Safety, effectiveness and cost efficacy of diagnostic electrophysiology and radiofrequency ablation in a district general hospital.

Electrophysiological studies (EPS) are now being performed in district general hospitals (DGH) in the UK. In order to audit our results, a prospective database was established for all patients undergoing EPS and radiofrequency (RF) ablation at Eastbourne District General Hospital, East Sussex. Between 1 January 1997 and 1 July 2000, 300 EPS procedures were performed, resulting in 155 RF ablations. The average RF ablation procedure time was 119.3 minutes with an average fluoroscopy time of 19.1 minutes. Cost per RF ablation procedure was 1166.79 Pounds excluding use of facilities, pacemaker devices, medical nursing and radiography staffing costs. The overall success rate for RF ablation was 93.6% with a major complication rate of 0.6%, a total complication rate of 3.9% and no associated mortality. We have shown that RF ablation can be performed safely, effectively and economically in a DGH setting with a high rate of success and a low complication rate.

Influence of clinical and angiographic factors on development of collateral channels.

BACKGROUND: The degree of coronary collateralization is believed to be related to several clinical and angiographic factors. The duration and frequency of angina may be important factors in determining development of collateral channels. OBJECTIVE: To assess these factors for a consecutive series of patients suspected to have coronary artery disease. METHODS: Patients without at least one stenosis of < 50% and patients who had previously undergone bypass surgery were excluded from our study. Severity of stenosis was quantified by digital analysis, antegrade flow in terms of TIMI grade, and collaterals using the Rentrop classification. RESULTS: We reviewed 106 patients [mean age 61 years (range 35-84), 77.6% men]. Of these, 22 (21%) had presented with an acute coronary syndrome on this admission, whilst 46 patients (43%) had previously had an acute coronary syndrome. Collaterals were more likely in patients with stenoses of > 90% (Spearman correlation 0.65, P < 0.001) in patients with lower than normal TIMI flow grade (Spearman correlation 0.86, P < 0.01) and were related to regions of hypokinesis (Spearman correlation 0.35, P < 0.01). Significant collaterals were present in 14 patients (13%) despite their having TIMI grade II/III flow. Two of these patients had grade 2/3 collaterals with TIMI grade II/III antegrade flow. Degree of collateralization was not related to chronicity and frequency of symptoms, age, risk factors for atherosclerosis and nature of presentation (i.e. acute or stable symptoms). CONCLUSION: The likelihood of coronary collateralization cannot be prospectively predicted from clinical history alone, but appears to be largely a function of severity of stenosis and level of antegrade flow. A few patients develop high-grade collateral channels despite the presence of good antegrade flow.

Dissection of the coronary sinus secondary to pacemaker lead manipulation.

We report a 64-year-old man with atrial fibrillation and impaired left ventricular function in whom pacemaker lead manipulation during biatrial pacemaker lead removal and biventricular pacemaker lead insertion caused coronary sinus dissection. After further manipulation of the biventricular pacing lead, the true lumen of the coronary sinus could be entered and satisfactory left ventricular pacing undertaken. The dissection was managed conservatively without long-term sequelae.

Stabilisation of medically refractory ventricular arrhythmia by intra-aortic balloon counterpulsation.

OBJECTIVE: To review the efficacy of intra-aortic balloon counterpulsation (IABCP) in medically refractory ventricular arrhythmia. DESIGN: Retrospective analysis of the outcome of patients with ventricular arrhythmia treated with IABCP after transfer between 1992 and 1997. SETTING: Tertiary cardiac referral centre. PATIENTS: 21 patients (mean age 58 years) who underwent IABCP for control of ventricular arrhythmia. All had significant left ventricular impairment (mean ejection fraction 28.6%); 18 had coronary artery disease. RESULTS: Before IABCP, 10 patients had incessant monomorphic ventricular tachycardia and 11 had paroxysmal ventricular tachycardia and/or ventricular fibrillation (VT/VF). IABCP resulted in suppression of ventricular arrhythmia in 18 patients, of whom 13 were weaned from IABCP. After stabilisation of ventricular arrhythmia, 10 patients were maintained on medical treatment alone and one underwent endocardial resection. IABCP was maintained until cardiac transplantation in five patients. One patient had a fatal arrest before discharge and one died from progressive heart failure. IABCP failed to control ventricular arrhythmia in three patients and was subsequently discontinued. A cardiac assist device was employed in one of these until cardiac transplantation; the other two were eventually stabilised on medical treatment. Nineteen patients were discharged from hospital. Overall survival was 95% at mean follow up of 25.7 months. CONCLUSIONS: IABCP can be an effective means of controlling refractory ventricular arrhythmia, allowing time for the institution of more definitive treatment.

