Introduction Current guidelines recommend aortic valve replacement in patients with apparently asymptomatic severe aortic stenosis, who exhibit symptoms or a decrease in blood pressure on exercise testing. However, the additional information provided by cardiopulmonary exercise testing (CPET) is limited. This study sought to establish the additional information provided by CPET in this context. Methods An analysis of patients with aortic stenosis undergoing CPET in an enhanced valve surveillance clinic was performed. Symptom limited cardiopulmonary exercise testing with respiratory gas exchange analysis was used, and the patients were encouraged to exercise until exhaustion. Results 71 patients with moderate to severe aortic stenosis and good left ventricular function (AVVmax 4 0.5m/s MG 38 11mmHg, AVA 0.9 0.2cm2, LVEF 60 8%)were included in the analysis. The mean age was 74.2 12.1 years and 51 patients (70.4%) were male. 33 (46.5%) patients had a background of hypertension, 12 (16.9%) had diabetes mellitus and 8 (11.3%) had coronary artery disease. All patients denied cardiovascular symptoms at baseline. A total of 119 CPETs were performed. All patients exercised to respiratory exchange ratio (RER) >1.1 indicating good effort. Of the 71 patients, 26 (37%) exhibited a peak VO2 <84% predicted. 11 patients (15.5%) developed breathlessness on exertion, 7 (9.9%) exhibited a fall in blood pressure below baseline and 3 (4.2%) developed ST depression. 18 patients (25.3%) had a peak VO2 <84% predicted, but without symptoms, fall in blood pressure or ST depression. There was a significant correlation between peak VO2 and AVA (r= 0.24, p= 0.047, but not between peak VO2 and transaortic velocity (r=0.117, p=0.339) and peak VO2 and mean gradient (r=0.139, p= 0.256). Over a median follow up time of 8 months (IQR 4 to 28 months), 28 patients (39%) were referred for aortic valve intervention. There were 3 deaths. Logistic regression showed that aortic valve area and peak VO2 were not significant predictors for clinical events. Conclusion Our data demonstrates that a significant proportion of patients with apparently asymptomatic aortic stenosis exhibit exercise limitation as measured by peak VO2. Cardiopulmonary exercise testing may provide incremental objective evidence of early deterioration, over and above parameters obtained from conventional treadmill testing, as suggested by current guidelines. Conflict of Interest nil

A proportion of patients who undergo an initial lead extraction procedure will require a second, repeat extraction. Data regarding this clinical entity are scarce and neither the predisposing risk factors for, nor outcomes from, these procedures have been described previously. We sought to determine the incidence, risk factors, and outcomes of repeat lead extraction.

OBJECTIVES:This study sought to test the feasibility of a purpose-built, integrated software platform to process, analyze, and overlay cardiac magnetic resonance (CMR) data in real time within a combined cardiac catheter laboratory and magnetic resonance imaging scanner suite (X-MRI) to guide left ventricular (LV) lead implantation.BACKGROUND:Suboptimal LV lead position is a major determinant of poor cardiac resynchronization therapy (CRT) response, and the optimal site is highly patient specific. Pacing myocardial scar is associated with poorer outcomes; conversely, targeting latest mechanical activation (LMA) may improve them.METHODS:Fourteen patients (age 74 ± 5.1 years; New York Heart Association functional class: 2.7 ± 0.4; 86% ischemic with ejection fraction 27 ± 7.6%; QRSd: 157 ± 19 ms) underwent CMR followed by immediate CRT implantation using derived scar and dyssynchrony data, overlaid onto fluoroscopy in an X-MRI suite. Rapid LV segmentation enabled detailed scar quantification, identification of LMA segments, and selection of myocardial targets. At coronary venography, the CMR-derived 3-dimensional shell was fused, enabling identification of viable venous targets subtended by target segments for LV lead placement.RESULTS:The platform was successful in all 14 patients, of whom 10 (71%) were paced in pre-procedurally defined target segments. Pacing in CMR-defined target segments (out of scar) showed a significant decrease in the LV capture threshold (mean difference: 2.4 [1.5 to 3.2]; p < 0.001) and shorter paced QRS duration (mean difference: 25 [15 to 34]; p < 0.001) compared with pacing in areas of CMR determined scar. In 5 (36%) patients with extensive scar in the posterolateral wall, CMR guidance enabled successful lead delivery in an alternative anatomically favorable site. Radiation dose and implant times were similar to historical controls (p = NS).CONCLUSIONS:Real-time CMR-guided LV lead placement is feasible and achievable in a single clinical setting and may prove helpful to preferentially select sites for LV lead placement.

