Simplified electrocardiogram sampling maintains high diagnostic capability for atrial fibrillation: implications for opportunistic atrial fibrillation screening in primary care.

AIMS: Atrial fibrillation (AF) is a major cause of morbidity, mortality, and health resource consumption. However, as many patients with chronic AF are asymptomatic, rapid, accurate opportunistic screening is needed in primary care to detect AF. Conventional electrocardiogram (ECG) technology is too clumsy and time consuming for mass opportunistic screening, thus technology that allows easy, rapid, yet accurate AF screening is required. To address this requirement a prototype hand-held electrode assembly was developed. We hypothesized that a 6-lead frontal-plane ECG acquired from this apparatus in a seated, clothed patient would be as accurate at detecting AF as conventional 12-lead ECG in the undressed, supine patient (the 'gold standard'). METHODS AND RESULTS: Electrocardiograms were obtained from 78 patients with AF and 79 with sinus rhythm (SR). All had a conventional 12-lead ECG, a 6-lead ECG from conventionally positioned limb electrodes, a supine 6-lead recording using the prototype recorder placed on the lower thorax/upper abdomen, and a 6-lead prototype recording in the seated patient, the latter with loosened clothing only. Electrocardiograms were randomly and blindly assessed by two cardiologists for (i) diagnosis of AF vs. SR and (ii) tracing quality (subjectively assessed as good, adequate, or bad). Compared with conventional 12-lead ECG recordings, all 'new' recording methods performed satisfactorily with sensitivities ≥90% (90-99%), specificities ≥94% (94-100%), positive predictive values ≥94% (94-100%), negative predictive values ≥90% (90-99%), and accuracies ≥93% (93-99%). Tracing quality was higher in conventional 12-lead recordings (71 and 80% were assessed as good by the two observers) compared with conventional 6-lead (57 and 59%), supine prototype (41 and 31%), and sitting prototype (39 and 19%). CONCLUSIONS: Despite inferior electrocardiographic quality a 6-lead frontal plane ECG acquired by a simple prototype hand-held electrode assembly allowed reliable differentiation of AF from SR compared with standard 12-lead ECG.

Safety and acceptability of implantation of internal cardioverter-defibrillators under local anesthetic and conscious sedation.

BACKGROUND: Implantation and testing of implantable defibrillators (ICDs) using local anesthetic and conscious sedation is widely practiced; however, some centers still use general anesthesia. We assessed safety and patient acceptability for implantation of defibrillators using local anesthetic and conscious sedation. METHODS: The records of 500 consecutive device implants from two UK cardiac centers implanted under local anesthetic and conscious sedation from January 1996 to December 2004 were reviewed. Procedure time, left ventricular ejection fraction (LVEF) sedative dosage (midazolam), analgesic dosage (fentanyl or diamorphine), requirement for drug reversal, and respiratory support were recorded. Patient acceptability of the procedure was also assessed. RESULTS: Of 500 implants examined, 387 were ICDs, 88 were biventricular ICDs, and 25 were generator changes. Patients with biventricular-ICDs had significantly longer (mean +/- SD) procedure times 129.7 +/- 7.6 minutes versus 63.3 +/- 32.3 minutes; P < 0.0001 and lower LVEF 24.4 +/- 8.4% versus 35.7 +/- 15.4%; P < 0.0001. There were no differences in the doses (mean +/- SD) of midazolam 8.9 +/- 3.5 mg versus 8.0 +/- 3.1 mg; P = NS, diamorphine 4.3 +/- 2.0 mg versus 3.8 +/- 1.7 mg; P = NS or fentanyl 94.4 +/- 53.7 mcg versus 92.2 +/- 48.6 mcg; P = NS, between the two groups. There were no deaths or tracheal intubations in either group. Acceptability was available for 373 of 500 (75%) patients, 41 of 373 (11%) described "discomfort," but from these 41 patients only 14 of 373 (3.8%) declined a second procedure under the same conditions. CONCLUSIONS: Implantation of defibrillators under local anesthetic and sedation is safe and acceptable to patients. General anesthesia is no longer routinely required for implantation of defibrillators.

