Is His-optimized superior to conventional cardiac resynchronization therapy in improving heart failure? Results from a propensity-matched study.

BACKGROUND: His bundle pacing (HBP), alone or optimized in association with coronary sinus pacing (HBP+LV) has recently been proposed as an alternative to conventional cardiac resynchronization therapy (CRT). However, there is lack of controlled studies that assessed clinical outcome. METHODS: We did a single-center, propensity-score matched, case-control study of comparison of HBP and HBP+LV versus conventional CRT in patients with heart failure (HF) and standard indications for CRT. The study group patients were consecutively enrolled in the year 2019. The control group patients were selected, by propensity score matching, among those CRT implantations performed in the years 2015-2018. RESULTS: There were 27 patients in each group. In the active group, 12 (44%) patients received HBP alone and 12 (44%) patients HBP+LV pacing. HBP failed in three (11%) patients. In the control group, conventional CRT was achieved in 26 (96%) patients and failed in one. Paced QRS width was shorter in the active than in the control group (128 ± 18 vs. 148 ± 27 ms, p = .004). During a mean of 9.6 months of follow-up, a composite clinical outcome of death, hospitalization for HF or worsening HF occurred in three (11%) in the active group and in four (15%) in the control group, p = .58. No difference was also observed with softer endpoints: NYHA class (1.9 ± 0.7 vs. 2.1 ± 0.7), subjective improvement (74% vs. 74%) and LV ejection fraction (40.7% vs. 40.7%). CONCLUSION: Compared with conventional CRT, a shorter QRS width can be obtained with HBP alone or in association with coronary sinus pacing but we were unable to show a better clinical outcome. There is urgent need for large, randomized trials.

Left bundle branch area pacing in a young athlete with progressive cardiac conduction (Lev-Lenegre) disease.

We present the case of a professional soccer player affected by right bundle branch block and symptomatic 2:1 atrio-ventricular block during effort, due to progressive cardiac conduction disease (Lev-Lenegre disease), who received successful left bundle branch area pacing after a failed attempt at His bundle pacing. The electrocardiographic outcome of paced QRS was consistent with a rapid electrical activation of the left ventricle through the Purkinje system. The pursue of physiological pacing was preferred over conventional, given the young age of our patient and the expectedly high burden of stimulation, to reduce the long-term risk of pacing-induced cardiomyopathy.

The relationship between anatomy and electrical parameters in His bundle pacing: A transthoracic echocardiography evaluation.

PURPOSE: The implantation site of the His bundle (HB) lead may influence pacing parameters. Our aim was to characterize the anatomical location of the HB lead tip and its relationship with acute electrical parameters. METHODS: Consecutive patients who underwent HB lead implantation, guided by standard fluoroscopy and electrophysiology, were prospectively enrolled. The relationship between HB lead tip and tricuspid valve plane (TVP) was assessed with post-procedure transthoracic echocardiography. RESULTS: Twenty-five patients were studied. In 11 patients (44%), the HB lead tip did not cross the TVP (A group): in 7 cases it was screwed in the right atrium at a mean distance of -6.1 mm from the TVP and, in 4 cases, at the level of the tricuspid annulus. In the remaining 14 patients (56%), the lead tip crossed the TVP (V group): it was screwed in the right ventricle at a mean distance of 9.3 mm from the TVP. A and V groups had comparable HB capture thresholds (1.6 ± 1 V vs 1.7 ± 0.7 V, 1 ms pulse-width; p = 0.66); selective HB capture was significantly more represented in the A group (91% vs 21%; p = 0.001). Significantly higher R-wave amplitudes were seen in the V group (6.7 ± 3 vs 2.5 ± 1.7 mV; p = 0.0004), and they positively correlated with the distance from the TVP (p = 0.0038). Atrial oversensing was never observed. CONCLUSION: In a consecutive cohort of HB pacing recipients, the rate of patients who had an effective HB capture in the atrium was substantial and was characterized by different electrophysiological properties than in the ventricle.