AIMS:This prospective randomized controlled study evaluated the first-line use of a novel remotely monitored implantable loop recorder (ILR) in the initial investigation of unexplained syncope, and compared this to conventional therapy and a dedicated Syncope Clinic (SC).METHODS AND RESULTS:A total of 246 patients (mean age 70.3 years) were randomly allocated to conventional management, SC alone, ILR alone, or SC + ILR. Median follow-up was 20 months (IQR 15-25 months). Time to electrocardiogram (ECG) diagnosis was significantly shorter with ILR alone vs. conventional [hazard ratio (HR) 35.5, P = 0.0004] and with SC vs. conventional (HR 25.6, P = 0.002). Seventy-four per cent of first syncopal events documented in the SC groups occurred during provocative tilt testing. Twenty-two per cent of patients who received an ILR were found to have a bradycardia indication for permanent pacing, compared with 3% of patients who did not. Overall, more investigative tests were undertaken in the conventional group than in any other. Only patients who received an ILR had a significant increase in time to second syncope (P = 0.02), suggesting successful diagnosis and management of treatable causes of syncope.CONCLUSIONS:Implantable loop recorder monitoring achieved a more rapid diagnosis in unexplained syncope than usual care. Conventional management of syncope failed to achieve an ECG diagnosis despite a large number of investigative tests. Syncope Clinic and provocative tilt testing delivered a rapid ECG diagnosis, but did not prevent recurrent syncope. Implantable loop recorders offered rapid diagnosis, increased the likelihood of syncope being reported, demonstrated a high rate of intermittent bradycardia requiring pacing, and reduced recurrent syncope.

Introduction Cardiac resynchronisation therapy (CRT) improves symptoms of heart failure (HF) in the majority of patients but echocardiographic measures of selection have produced disappointing results. These measurements are often carried out at rest. Exercise can alter the magnitude and extent of ventricular dyssynchrony and dynamic changes vary between patients. The aim of this study was to determine whether changing dyssynchrony by exertion would predict a positive response to CRT. Method 38 patients with symptomatic heart failure were included in this study. All patients had a depressed LVEF (<35%) and were clinically selected for CRT therapy. Two comparator groups were formulated: Phasers – subjects whose total mechanical delay (normalised for RR interval) decreased with exercise, and dephasers – subjects whom normalised mechanical remained stable or increased. Mechanical delay was defined from spectral tissue Doppler imaging, time from R wave to onset of post isovolumic S’ at the lateral right and left ventricular annular and interventricular septum. The primary end point was VO2peak at 3 months post implant. Results The overall population showed significant improvements in NYHA class, quality of life, LVEF, resting S’, end diastolic and systolic volumes, and dimensions following CRT at 3 months. No significant improvements were observed for exercise parameters including VO2peak. 14 phasers and 24 dephasers were identified and no differences were found for VO2peak or for any other parameters obtained at 3 months (table 1). Conclusion All patients showed that CRT significantly improved echocardiographic and functional parameters, no improvements were observed for exercise parameters. Exercise dyssynchrony was unable to identify if patients responded positively to CRT therapy. Both phasers and dephasers responded in a similar way to CRT.

