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.

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.

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.

Myocardial infarction and biventricular free-wall rupture with shunting through a false aneurysm.

A 65-year-old man presented with acute inferior myocardial infarction and received thrombolytic therapy with clinical evidence of coronary arterial recanalisation. Recovery was uncomplicated until- the eighth day when he experienced recurrent chest pain with evidence of reinfarction in the same territory. This was associated with the development of a pansystolic murmur and cardiogenic shock. Cardiac catheterisation showed right coronary arterial occlusion and inferior infarction with a false aneurysm and a left-to-right shunt (shunt ratio 2.5:1). Surgery confirmed the formation of a false aneurysm caused by rupture of the free walls of both ventricles. Importantly, however, the interventricular septum was intact and the left-to-right shunt was through the false aneurysm itself. This is the first report of biventricular free-wall rupture with shunting through a false aneurysm treated successfully by surgery.

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.

Open access exercise electrocardiography: does it improve the management of cardiovascular disease in the community?

In this study the use of exercise electrocardiography, by 47 general practitioners in South East Kent has been evaluated. Of 110 consecutive requests the majority (88%) were for diagnostic purposes, while only 7% were for prognostic assessment. Many of those referred were young or had non-cardiac chest pain and in 59% of cases the test result was unlikely to alter the clinical assessment of the probability of ischaemic heart disease (IHD). The test result influenced patient management in 85% of cases. Only 15% of patients were subsequently referred to the district general hospital although all had been considered for referral prior to the test. Although referral for invasive investigation of six patients was expedited by the provision of stress testing, in five patients general practitioners failed to consider any further investigation despite the patient having a strongly positive test. General practitioners use exercise electrocardiography primarily to exclude IHD in patients at low risk and provide reassurance. They rarely use the test as a means to guide management of those with known or probable IHD.

Open access exercise electrocardiography: a service to improve management of ischaemic heart disease by general practitioners.

An initial study of the use of open access exercise electrocardiography by general practitioners (GPs) in South East Kent showed that patient selection and interpretation of test results was frequently incorrect. After issuing guidelines, modifying the request form and instituting registrar review of all requests, significant improvements in both referral pattern, result interpretation and patient management have resulted. Forty-nine GPs requested 110 exercise tests during 1988/89. Twelve per cent were not undertaken after discussion with the referring practitioner. Eighty-four per cent of those tested would have been referred to the district general hospital cardiology outpatient department in the absence of open access exercise electrocardiography service. Six per cent of patients were referred directly for invasive investigation. Thirty-five per cent were referred to the district general hospital cardiology outpatient department, whilst 42% were spared hospital referral based on the result of the investigation. Better use of the modified service was suggested by: referral of fewer patients with non-cardiac chest pains (P = 0.002); more patients with a moderate pre-test probability of ischaemic heart disease (P less than 0.05); fewer inappropriate requests (P less than 0.01); and fewer inappropriately undertaken tests (P less than 0.001) than in the previous study. All patients with strongly positive test results were appropriately managed. Open access exercise electrocardiography in the format investigated is potentially a cost-effective and useful tool to improve diagnosis and management of heart disease by GPs.

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.

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.

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.

Cardiac involvement by lymphoma: diagnostic difficulties.

A patient presenting with recurrent tamponade was subsequently shown to have non-Hodgkin's lymphoma. Catheterization demonstrated obstruction of the tricuspid valve by tumour and shunting through a patent foramen ovale. The difficulties in making an ante-mortem diagnosis of cardiac lymphoma are discussed.

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.

Influence of propranolol on the ventricular depolarization gradient.

Sensing of the ventricular depolarization gradient (VDG) has recently been used as the basis of a closed-loop rate responsive pacemaker. Factors influencing this aspect of the evoked response have not been fully evaluated although previous reports have suggested that sympathetic stimulation and circulating catecholamines are primarily responsible for the observed changes during stress and exercise. In five patients (Table I), four males and one female (mean age 60.4 +/- 10.1 years) implanted with the Prism pacemaker, the pacing response to exercise and tilting was assessed before and after the infusion of propranolol. There was an increase in the pacing rate in all patients during the infusion of the drug (mean 27 +/- 12.9 beats/min) suggestive of a direct drug effect on the VDG. The rate control parameter (RCP) of the pacemaker, the numerical equivalent of the VDG, was significantly different after the administration of propranolol (P less than 0.01). However, exercise performance and pacing rate behavior were not different after beta blockade. The pacing rate increase observed when tilting patients to the supine position was not altered by propranolol. Out date suggest that factors other than adrenergic stimulation may be of importance in affecting the ventricular evoked response and accordingly the rate adaptation of the Prism pacemaker.