Diagnostic yield of an ambulatory patch monitor in patients with unexplained syncope after initial evaluation in the emergency department: the PATCH-ED study.

OBJECTIVES: Diagnosing underlying arrhythmia in ED syncope patients remains problematic. This study investigates diagnostic yield, event prevalence, patient satisfaction and compliance, and influence on resource utilisation of an ambulatory patch monitor in unexplained ED syncope patients. METHODS: Prospective pilot study conducted in a single tertiary ED in Scotland between 17 November 2015 and 16 June 2017 with a historical unmatched comparator group. Patients 16 years or over presenting within 6 hours of unexplained syncope were fitted in the ED with an ambulatory patch ECG recorder (Zio XT monitor), which continuously records a single-lead ECG for up to 14 days. Patients with an obvious underlying cause were excluded. An unmatched historical group of 603 syncope patients with no obvious diagnosis in ED, recruited to a prior cohort study (2007-2008), were used as a comparator. Primary endpoint was symptomatic significant arrhythmia at 90-day follow-up. RESULTS: During the prospective study period, 86 patients were recruited. 90-day diagnostic yield for symptomatic significant arrhythmia was 10.5% (95% CI 4.0 to 16.9; 9 of 86) versus 2.0% (95% CI 0.9 to 3.1; 12 of 603) in the comparator group. 24 patients (27.9%) had a significant arrhythmia (five serious); 26 patients (30.2%) had serious outcomes (major adverse cardiac event and/or death). Blinded patch report review suggested the patch would significantly reduce requirement for standard outpatient ambulatory ECG monitoring. 56 of 76 returned patches had a diagnostic finding within±45 s of a triggered/diary event (73.7% diagnostic utility; 95% CI 63.7 to 83.6); 34 of 56 (61%) for sinus rhythm or ectopic beats only. CONCLUSIONS: Routine, early ambulatory ECG monitoring in ED patients with unexplained syncope is probably warranted. A large-scale trial comparing this approach to standard care with cost-effectiveness and safety analysis is now required. TRIAL REGISTRATION: NCT02683174.

Multi-centre Randomised Controlled Trial of a Smartphone-based Event Recorder Alongside Standard Care Versus Standard Care for Patients Presenting to the Emergency Department with Palpitations and Pre-syncope: The IPED (Investigation of Palpitations in the ED) study.

BACKGROUND: Patients with palpitations and pre-syncope commonly present to Emergency Departments (EDs) but underlying rhythm diagnosis is often not possible during the initial presentation. This trial compares the symptomatic rhythm detection rate of a smartphone-based event recorder (AliveCor) alongside standard care versus standard care alone, for participants presenting to the ED with palpitations and pre-syncope with no obvious cause evident at initial consultation. METHODS: Multi-centre open label, randomised controlled trial. Participants ≥ 16 years old presenting to 10 UK hospital EDs were included. Participants were randomised to either (a) intervention group; standard care plus the use of a smartphone-based event recorder or (b) control group; standard care alone. Primary endpoint was symptomatic rhythm detection rate at 90 days. Trial registration number NCT02783898 (ClinicalTrials.gov). FINDINGS: Two hundred forty-three participants were recruited over an 18-month period. A symptomatic rhythm was detected at 90 days in 69 (n = 124; 55.6%; 95% CI 46.9-64.4%) participants in the intervention group versus 11 (n = 116; 9.5%; 95% CI 4.2-14.8) in the control group (RR 5.9, 95% CI 3.3-10.5; p < 0.0001). Mean time to symptomatic rhythm detection in the intervention group was 9.5 days (SD 16.1, range 0-83) versus 42.9 days (SD 16.0, range 12-66; p < 0.0001) in the control group. The commonest symptomatic rhythms detected were sinus rhythm, sinus tachycardia and ectopic beats. A symptomatic cardiac arrhythmia was detected at 90 days in 11 (n = 124; 8.9%; 95% CI 3.9-13.9%) participants in the intervention group versus 1 (n = 116; 0.9%; 95% CI 0.0-2.5%) in the control group (RR 10.3, 95% CI 1.3-78.5; p = 0.006). INTERPRETATION: Use of a smartphone-based event recorder increased the number of patients in whom an ECG was captured during symptoms over five-fold to more than 55% at 90 days. This safe, non-invasive and easy to use device should be considered part of on-going care to all patients presenting acutely with unexplained palpitations or pre-syncope. FUNDING: This study was funded by research awards from Chest, Heart and Stroke Scotland (CHSS) and British Heart Foundation (BHF) which included funding for purchasing the devices. MR was supported by an NHS Research Scotland Career Researcher Clinician award.

Multi-centre randomised controlled trial of a smart phone-based event recorder alongside standard care versus standard care for patients presenting to the Emergency Department with palpitations and pre-syncope - the IPED (Investigation of Palpitations in the ED) study: study protocol for a randomised controlled trial.

