Mark Anderson

Fitness to fly for passengers with cardiovascular disease.

Following this review of evidence and after due consideration, it is clear that there are few cardiovascular conditions that warrant the denial of fitness to fly as a passenger. Given the right aircraft, on-board equipment and appropriately qualified and experienced escort personnel, aircraft can act as flying intensive care units and carry extremely ill passengers.1 For those with cardiovascular disease who are not critically ill but who wish to fly on commercial aircraft, the aircraft environment does not pose a significant threat to their health. It is only when their underlying condition is associated with a significant risk of acute deterioration that reasonable restrictions should apply. For those at the more severe end of the spectrum of their specific cardiovascular condition, services exist to help make the journey more easily and safely. Most carriers and airport authorities provide assistance on the ground and in the air. Oxygen is available on most major carriers, although this is sometimes subject to a charge and at least 7 days notice is normally required.2 Passengers are advised to plan their arrival at the airport in plenty of time to avoid having to rush and to warn the carrier and/or airport authority of any requirements for assistance, including requirement for in-flight oxygen, well in advance of the date of departure. They are strongly advised to ensure they have an appropriate supply of their medication, a clear list of the medications and doses they take and a letter of explanation from their doctor regarding their condition, drugs, allergies and devices (eg, pacemaker). Physicians are advised to consider the stability of a passengers condition and apply the guidance herein. The authors have contributed to this document in good faith and consider it to be an honest conclusion of the review of evidence and assessment of the …

Late failure of a single-coil transvenous implantable cardioverter-defibrillator lead associated with conductor separation

Two patients with the same model of single-coil active fix implantable defibrillator lead presented with evidence of lead malfunction, in one case with an abrupt rise in pacing impedance and threshold and in the other with evidence of over-sensing. In both cases, the chest radiograph showed separation of conductors in the defibrillation lead from the main body of the lead.

Intravascular ultrasound imaging of the coronary arteries: an in vitro evaluation of measurement of area of the lumen and atheroma characterisation

Objective—To assess the accuracy of measurement of area of the lumen, and sensitivity, and specificity of detection of atheroma in coronary arteries in vitro with a commercially available 20 MHz intravascular ultrasound system. Setting—A teaching hospital department of cardiology with the support of the department of cardiovascular pathology. Procedure—10 segments of coronary artery were removed from cadaver hearts. Intravascular ultrasound imaging was performed at fixed levels and the vessels were then sectioned and photographed before histological preparation. An independent blinded observer measured luminal area and assessed the presence of atheroma on the intravascular ultrasound images of 76 vessel sections (304 quadrants). The sensitivity and specificity of detection of atheroma was assessed in comparison with the histologically prepared sections. Luminal areas from intravascular ultrasound, photographs of cross sections of the vessels and histological sections were compared with the technique of limits of agreement. Results—Overall 36% of the 304 quadrants studied histologically had identifiable atheroma. Intravascular ultrasound sensitivity for atheroma was 0·593 and the specificity was 0·839. The positive predictive value was 0·674, and the relative risk 3·139. Values for area of the vessel lumen were on average 9·4 mm2 (confidence interval (CI) 8·6–10·2 mm2) larger than those measured from photographs and 10·7 (CI 9·8–11·6 mm2) larger than those measured from the histological sections. Conclusions—The intravascular ultrasound system assessed in this study significantly overestimated coronary vessel luminal area and had low sensitivity and specificity for detection of atheroma. Improvements in image resolution are required before this system can provide useful information on coronary artery size and morphology.

Combined subpectoral implantation of a cardioverter defibrillator and breast augmentation surgery in a patient with Emery–Dreifuss muscular dystrophy

We present the case of a 28-year-old female with Emery-Dreifuss muscular dystrophy and breast hypoplasia, who underwent implantation of a subpectoral defibrillator and bilateral breast augmentation during a single elective procedure at our institution.

