Clinical implementation of cardiac resynchronization therapy-regional disparities across selected ESC member countries.

BACKGROUND: The present analysis aimed to estimate the penetration of cardiac resynchronization therapy (CRT) on the basis of the prevalence and incidence of eligible patients in selected European countries and in Israel. METHODS AND RESULTS: The following countries were considered: Italy, Slovakia, Greece, Israel, Slovenia, Serbia, the Czech Republic, Poland, Romania, Hungary, Ukraine, and the Russian Federation. CRT penetration was defined as the number of patients treated with CRT (CRT patients) divided by the prevalence of patients eligible for CRT. The number of CRT patients was estimated as the sum of CRT implantations in the last 5 years, the European Heart Rhythm Association (EHRA) White Book being used as the source. The prevalence of CRT indications was derived from the literature by applying three epidemiologic models, a synthesis of which indicates that 10% of heart failure (HF) patients are candidates for CRT. HF prevalence was considered to range from 1% to 2% of the general population, resulting in an estimated range of prevalence of CRT indication between 1000 and 2000 patients per million inhabitants. Similarly, the annual incidence of CRT indication, representing the potential target population once CRT has fully penetrated, was estimated as between 100 and 200 individuals per million. The results showed the best CRT penetration in Italy (47-93%), while in some countries it was less than 5% (Romania, Russian Federation, and Ukraine). CONCLUSION: CRT penetration differs markedly among the countries analyzed. The main barriers are the lack of reimbursement for the procedure and insufficient awareness of guidelines by the referring physicians.

Level of patient and operator dose in the largest cardiac centre in Greece.

The objective of this study was to investigate the patient and staff doses in the most frequent interventional cardiology (IC) procedures performed in Onassio, the largest Cardiac Centre in Greece. Data were collected from three digital X-ray systems for 212 coronary angiographies, 203 percutaneous transluminal coronary angioplasties (PTCA) and 134 various electrophysiological studies. Patient skin dose was measured using suitably calibrated slow radiotherapy films and cardiologist dose using suitably calibrated thermoluminescent dosemeters placed on left arm, hand and foot. Patient median dose area product (DAP) (all examinations) ranged between 6.7 and 83.5 Gy cm2. Patient median skin dose in PTCA was 799 mGy (320-1660 mGy) and in RF ablation 160 mGy (35-1920 mGy). Median arm, hand and foot dose to the cardiologist were 12.6, 27 and 13 microSv, respectively, per procedure. The great range of radiation doses received by both patients and operators confirms the need for continuous monitoring of all IC techniques.

Cryoablation for atrial fibrillation and antiarrhythmic drug pretreatment: a single referral center experience.

OBJECTIVE: Pulmonary vein isolation (PVI) ablation has emerged as the gold standard of ablative strategies to treat medically refractory paroxysmal and persistent atrial fibrillation (AF). Regardless of the superiority of catheter ablation based on PVI over antiarrhythmic drug therapy, recurrence rates of AF remain higher than desired. PVI via cryoablation has rapidly become a mainstream treatment for AF, due to its effectiveness and fast learning curve. Our objective was to assess the safety and efficacy of cryoablation in a single referral center. PATIENTS AND METHODS: This is a retrospective analysis of results after cryoablation treatment of AF over three years. 146 patients with AF underwent a cryoablation procedure in our clinical center and were followed-up for three years after the procedure. All patients received cryoablation of the pulmonary veins, although concomitant procedures were performed in 6 patients (re-ablation), including radiofrequency and cryoablation. RESULTS: Cryoablation was clinically successful in 90.83% of the patients with paroxysmal AF and 60% of those with persistent AF. The clinical success of cryoablation was correlated with pretreatment with amiodarone and in the case of re-ablation. Concerning postoperative complications, major bleeding was correlated with female gender, treatment with rivaroxaban and amiodarone. CONCLUSIONS: Among large trials, freedom from recurrent AF is about 65% with follow-up limited to 1 to 2 years. PVI via balloon cryoablation is a safe and efficient guideline-based treatment for AF, producing a durable event-free result in most patients out to 3 years with better outcomes than previously reported.

Methodology of head-up tilt testing in patients with unexplained syncope.