Additional benefits of nonconventional modalities of cardiac resynchronization therapy using His bundle pacing.

INTRODUCTION: Dyssynchrony persists in many patients despite cardiac resynchronization therapy (CRT). Aim of this proof-of-concept study was to achieve better CRT, with a QRS approximating the normal width and axis, by using His bundle pacing (HBP) and nonconventional pacing configurations. METHODS AND RESULTS: In 20 patients with CRT indications, we performed an acute intrapatient comparison between conventional biventricular (CONV) and three nonconventional pacing modalities: HBP alone, His bundle, and coronary sinus pacing (HBP + CS), and HBP + CS plus right ventricular pacing (TRIPLE). Electrical dyssynchrony was assessed by means of QRS width and axis; "quasi-normal" axis meant an R/S ratio ≥ 1 in leads I and V6 and ≤1 in V1. Mechanical dyssynchrony was assessed by speckle tracking echocardiography. QRS width was 153 ± 18 ms on CONV, shortened to 137 ± 16 ms on HBP + CS (P = .001) and to 130 ± 14 ms on TRIPLE (P = .001), while it remained unchanged on HBP (159 ± 32 ms; P = .17). The rate of patients with "quasi-normal" axis was 5% on CONV, and increased to 90% on HBP (P = .0001), to 63% on HBP + CS (P = .001), and to 44% on TRIPLE (P = .02). On radial strain analysis, the time-to-peak difference between anteroseptal and posterolateral segments was 143 ± 116 ms on CONV, shortened to 121 ± 127 ms on HBP (P = .79), to 67 ± 70 ms on HBP + CS (P = .02), and to 76 ± 55 ms on TRIPLE (P = .05). On discharge, HBP was chosen in 15% of patients, HBP + CS in 55%, and TRIPLE in 30%; CONV was never chosen. CONCLUSION: Nonconventional modalities of CRT provide acute additional electrical and mechanical resynchronization. An interpatient variability exists.

Complementary effectiveness of carotid sinus massage and tilt testing for the diagnosis of reflex syncope in patients older than 40 years: a cohort study.

AIMS: Indications, methodology, and diagnostic criteria for carotid sinus massage (CSM) and tilt testing (TT) have been standardized by the 2018 Guidelines on Syncope of the European Society of Cardiology. Aim of this study was to assess their effectiveness in a large cohort which reflects the performance under 'real-world' conditions. METHODS AND RESULTS: We analysed all patients who had undergone CSM and TT in the years 2003-2019 for suspected reflex syncope. Carotid sinus massage was performed according to the 'Method of Symptoms'. Tilt testing was performed according to the 'Italian protocol' which consists of a passive phase followed by a sublingual nitroglycerine phase. For both tests, positive test was defined as reproduction of spontaneous symptoms in the presence of bradycardia and/or hypotension. Among 3293 patients (mean age 73 ± 12 years, 48% males), 2019 (61%) had at least one test positive. A bradycardic phenotype was found in 420 patients (13%); of these, 60% were identified by CSM, 37% by TT, and 3% had both test positive. A hypotensive phenotype was found in 1733 patients (53%); of these, 98% were identified by TT and 2% had both TT and CSM positive. CONCLUSION: The overall diagnostic yield of the tests in patients >40-year-old with suspected reflex syncope was 61%. Both CSM and TT are useful for identifying those patients with a bradycardic phenotype, whereas CSM has a limited value for identifying the hypotensive phenotype. Since the overlap of responses between tests is minimal, both CSM and TT should be performed in every patient over 40 years receiving investigation for unexplained but possible reflex syncope.

Reproducibility of carotid sinus massage.

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

Optimization of coronary sinus lead placement targeted to right-to-left delay in patients undergoing cardiac resynchronization therapy.

