Sinus arrest was the most frequent finding among CSH patients but not among controls (72 vs. 28%, P = 0.003). After ILR documentation, 14 CSH patients with asystole received dual-chamber pacemaker implantation; during 35 +/- 22 months of follow-up, 2 syncopal episodes recurred in 2 patients (14%), and pre-syncope occurred in another 2 patients (14%). Syncope burden decreased from 1.68 (95% confidence interval 1.66 - 1.70) episodes per patient per year before to 0.04 (0.038-0.042) after pacemaker implant (98% relative risk reduction).

CONCLUSIONS

In patients with suspected neurally mediated syncope, the finding of cardioinhibitory CSH predicts an asystolic mechanism at the time of spontaneous syncope and, consequently, suggests a possible benefit of cardiac pacing therapy.

Recurrent Unexplained Palpitations (RUP) Study

OBJECTIVES

The aim of the study was to compare the diagnostic yield and the costs of implantable loop recorder (ILR) with those of the conventional strategy in patients with unexplained palpitations.

BACKGROUND

In patients with unexplained palpitations, especially in those with infrequent symptoms, the conventional strategy, including short-term ambulatory electrocardiogram (ECG) monitoring and electrophysiological study, sometimes fails to establish a diagnosis.

METHODS

We studied 50 patients with infrequent (< or =1 episode/month), sustained (>1 min) palpitations. Before enrollment, patients had a negative initial evaluation, including history, physical examination, and ECG. Patients were randomized either to conventional strategy (24-h Holter recording, a 4-week period of ambulatory ECG monitoring with an external recorder, and electrophysiological study) (n = 24) or to ILR implantation with 1-year monitoring (n = 26). Hospital costs of the 2 strategies were calculated.

RESULTS

A diagnosis was obtained in 5 patients in the conventional strategy group, and in 19 subjects in the ILR group (21% vs. 73%, p < 0.001). Despite the higher initial cost, the cost per diagnosis in the ILR group was lower than in the conventional strategy group (euro 3,056 +/- euro 363 vs. euro 6,768 +/- euro 6,672, p = 0.012).

CONCLUSIONS

In subjects without severe heart disease and with infrequent palpitations, ILR is a safe and more cost-effective diagnostic approach than conventional strategy.

Left ventricular electromechanical delay in patients with heart failure and normal QRS duration and in patients with right and left bundle branch block

AIMS

We sought to define the reference values of intra-left ventricular (LV) electromechanical delay (EMD), and to assess the prevalence (and pattern) of intra-LV dyssynchrony in patients with heart failure (HF) and normal QRS and in patients with right and left bundle branch block.

METHODS AND RESULTS

We used tissue Doppler imaging echocardiography and a six-LV wall model to study LV EMD in 103 patients [41 with HF and normal QRS, 22 with right bundle branch block (RBBB), and 40 with left bundle branch block (LBBB)], and in 59 controls. In controls, the median intra-LV EMD was 17 ms, (inter-quartile range 13-30); 95% of controls had a value < or =41 ms. Patients showed a longer intra-LV EMD than controls: 33 ms (20-57) in patients with normal QRS, 32 ms (23-50) in RBBB patients, and 50 ms (30-94) in LBBB patients. Intra-LV dyssynchrony (defined as intra-LV EMD >41 ms) was present in 39, 36, and 60% of the patients, respectively. On average, HF patients showed the same pattern of activation as controls, from the septum to the posterior wall, but activation times were significantly prolonged. In RBBB patients the activation sequence was directed from inferior to anterior and in LBBB from anterior to inferior wall.

CONCLUSIONS

Left ventricular dyssynchrony was present in several patients with HF and normal QRS, and in patients with RBBB; conversely, 40% of LBBB patients showed values of LV EMD within the normal range. Left ventricular activation sequence was different between groups. Assessment of LV synchronicity by means of imaging techniques may be more important than QRS duration or morphology in selecting patients for cardiac resynchronization treatment.

[Comparative study of results of catheter ablation in ventricular tachycardia of different etiologies]

BACKGROUND

The aim of this study was to assess long-term results and adverse events in patients with ventricular tachycardia from different etiologies.

METHODS

The recurrence rate of tachycardia, consequent further therapies (other catheter ablation procedures, drug therapy and implantable defibrillator) and clinical events have been assessed in 60 consecutive patients undergoing ventricular tachycardia catheter ablation between January 2000 and December 2004.

RESULTS

During a median follow-up of 20 months (interquartile range 13-36 months), tachycardia recurred in 27 patients (45%) after a median of 3 months (interquartile range 1-12 months). A second procedure was performed in 11 patients; it was successful in 8 patients. Four patients underwent pharmacological therapy which was successful in all cases. Overall, after ablation (> or =1 procedures) and pharmacological therapy, tachycardia was cured in 75% of cases. All the 20 patients without structural heart disease were cured with ablation vs. 62% of patients with heart disease (p = 0.001). Patients with dilated cardiomyopathy reported worst results (33% success, p = 0.03). Recurrences were predicted by acute failure of procedure (p = 0.05), presence of heart disease (p = 0.006) and history of atrial arrhythmias (p = 0.02). On a multivariate analysis, only structural heart disease continued to be an independent predictor of ventricular tachycardia recurrence.