BACKGROUND: Palpitations and pre-syncope are together responsible for 300,000 annual Emergency Department (ED) attendances in the United Kingdom (UK). Diagnosis of the underlying rhythm is difficult as many patients are fully recovered on ED arrival; and examination and presenting electrocardiogram (ECG) are commonly normal. The only way to establish the underlying heart rhythm is to capture an ECG during symptoms. Recent technology advances have led to several novel ECG monitoring devices appearing on the market. This trial aims to compare the symptomatic rhythm detection rate at 90 days of one such smart phone-based event recorder (AliveCor Heart Monitor and AliveECG) with standard care for participants presenting to the ED with palpitations and pre-syncope and no obvious cause in the ED. METHODS/DESIGN: This is a multi-centre hospital ED / Acute Medical Unit (AMU) open label, randomised controlled trial. Participants will be recruited in 10 tertiary and district general hospitals in the UK. Participants aged ≥ 16 years presenting with an episode of palpitations or pre-syncope with no obvious cause and whose underlying ECG rhythm during these episodes remains undiagnosed after clinical assessment will be included. Participants will be randomised to either: (1) the intervention arm, standard care plus the use of a smart phone-based event recorder; or (2) the control arm, standard care. Primary endpoint will be symptomatic rhythm detection rate at 90 days. A number of secondary clinical, process and cost-effectiveness endpoints will be collected and analysed. Analysis will be on an intention-to-treat basis. DISCUSSION: The Investigation of Palpitations in the ED (IPED) study aims to recruit 242 participants across 10 hospital sites. It will be the first study to investigate the ability of a smart phone-based event recorder to detect symptomatic cardiac rhythms compared to standard care for ED patients with palpitations and pre-syncope with no obvious cause in the ED. This smart phone event recorder will allow ED patients who have presented with palpitations or pre-syncope to record their ECG tracing if they have a further episode and may increase the rate of underlying rhythm diagnosis. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02783898 . Registered on 26 May 2016.

Radiofrequency ablation in children with asymptomatic Wolff-Parkinson-White syndrome.

BACKGROUND: Ventricular fibrillation can be the presenting arrhythmia in children with asymptomatic Wolff-Parkinson-White syndrome. Deaths due to this arrhythmia are potentially preventable. METHODS: We performed a randomized study in which prophylactic radiofrequency catheter ablation of accessory pathways was compared with no ablation in asymptomatic children (age range, 5 to 12 years) with the Wolff-Parkinson-White syndrome who were at high risk for arrhythmias. The primary end point was the occurrence of arrhythmic events during follow-up. RESULTS: Of the 165 eligible children, 60 were determined to be at high risk for arrhythmias. After randomization, but before any ablation had been performed, the parents withdrew 13 children from the study. Of the remaining children, 20 underwent prophylactic ablation and 27 had no treatment. The characteristics of the two groups were similar. There were three ablation-related complications, one of which led to hospitalization. During follow-up, 1 child in the ablation group (5 percent) and 12 in the control group (44 percent) had arrhythmic events. Two children in the control group had ventricular fibrillation, and one died suddenly. The cumulative rate of arrhythmic events was lower among children at high risk who underwent ablation than among those at high risk who did not. The reduction in risk associated with ablation remained significant after adjustment in a Cox regression analysis. In both the ablation and the control groups, the independent predictors of arrhythmic events were the absence of prophylactic ablation and the presence of multiple accessory pathways. CONCLUSIONS: In asymptomatic, high-risk children with the Wolff-Parkinson-White syndrome, prophylactic catheter ablation performed by an experienced operator reduces the risk of life-threatening arrhythmias.

Transcatheter radiofrequency ablation of atrial fibrillation in patients with mitral valve prostheses and enlarged atria: safety, feasibility, and efficacy.

OBJECTIVES: Few data have been published on transcatheter ablation of atrial fibrillation (AF) in patients with mitral valve prostheses. Thus, we sought to report our experience. BACKGROUND: Ablation is an effective treatment for AF. Patients with prosthetic mitral valves represent a special group because of an increased risk from the ablation procedure due to the possibility of damage to the prosthetic valve. METHODS: Between July 2001 and July 2003, 26 patients with mitral valve prostheses (MVP) underwent circumferential pulmonary vein ablation for AF. A matched group of 52 ablated patients without MVP acted as control subjects. After a blanking period of three months, a follow-up of 12 months was considered for MVP patients and controls. Holter recordings were performed in all subjects at 3, 6, and 12 months. RESULTS: Radiation exposure was higher in the MVP group, with fluoroscopy times of 35.3 +/- 21 min versus 20.9 +/- 15 min in controls. At the end of follow-up, 73% of MVP patients were in sinus rhythm, compared with 75% of controls. Atrial tachycardia occurred in six (23%) MVP patients, requiring repeat ablation in three, and one (2%) control subject, which settled without treatment. One transient ischemic attack and one femoral pseudoaneurysm occurred in the MVP group. No complications occurred in the control group. CONCLUSIONS: Ablation of AF in patients with MVP is feasible, with outcomes similar to those of standard patients. Complications were higher among MVP patients with a greater radiation exposure and a higher incidence of post-ablation atrial tachycardia.

