European survey on efficacy and safety of duty-cycled radiofrequency ablation for atrial fibrillation

AIMS

Duty-cycled radiofrequency ablation (RFA) has been used for atrial fibrillation (AF) for around 5 years, but large-scale data are scarce. The purpose of this survey was to report the outcome of the technique.

METHODS AND RESULTS

A survey was conducted among 20 centres from seven European countries including 2748 patients (2128 with paroxysmal and 620 with persistent AF). In paroxysmal AF an overall success rate of 82% [median 80%, interquartile range (IQR) 74-90%], a first procedure success rate of 72% [median 74% (IQR 59-83%)], and a success of antiarrhythmic medication of 59% [median 60% (IQR 39-72%)] was reported. In persistent AF, success rates were significantly lower with 70% [median 74% (IQR 60-92%)]; P = 0.05) as well as the first procedure success rate of 58% [median 55% (IQR 47-81%)]; P = 0.001). The overall success rate was similar among higher and lower volume centres and were not dependent on the duration of experience with duty-cycled RFA (r = -0.08, P = 0.72). Complications were observed in 108 (3.9%) patients, including 31 (1.1%) with symptomatic transient ischaemic attack or stroke, which had the same incidence in paroxysmal and persistent AF (1.1 vs. 1.1%) and was unrelated to the case load (r = 0.24, P = 0.15), bridging anticoagulation to low molecular heparin, routine administration of heparin over the long sheath, whether a transoesophageal echocardiogram was performed in every patient or not and average procedure times.

CONCLUSION

Duty-cycled RFA has a self-reported success and complication rate similar to conventional RFA. After technical modifications a prospective registry with controlled data monitoring should be conducted to assess outcome.

It's good to talk! Changes in coronary revascularisation practice in PCI centres without onsite surgical cover and the impact of an angiography video conferencing system

INTRODUCTION

Percutaneous coronary intervention (PCI) activity has increased more than 6 fold in the last 15 years. Increased demand has been met by PCI centres without on-site surgical facilities. To improve communication between cardiologists and surgeons at a remote centre, we have developed a video conferencing system using standard internet links. The effect of this video data link (VDL) on referral pattern and patient selection for revascularisation was assessed prospectively after introduction of a joint cardiology conference (JCC) using the system.

METHODS

Between 1st October 2005 and 31st March 2007, 1346 patients underwent diagnostic coronary angiography (CA). Of these, 114 patients were discussed at a cardiology conference (CC) attended by three consultant cardiologists (pre-VDL). In April 2007, the VDL system was introduced. Between 1st April 2007 and 30th September 2008, 1428 patients underwent diagnostic CA. Of these, 120 patients were discussed at a JCC attended by four consultant cardiologists and two consultant cardiothoracic surgeons (post-VDL). Following case-matching for patient demographics and coronary artery disease (CAD) severity and distribution, we assessed the effect upon management decisions arising from both the pre- and post-VDL JCC meetings.

RESULTS

When comparing decision-making outcomes of post-VDL JCC with pre-VDL CC, significantly fewer patients were recommended for PCI (36.8% vs. 17.2% respectively, p = 0.001) and significantly more patients were recommended for surgery (21.1% vs. 48.4% respectively, p < 0.001). There were no significant differences in waiting times for PCI following JCC discussion; however, waiting times for surgical revascularisation were significantly reduced (140.9 ± 71.8 days vs. 99.4 ± 56.6 days respectively, p = 0.045).

CONCLUSIONS

  The VDL system provides a highly practical method for PCI centres without onsite surgical cover to discuss complex patients requiring coronary revascularisation and significantly increases the number of patients referred for surgical revascularisation rather than PCI.

The evaluation of pulmonary vein isolation and wide-area left atrial ablation to treat atrial fibrillation in patients with implanted permanent pacemakers: the Previously Paced Pulmonary Vein Isolation Study

BACKGROUND

The practise of catheter ablation for atrial fibrillation (AF) is increasing rapidly and is recommended as the treatment of choice in many patient subgroups. At present, the efficacy of this procedure has been assessed by means of electrocardiographic recording, intermittent Holter monitoring and evaluation of patient symptoms. We sought to evaluate the true efficacy of this procedure in patients with sophisticated permanent pacemakers capable of continuous long-term cardiac rhythm monitoring.