CONCLUSIONS

Catheter ablation of ventricular tachycardia has a high percentage of recurrences in patients with heart disease, whereas is curative in subjects without structural heart disease.

Lack of correlation between the responses to tilt testing and adenosine triphosphate test and the mechanism of spontaneous neurally mediated syncope

AIMS

We prospectively correlated the results of tilt testing (TT) and adenosine triphosphate test (ATP) with the findings observed during a spontaneous syncopal relapse by means of an implantable loop recorder (ILR) in patients with a clinical diagnosis of neurally mediated syncope.

METHODS AND RESULTS

We included patients with three or more clinically severe syncopal episodes in the last 2 years without significant electrocardiographic and cardiac abnormalities. Patients with orthostatic hypotension and carotid sinus syncope were excluded. After ILR implantation, patients were followed until the first documented syncope. Among 392 enrolled patients, 343 underwent TT, which was positive in 164 (48%), and 180 ATP test, which was positive in 53 (29%). Syncope was documented by ILR in 106 (26%) patients after a median of 3 months. Patients with positive and negative TT had similar baseline characteristics, syncopal recurrence rate, and mechanism of syncope, but those with positive TT had more frequently no or slight rhythm variations during spontaneous syncope (45 vs. 21%, P=0.02). An asystolic pause was more frequently found during spontaneous syncope than during TT (45 vs. 21%, P=0.02), but there was a trend for those with an asystolic response during TT also to have an asystolic response during spontaneous syncope (75 vs. 37%, P=0.1). Patients with positive ATP test responses showed syncopal recurrence rates and mechanism of syncope similar to those with negative ATP tests.

CONCLUSION

In patients with neurally mediated syncope, clinical characteristics, outcome, and mechanism of syncope are poorly correlated and not predicted by the results of TT and ATP test. Therefore, these tests are of little or no value in guiding specific therapy.

Effects of right ventricular pacing on intra-left ventricular electromechanical activation in patients with native narrow QRS

Some patients with right ventricular (RV) apical pacing show contractile asynchrony of the left ventricle. Whether the asynchrony is due to RV pacing or was a preexistimg condition remains unknown. The aim of this study was to evaluate how much pacing from the RV apex affects left ventricular (LV) electromechanical activation and to assess whether the extent of LV asynchrony during RV pacing can be predicted by clinical, electrocardiographic, or echocardiographic findings obtained during spontaneous rhythm. We evaluated 56 patients with narrow QRS and preserved atrioventricular conduction who received permanent backup RV pacing. Intra-LV electromechanical activation was assessed during spontaneous rhythm and during pacing using tissue Doppler echocardiography. An abnormal intra-LV electromechanical delay (EMD) (defined as a >41-ms difference between the faster and slower activated LV wall) was found in 15 patients (27%) during spontaneous rhythm and 28 patients (50%) during RV pacing (p<0.001). Of the 9 baseline variables (age, gender, history of heart failure, QRS duration in spontaneous rhythm and during pacing, LV end-diastolic and end-systolic diameters, LV ejection fraction, and intra-LV EMD in spontaneous rhythm), an abnormal baseline intra-LV EMD and QRS duration of >85 ms were independent predictors of an abnormal intra-LV delay during RV pacing. RV apical pacing induces asynchrony of LV contractions in a substantial percentage of patients but not in all. Although normal baseline intra-LV electromechanical activation cannot exclude the development of significant asynchrony during RV pacing, the presence of preimplant LV asynchrony predicts for a worsening of this detrimental effect.

Early application of an implantable loop recorder allows effective specific therapy in patients with recurrent suspected neurally mediated syncope

AIMS

This prospective multicentre observational study assessed the efficacy of specific therapy based on implantable loop recorder (ILR) diagnostic observations in patients with recurrent suspected neurally mediated syncope (NMS).

METHODS AND RESULTS

Patients with three or more clinically severe syncopal episodes in the last 2 years without significant electrocardiographic and cardiac abnormalities were included. Orthostatic hypotension and carotid sinus syncope were excluded. After ILR implantation, patients were followed until the first documented syncope (Phase I). The ILR documentation of this episode determined the subsequent therapy and commenced Phase II follow-up. Among 392 patients, the 1-year recurrence rate of syncope during Phase I was 33%. One hundred and three patients had a documented episode and entered Phase II: 53 patients received specific therapy [47 a pacemaker because of asystole of a median 11.5 s duration and six anti-tachyarrhythmia therapy (catheter ablation: four, implantable defibrillator: one, anti-arrhythmic drug: one)] and the remaining 50 patients did not receive specific therapy. The 1-year recurrence rate in 53 patients assigned to a specific therapy was 10% (burden 0.07 +/- 0.2 episodes per patient/year) compared with 41% (burden 0.83 +/- 1.57 episodes per patient/year) in the patients without specific therapy (80% relative risk reduction for patients, P = 0.002, and 92% for burden, P = 0.002). The 1-year recurrence rate in patients with pacemakers was 5% (burden 0.05 +/- 0.15 episodes per patient/year). Severe trauma secondary to syncope relapse occurred in 2% and mild trauma in 4% of the patients.

CONCLUSION

A strategy based on early diagnostic ILR application, with therapy delayed until documentation of syncope allows a safe, specific, and effective therapy in patients with NMS.