Endocardial impedance mapping during circumferential pulmonary vein ablation of atrial fibrillation differentiates between atrial and venous tissue.

BACKGROUND: Circumferential pulmonary vein ablation (CPVA) is an effective treatment for atrial fibrillation (AF). Accurate left atrial (LA) mapping is essential for creating lesions at the LA-pulmonary vein (PV) junction, avoiding PV stenosis. OBJECTIVES: The purpose of this study was to establish whether endocardial impedance varies within the LA and PVs and whether it is a useful tool for mapping and ablation. METHODS: Pilot Phase: Three-dimensional LA maps were created using CARTO. Impedance (Z) was measured using a radiofrequency generator at multiple points in the LA, PV ostia (PVO), and deep PVs in 79 patients undergoing their first AF ablation (group 1) and 29 patients undergoing repeat CPVA (group 2). Prospective Phase: In an additional 20 patients, using pilot phase data, one operator defined catheter tip location as either LA or PVO based on CARTO and fluoroscopy. A second operator blinded to CARTO simultaneously did the same based on impedance at 15 +/- 4 points per patient. RESULTS: Group 1: Z(LA) was 99.4 +/- 9.0 omega. Z(PVO) was higher (109.2 +/- 8.5 omega), rising further as the catheter advanced into deep PV (137 omega +/- 18). Z(PVO) differed from Z(LA) by 9 +/- 4 omega. Group 2 had a lower Z(LA) and Z(PVO) compared with group 1 (P <.05). Impedance monitoring differentiated between LA and PVO, with 91% specificity and sensitivity, 96% positive predictive value, and 81% negative predictive value. At 3-month follow-up, no patients had evidence of PV stenosis on magnetic resonance imaging. CONCLUSION: Impedance mapping reliably identifies the LA-PV transitional zone, facilitating AF ablation, and its use is associated with a low incidence of PV stenosis.

Noxious arousal induces T-wave changes in healthy subjects.

BACKGROUND: Sudden arousal has been associated with sudden cardiac death in individuals with ischemic heart disease, cardiac arrhythmias, and the congenital long QT syndrome. This study aimed to determine the effects of arousal on ventricular repolarization in normal individuals by examining the dynamic QT interval-heart rate relationship and T-wave morphology changes under various "arousal" scenarios. METHODS: Eighteen healthy subjects (6 women and 12 men; median age, 22 years) underwent 4 separate 24-hour electrocardiogram recordings using 2-channel Holter recorders. The protocol contained 5 different arousal events: (1) natural waking (woke naturally, then stood up), (2) morning alarm (woken by alarm in the morning, then stood up); (3) night alarm (woken by alarm during the night, then stood up), (4) morning alarm-remain lying (woken by alarm in the morning but remained supine), and (5) lying to standing (stood up from a supine position during the day). Holter recordings were analyzed using a commercial package for dynamic assessment of the QT/RR relationship. RESULTS: In the 20 minutes after arousal, no changes were seen in overall QT/RR relationship in any of the groups. However, marked T-wave morphology changes, including T-wave inversion, were observed in all the arousal events. Postural changes only accounted for a small proportion of change in T-wave morphology. CONCLUSIONS: In healthy subjects, noxious arousal causes marked changes in the morphology of the T wave. This may reflect abnormal adaptation of repolarization to sudden changes in heart rate and autonomic tone.

Atrio-esophageal fistula as a complication of percutaneous transcatheter ablation of atrial fibrillation.

BACKGROUND: Radiofrequency ablation for atrial fibrillation is becoming widely practiced. METHODS AND RESULTS: Two patients undergoing circumferential pulmonary vein ablation for atrial fibrillation in different centers developed symptoms compatible with endocarditis 3 to 5 days after the procedure. Their clinical condition deteriorated rapidly, and both suffered multiple gaseous and/or septic embolic events causing cerebral and myocardial damage. One patient survived after emergency cardiac and esophageal surgery; the other died of extensive systemic embolization. An atrio-esophageal fistula was identified in both patients. CONCLUSIONS: Atrio-esophageal fistulas can occur after catheter ablation in the posterior wall of the left atrium. This diagnosis should be excluded in any patient with symptoms or signs of endocarditis after left atrial ablation, and expeditious cardiac surgery is critical if the diagnosis is confirmed. Lower power and temperature settings for applications of radiofrequency energy along the posterior left atrial wall may prevent further cases of fistula formation.