AIMS: Anatomical placement of the coronary sinus (CS) lead in basal or mid-ventricular positions of the posterior and lateral walls is associated with a better clinical outcome of cardiac resynchronization therapy (CRT). We hypothesized that optimization of CS lead placement targeted the right-to-left electrical delay (RLD) predicts an additional clinical benefit. METHODS AND RESULTS: The CS lead was placed according to current standards in 90 patients (Conventional group) and at the site of the longest RLD in 121 patients (RLD group). Non-responders were defined as those who died or underwent hospitalization for heart failure or did not improve in their Clinical Composite Score within 6 months. There were 67 (32%) non-responders. Compared with Conventional group, the final CS pacing site was more frequently in the basal segments in the RLD group (40% vs. 23%, P = 0.007); moreover, the RLD ratio (%RLD) of the total QRS width was longer (77 ± 13 vs. 73 ± 15, P = 0.05) and biventricular QRS shortened more from the baseline (-31 ± 21 ms vs. -21 ± 26 ms, P = 0.004). Nevertheless, the rate of non-responders was similar in the RLD and Conventional groups (35% vs. 28%, P = 0.30), as was %RLD (76 ± 16 vs. 75 ± 13, P = 0.66). QRS width during right ventricular (RV) pacing was an independent predictors of adverse outcome, with a 2% increase in the risk of failure for each 1 ms increase in QRS (P = 0.006). CONCLUSION: Optimization of CS lead placement targeted to latest electrical activation does not provide additional clinical benefit to anatomical placement in basal or mid-ventricular positions of the posterior and lateral walls. QRS width during RV pacing was a strong predictor of CRT failure. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov. Unique identifier: NCT03204864.

Optimization of coronary sinus lead placement targeted to the longest right-to-left delay in patients undergoing cardiac resynchronization therapy: The Optimal Pacing SITE 2 (OPSITE 2) acute study and protocol.

AIMS: Left ventricular (LV) lead positioning at the site of delayed electrical activation is associated with better response to cardiac resynchronization therapy (CRT). We hypothesized that a long electrical conduction delay between right ventricular (RV) and coronary sinus (CS) leads during RV pacing (RLD index) is correlated with a better clinical outcome METHODS AND RESULTS: RLD is measured intraprocedurally, during RV pacing, as the time interval between the intracardiac electrograms of RV and CS leads. Initially, we did a prove-of-concept, feasibility, acute study in 97 patients who underwent CRT implantation. The CS lead position was assessed in the 40° right anterior oblique and 40° left anterior oblique views and assigned to one of 11 prespecified segments of a schematic eyeball depiction of the LV walls. Acute outcomes were QRS width during biventricular (BIV) pacing. The longest RLD were found in the basal and mid lateral segments; these accounted for 82% and 78%, respectively, of the total QRS width (%RLD). %RLD was inversely correlated with BIV-paced QRS (P  =  0.0001). A similar slope was present either in the 78 patients with preserved atrioventricular (AV) conduction and in the 19 without AV conduction (- 0.34 vs - 0.27, P  =  0.7). CONCLUSION: We showed that RLD can be used to guide lead placement at the time of CRT implantation and that it is correlated with BIV-QRS width, an indirect predictor of clinical outcome. Based on these findings we started the prospective, multicenter Optimal Pacing SITE 2 (OPSITE 2) trial with the objective to demonstrate a relationship between RLD and clinical outcomes assessed as death, hospitalization for heart failure, New York Heart Association class, and clinical composite score. The protocol is provided.

Long-Term Results After Single and Multiple Procedures of Ablation of Ventricular Tachycardia.