Seven-year follow-up after catheter ablation of atrioventricular nodal re-entrant tachycardia

BACKGROUND

Radiofrequency catheter ablation is considered to be a curative therapy for patients with atrioventricular nodal re-entrant tachycardia (AVNRT). Nevertheless, there is little information available with respect to long-term results and the consequences of catheter ablation. The present study aimed to assess the long-term results (a minimum of 5 years) and clinical events.

PATIENTS AND METHODS

The recurrence rate of AVNRT, the development of late atrioventricular block and the presence of other arrhythmias (atrial flutter and fibrillation) were assessed in 131 consecutive patients who were undergoing catheter ablation between January 1992 and December 1998.

RESULTS

During a mean follow-up of 7.2 +/- 2.5 years, tachycardia recurred in 13 patients (10%) after a median time of 6 months (interquartile range 4-24 months) and a second procedure was perfomed. Atrioventricular block occurred in two patients (1.5%) after 1 and 13 months. Atrial fibrillation recurred in seven (44%) of 16 patients in whom atrial fibrillation or flutter was present before ablation after a median of 12 months (interquartile range 9-15 months). Overall, all these events occurred after a median of 9 months (interquartile range 4-17 months). Subsequently, no event related to the arrhythmia or to the procedure was observed. A new onset atrial fibrillation, probably not related to AVNRT, occurred late in the follow-up in a further three patients.

CONCLUSIONS

Arrhythmic events are not infrequent after catheter ablation of AVNRT during the early years after ablation, but they are unlikely during the subsequent long-term follow-up.

Relation of clinical presentation of syncope to the age of patients

The aim of the study was to evaluate the effect of patient age on the clinical presentation of syncope and to establish the diagnostic value of clinical history in older patients. A total of 485 consecutive patients with unexplained syncope referred to secondary and tertiary hospitals were divided into 2 predefined age groups: 224 patients <65 years and 261 patients > or =65 years. The diagnostic criteria for the cause of syncope were developed before the beginning of the study. The clinical features of syncope were analyzed using a standard 46-item form. A cardiac cause of syncope was established in 27 younger (12%) and 89 older (34%) patients. A neurally mediated cause was established in 154 younger (68%) and 142 older (54%) patients. In patients > or =65 years, the clinical features of cardiac and neurally mediated syncope were very similar. The diagnosis of the cause of syncope was possible on the basis of the history alone in 26% younger and 5% older patients (p <0.0001). Myoclonic movements, effort syncope, and supine position during loss of consciousness were the most specific (97%, 99%, and 99%, respectively) diagnostic criteria for a cardiac cause of syncope in older patients, but, all together, they accounted for only 14% of patients. In conclusion, compared with younger patients, the medical history has a limited value in the diagnosis of the cause of syncope in older patients. The specificity of some features is high but these can be observed in only a minority of patients.

A new management of syncope: prospective systematic guideline-based evaluation of patients referred urgently to general hospitals

AIMS

The guidelines of the European Society of Cardiology (ESC) define the current standard for the management of syncope, but are still incompletely applied in the clinical setting.

METHODS AND RESULTS

Prospective systematic evaluation, on strict adherence to the guidelines, of consecutive patients referred for syncope to the emergency departments of 11 general hospitals. In order to maximize the application, a decision-making guideline-based software was used and trained core medical personnel were designated-both locally in each hospital and centrally-to verify adherence to the diagnostic pathway and give advice on its correction. A diagnostic work-up consistent with the guidelines was completed in 465/541 patients (86%). A definite diagnosis was established in 98% (unexplained in 2%): neurally mediated syncope accounted for 66% of diagnosis, orthostatic hypotension 10%, primary arrhythmias 11%, structural cardiac or cardiopulmonary disease 5%, and non-syncopal attacks 6%, respectively. The initial evaluation (consisting of history, physical examination, and standard electrocardiogram) established a diagnosis in 50% of cases. Hospitalization for the management of syncope was appropriate in 25% and was required for other reasons in a further 13% of cases. The median in-hospital stay was 5.5 days (interquartile range, 3-9). Apart from the initial evaluation, a mean of 1.9+/-1.1 appropriate tests per patient was performed in 193 patients and led to a final diagnosis in 182 of these (94%).

CONCLUSION

The results of this study assess the current standard for the management of syncope on the basis of a rigorous adherence to guidelines of the ESC and provide a frame of reference for daily activity when dealing with syncope.

Two unusual cases of coincident atrioventricular nodal reentrant tachycardia and ventricular tachycardia

The simultaneous occurrence of narrow and wide QRS complex tachycardias was observed in 2 patients evaluated at our electrophysiological centers. Electrophysiological testing revealed the coexistence of two types of arrhythmia (atrioventricular nodal reentrant tachycardia and verapamil-sensitive left ventricular tachycardia) in one patient and of three types of arrhythmia (atrioventricular nodal reentrant tachycardia, ventricular tachycardia originating from the right ventricular outflow tract, and left ventricular tachycardia) in the other. Both patients underwent successful radiofrequency ablation of all the types of tachycardia.