Prolonged 60 degree head-up tilt has been shown to be valuable in the investigation of unexplained syncope, diagnosing neurally mediated bradycardia/hypotension or malignant vasovagal syndrome. To evaluate the methodology of tilt testing, the following were examined: reproducibility of results, tilt duration, angle of tilt, method of tilt support and effect of age in patients and control subjects. Seventy-one patients with recurrent unexplained syncope underwent 60 min of 60 degree tilt; 53 (75%) had an abnormal test with vasovagal syncope at 24 +/- 10 min (mean +/- SD). Tilting to 60 degrees resulted in an abnormal test in only 2 (7%) of 27 control subjects without cardiovascular symptoms (p less than 0.001); and 5 (15%) of 34 patients with syncope and documented conduction tissue disease (p less than 0.001). Of 15 youthful fainters, 3 (20%) had vasovagal reactions as did 1 (8%) of 12 asymptomatic youthful control subjects. These 12 control subjects also underwent tilting with a saddle support and 7 (67%) had vasovagal reactions. It is concluded that the duration of tilting at 60 degrees should be 45 min (mean time to syncope +2 x SD in the 53 patients with abnormal results). Twenty percent of patients with an abnormal tilt test may not demonstrate syncope with repeat tilting. Saddle tilt testing in unexplained syncope may result in a loss of specificity. Tilting at less than 60 degrees results in a loss of sensitivity. Head-up tilt may be less useful in youthful subjects with vasovagal syncope than in other subjects.

Provocation of neurocardiogenic syncope by clomipramine administration during the head-up tilt test in vasovagal syndrome.

OBJECTIVES: We sought to test the hypothesis that activation of the serotonergic system in patients with vasovagal syndrome during the head-up tilt test provokes syncope. BACKGROUND: Central serotonergic activation participates in the pathogenesis of neurocardiogenic syncope. Drugs increasing serotonin (5-HT) in the central nervous system have not been tested as drug challenges during the head-up tilt test with clomipramine (Clom-HUT). METHODS: The serotonergic re-uptake inhibitor clomipramine was infused (5 mg in 5 min) at the start of Clom-HUT in 55 patients (mean age 40 +/- 17 years) with a positive history of recurrent neurocardiogenic syncope and in 22 healthy control subjects (mean age 46 +/- 15 years). Blood samples were taken at 0, 5, 10 and 20 min for estimation of plasma prolactin and cortisol as neuroendocrine indicators of central serotonergic responsivity. All subjects had been previously tested with a basic 60 degrees head-up tilt test (B-HUT) for 30 min, and if negative, isoproterenol infusion was given at the end of the test. RESULTS: Twenty-nine (53%) of the 55 patients and none of the 22 control subjects had a positive result in the B-HUT. With Clom-HUT, the proportion of patients who experienced a positive response increased to 80% (n = 44), although this happened to only one control subject. Prolactin and cortisol plasma levels increased significantly in the positive Clom-HUT patient group only. CONCLUSIONS: The results indicate an increased responsivity of the central serotonergic neural system in subjects with vasovagal syndrome, the activation of which leads to sympathetic withdrawal. The use of clomipramine infusion with the tilt test seems to considerably improve its diagnostic value.

Decreased post-myocardial infarction heart rate variability and cardiac denervation assessed by metaiodobenzylguanidine scintigraphy.

Decreased heart rate variability, assessed 2 weeks after uncomplicated acute myocardial infarction, is related to the extent of 1-123-metaiodobenzylguanidine-derived efferent sympathetic cardiac denervation. This postinfarction cardiac denervation could be the substrate of reduced postinfarction heart rate variability.

Hormonal responses during tilt-table test in neurally mediated syncope.

The hormonal profile during tilt testing was examined in syncopal patients. An increase in the growth hormones cortisol and prolactin was found during syncope, suggesting an implication of central serotonergic activation.

Cardiac denervation after radiofrequency ablation of supraventricular tachycardias.