The use of a "side-wire" permanent transvenous pacing electrode for left ventricular pacing.

It has been reported that biventricular pacing can improve the symptomatic status of patients with heart failure. However, using currently available transvenous left ventricular pacemaker leads the implantation procedure is difficult and has a high failure rate. We report the successful use of a new type of left ventricular pacing lead, the 'side-wire' pacing lead. This lead is initially introduced through a specifically designed guiding sheath to aid coronary sinus cannulation and then over a pre-positioned guide wire to aid final positioning. The more widespread introduction of this type of left ventricular pacing lead may reduce the difficulty of left ventricular pacing via the coronary sinus and thus improve the overall success rate of this therapeutic approach.

Biventricular implantable cardioverter defibrillator use in a patient with heart failure and ventricular tachycardia secondary to Emery-Dreifuss syndrome.

We report a case of fully transvenous single-unit biventricular implantable cardioverter defibrillator (ICD) use in a 43-year-old woman with a manifesting carrier form of muscular dystrophy (Emery-Dreifuss syndrome). The indication for biventricular ICD use was progressive heart failure with ventricular arrhythmia, permanent atrial fibrillation and previous VVIR pacemaker insertion. Single-unit transvenous biventricular ICD implantation was undertaken without complication. No potentially serious device malfunction was noted during subsequent follow-up. We conclude that single-unit biventricular ICD implantation is feasible for pacing and ventricular tachyarrhythmia control in patients with underlying atrial fibrillation.

Direct relationship between ischaemic burden and myocardial release of products of lipid peroxidation in patients undergoing percutaneous transluminal coronary angioplasty.

BACKGROUND: Recent studies have shown that free radical activity is increased in humans during percutaneous transluminal coronary angioplasty. These studies, however, have failed to localize the site of free radical activity or to demonstrate a relationship between ischaemic burden and free radical production. METHODS: The relationship between ischaemic burden and subsequent lipid peroxidation was studied during 16 inflations in eight patients undergoing angioplasty to anterior descending artery lesions. Two inflations 15 min apart were studied in each patient, one using a conventional (occlusive) balloon and one using the ACS Rx 'perfusion' balloon. The severity of the ischaemic insult associated with each inflation was assessed by contrast ventriculography, change in left ventricular end-diastolic pressure and myocardial lactate release 30 s after balloon deflation. Plasma levels of lipid peroxidation products were assessed by analysis of thiobarbituric-acid-reactive substances. RESULTS: A direct relationship was observed between the ischaemic burden and the myocardial release of lipid peroxidation products over the first 4 min after balloon deflation (F = 5.6; P < 0.006). In each patient, one of the inflations was associated with a greater degree of ischaemia. Left ventricular ejection fraction was lower (P < 0.001) and left ventricular end-diastolic pressure was higher (P < 0.002) during the 'ischaemic' inflations. Myocardial release of lipid peroxidation products was significantly higher after the 'ischaemic' balloon inflation (F = 7.65; P < 0.009). CONCLUSION: Brief periods of human myocardial ischaemia result in myocardial release of lipid peroxidation products in direct proportion to the severity of the preceding ischaemic insult.

Haemodynamic deterioration after treatment with adenosine.

A 26 year old woman presented with a narrow complex tachycardia with a rate of 210 beats/min. Adenosine converted this to atrial fibrillation with a rate of 280 beats/min with associated haemodynamic deterioration that needed electrical cardioversion.

Survey of the attitudes of British physicians to pacing.