Objective Cardiopulmonary exercise testing (CPET) is non-invasive and safe, reliable and reproducible and has been robustly demonstrated to be linked to clinical end-points such as hospitalisation and death. CPET provides objective information on exercise capacity. However in practice, CPET data can be difficult to interpret. We examined the validity of standard CPET parameters in patients with atrial fibrillation (AF). Methods and results Standard CPETs were prospectively performed in 69 patients (mean age 64) with paroxysmal AF. The ratio of ventilation to carbon dioxide elimination (VE/VCO2) measured at the ventilatory threshold (VT) correlated with VE/VCO2 across the test (r = 0.84, p < 0.001) and at its nadir (rho = 0.92, p < 0.001). Peak end-tidal carbon dioxide (ETCO2) correlated well with ETCO2 at peak exertion (r = 0.88, p < 0.001) and at rest (r = 0.68, p < 0.001). However, absolute VE/VCO2 and ETCO2 values were significantly different with different measurement methods. Unadjusted peak oxygen uptake (VO2) correlated with VO2 at the VT (rho = 0.94, p < 0.001), and oxygen uptake efficiency slope (OUES; rho = 0.92, p < 0.001). However, once OUES and VO2peak were indexed against standard reference ranges, they had a lower level of agreement (rho = 0.78, p < 0.001). Alternative formulae for predicting VO2peak returned markedly different results. In 34 of 69 (49%) of patients, the% predicted VO2peak appeared above normal (>100% predicted) in one reference range, but abnormal (<84% predicted) in another. Conclusions In patients with paroxysmal AF, CPET data were sufficiently consistent that peak exercise capacity could be predicted from submaximal measures. However, in this population, reference ranges for VO2peak were markedly inconsistent. Adjusted values for VO2peak and OUES should be interpreted with caution in these patients.

AIMS:The number of procedures involving upgrade or revision of cardiac implantable electronic devices (CIEDs) is increasing and the risks of adding additional leads are significant. Central venous occlusion in patients with pre-existing devices is often asymptomatic and optimal management of such patients in need of device revision/upgrade is not clear. We sought to assess our use of laser lead extraction in overcoming venous obstruction.METHODS AND RESULTS:Patients in need of device upgrade/revision underwent pre-procedure venography to assess venous patency. In patients with venous occlusion or stenosis severe enough to preclude passage of a hydrophilic guide wire, laser lead extraction with retention of the outer sheath in the vasculature was performed with the aim of maintaining a patent channel through which new leads could be implanted. Data were recorded on a dedicated database and patient outcomes were assessed. Between July 2004 and April 2012, laser lead extractions were performed in 71 patients scheduled for device upgrade/revision who had occluded or functionally obstructed venous anatomy. New leads were successfully implanted across the obstruction in 67 (94%) cases. There were two major complications (infection) and four minor complications with no peri-procedural mortality. Device follow-up was satisfactory in 65 (92%) cases with mean follow-up up to 26 ± 19 months.CONCLUSION:Laser lead extraction is a safe and effective option when managing patients with central venous obstruction in need of CIED revision or upgrade.

AIMS:Current quality measures of percutaneous coronary intervention (PCI) procedures are based on the incidence of major adverse cardiac events (MACE). This crude marker ignores the many clinical nuances that make for sound decision making in PCI. We have established a prospective peer review audit tool to determine the quality of PCI within our cardiac network, which consists of five PCI hospitals serving a population of 1.4 million people in Sussex, UK.METHODS AND RESULTS:Analysis of 10% of all PCI cases selected at random each month by a non-clinical audit manager is made by a rotating panel of two PCI operators and one cardiac surgeon. Each PCI case is assessed for anatomical suitability, lesion severity, strategic appropriateness and final outcome. Panel findings were reported back to the operator and the audit manager. A total of 326 cases were assessed by the review committee. Results were disseminated to individual operators. Coronary anatomy and lesion severity were considered appropriate for PCI in 94.2% and 96.0% of cases, respectively. Appropriateness of strategy was confirmed in 86.2% and the outcome considered satisfactory in 90.8%. A total of 242 subsequent cases were analysed to assess practice trends. This analysis demonstrated a statistically significant improvement in clinical decision making with respect to appropriateness of strategy (from 86.2% to 92.6%; p=0.004).CONCLUSIONS:Prospective peer review of percutaneous coronary intervention cases by a rotating regional committee is valuable in ensuring procedural quality.