Inappropriate sinus tachycardia and atrial arrhythmias have been reported after radiofrequency ablation. Previous studies have suggested that cardiac denervation is a possible explanation for these rhythm disturbances. The aim of this study was to investigate possible alterations in autonomic innervation of the heart after ablation using the techniques of heart rate variability (HRV) analysis and metaiodobenzylguanidine (I-123 MIBG) scintigraphy. The subjects of this study were 30 consecutive patients aged 25 to 40 years, without structural heart disease, who underwent radiofrequency ablation of atrioventricular nodal slow pathways, and posteroseptal and left lateral accessory pathways because of symptomatic recurrent reentrant tachycardias. Time and frequency domain analysis of HRV after ablation revealed a significant reduction in the indexes of the mean of all 5-minute standard deviation of RR intervals (p = 0.042), low frequency (p = 0.0005), and total frequency (p = 0.008) compared with preablation values in the group of patients who underwent atrioventricular nodal slow pathway ablation. Patients who underwent ablation of a posteroseptal accessory pathway also had significant attenuation of the indexes of standard deviation about the mean RR interval (p = 0.03), standard deviation of 5-minute mean RR intervals (p = 0.006), and low-frequency (p <0.0001), and high-frequency (p <0.0001) components. Significant I-123 MIBG map defects, indicating efferent cardiac sympathetic denervation, were also found in the same groups of patients: atrioventricular nodal group (p = 0.0024), posteroseptal accessory pathway group (p = 0.0007). None of the above changes in HRV and 123-I MIBG scintigraphy were seen in patients who underwent ablation of left lateral accessory pathways. We conclude that radiofrequency ablation in the anterior, mid-, and posterior regions of the low intraatrial septum may disrupt sympathetic fibers located in these regions, causing cardiac sympathetic denervation. The density of these fibers appear to be less along the left atrioventricular groove.

Left atrial function and atrial natriuretic factor/cyclic guanosine monophosphate changes in DDD and VVI pacing modes.

Left atrial systolic function and the plasma of atrial natriuretic factor (ANF) and cyclic guanosine monophosphate (cGMP) were investigated as possible markers for the development of pacemaker syndrome during VVI pacing. Patients who developed pacemaker syndrome during VVI pacing had a significant decrease in left atrial emptying fraction and a substantial increase in ANF and cGMP plasma levels.

Prospective randomized trial of external versus internal transcatheter cardioversion in patients with chronic atrial fibrillation.

To evaluate the safety and long-term efficacy of internal transcatheter cardioversion, forty patients with chronic, lone atrial fibrillation were studied. The patients were randomised to internal transcatheter cardioversion or to conventional external cardioversion. In cases where the procedure was unsuccessful, cross-over to the alternate method was performed. Oral anticoagulation therapy was started three weeks prior to the procedure and was maintained for another three weeks following successful cardioversion. Sinus rhythm was restored in 16/18 patients (88%) in the internal cardioversion group, versus 9/22 patients (40%) in the external cardioversion group (p < 0.01). In addition, 8/13 (61%) patients who were crossed-over to internal cardioversion were successfully cardioverted to sinus rhythm. In contrast, both patients who were crossed-over to external cardioversion remained in atrial fibrillation. During a mean follow-up period of 23 months, 13 (39.3%) patients maintained sinus rhythm. Using the intention to treat principle, the recurrence rate was not statistically different between the two methods. It is concluded that internal cardioversion is more effective in acutely restoring sinus rhythm compared to external cardioversion. However, both methods have similar long-term recurrence rates.

Short-term outcome and attainment of secondary prevention goals in patients with acute coronary syndrome--results from the countrywide TARGET study.

BACKGROUND/OBJECTIVES: Acute coronary syndromes (ACS) continue to pose a significant medical and socioeconomic burden worldwide. Optimal management strategy aims to improve short and long-term outcome. The present study aims to assess short-term outcome of real-world ACS patients and evaluate the achievement rate of secondary prevention goals. METHODS: The TARGET study is an observational study enrolling 418 consecutive ACS patients from 17 centers countrywide (78.0% males, 63.9 ± 12.9 years). After the in-hospital phase, patients were followed for 6 months. In total, 366 patients were included in the prospective phase of the study. At the end of the follow-up, mortality, major adverse cardiovascular events (MACE), prescription pattern of cardiovascular medications, lipid levels, adherence rate to treatment and behavioral recommendations were measured. RESULTS: The overall mortality was 4.8% and the rate of MACE was 17.5%. At 6 months, a significantly lower proportion of patients received antiplatelet agents and statins as compared to hospital discharge. At the end of the follow-up, 87.7% of patients remained on statin treatment, yet only 18.2% of patients had LDL cholesterol levels less than 70 mg/dL. The adherence pattern to lifestyle and dietary recommendations remained low (66.2% quit smoking, 55.8% and 81.3% followed physical activity and dietary recommendations respectively). CONCLUSION: Despite the low rate of mortality and MACE occurrence rate in this countrywide observational study, the attainment rate of secondary prevention goals is relatively poor. Improvement interventions focusing in these gaps of optimal care provision are expected to have a favorable impact on the prognosis of real world ACS patients.