Routine issuance of clinical magnets to patients receiving implantable defibrillators: retention of information and appropriateness of use

Background The application of a clinical magnet over an implantable cardioverter defibrillator (ICD) can be used to suspend tachycardia therapies in patients receiving recurrent or inappropriate shocks. In our institution, they have been routinely issued to patients undergoing ICD implantation during the past 5 years. The purpose of this survey was to investigate how well information concerning their use had been retained, and in what circumstances the magnets had been used. Methods We sent a questionnaire to 476 patients, and received a response from 343 (72%). Data was collated using ‘Microsoft Excel’, cross-referenced against our own pacing database, and analysed using basic statistical methods. Results 256 (74.6%) patients recalled being issued with a magnet. 48% of these were still in possession of their written information leaflet at the time of survey; 62% felt that they were able to remember when and how to use the magnet—with patients who had received written instructions and verbal reinforcement demonstrating the best recall. 8% of patients had used their magnets and the most common reason for use was multiple or inappropriate shocks. In addition, almost half of the patients who had suffered inappropriate shocks had been able to successfully use their magnets. No cases of harm related to magnet use were identified. Conclusions The results of our survey suggest that routinely issuing clinical magnets to ICD patients is a safe and effective practice, and a small but significant number of patients were able to utilise their magnets in clinically important situations.

32 Influence of Sleep Apnoea on Biventricular Pacing, Heart Rate Trend and Tachyarrhythmia’s in Heart Failure Patients who have undergone Cardiac Resynchronisation Therapy

Introduction Sleep apnoea syndrome (SAS) has been reported in 40–60% of people with heart failure (HF)1 with varying reports as to whether this is predominantly central or obstructive. Undiagnosed intermittent hypoxia during sleep increases sympathetic activation and endothelial dysfunction so may worsen cardiac outcomes. SAS also prevents the normal drop in heart rate that accompanies the onset of sleep and coupled with reflex increases in central sympathetic outflow could lead to the development of recurrent nocturnal ischaemia and arrhythmias.2 We compared average heart rate, percentage of Biventricular pacing and logged tachyarrhythmia’s in those with and without recently diagnosed SAS in a specific cohort of HF patients who underwent cardiac resynchronisation therapy (CRT). Method Prospective, cross-sectional study. 37 Consecutive HF patients, 30 males, mean (SD) age= 69.8 (8.4) yrs, BMI 29.3 (8.7) kg/m2, and mean LVEF 25 (7)% – who were referred to a UK tertiary cardiac centre for CRT according to National Guidelines. They underwent baseline limited channel sleep studies (Apnea LinkTM ResMed, Abingdon, UK) immediately prior to CRT. All patients were deemed on optimal medication at the discretion of a cardiologist. None had known SAS. An apnoea hyopnea index (AHI) >15 events per hour was deemed a positive result for treatable SAS according to UK guidelines. Average heart rate, percentage of biventricular pacing and logged tachyarrhythmias were obtained from six weeks post CRT follow up. Results 20 from 37 (54%) had an AHI >15 events per hour. All 20 patients had predominantly obstructive sleep apnoea, 5 of these 17 patients had some central sleep apnoea, but this was still less than their obstructive episodes. None had predominantly central sleep apnoea. Abstract 32 Table 1 Variable SAS yes (n = 20) SAS no (n = 17) p-value Age (yrs) 69.2 (10.6) 70.1 (10.8) 0.5 BMI (kg/m2) 29 (6.8) 29 (6.5) 0.5 LVEF 24.9 (7.7) 25 (7.5) 0.6 QRS prior to CRT 162.9 (25.3) 163 (24) 0.5 Average Heart Rate 69.8 (9.8) 69.3 (9.5) 0.4 % Biventricular Pacing 96.5 (5.4) 96.7 (5.3) 0.2 Data expressed as means (SD) Abstract 32 Table 2 Number of patients with tachyarrhythmia’s Tachyarrhythmias PAF/SVT NSVT/VT SAS yes (n = 20) 20% 30% SAS No (n = 17) 5% 23% Conclusion There is a high prevalence (54%) of significant SAS in the group of heart failure patients referred for CRT. Unlike other studies we found a relatively low prevalence of central sleep apnoea. There was no difference in average heart rate and percent of biventricular pacing in those with and without SAS. However there is increased incidence of tachyarrhythmias in those with SAS and this might be explained by recurrent hypoxia and increased sympathetic activity in sleep apnoea patients. References Eur Resp J. 2007;29(6):1201-5 Circulation 2003;107:1671-8

68 The Incidence of Pathogenic Mutations in Index Cases of HCM, LQTS and CPVT: Results from a Clinical Testing Programme in Wales