Hybrid long-term temporary pacing.

Prolonged temporary pacing is associated with frequent complications. We describe a patient with aortic endocarditis and acquired tri-fascicular block in whom back-up pacing was indicated. Using a Seldinger technique via a subclavian approach, a permanent active-fixation lead was positioned in the right ventricle. The lead was tunnelled subcutaneously for 6 cm, and the proximal end was connected to a standard single chamber pulse generator. The procedure was well tolerated and over a period of four months there were no complications or infection. The PR interval subsequently reduced in duration to 200 ms and as no episodes of AV block had occurred, the lead was easily removed with retraction of the helix and gentle traction.

Aortic valve replacement in a Jehovah's Witness: a case of multi-disciplinary clinical management for bloodless surgery.

An 81-year-old female Jehovah's Witness (JW) patient with severe aortic stenosis required aortic valve replacement (AVR). However, the patient's religious beliefs precluded the use of primary blood components. Since the definitive treatment of AVR required bloodless open heart surgery, careful peri-operative plans were set forth by a multi-disciplinary team involving the cardiothoracic surgeon, haematologist and anaesthetist. The patient went on to successfully recover postoperatively. This case highlights: 1) The importance of carefully navigating through the most recent clinical and ethical protocol involved in the surgical management of JW's. 2) The importance of preparing individually tailored pre, intra and postoperative plans that are delivered through a multi-disciplinary clinical team to ensure the best and safest possible outcomes.

Abnormalities of the repolarization characteristics of patients with heart failure progress with symptom severity.

BACKGROUND: Congestive heart failure is a common condition with high mortality. Many of these deaths are sudden and unexpected. Ventricular action potential, surface repolarization (QT interval), and dispersion of repolarization are prolonged in the failing heart, contributing to arrhythmogenesis and sudden death. We studied the relationship between QT and heart rate (RR interval) from ambulatory recordings using a novel method in patients with ischemic heart disease and varying degrees of left-ventricular impairment (IHD) and compared them to healthy subjects (HS). We compare the degree of abnormality with the functional impairment and ejection fraction. METHODS: Using a previously described automated method for continuous estimation of the QT/RR characteristic that incorporates a correction formula for compensation of QT adaptation lag (VERDA, Del Mar Reynolds Medical Ltd., Hertford, UK), we compared recordings from 41 IHD patients with age-matched HS. RESULTS: IHD Patients have prolonged 24-hour mean QTo (461 ms vs 426 ms, P < 0.01), and abnormal rate dependence relative to controls (24-hour mean slope: 0.20 vs 0.14, P < 0.001; J: 0.38 vs 0.28, P < 0.001). There is increased temporal variation in J with respect to HS. These abnormalities of repolarization increase with worsening NYHA class, but do not correlate with ejection fraction. CONCLUSIONS: The use of a universal correction formula to compare dynamic QT data in IHD patients is inappropriate. The observed progressive abnormalities may be responsible for the high incidence of sudden death through promotion of arrhythmias.

Left atrial tachycardia after circumferential pulmonary vein ablation for atrial fibrillation: electroanatomic characterization and treatment.

OBJECTIVES: The purpose of this study was to evaluate the electroanatomic characteristics of left atrial tachycardia (AT) in a series of patients who underwent circumferential pulmonary vein ablation (CPVA) and to describe the ablation strategy and clinical outcome. BACKGROUND: Circumferential pulmonary vein ablation is an effective treatment for atrial fibrillation. A potential midterm complication is the development of left AT. There are only isolated reports describing mapping and ablation of such arrhythmias. METHODS: Thirteen patients (age 57.4 +/- 8.9 years, five female) underwent mapping and ablation of 14 left ATs via an electroanatomic mapping system a mean of 2.6 +/- 1.6 months after CPVA. RESULTS: Three patients were characterized as having focal AT (cycle length: 266 +/- 35.9 ms). Of 11 macro-re-entrant tachycardias studied in the remaining 10 patients (cycle length: 275 +/- 75 ms), 5 showed single-loop and 6 dual-loop circuits. Re-entrant circuits used the mitral isthmus, the posterior wall, or gaps on previous encircling lines. Such gaps and all three foci occurred anterior to the left superior pulmonary vein or at the septal aspect of the right pulmonary veins. Thirteen of 14 tachycardias (93%) were successfully ablated. CONCLUSIONS: Left AT after CPVA can be due to a macro-re-entrant or focal mechanism. Re-entry occurs most commonly across the mitral isthmus, the posterior wall, or gaps on previous ablation lines. Such gaps and foci occur most commonly at the anterior aspect of the left superior pulmonary vein and at the septal aspect of the right pulmonary veins. These arrhythmias can be successfully mapped and ablated with an electroanatomic mapping system.