Prolonged asystole during head-up tilt testing with clomipramine infusion.

This case report describes a patient with a history of neurocardiogenic syncope, who had had a negative head-up tilt test with isoprenaline, but he experienced a prolonged asystole during a head-up tilt test with clomipramine (serotonin reuptake inhibitor) 24 h later. This patient was successfully treated with fluoxetine.

Dual chamber pacing aborts vasovagal syncope induced by head-up 60 degrees tilt.

To determine if pacing might prevent syncope in cardioinhibitory 'Malignant Vasovagal Syndrome' (also known as 'Neurally-Mediated Bradycardia/Hypotension'), a study of dual chamber pacing during head-up 60 degrees tilt was undertaken. Paired invasive tilts were performed in 10 patients who had a history of recurrent syncope, normal routine investigations including electrophysiological study and prior tilt-induced vasovagal syncope. Vasovagal reactions of identical severity were produced by prolonged 60 degrees head-up tilt on consecutive days in seven out of 10 patients. On day 2, without pacing, seven patients had tilt-induced vasovagal reactions and six became syncopal during the reaction. On day 3, with temporary DVI pacing with rate hysteresis, seven patients had tilt-induced vasovagal reactions and 1 patient was syncopal. Syncope was aborted in the other five patients. DVI pacing significantly improved cardiac index (CI) (one +/- 0.2 to 1.6 +/- 0.3 L/min/m2, P less than 0.01) and mean arterial blood pressure (MABP) (30 +/- 11 to 48 +/- 12 mmHg, P less than 0.01) during vasovagal reactions on day 3 compared with day 2. The mean period of time that patients could tolerate in the tilted position after the onset of the tilt-induced vasovagal reaction was significantly prolonged by pacing from 0.9 +/- 1.2 to 3.2 +/- 1.6 min (P less than 0.01). Dual chamber pacing may abort syncope in 85% of patients with cardioinhibitory malignant vasovagal syndrome. Pacing may prolong consciousness sufficiently during a vasovagal reaction to allow injury to be avoided.

Myocarditis in beta-thalassemia major. A cause of heart failure.

BACKGROUND: Although acute pericarditis is a common complication of beta-thalassemia major, the prevalence and consequences of myocarditis in this disease have not been investigated. METHODS AND RESULTS: A prospective 5-year follow-up study was carried out in all patients with beta-thalassemia major in whom the diagnosis of acute infectious myocarditis could be established between 1977 and 1986. A similar number of age- and sex-matched control subjects with beta-thalassemia and normal left ventricular function and no evidence of myocarditis were also followed for 5 years. Of 1048 patients with beta-thalassemia major, 47 patients (age, 15 +/- 2.5 years) with precordial chest pain were diagnosed as having acute infectious myocarditis. Myocardial biopsy was diagnostic in 26 patients, border-line in 14 patients, and nondiagnostic in 7 patients. Acute heart failure with left ventricular dysfunction (left ventricular ejection fraction, 25 +/- 11%) developed in 11 patients (23.4%) with myocarditis, and 8 of them died within 1 month to 1 year after diagnosis. Thirteen patients with myocarditis (27.6%) developed chronic heart failure (left ventricular ejection fraction, 26 +/- 13%) within 3 +/- 1.3 years, and 10 of them died within 8 +/- 3 months. Left ventricular systolic and diastolic functions of the control subjects did not change significantly during the 5-year period (left ventricular ejection fraction, 63 +/- 11% versus 65 +/- 7%; P = NS). However, left ventricular restrictive abnormalities (early diastole/late diastole, > 2.2; deceleration time, < 110 milliseconds) combined with right ventricular dilatation (> 30 mm internal diameter) and right-sided heart failure developed in 3 patients with extremely high mean serum ferritin levels. No significant difference was found in mean levels of serum ferritin and pretransfusion hemoglobin between patients with and those without myocarditis. CONCLUSIONS: In patients with beta-thalassemia, myocarditis appears to be involved in the pathogenesis of left ventricular systolic dysfunction, being the main cause of death. Iron overload appears to provoke left ventricular restrictive abnormalities combined with right ventricular enlargement and dysfunction.

c-AMP and ANP levels in VVI and DDD pacing with different AV delays during daily activity and exercise.