Proposed electrocardiographic classification of spontaneous syncope documented by an implantable loop recorder

Uniform data from the literature show that the mechanism of syncope recorded by implantable loop recorder is extremely heterogeneous and a wide variety of rhythm disturbances is recorded at the time of syncope. Therefore, the proposed classification aims to group the observations into homogeneous patterns in order to define an acceptable standard useful for future studies and clinical practice.

The usage and diagnostic yield of the implantable loop-recorder in detection of the mechanism of syncope and in guiding effective antiarrhythmic therapy in older people

OBJECTIVES

To evaluate the usage and diagnostic yield of the implantable loop-recorder (ILR) in detection of the mechanism of syncope and in guiding therapy in patients aged >/=65 years and comparing them with those <65 years.

DESIGN

This was a two-hospital, observational, prospective study in consecutive patients with unexplained syncope who underwent an ILR implantation. Between November 1997 and December 2002, a total of 2052 patients with syncope were evaluated (local population of 590,000 inhabitants). The diagnosis remained unexplained in 371 (18%). Of these, 103 patients (5% of the total, 28% of those with unexplained syncope) received an ILR.

RESULTS

There were 70 (76%) patients aged >/=65 years and 25 (24%) <65 years. ILR implantation was 110 and 9 per million inhabitants per year, respectively. During a mean follow-up of 14+/-10 months, syncope was recorded in 52 patients. Compared with younger patients those older had a 2.7 higher syncope recurrence rate (56% vs 32%, P=0.03); arrhythmias were 3.1 times more likely to be responsible for syncope (44% vs 20%, P=0.03). More patients >/=65 years finally received ILR-guided therapy (42% vs 20%, P=0.04). Among the 29 patients (25 of those >/=65 years) who received specific antiarrhythmic therapy, only one (3%), had recurrence of syncope during the subsequent follow-up of 40+/-18 months.

CONCLUSIONS

In patients referred for investigation of unexplained syncope, the older subjects are more likely to have an indication for ILR implantation than those younger, ILR has a higher diagnostic value, an arrhythmia is more likely to be detected and successfully treated.

Simultaneous Dual Fast and Slow Pathway Conduction upon Induction of Typical Atrioventricular Nodal Reentrant Tachycardia: Electrophysiologic Characteristics in a Series of Patients

INTRODUCTION

Simultaneous dual atrioventricular nodal conduction (SDNC) through slow (SP) and fast pathway (FP) is a rare phenomenon observed upon the induction of atrioventricular nodal reciprocating tachycardia (AVNRT). The aim of this study is to report the electrophysiological features of patients showing typical AVNRT induced through SDNC.

METHODS AND RESULTS

Among 461 consecutive patients with typical AVNRT submitted to radiofrequency catheter ablation (RFCA), seven patients (1.5%) with SDNC at tachycardia onset (group I: 6 female; age 60-72 years, mean 65.2 +/- 3.8 years) and 118 age-matched controls (group II: 60 female; age 60-88 years, mean 68.4 +/- 6.8 years) were considered. Controls were further subdivided into two subgroups according to age: subgroup A (94 patients, age 60-75 years) and subgroup B (24 patients, age >75 years). The value of the following parameters was significantly higher in group I than in group II and in subgroup A: A-H interval [113 +/- 26 vs. 89 +/- 27 (P < 0.01) vs. 84 +/- 19 (P < 0.001)], ventriculoatrial conduction effective refractory period [355 +/- 85 vs. 293 +/- 87 (P < 0.05) vs. 281 +/- 82 (P < 0.05)], SP conduction time upon AVNRT induction [444 +/- 104 vs. 350 +/- 72 (P < 0.01); vs. 345 +/- 67 (P < 0.001)], AVNRT cycle length [484 +/- 103 vs. 396 +/- 71 ms (P < 0.05); vs. 384 +/- 69 (P < 0.05)], and rate of AVNRT induction from ventricle [71% vs. 10% (P = 0.001); vs. 6% (P = 0.001)]. Differences were mostly not significant between group I and subgroup B. SP location and RFCA success rate were similar in all groups.

CONCLUSION

In a population of AVNRT patients, SDNC at AVNRT induction is infrequent and it prevails beyond the fifth decade of life and in females. SDNC is associated with peculiar AVN conduction features, which resemble the age-related modifications of AVN conduction.

A randomized, double-blind, placebo-controlled study of permanent cardiac pacing for the treatment of recurrent tilt-induced vasovagal syncope. The vasovagal syncope and pacing trial (SYNPACE)

AIMS

Recently, some studies revealed the efficacy of pacemaker implantation in decreasing recurrences in patients with vasovagal syncope. As these studies were not blinded or placebo-controlled, the benefits observed might have been due to a bias in the assessment of outcomes or to a placebo effect of the pacemaker. We performed a randomized, double-blind, placebo-controlled study in order to ascertain if pacing therapy reduces the risk of syncope relapse.

METHODS AND RESULTS

Twenty-nine patients (53 +/- 16 years; 19 women) with severe recurrent tilt-induced vasovagal syncope (median 12 syncopes in the lifetime) and 1 syncopal relapse after head-up tilt testing underwent implantation of a pacemaker, and were randomized to pacemaker ON or to pacemaker OFF. During a median of 715 days of follow-up, 8 (50%) patients randomized to pacemaker ON had recurrence of syncope compared to 5 (38%) of patients randomized to pacemaker OFF (p = n.s.); the median time to first syncope was longer in the pacemaker ON than in pacemaker OFF group, although not significantly so (97 [38-144] vs 20 [4-302] days; p = 0.38). There was also no significant difference in the subgroups of patients who had had a mixed response and in those who had had an asystolic response during head-up tilt testing.