INTRODUCTION: The aim of this study was to assess long-term results after single and multiple procedures of catheter ablation of ventricular tachycardia (VT). While it is generally accepted that multiple procedures are sometimes necessary in order to achieve long-term clinical success, the literature on this issue displays wide variability. METHODS: We assessed the outcome of 160 consecutive patients who underwent 214 ablation procedures in the period 2008 to May 2015: 93 had overt structural heart disease (SHD) (previous myocardial infarction in 74 cases) and 67 had no SHD. RESULTS: After the first procedure, the 1-year actuarial recurrence rates were 25% in patients with SHD and 5% in those without. However, recurrences increased progressively after the first year, reaching 46% and 35%, respectively, at 5 years. Overall, VT recurred in 35/93 (38%) patients with SHD and 22/67 (33%) patients without. Redo (1 to 4) procedures were performed in 28 (20%) patients with SHD and 18 (27%) patients without. After the last procedure, the 1-year actuarial recurrence rates were 5% in patients with SHD and 7% in those without, and the corresponding rates at 5 years were 23% and 7%. During follow-up, 21 patients died (all in the SHD group): no death was related to VT recurrence. CONCLUSIONS: During long-term follow-up, VT frequently recurs after the first procedure, both in patients with SHD and in those without; multiple procedures are needed in order to increase the success rate.

Syncope in patients paced for atrioventricular block.

AIMS: Although syncope is the main reason for cardiac pacing in ∼40% of patients affected by atrioventricular block (AVB), very few data are available on the benefit of cardiac pacing in preventing syncopal recurrences. METHODS AND RESULTS: We retrospectively evaluated 229 consecutive patients (124 males, age 80 ± 10 years) who had received a permanent pacemaker from January 2009 to December 2013 for AVB and syncope (94 patients, 41%) or AVB without syncope (135 patients, 59%). In patients with AVB and syncope, a third-degree or Mobitz II second-degree AVB had been documented in 73 and was only suspected in another 21, all of whom had bundle branch block. Follow-up was available in 223 patients. At 5 years, the actuarial syncope recurrence rate was 1% (95% CI, 0-3) in patients with documented AVB plus syncope and 3% (95% CI, 1-5) in those without syncope, whereas it was 14% (95% CI, 0-28) in patients with undocumented AVB plus syncope (P = 0.001). The actuarial combined recurrence rate of syncope and/or pre-syncope was 2% (95% CI, 0-4) in patients without syncope, 8% (95% CI, 0-17) in patients with documented AVB plus syncope, and 19% (95% CI, 1-37) in patients with undocumented AVB plus syncope, P = 0.002. All syncopes occurred in patients without overt structural heart disease (SHD), the corresponding actuarial estimate being 4% (95% CI, 0-6) at 1 year and 6% (95% CI, 4-8) at 5 years (P = 0.002 vs. patients with SHD). CONCLUSIONS: Cardiac pacing is highly effective in preventing syncopal recurrences when AVB is documented. Syncope may recur in a non-negligible minority of paced patients when AVB is suspected but not documented and in patients without SHD.

Long-Term Outcome of Patients with Bifascicular Block and Unexplained Syncope Following Cardiac Pacing.

BACKGROUND: According to the ACC/AHA/HRS guidelines, cardiac pacing is reasonable in patients with bifascicular block (BF-B) and syncope when other causes have been excluded. The purpose of this study was to assess the long-term outcome of patients with BF-B and unexplained syncope following cardiac pacing. METHODS AND RESULTS: Between 2009 and 2015, we identified 43 consecutive patients (mean age of 78 ± 12 years, 64% males) who presented with syncope and BF-B and had received a pacemaker (PM). During a mean follow-up period of 31 ± 21 months, syncope recurred in seven patients (16%): 7% (95% standard error [SE] ± 3%) at 1 year and 18% (95% SE ± 7%) at 5 years. At univariable analysis, the only predictor of syncope recurrence was empiric pacing (P = 0.03). There were no syncope recurrences in the 12 patients who received a PM following a positive electrophysiological study (EPS) and the five patients with documentation of paroxysmal atrioventricular block (AVB) during cardiac monitoring (insertable loop recorder [ILR]), (EPS/ILR Group, n = 17) compared to seven of 26 (27%) patients who received empiric pacing (Empiric Group, n = 26; P = 0.02). Progression to high-degree AVB was documented during follow-up in 16 (37%) patients: nine of 17 (53%) patients in the EPS/ILR Group and seven of 26 (27%) patients in the Empiric Group (P = 0.11). There were no injuries reported during ILR monitoring. CONCLUSIONS: We have shown that syncope recurs not infrequently in patients with BF-B who received pacing for syncope. Nearly one in four patients who had empiric pacing suffered syncope recurrence compared to no recurrences in patients who received a PM following a positive EPS or documentation of transient AVB.