Nine patients (three males) mean age 68 +/- 8 years, having complete heart block, and paced in the DDD mode were examined in VVI and DDD pacing with 100 and 150 ms atrioventricular delays (AVD) during rest and exercise. Plasma atrial natriuretic peptide (ANP) and cyclic AMP (c-AMP) were measured at rest and at peak exercise test. ANP plasma levels at rest were significantly higher in VVI pacing compared to 150 AVD (P less than 0.03). On exercise, ANP release was statistically increased only in DDD with 150 ms AVD, while in VVI it remained in high levels at exercise but no significant change was found (p:ns). c-AMP during rest was unchanged in any pacing mode or AVD, but on exercise DDD pacing with short AVD (100 ms) released lower c-AMP plasma levels, than at rest (p:ns). DDD pacing with long AVD (150 ms) during exercise produced statistically higher c-AMP plasma levels (P less than 0.05) than at rest. Also in VVI pacing the c-AMP plasma levels were statistically higher than at rest (P less than 0.02). Adrenergic activity seems to be lower during exercise in DDD pacing with shorter AVD (100 ms) than in DDD with 150 ms AVD or VVI pacing. No difference was found in c-AMP plasma levels at rest. ANP release was also found to be lower at exercise in DDD pacing with short AVD (100 ms) than in DDD with 150 ms AVD. ANP plasma levels at rest were statistically higher in VVI pacing.

Head-up tilt test with clomipramine challenge in vasovagal syndrome--a new tilt testing protocol.

PURPOSE: The aim of the study was to randomly compare clomipramine, used as a challenge-agent during head-up tilt test, with isoproterenol, used in the conventional test, in patients with vasovagal syndrome. SUBJECTS AND METHODS: The serotonergic re-uptake inhibitor clomipramine was infused (5mg in 5min) at the start of head-up tilt test (Clom-HUT) in 126 patients (mean age 41+/-16 years) with positive history of recurrent neurocardiogenic syncope, and in 54 healthy control subjects (mean age 46+/-15 years). All subjects had also been tested with a conventional 60 degrees head-up tilt test (Con-HUT) for 30 min and, if negative, isoproterenol infusion was performed at the end of the test. The two tests were performed in a random order with a 24-h interval between them. RESULTS: Fifty-two of the 126 patients (41%) and two of the 54 controls had a positive response to Con-HUT. In the Clom-HUT the proportion of patients who experienced a positive response increased to 83% (105 subjects), while this happened only to four control subjects. The predictive accuracy of Clom-HUT increased compared to Con-HUT from 58 to 86%, respectively. CONCLUSION: The results indicate an increased responsiveness of central serotonergic neural system in subjects with vasovagal syndrome, the activation of which leads to sympathetic withdrawal. The use of clomipramine infusion during tilt test seems to improve considerably its diagnostic value.

Clinical, adrenergic and heart endocrine measures in chronic atrial fibrillation as predictors of conversion and maintenance of sinus rhythm after direct current cardioversion.