CONCLUSION

Our data were unable to show a superiority of active pacing versus inactive pacing in preventing syncopal recurrence in patients with severe recurrent tilt-induced vasovagal syncope.

Comparative assessment of right, left, and biventricular pacing in patients with permanent atrial fibrillation

AIMS

Left ventricular (LV) and biventricular (BiV) pacing are potentially superior to right ventricular (RV) apical pacing in patients undergoing atrioventricular (AV) junction ablation and pacing for permanent atrial fibrillation.

METHODS AND RESULTS

Prospective randomized, single-blind, 3-month crossover comparison between RV and LV pacing (phase 1) and between RV and BiV pacing (phase 2) performed in 56 patients (70+/-8 years, 34 males) affected by severely symptomatic permanent atrial fibrillation, uncontrolled ventricular rate, or heart failure. Primary endpoints were quality of life and exercise capacity. Compared with RV pacing, the Minnesota Living with Heart Failure Questionnaire (LHFQ) score improved by 2 and 10% with LV and BiV pacing, respectively, the effort dyspnoea item of the Specific Symptom Scale (SSS) changed by 0 and 2%, the Karolinska score by 6 and 14% (P<0.05 for BiV), the New York Heart Association (NYHA) class by 5 and 11% (P<0.05 for BiV), the 6-min walked distance by 12 (+4%) and 4 m (+1%), and the ejection fraction by 5 and 5% (P<0.05 for both). BiV pacing but not LV pacing was slightly better than RV pacing in the subgroup of patients with preserved systolic function and absence of native left bundle branch block. Compared with pre-ablation measures, the Minnesota LHFQ score improved by 37, 39, and 49% during RV, LV, and BiV pacing, respectively, the effort dyspnoea item of the SSS by 25, 25, and 39%, the Karolinska score by 39, 42, and 54%, the NYHA class by 21, 25, and 30%, the 6-min walking distance by 35 (12%), 47 (16%), and 51 m (19%) and the ejection fraction by 5, 10, and 10% (all differences P<0.05).

CONCLUSIONS

Rhythm regularization achieved with AV-junction ablation improved quality of life and exercise capacity with all modes of pacing. LV and BiV pacing provided modest or no additional favourable effect compared with RV pacing.

Incidence, diagnostic yield and safety of the implantable loop-recorder to detect the mechanism of syncope in patients with and without structural heart disease

AIM

To evaluate the incidence, diagnostic yield and safety of implantable loop recorders (ILRs) in patients with or without structural heart disease (SHD).

METHODS AND RESULTS

Two-hospitals, observational, prospective study in consecutive patients with unexplained syncope who underwent an ILR implantation. Between November 1997 and December 2002, a total of 2052 patients with syncope were evaluated (referral population of 590000 inhabitants). The diagnosis remained unexplained in 371 (18%). Of these, 103 patients (5% of total, 28% of unexplained syncope) received an ILR. SHD was present in 38 (37%), and absent in 65 (63%). During a median follow-up of 13 months, syncope was recorded in 52 patients. While patients with and without SHD had similar incidence of syncope recurrence, its mechanism was different. Patients with SHD more frequently had paroxysmal AV block and tachyarrhythmias and patients without SHD more frequently had sinus bradycardia/sinus arrest or no arrhythmia. More patients with SHD finally received an ILR-guided therapy. Sudden death occurred in one patient with SHD. Five syncope-related injuries were noted in 3 patients.

CONCLUSION

The mechanism of syncope is different in patients with and without SHD; diagnostic yield and safety are similar in both groups. About 28% of patients with unexplained syncope have an indication to ILR implantation. The need for ILR implantation in the general population is 34 implants/million inhabitants/year.

Outcome after cavo-tricuspid isthmus ablation in patients with recurrent atrial fibrillation and drug-related typical atrial flutter

This study evaluates the long-term clinical outcome of 56 consecutive patients affected by atrial fibrillation and drug-related typical atrial flutter who underwent cavo-tricuspid isthmus radiofrequency ablation. Symptomatic arrhythmic events recurred after ablation in 64% of the patients during follow-up of 19 +/- 9 months. Even in those who had recurrences, there was a substantial reduction in the incidence of episodes, quality of life was improved, and hospitalizations decreased.

Efficacy and feasibility of isometric arm counter-pressure manoeuvres to abort impending vasovagal syncope during real life

AIMS

Isometric arm exercises are able to increase blood pressure during the phase of impending vasovagal syncope. We evaluated their efficacy and feasibility during daily life in a group of 29 consecutive patients affected by vasovagal syncopes.

METHODS

The patients were trained to use arm tensing and/or handgrip in case of occurrence of symptoms of impending syncope.