OBJECTIVES: To assess how the opinions of cardiologists, physicians, and general practitioners on the indications for permanent pacing compare with published guidelines, and to determine whether resources, pacing experience, and position influence referral practices. DESIGN: Anonymous postal survey by questionnaire from St Bartholomew's Hospital, London and the King's Fund Institute, London. The questionnaire established the respondent's position, resources, and previous pacing experience. Eleven clinical and electrocardiographic situations were described and respondents were asked to decide on whether pacing was indicated. The responses received were compared with the guidelines provided by the 1984 American College of Cardiology/American Heart Association task force. PARTICIPANTS: The 630 members of the British Cardiac Society, 1370 randomly selected general physicians, and 2000 general practitioners. RESULTS: Patients with symptoms were more likely to be referred for pacing than symptom free patients regardless of underlying aetiology. In relatively symptom free patients the frequency with which pacing was recommended was low, even when it was unequivocally indicated on prognostic grounds. Failure to recommend pacing was unrelated to diagnostic facilities or referral difficulties. Respondents with pacing experience were more likely to recommend pacing. CONCLUSIONS: The physicians surveyed had a conservative approach towards recommending pacing. Most physicians were influenced predominantly by symptoms and the prognostic indications for pacing were not well appreciated.

The use of intra-aortic balloon counterpulsation in malignant ventricular arrhythmias.

We describe a patient with recurrent ventricular arrhythmias post anterior myocardial infarction who stabilised following intra-aortic balloon counterpulsation. Antiarrhythmic drugs and continuous ventricular pacing were ineffective. The possible mechanisms of the improvement with counterpulsation and other treatment options are discussed.

A prospective study of the efficacy and safety of adjuvant metoprolol and xamoterol in combination with amiodarone for resistant ventricular tachycardia associated with impaired left ventricular function.

Combination antiarrhythmic drug therapy may be more effective than treatment with a single agent for control of refractory cases of sustained ventricular tachycardia (VT). In a prospective randomized crossover study of 20 patients with impaired left ventricular function (ejection fraction of 28% +/- 8%) and recurrent VT in spite of treatment with amiodarone, we compared the efficacy and safety of adjuvant therapy with metoprolol, 50 mg two times daily and xamoterol, 200 mg two times daily. Metoprolol caused hemodynamic deterioration in five patients, and only one also experienced intolerance to xamoterol. Sustained VT was inducible in all 20 patients who were receiving amiodarone alone but was suppressed or rendered nonsustained in 8 of 20 patients during treatment with amiodarone plus xamoterol and in 6 of 17 patients during treatment with amiodarone plus metoprolol. Addition of xamoterol restored sinus rhythm in four patients who presented with incessant VT, and metoprolol was effective for three of them. Neither beta-blocker significantly altered tachycardia cycle length or any electrophysiologic parameter other than the slowing of the sinus rate. Both beta-blockers suppressed exercise-induced VT in 3 of 4 patients, and addition of xamoterol significantly increased treadmill exercise duration (7.1 +/- 1.8 min) compared with administration of amiodarone alone (3.8 +/- 1.5 min; p < 0.01). Fourteen patients were discharged with prescriptions for amiodarone-beta-blocker combinations. During a mean follow-up period of 13 months (range, 2 to 24 months), there were three cases of recurrent VT (in all patients VT remained inducible) and no sudden deaths.(ABSTRACT TRUNCATED AT 250 WORDS)

Differentiation between monomorphic ventricular tachycardia and sinus tachycardia based on the right ventricular evoked potential.

The differentiation between ventricular tachycardia (VT) and sinus tachycardia (ST) is problematic in some patients with implantable defibrillators and/or antitachycardia pacemakers. The integral of the ventricular endocardial evoked response, or paced depolarization integral (PDI), has been demonstrated to undergo characteristic changes with a variety of stimuli including catecholamines, pacing rate, and exercise. We hypothesized that the PDI recorded from a unipolar transvenous right ventricular endocardial catheter would differentiate VT from ST. The PDI was calculated from a unipolar pacing stimulus, delivered via a cathode in the right ventricular apex, and the reference electrode, a quadripolar catheter positioned in the superior vena cava. PDIs were measured in 22 patients during VT and sinus rhythm. The PDI measured during sinus rhythm was 579 +/- 240 microV-sec and the PDI during VT was 894 +/- 411 microV-sec (P < 0.001). In a subset of seven patients, PDIs were measured during VT, sinus rhythm, and ST induced by catecholamine infusion or exercise. In this subset, the PDI during sinus rhythm was 645 +/- 295 microV-sec, during ST 588 +/- 308 microV-sec (9% decrease from sinus, P = 0.05), and during VT 863 +/- 342 microV-sec (33.9% increase, P = 0.01). These data indicate that the measurement of the PDI is potentially useful in differentiating VT from ST.