The aim of this study was to evaluate clinical, adrenergic and endocrine factors that could predict sinus rhythm maintenance after direct current cardioversion in chronic atrial fibrillation. Nineteen patients with chronic non-rheumatic atrial fibrillation (mean duration 6 +/- 5 months) were studied. They were exercised 24 h before cardioversion at maximum effort with the Naughton protocol. Heart rate and blood pressure at rest and exercise were recorded and blood samples were taken for the assessment of adrenergic activity, by measuring cyclic adenosine monophosphate, heart endocrine function, atrial natriuretic peptide and its second messenger, cyclic guanosine monophosphate. Fifteen of the 19 patients were initially converted to sinus rhythm (eight patients with external and seven patients with internal DC shocks). After 3 months eight patients remained in sinus rhythm and 11 had relapsed, most of them within the first month. On exercise the chronotropic response was lower in the group who remained in sinus rhythm than in the group in atrial fibrillation (peak heart rate 147 +/- 11 beats.min-1 vs 165 +/- 24 beats.min-1 P = 0.02). During exercise, the systolic blood pressure in the sinus group reached higher values than in the group who relapsed (192 +/- 17 mmHg vs 176 +/- 18 mmHg, P = 0.03). Cyclic adenosine monophosphate increased significantly from rest to peak exercise in the sinus rhythm group (from 23 +/- 9 pmol.ml-1 to 31 +/- 15 mol.ml-1, P = 0.02) while it remained unchanged in the atrial fibrillation group (25 +/- 10 pmol.ml-1 to 24 +/- 8 pmol.ml-1, P = 0.02). For all 19 patients the difference in cyclic adenosine monophosphate between rest and exercise was negatively correlated with maximum heart rate (r = 0.58, P = 0.009). Atrial natriuretic peptide increased from rest to peak exercise in the sinus rhythm group (from 129 +/- 58 fmol.ml-1 to 140 +/- 66 fmol.ml-1) while it remained unchanged in the group in which atrial fibrillation persisted or recurred (from 112 +/- 58 fmol.ml-1 to 111 +/- 53 fmol.ml-1, P = 0.002). A significant correlation between atrial natriuretic peptide and cyclic guanosine monophosphate levels at exercise before cardioversion was found for the sinus rhythm group only (r = 0.76, P = 0.02). In patients with non-rheumatic chronic atrial fibrillation evaluation of clinical parameters such as heart rate and blood pressure changes during maximal exercise can be useful in the choice of suitable therapy. An inadequate increase in plasma cyclic-adenosine monophosphate and atrial natriuretic peptide on exercise could predict patients with more severe underlying disease, where cardioversion should not be recommended.

Natural history of sinus node chronotropy in paced patients.

The natural history of chronotropic incompetence is not clear. To assess this, we evaluated corrected sinus node recovery time (cSNRT) and sinus node chronotropy at rest and during exercise in two groups of syncopal patients with sinus node disease. Group A comprised patients with resting bradycardia but normal cSNRT and group B had resting bradycardia and prolonged cSNRT (greater than 1000 ms). An additional two groups (C and D) were studied. Group C comprised patients with complete AV (CAVB) and no evidence of sinus node disease and group D were asymptomatic controls of similar age. At diagnosis, patients with symptomatic bradycardia but normal cSNRT and no evidence of carotid sinus syndrome (group A) had resting bradycardia and impaired peak heart rate (PHR-I) on exercise compared to controls (P less than 0.001 and P less than 0.05, respectively), but no reduction in exercise duration. At follow-up group A patients demonstrated an increase in resting rate that was significantly slower than the controls (P less than 0.01). Peak heart rate (PHR-II) also remained significantly slower (P less than 0.05). There was no difference in exercise duration between groups A and D at follow-up. Group B was further subdivided according to follow-up findings of preservation of atrial activity in seven patients (group B-1) and junctional rhythm without any atrial activity in four patients (group B-2). Retrospective analysis showed no significant difference in resting heart rate at initial examination but group B-2 showed a significantly lower peak heart rate on exercise compared with B-1 (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

The incidence of malignant vasovagal syndrome in patients with recurrent syncope.

We reviewed 322 patients with recurrent syncope between 1984 and 1988. Investigation included limited intracardiac electrophysiological study in all cases with programmed extra-stimulus studies in 48 cases. In 93 patients (29%), all investigations were normal, (including negative extrastimulus in 30). In the other 229 cases syncope was explained by AV-block (n = 111, 34%), sinus node disease (n = 68, 21%), carotid sinus syndrome (n = 32, 10%) and inducible sustained tachyarrhythmia (n = 18, 6%). Prolonged 60 degrees head-up tilt was performed in 71 out of 93 patients with unexplained syncope, and reproduced vasovagal syncope and presenting symptoms in 53 (75%), or 16% of the whole population reported. These patients were diagnosed as having malignant vasovagal syndrome. Positive tilts were significantly less common in a group of 27 subjects of similar age without a history of syncope (7%), and a random sample of 37 patients with atrioventricular block (n = 16), sick sinus syndrome (n = 18) and inducible tachyarrhythmia (n = 3), (19%, 11% and 0% respectively, P less than 0.01). From this retrospective review it appears, therefore, that tilt testing is a valuable provocative tool for vasovagal syncope and may reduce the number of syncopal patients that remain undiagnosed, although these early observations do not allow an exact appraisal of the sensitivity and specificity of the tilt test.