RESULTS

During 14+/-6 months of follow-up, 260 episodes of impending syncope were reported by 19 patients; the manoeuvres were self-administered by these patients in 98% of cases and were able to abort syncope in 99.6% of cases. Overall, 5 episodes of syncope occurred in 5 patients (17%), in 4 cases without and in 1 with activation of the manoeuvres. Syncope recurred in 4 (40%) of 10 patients aged >65 years versus only 1 (5%) of 19 patients aged < or =65 years, p=0.03. The non-responders had more episodes of impending syncope than responders (37+/-32 vs 3+/-4, p=0.001). Among 19 clinical variables, age in years was the only significant predictor of syncopal recurrence. No patients had injury or other adverse morbidity related to the relapses.

CONCLUSIONS

Isometric arm counter-pressure manoeuvres are able to abort impending vasovagal syncope in most patients aged < or =65 years. Arm counter-pressure manoeuvres are feasible, safe and well accepted by the patients in the daily life.

Clinical spectrum of neurally mediated reflex syncopes

AIMS

The clinical features of the various types of neurally mediated reflex syncope have not been systematically investigated and compared. We sought to assess and compare the clinical spectrum of neurally mediated reflex syncopes.

METHODS AND RESULTS

Four hundred sixty-one patients with syncope were prospectively evaluated and 280 had neurally mediated reflex syncope. Each patient was interviewed using a standard questionnaire. A cause of syncope was assigned using standardized diagnostic criteria. Typical vasovagal syncope was diagnosed in 39 patients, situational syncope in 34, carotid sinus syncope in 34, tilt-induced syncope in 142 and complex neurally mediated syncope (positive response to both carotid sinus massage and tilt test) in 31. The clinical features of situational, carotid sinus, tilt-induced and complex neurally mediated syncope were very similar. By contrast, typical vasovagal syncope differed from other neurally mediated syncopes not only in terms of its precipitating factors (fear, strong emotion, etc.), which constituted predefined diagnostic criteria, but also in the variety of its clinical features (lower age and prevalence of organic heart disease, higher prevalence of prodromal symptoms, and of autonomic prodromes, longer duration of prodromes, higher prevalence of symptoms during the recovery phase and lower prevalence of trauma).

CONCLUSION

The clinical spectrum of neurally mediated reflex syncopes demonstrates much overlap between them. However, when the afferent neural signals are localized in cortical sites, as in typical vasovagal syncope, symptoms are more frequent and of longer duration.

[How is syncope studied in the Italian hospitals?]

BACKGROUND

The aim of this study was to evaluate how the main tests for the diagnostic assessment of syncope are currently performed in the Italian hospitals.

METHODS

During the early 2003 dedicated questionnaires were administered to about 400 Italian hospitals. About each test information was requested relative to: test protocol, laboratory equipment, patients evaluated during 2002.

RESULTS

Eighty-four hospitals answered the questionnaire. A syncope-dedicated ambulatory (at least once a week) was available during 2002 in 59/84 hospitals, and 56 were dependent on the Cardiology Division. Carotid sinus massage was performed either in clinostatic and in orthostatic position in 60 Centers and was repeated after atropine in 15. To define the test positivity, 35 Centers followed the "symptom method". Only 15 Centers performed > 100 procedures during 2002 (range 3-500). Tilt testing was performed in 72 hospitals. A dedicated tilting bed was available in 65 Centers, continuous beat-to-beat pressure measurement in 22. Out of the 72 Centers, 55 followed the so-called "Italian protocol" as the main methodology of the test. Only 17 Centers performed > 100 procedures during 2002 (range 3-500). Adenosine test was performed in 26 hospitals, the median dose of drug was 18 mg (range 6-20 mg); 25 out 26 Centers considered the test as positive when an asystolic pause > or = 6 s was observed. Only 6 Centers performed > 15 procedures during 2002 (range 1-204). An implantable loop recorder was available in 48 Centers. The number of implant procedures during 2002 varied among the Centers from 1 to 22.

CONCLUSIONS

A great variability was observed concerning the methodology of each test and the number of procedures performed. Thus, a standardization effort about the methodology of syncope study is still needed by the medical associations.

The diagnostic value of ATP testing in patients with unexplained syncope

A minority of patients with unexplained syncope has an increased susceptibility to adenosine triphosphate (ATP) injection. In these 'hypersensitive' patients, owing to its powerful cardiac and hypotensive effects, endogenous adenosine released under physiological and pathological conditions could trigger bradycardia and/or hypotension and cause syncope. This hypothesis still needs to be proven. However, there is some evidence that the ATP test identifies a group of patients with otherwise unexplained syncope with definite clinical features, absence of structural heart disease and benign prognosis. The mechanism of syncope is heterogeneous; indeed, in cases of electrocardiographic documentation of spontaneous syncope, either a long ventricular pause (mainly due to paroxysmal atrioventricular (AV) block) or no rhythm variations or even tachycardia were documented. ATP-positive patients have clinical features and mechanisms of syncope which are different from tilt-positive patients. Owing to its low positive predictive value, the ATP test is of little value in selecting treatment. A favourable outcome suggests a strategy of postponing treatment, in particular pacemaker therapy, until a definite diagnosis can be made by documenting a spontaneous syncopal relapse.

Clinical and electrophysiological characteristics in patients with atrioventricular reentrant and atrioventricular nodal reentrant tachycardia

AIM

To compare clinical, electrophysiological characteristics and transcatheter ablation results between two groups of patients, one with atrioventricular reentrant tachycardia (AVRT) and the other with atrioventricular nodal reentrant tachycardia (AVNRT).