Transtelephonic interrogation of the implantable cardioverter defibrillator.

Third generation implantable cardioverter defibrillators (ICDs) have extensive memory capability to store data about the patient's arrhythmias and the effect of therapies delivered by the ICD. However, this data has so far been accessible only when the patient attends the pacing clinic. Two Medtronic 9421 PCD TeletraceR transmitters have been used to interrogate Medtronic 7216A and 7217B PCD S at distances of up to 300 miles from our hospital and transmit the data to a 9420 PCD TeletraceR receiver. Successful transmission of data has been obtained on 50 occasions with 100% data concordance with repeat transmission. The system can reduce the number of unscheduled clinic visits, reduce delay in making a diagnosis following unexpected delivery of a shock therapy, and reassure patients about to be discharged following ICD implantation. The benefits are magnified where patients reside far away from the implanting center.

Comparative electrophysiological effects of captopril or hydralazine combined with nitrate in patients with left ventricular dysfunction and inducible ventricular tachycardia.

OBJECTIVE: To assess the electrophysiological and antiarrhythmic effects of pharmacological load manipulation by an angiotensin converting enzyme (ACE) inhibitor (captopril) and a direct vasodilator (hydralazine plus isosorbide mononitrate) in patients with inducible ventricular tachycardia and impaired left ventricular function. DESIGN: Randomised open label cross-over comparison of three regimens. SETTING: Tertiary arrhythmia referral centre. SUBJECTS: Eight patients with reduced left ventricular function and sustained ventricular tachycardia inducible by programmed stimulation. INTERVENTIONS: Three treatment regimens each of 48 hours duration: captopril, hydralazine plus isosorbide mononitrate, and control (no vasodilator). MAIN OUTCOME MEASURES: Changes in central haemodynamics, electrophysiological parameters, and induction of ventricular tachycardia during treatment with captopril, or hydralazine combined with nitrate, compared with a control period. RESULTS: Both vasodilator treatments produced similar balanced reductions in peak systolic pressures and filling pressures compared with controls. Captopril had no effect on sinus cycle length, atrial refractoriness, or intraventricular conduction, but prolonged ventricular effective and functional refractory periods and QT interval during constant rate atrial pacing. Hydralazine combined with nitrate did not significantly alter any electrophysiological variable. Ventricular tachycardia was similarly inducible during all three periods. CONCLUSIONS: Load manipulation by captopril but not hydralazine combined with nitrate prolonged ventricular refractoriness and repolarisation, possibly reflecting a combination of mechano-electrical effect with the restraining influence of ACE inhibitors on reflex sympathetic stimulation.

The electrophysiological effects of flosequinan.

We have evaluated the acute electrophysiological effects of flosequinan in 18 patients with normal ventricular function. Following intravenous infusion of flosequinan 100 mg over 1 h, mean (SD) systolic blood pressure fell from 131 +/- 19 to 120 +/- 22 mmHg (P less than 0.02) and there was significant shortening of sinus cycle length (732 +/- 151 to 575 +/- 93 ms, P less than 0.001), AH interval (110 +/- 45 to 71 +/- 19 ms, P less than 0.01), QRS duration (98 +/- 28 to 91 +/- 26 ms, P less than 0.02) and QT interval (373 +/- 47 to 337 +/- 35 ms, P less than 0.001), but no change in sinus node recovery time, intra-atrial conduction time, HV interval or the corrected QTc interval. There was a reduction in both anterograde atrioventricular Wenckebach cycle length (299 +/- 53 to 259 +/- 52 ms, P less than 0.01) and retrograde ventriculoatrial Wenckebach cycle length (375 +/- 77 to 300 +/- 56 ms, P less than 0.01). There was no change in atrial or ventricular effective refractory period (ERP) but atrial functional refractory period (FRP) shortened (233 +/- 31 to 212 +/- 24 ms, P = 0.07) as did ventricular FRP (249 +/- 24 to 234 +/- 21 ms, P less than 0.01). Patients received an oral dose of flosequinan 50 mg 12 h later. By 24 h, sinus cycle length, QRS duration and the QT interval had all returned towards baseline values, but ventricular ERP had lengthened (199 +/- 22 to 215 +/- 26 ms, P less than 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)