International guidelines suggest that a significant majority of patients with Hypertrophic Cardiomopathy (HCM), Long QT syndrome (LQTS) and Catecholaminergic Polymorphic Centricular Tachycardiac (CPVT) will be found to have a disease causing mutation on genetic testing. Until recently genetic testing was not available for patients in Wales with these conditions. From 2013 funding has been made available to test index cases to allow cascade testing of family members. We present the results of the first full year of testing. Patients with a clinical diagnosis of HCM, LQTS or CPVT in whom family cascade testing would be clinically useful were referred to one of 3 Cardiogenetics MDTs. Cases where diagnostic and family criteria were met were referred on for genetic counselling prior to testing. Samples were sent to an accredited laboratory for testing for HCM (MYH7, MYBPC3, TNNT2 and TNNI3), LQTS (KCNQ1, KCNH2, KCNE1, KCNE2 and SCN5A) or CPVT (RYR2) mutations. Results were returned to the All Wales Genetic service for collation and distribution to the patients and MDTs. In the first full year of testing (2013/2014) 75 patients were tested, 45 for HCM, 28 for LQT and 2 for CPVT. The results of testing are shown in the Figure 1. Number of cases: Abstract 68 Figure 1 Results of gene testing in HCM, LQTS and CPVT index cases Of the 45 index cases with HCM tested only 10 (22%) had a recognised pathogenic mutation whilst for LQT 8 of 28 tested had a pathogenic mutations (28%). Variants of unknown significance accounted for another 11% (HCM) and 7% (LQT) of cases. Only two cases were tested for CPVT and 1 had a pathogenic mutation (50%). Over the period of this study 47 cascade tests were performed in HCM and LQT families. Of these 30 were negative for the identified pathogenic mutation enabling these patients to be removed from clinical surveillance programmes. In this real world clinical testing programme of index cases with HCM, LQTS or CPVT, pathogenic mutation rates were substantially lower than reported in international guidelines. Away from specialist centres where large families with multiple affected members may tend to congregate pathogenic mutation rates may be lower than reported. Nonetheless cascade testing from affected families identified a significant number of individuals who could be removed from long-term clinical surveillance with potential savings in resources.

98 Are we seeing more cases of Infective Endocarditis after Nice CG64 Recommended Cessation of the use of Antibiotic Prophylaxis? The Welsh Experience

Background Infectious endocardits (IE) is a rare condition associated with high morbidity and mortality. IE develops as a result of a complex interaction between the vascular endothelium, haemostatic mechanisms, the immune system and exposure to the causative microorganism. Historically cardiologists have utilised prophylactic antibiotics to cover procedures known to cause bacteraemia such as dental surgery to prevent IE. However, this practice was without evidence base and its efficacy questioned. In 2008 NICE CG64 was published advocating a radical change in practice, recommending cessation of chemoprophylaxis for the prevention of IE. In this study we aim to assess the impact of NICE CG 64 in Wales. Methods Chemoprophylaxis was most commonly prescribed in the form of a single 3 g oral dose of Amoxicillin or a 600 mg oral dose of Clindamycin. We obtained data of all prescriptions for either Amoxicillin 3 g or Clindamycin 600 mg in Wales from 2001 to 2012. We obtained data on diagnosis of IE including the causative microorganism from PEDW database (Patient Episode Database for Wales) via SAIL databank (Secure Anonymised Information Linkage) to assess the impact of NICE CG64. Previous studies have suggested an upward trend in the incidence of IE prior to the introduction of NICE CG64. We therefore performed analysis of our data using a Poisson regression model with identity link function to correct for any trend in our data. Results Prescriptions of Amoxicillin 3 g and Clindamycin 600 mg reduced by 77% and 92% (p < 0.001) respectively confirming at least partial adoption of NICE CG64. There was a non-significant increase in total numbers of cases of IE seen after 2008 (p = 0.135) and a significant increase in IE caused by oral streptococcus (p = 0.028). When correction was performed to adjust for the upward trend seen prior to NICE CG64 in 2008 the increase in IE caused by oral streptococcus ceased to be significant. Abstract 98 Figure 1 Abstract 98 Figure 2 Conclusion The reduction in antibiotic prescriptions seen after 2008 provides evidence that NICE CG64 is being followed in Wales. NICE CG64 accepted that patients who had previously received chemoprophylaxis may continue this practice which may explain the number of prescriptions seen following 2008. Alternatively practitioners may be following international guidance from AHA 2007 and ESC 2009 that continue to recommend chemoprohylaxis in high risk patients. Despite the major change in prescribing of chemoprophylaxis observed we only identified a gradual, non-significant increasing trend in the incidence of IE. This trend may be explained by increasing population size and improved diagnostics. There was no significant deviation in this linear trend with the introduction of NICE CG64 in 2008 providing support that the cessation of chemoprophylaxis has not resulted in a large increase in the incidence of IE over a four year period.