METHODS

The study population consisted of 94 consecutive patients who underwent endocavitary electrophysiological study and radiofrequency (RF) ablation: 46 patients had AVRT due to an accessory pathway with only retrograde conduction while 48 patients had AVNRT.

RESULTS

In relation to general and clinical characteristics, differences between the two groups emerged regarding the age of symptom onset (25+/-16 vs 37+/-17 years, p=0.001), the prevalence of heart disease (8 vs 31%, p=0.001) and the correct diagnosis on surface ECG (50 vs 79%, p=0.001). Clinical presentation was quite similar apart from a higher prevalence of fatigue and sweating in the AVNRT group. Transcatheter RF ablation therapy results were similar.

CONCLUSIONS

Patients with AVRT have a lower mean age at arrhythmia symptom onset compared with those with AVNRT and have fewer associated cardiac abnormalities. Clinical presentation is quite similar as well as their outcome after ablation. A correct diagnosis by standard ECG is more frequent in AVNRT.

Management of patients with syncope referred urgently to general hospitals

OBJECTIVE

To evaluate the incidence and the strategy of management of syncope admitted urgently to a general hospital.

BACKGROUND

The management of patients with syncope is not standardized.

METHODS

The study was a prospective observational registry from a sample of 28 general hospitals in Italy and enroled all consecutive patients referred to their emergency rooms from November 5th 2001 to December 7th 2001 who were affected by transient loss of consciousness as the principal symptom.

RESULTS

The incidence of syncope was 0.95% (996 of 105,173 patients attending). Forty-six percent were hospitalized, mostly in the Department of Internal Medicine. The mean in-hospital stay was 8.1+/-5.9 days. A mean of 3.48 tests was performed per patient. A definite diagnosis was made in 80% of cases, neurally-mediated syncope being the most frequent. The findings of each of the 28 hospitals participating in the survey were separately evaluated. We observed great inter-hospital and inter-department heterogeneity regarding the incidence of emergency admission, in-hospital pathways, most of the examinations performed and the final assigned diagnosis. For example, the execution of carotid sinus massage ranged from 0% in one hospital to 58% in another (median 12.5%); tilt testing ranged from 0 to 50% (median 5.8%); the final diagnosis of neurally-mediated syncope ranged from 10 to 78.6% (median 43.3%).

CONCLUSION

Great inter-hospital and inter-department heterogeneity in the incidence and management of syncope was observed in general hospitals. As a consequence, we were unable to describe a uniform strategy for the management of syncope in everyday practice.

Management of syncope referred urgently to general hospitals with and without syncope units

OBJECTIVE

We tested the hypothesis that management of patients with syncope admitted urgently to a general hospital may be influenced by the presence of an in-hospital structured syncope unit.

BACKGROUND

The management of syncope is not standardized. Methods We compared six hospitals equipped with a syncope unit organized inside the department of cardiology with six matched hospitals without such facilities. The study enroled all consecutive patients referred to the emergency room from 5 November 2001 to 7 December 2001 who were affected by transient loss of consciousness as their principal symptom.

RESULTS

There were 279 patients in the syncope unit hospitals and 274 in the control hospitals. In the study group, 30 (11%) patients were referred to the syncope unit for evaluation. In the study group, 12% fewer patients were hospitalized (43 vs 49%, not significant) and 8% fewer tests were performed (3.3+/-2.2 vs 3.6+/-2.2 per patient, not significant). In particular, the study group patients underwent fewer basic laboratory tests (75 vs 86%, P=0.002), fewer brain-imaging examinations (17 vs 24%, P=0.05), fewer echocardiograms (11 vs 16%, P=0.04), more carotid sinus massage (13 vs 8%, P=0.03) and more tilt testing (8 vs 1%, P=0.000). In the study group, there was a +56% rate of final diagnosis of neurally mediated syncope (56 vs 36%, P=0.000).

CONCLUSION

Although only a minority of patients admitted as an emergency are referred to the syncope unit, overall management is substantially affected. It is speculated that the use of a standardized approach, such as that typically adopted in the syncope unit, is able to influence overall practice in the hospital.

Mechanism of syncope in patients with positive adenosine triphosphate tests

OBJECTIVES

We prospectively evaluated the mechanism of syncope in patients with positive adenosine triphosphate (ATP) tests (defined as the induction of atrioventricular [AV] block with a ventricular pause >/=6 s after an intravenous bolus of 20 mg ATP).

BACKGROUND

Patients with unexplained syncope tend to have more positive ATP tests results than those without syncope.

METHODS

An implantable loop recorder (ILR) was inserted in 36 ATP-positive patients (69 +/- 10 years; 22 women; median of 6 syncopal episodes); 15 of them also had a positive response to tilt testing.

RESULTS

During the follow-up of 18 +/- 9 months, 18 patients (50%) had syncopal recurrence and 16 (44%) had an electrocardiographically documented episode: AV block (n = 3: paroxysmal in 2 and permanent in 1), AV block followed by sinus arrest (n = 1), sinus arrest (n = 5), sinus bradycardia <40 beats/min (n = 2), normal sinus rhythm (n = 2), sinus tachycardia (n = 1), rapid atrial fibrillation (n = 1), and ectopic atrial tachycardia (n = 1). Bradycardia was documented in a total of 11 cases (69%), and a long ventricular pause (4 to 29 s) was present in eight cases (50%). All three patients with ILR-documented AV block had previously had a negative tilt test, whereas seven of eight with ILR-documented sinus bradycardia or sinus arrest had previously had a positive tilt test.