session 4: Outcomes of various pacing modalities Monday, April 14, 2008, 2:00 P.M.–3:30 P.M. Room Sormiou 4-1 The relationship between right ventricular pacing and atrial fibrillation burden in patients with paroxysmal atrial fibrillation McIntosh Robert, Veasey Rick, Hong Paul, Silberbauer John, Lloyd Guy, Patel Nik, Sulke Neil Department of Cardiology, Eastbourne General Hospital, Eastbourne, UK of Great Britain and Northern Ireland Background Right ventricular pacing has no effect on atrial fibrillation (AF) burden, in the short or medium term, in patients with paroxysmal atrial fibrillation (PAF). The effects of right ventricular pacing on PAF in the long term are unknown (unlike persistent AF). We evaluated the effect of right ventricular pacing on AF burden in patients with symptomatic drug resistant PAF. Methods Short and long term pacing data from 62 patients with Vitatron Selection 9000, Vitatron T70, Medtronic Enrhythm or Symphony DR2550 pacemakers were analysed. These pacemakers have sophisticated AF diagnostic Holters that accurately demonstrate AF burden. The devices also record the quantity of sensed sinus and ventricular activity as well as the percentage of ventricular and atrial pacing delivered. By analysing implanted pacemaker data at short and long term follow-up the effect of ventricular pacing (VP) on AF burden was assessed. Results 62 patients (age 74±8, 46.8% male) underwent Holter interrogation following an induction period of 1 month and again after long term follow-up of at least 1 year (mean 1,020±573 days). No significant increase in delivered ventricular pacing over time was observed (52.7± 35% to 51.8±39, p=0.9). AF burden increased slightly over time (13.1±16.2% to 18.0±28.8) however, this change was not significant (p=0.1). There was no statistically significant correlation between the amount of ventricular pacing delivered and change in AF burden (r=0.155, p=0.2; Fig 1). Conclusions In patients with symptomatic pre-implant PAF, increased right ventricular apical pacing does not affect arrhythmia burden in either the short or long term. This is in contradistinction to persistent AF studies and suggests different arrhythmia mechanisms. 4-2 Long-term evaluation of direct His-bundle pacing Pignalberi Carlo, Ricci Renato Pietro, Tola Gianfranco, Santini Massimo Cardiology Department, San Filippo Neri Hospital, Rome, Italy Background Among the alternative pacing sites, direct His bundle pacing constitutes the most promising and the earliest technique. Nevertheless, its long-term evaluation is still not available. Objective The aim of our study is to evaluate the feasibility and safety of direct His bundle pacing after a long-term follow-up. Methods Between March 2004 and February 2005, nine patients (pts) with normal A–V conduction have been implanted with a dual-chamber pacemaker, according to International Guidelines (eight pts with sick sinus syndrome and one with vaso-vagal syndrome). Pacing threshold, sensing and impedance have been tested in all the pts every 6 months; the mean duration of follow-up was 27±13 months. J Interv Card Electrophysiol (2008) 21:105–108 DOI 10.1007/s10840-008-9226-1

Cardiac resynchronization therapy is an accepted treatment for heart failure but it may be necessary to explant these systems along with their leads. The evidence base for coronary sinus (CS) lead extractions is limited. We aimed to evaluate the percutaneous removal of these leads and the utility of laser extraction when necessary.Of 265 patients referred for lead extraction between January 2004 and June 2008, 32 (12.1%) involved CS leads (30 males, mean age 67 years). Mean implantation time was 26.5 +/- 28.7 months (range 1-116 months). Indications for extraction were pocket infection (34.4%), lead malfunction (43.8%), skin erosion (15.6%), and endocarditis (6.2%). Twenty-eight (87.5%) CS leads were removed with manual traction, with laser utilized in four cases (12.5%). No major complications of CS laceration, pericardial effusion, emergency surgery, or death occurred.Our experience supports the percutaneous extraction of CS leads as a safe and effective procedure including the utility of laser when necessary.