Clinical context and outcome of carotid sinus syndrome diagnosed by means of the 'method of symptoms'.

AIMS: The prevalence and outcome of carotid sinus syndrome (CSS) reported in the literature vary owing to differences in indications and methods of carotid sinus massage (CSM). METHODS AND RESULTS: We performed CSM on all patients aged 40 years and above with unexplained syncope after the initial evaluation. Carotid sinus massage was performed in the supine and standing positions on both sides for 10 s during continuous electrocardiogram and blood pressure monitoring; CSS was diagnosed in the event of an abnormal response to CSM in association with reproduction of spontaneous symptoms ('method of symptoms'). From July 2005 to July 2012, CSS was found in 164 (8.8%) of 1855 patients (mean age 77 ± 9 years, 73% males): 81% had an asystolic reflex (mean pause 7.6 ± 2.2 s) and 19% a vasodepressor reflex (mean lowest systolic blood pressure 65 ± 15 mmHg). Potential multifactorial causes of syncope (orthostatic hypotension, bundle branch block, bradycardia, tachyarrhythmias) were found in 74% of patients. One hundred forty-one patients received the proper care [advice on lifestyle measures in all, discontinuation (#40) or reduction (#17) of antihypertensive drugs, pacemaker implantation (#57)] and were followed up for 39 ± 25 months. Syncope recurred in 23 patients; the actuarial syncopal recurrence rate was 7% at 1 year and 26% at 5 years. Total syncopal episodes decreased from 91 per year during the 2 years before evaluation to 21 episodes per year during follow-up (P = 0.001). On Cox proportional-hazards regression, a mixed or vasodepressor response to tilt testing was the only independent predictor of syncopal recurrence (hazard ratio = 1.8; P = 0.01). CONCLUSION: Carotid sinus massage by means of the 'method of symptoms' indentifies a clinical syndrome with definite features and outcome. A treatment strategy involving lifestyle measures, reduction of antihypertensive drugs and cardiac pacing when appropriate is effective in reducing the syncopal recurrence rate.

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).

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.

Resynchronization of the left ventricular contraction by tailored programming of right and left ventricular pacing.

AIMS: The prerequisite and the rationale for the benefit of cardiac resynchronization therapy (CRT) is that it is able to resynchronize left ventricular (LV) walls that have a delayed activation. METHODS AND RESULTS: In 69 consecutive patients who underwent biventricular (BIV) pacemaker implantation, we assessed the magnitude of intraventricular resynchronization achieved by means of simultaneous (BIV 0) and sequential BIV pacing (with an individually optimized VV interval value among +80 ms and -80 ms) using pulsed-wave tissue Doppler imaging techniques and in particular the measurement of the intra-LV electromechanical delay. The intra-LV delay was defined as the difference between the longest and the shortest activation time in the six basal segments of the LV. An abnormal intra-LV delay was defined as a value >41 ms. The intra-LV delay was 63 +/- 28 ms baseline, decreased to 44 +/- 26 ms with BIV 0 and to 26 +/- 15 ms with optimized BIV (P = 0.001). BIV 0 determined the shortest delay in 28 (41%) patients (23 +/- 12 ms). In 41 (59%) patients, a better resynchronization was achieved with optimized VV intervals (LV first in 32 and RV first in 5) or single-chamber pacing (LV in 3 and RV in 1). With BIV 0, the intra-LV delay remained abnormal in 41% and was longer than baseline in 30% of patients compared with 9 and 12% with optimized BIV, respectively (P = 0.001). CONCLUSION: A sub-optimal resynchronization is achieved with simultaneous BIV pacing in most patients. A tailored programming of the relative contribution of RV and LV pacing forms the prerequisite for improving CRT results.

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.

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.

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.