Management of atrial arrhythmias 3: paroxysmal atrial fibrillation.

This is the third in a series of four practical articles highlighting the important management steps for non-cardiologists and non-cardiac electrophysiologists dealing with patients with atrial fibrillation and common atrial flutter. This article will deal with care pathways and management principles for paroxysmal atrial fibrillation.

Practical management of common atrial arrhy thmias 2: common atrial flutter.

This is the second in a series of four practical articles highlighting the important management steps for noncardiologists and non-cardiac electrophysiologists dealing with patients with atrial fibrillation and common atrial flutter. This article will deal with care pathways and management principles for common atrial flutter.

Practical management of common atrial arrhythmias 1: cardioversion.

This is the first in a series of four practical articles highlighting the important management steps for non-cardiologists and non-cardiac electrophysiologists dealing with patients with atrial fibrillation and common atrial flutter. This article will deal with care pathways and management principles for cardioversion of atrial arrhythmias.

How to avoid a misdiagnosis in patients presenting with transient loss of consciousness.

Daily in the UK, frontline medical and paramedical staff are required to manage patients with "collapse ?cause". This universal colloquialism refers to patients who have had an abrupt loss of postural tone. Some of these patients would have had a "blackout" or a transient loss of consciousness (T-LOC). The three most important causes of T-LOC are syncope, epilepsy and psychogenic blackouts. Determining the correct cause is an important challenge; if the initial clinical diagnosis is wrong, investigations may be misdirected, and the final diagnosis and treatment incorrect. Syncope is much more common than epilepsy and may present with symptoms akin to the latter. This fact is not well appreciated and often leads to misdiagnosis. This article deals with the clinical features of the three main causes of blackouts, the value of investigations in arriving at a diagnosis and the problem of misdiagnosis. Pathways for managing patients presenting with blackouts are suggested.

Upgrading patients with chronic defibrillator leads to a biventricular system and reducing patient risk: contralateral LV lead placement.

Increasing numbers of patients with indwelling single- or dual- chamber internal cardioverter defibrillators (ICDs) will require upgrading of an existing system to a biventricular ICD providing cardiac resynchronization with back-up defibrillation. Upgrading, usually by the addition of a new left ventricular (LV) lead, can be technically challenging with central venous occlusion or stenosis often being the main obstacle to a successful procedure. We report a new technique of implanting a LV lead from the contralateral side to the existing ICD system to minimize the peri- and postoperative risk to the patient.

Biventricular pacing in a patient with ventilatory and inotropic dependant heart failure following coronary artery by-pass surgery.

Resynchronisation of intra- and interventricular conduction delay by biventricular pacing has become a proven therapy for selected heart failure patients. We present a case of biventricular pacing, used with great success, as a 'bail out' for a patient with refractory congestive heart failure following by-pass surgery.

Holter monitoring vs tilt testing in the investigation of suspected vasovagal syncope.

The aim of this study was to compare the diagnostic yield of 48-hour Holter monitoring with head-up tilt (HUT) test in patients presenting with blackouts suggestive of vasovagal syncope. One hundred and eighteen consecutive patients, 68 women, aged (mean [SD])50 +/- 20 years(range 16-88 years), underwent 48-hour Holter monitoring and 60 degrees HUT test within 3 months. Endpoints were symptom-ECG correlation during Holter monitoring and positive HUT test. Syncope occurred in 3 (3%) patients during Holter monitoring, the rhythm being sinus tachycardia in all. Presyncope was reported in 22 (19%), the rhythm being sinus tachycardia in 6, persistent atrial fibrillation in 2, and normal sinus rhythm in the remainder. Asymptomatic arrhythmias were recorded in 103 (87%) patients. Positive HUT tests occurred in 39 (33%), the pattern being mixed (VASIS type 1) in 14 (36%), cardioinhibitory (VASIS type 2) in 3 (8%), and vasodepressor (VASIS type 3) in 22 (56%). Change in patient management occurred in 3 (3%) patients following Holter monitoring and 39 (33%) patients following HUT test. Holter monitoring produces a low yield of clinically useful information in the investigation of suspected vasovagal syncope. An HUT test should be considered the primary investigation of choice in such patients.