CONCLUSIONS

In patients with adenosine-sensitive syncope, the mechanism of syncope is heterogeneous, although bradycardia is the most frequent finding. Adenosine triphosphate-induced AV block predicts AV block as the mechanism of spontaneous syncope in only a few tilt-negative patients.

Isometric arm counter-pressure maneuvers to abort impending vasovagal syncope

OBJECTIVES

We hypothesized that isometric arm exercises were able to increase blood pressure (BP) during the phase of impending vasovagal syncope and allow the patient to avoid losing consciousness.

BACKGROUND

Hypotension is always present during the prodromal phase of vasovagal syncope.

METHODS

We evaluated the effect of handgrip (HG) and arm-tensing in 19 patients affected by tilt-induced vasovagal syncope. The study consisted of an acute single-blind, placebo-controlled, randomized, cross-over tilt-table efficacy study and a clinical follow-up feasibility study.

RESULTS

In the acute tilt study, HG was administered for 2 min, starting at the time of onset of symptoms of impending syncope. In the active arm, HG caused an increase in systolic blood pressure (SBP) from 92 +/- 10 mm Hg to 105 +/- 38 mm Hg, whereas in the placebo arm SBP decreased from 91 +/- 11 mm Hg to 73 +/- 21 mm Hg (p = 0.008). Heart rate behavior was similar in the two arms. In the active arm, 63% of patients became asymptomatic, versus 11% in the control arm (p = 0.02); conversely, only 5% of patients developed syncope, versus 47% in the control arm (p = 0.01). The patients were trained to self-administer arm-tensing treatment as soon as symptoms of impending syncope occurred. During 9 +/- 3 months of follow-up, the treatment was actually performed in 95/97 episodes of impending syncope (98%) and was successful in 94/95 (99%). No patients suffered injury or other adverse morbidity related to the relapses.

CONCLUSIONS

Isometric arm contraction is able to abort impending vasovagal syncope by increasing systemic BP. Arm counter-pressure maneuvers can be proposed as a new, feasible, safe, and well accepted first-line treatment for vasovagal syncope.

A standardized conventional evaluation of the mechanism of syncope in patients with bundle branch block

BACKGROUND

The finding of bundle branch block in patients with syncope suggests that paroxysmal AV block may be the cause of syncope, even though its prevalence is unknown.

METHODS

We evaluated 55 consecutive patients with syncope and bundle branch block (mean age 75 +/- 8 years; median of two syncopal episodes per patient) referred to three Syncope Units. The hierarchy and appropriateness of diagnostic tests and the definitions of the final diagnoses followed standardized predefined criteria.

RESULTS

Cardiac syncope was diagnosed in 25 patients (45%): AV block in 20, sick sinus syndrome in 2, sustained ventricular tachycardia in 1, aortic stenosis in 2. Neurally mediated syncope was diagnosed in 22 (40%): carotid sinus syndrome in 5, tilt-induced syncope in 15, adenosine-sensitive syncope in 2. Syncope remained unexplained in 8 (15%).

CONCLUSIONS

Less than half of the patients with bundle branch block have a final diagnosis of cardiac syncope; in these patients, paroxysmal AV block is the most frequent but not the only mechanism supposed.

The application of a standardized strategy of evaluation in patients with syncope referred to three syncope units

BACKGROUND

The appropriate diagnostic work-up of patients with syncope is not well defined. We applied the guidelines of Italian 'Associazione Nazionale Medici Cardiologi Ospedalieri' to a group of consecutive patients with syncope referred to three Syncope Units. The aim of the study was to evaluate the applicability of those guidelines in the 'real world' and their impact on the use of the tests.

METHODS

We evaluated 308 consecutive patients with syncope (mean age 61 +/- 20 years; median of three syncopal episodes per patient). The hierarchy and appropriateness of diagnostic tests and the definitions of the final diagnosis followed standardized predefined criteria. In brief, all patients underwent initial evaluation consisting of history, physical examination, supine and upright blood pressure measurement and standard electrocardiogram (ECG) (only in patients > 45 years or with history of heart disease). Any subsequent investigations were based on the findings of the initial evaluation. Priority was given to cardiological tests (prolonged ECG monitoring, exercise test, electrophysiological study), or to neurally mediated tests (carotid sinus massage, tilt test, ATP test), or to neuro-psychiatric tests, as appropriate.

FINDINGS

The initial evaluation alone was diagnostic in 72 patients (23%). One further test was necessary for diagnosis in 65 patients (21%), > or = 2 tests in 64 (21%) and > or = 3 tests in 50 (16%). The diagnostic yield was 10% for ECG, 3% for echocardiogram, 16% for Holter, 5% for exercise test, 27% for electrophysiological study, 57% for carotid sinus massage, 52% for tilt testing and 15% for ATP test. At the end of the work-up the mechanism of syncope remained unexplained in 57 patients (18%).

CONCLUSIONS

When standardized criteria based on the appropriateness of indications are used, few simple tests are usually needed for diagnosis of syncope.