Effect of amiodarone on dispersion of atrial refractoriness and cycle length in patients with atrial fibrillation.

INTRODUCTION: Amiodarone is effective in preventing the recurrence of atrial fibrillation (AF) after cardioversion (CV). Dispersion of atrial refractoriness may be relevant to the generation of AF. We designed a study to determine the electrophysiologic effects of amiodarone in patients with previous early recurrence of AF after CV. METHODS AND RESULTS: Fifteen patients with previous AF recurrence (without antiarrhythmic drugs) after CV (CV1) were selected for amiodarone therapy and repeat CV (CVamio). Prior to CV1, mean AF cycle length (AFCL) had been recorded at four atrial sites (right atrial appendage [RAA], distal coronary sinus [DCS], right atrial lateral wall [LAT], and interatrial septum [IAS]) and dispersion of AFCL had been calculated. These patients were treated with amiodarone and, prior to CVamio, AFCL was recorded at the four atrial sites as for CV1. Between CV1 and CVamio, AFCL increased at all atrial sites: 153 +/- 13 msec to 179 +/- 14 msec at RAA, 144 +/- 12 msec to 174 +/- 18 msec at DCS, 158 +/- 13 msec to 182 +/- 16 msec at LAT, and 161 +/- 18 msec to 181 +/- 17 msec at IAS. Dispersion of AFCL decreased from 24 +/- 10 msec at CV1 to 15 +/- 11 msec at CVamio (P = 0.01). The median time in sinus rhythm increased from 3.12 hours post CV1 to 28 days post CVamio, (P < 0.02). CONCLUSION: Amiodarone causes a reduction in the dispersion of AFCL. This action may be relevant to the beneficial effects of amiodarone in patients with AF.

Clinical evaluation of a policy of early repeated internal cardioversion for recurrence of atrial fibrillation.

INTRODUCTION: The clinical value of cardioversion (CV) of persistent atrial fibrillation (AF) is limited by the high rate of early AF recurrence, which may be related to the persistence of atrial electrical remodeling. We examined the hypothesis that the likelihood of maintaining sinus rhythm after CV of persistent AF is significantly enhanced by a policy of early repeated CV. METHODS AND RESULTS: Fifty-nine patients with persistent AF underwent internal CV (CV 1). Those patients cardioverted were monitored with daily transtelephonic ECG. In the event of AF recurrence, these patients were admitted rapidly for repeat CV (CV 2) and, if further recurrence occurred, a third CV (CV 3) was performed. Daily ECG monitoring was continued until 1 month of sinus rhythm was maintained or a total of three CVs were performed. Of the 59 patients undergoing CV 1, 43 were discharged in sinus rhythm and 29 subsequently had AF recurrence during monitoring. Twenty-three of these underwent CV 2 and 11 of these underwent CV 3. Of those having repeated CVs, only 4 patients maintained sinus rhythm for 1 month (3 after CV 2 and 1 after CV 3). The remaining patients had repeated AF recurrence during the monitoring period. Mean time from AF recurrence to CV 2 was 20+/-13 hours and from AF recurrence to CV 3 was 13+/-7.2 hours. Atrial effective refractory periods increased from 189+/-16 msec at CV 1 to 215+/-18 msec at CV 3 (P < 0.05), indicating reversal of atrial electrical remodeling during this period. CONCLUSION: A policy of early repeated CVs for AF recurrence has very limited clinical value despite evidence of reversal of atrial electrical remodeling. The time between AF recurrence and repeat CV may need to be reduced further if such a policy is to succeed.