METHODS

Twenty-five patients (aged 63.7 (9.4), 20 men), seven with persistent AF and 18 with prolonged paroxysmal AF, underwent a mean of 1.7 AF ablation procedures. All the patients had previously been implanted with a pacemaker or atrial defibrillator device. Data were downloaded from the device Holter before catheter ablation and at 2, 4, 6 and 8 months postprocedure(s). The primary outcome measure was AF burden. The secondary outcomes were patient symptom and quality-of-life measures.

RESULTS

Initial AF burden was 43.8 (35.5)%. After catheter ablation(s), this was significantly reduced at 2 months to 23.8 (35.4)% (p=0.023), at 4 months to 21.4 (34.1)% (p=0.008), at 6 months to 14.5 (28.1)% (p=0.002) and at 8 months to 15.0 (29.4%) (p=0.003). Only nine (36%) of 25 patients demonstrated no recurrence of arrhythmia during follow-up completion, consistent with a long-term cure. Quality-of-life indices showed significant improvement after ablation.

CONCLUSIONS

Catheter ablation for AF significantly improves patient symptoms and reduces AF burden after long-term beat-to-beat monitoring by implanted cardiac pacemaker and defibrillator devices. However, AF recurrence is common after these procedures.

Pacing to Restore Right Ventricular Contraction After Surgical Disconnection for Arrhythmia Control in Right Ventricular Cardiomyopathy

Ventricular tachycardia in ARVC (arrhythmogenic right ventricular cardiomyopathy) is typically managed by ICD implantation, with a limited role of catheter ablation. Surgical disconnection of the right ventricular (RV) has been used to control ventricular tachycardia (VT) in ARVC, but it often led to refractory RV failure due to loss of RV contraction after surgery. We report multisite pacing to recruit the disconnected RV to prevent ventricular failure.

Pulmonary vein ablation for idiopathic atrial fibrillation: six month outcome of first procedure in 100 consecutive patients

OBJECTIVES

To report six month outcome in patients undergoing their first pulmonary vein ablation procedure for idiopathic atrial fibrillation (AF) at a "non-pioneering" hospital.

DESIGN

Prospective observational study.

SETTING

Specialist electrophysiology unit at a university hospital.

PATIENTS

The first 100 consecutive patients undergoing their first pulmonary vein catheter ablation procedure for highly symptomatic, drug resistant AF in the period 1999-2002.

MAIN OUTCOME MEASURES

Incidence of symptomatic or asymptomatic, Holter documented AF six months after ablation.

RESULTS

Mean patient age was 52 years (range 23-73 years), mean length of AF history 53 months (range 6-180 months), mean number of antiarrhythmic drug failures was 3 (range 1-5), and 81 were men. At the time of the ablation procedure, 64 had progressed to persistent AF and 23 had increased transverse left atrial diameter. The number of pulmonary veins ablated in each patient was one in 11, two in 45, three in 36, and four in 8. Six months after ablation, 55 patients were consistently in sinus rhythm, asymptomatic, and without any Holter evidence of AF. The chance of being in sinus rhythm was 73% (29 of 64) in those with paroxysmal as compared with only 45% (26 of 36) in those with persistent AF at the time of ablation (p = 0.01). Outcome was not influenced by patient age, length of AF history, or duration of persistent AF before ablation or to left atrial dimension. Follow up was complete and no patient has died or experienced a stroke during or after ablation; nor have any developed symptoms of late pulmonary vein stenosis. However, other complications occurred during or shortly after the procedure in 12 patients, including cardiac tamponade in six.

CONCLUSIONS

In selected patients with drug resistant AF, focal pulmonary vein catheter ablation offers a realistic prospect of achieving stable sinus rhythm compared with alternatives. However, it is a complex form of ablation with a significant risk of serious complications. Although a new milestone in arrhythmia management, the optimum ablation technique is still evolving and any impact on the natural history of AF remains to be determined.

Apical myocardial injury caused by collateralisation of a septal artery during ethanol septal ablation

In patients who are refractory to medical treatment of hypertrophic cardiomyopathy, surgical myomectomy or percutaneous transluminal alcohol septal myocardial ablation (PTSMA) is appropriate, with both the procedures having comparable results. In PTSMA ethanol is selectively injected into septal arteries supplying the hypertrophied septal myocardium. The authors describe a case of apical myocardial injury caused by passage of ethanol into the distal left anterior descending artery through a septal collateral that developed after double bolus injection of ethanol. They advocate single bolus injection of alcohol to avoid this complication.

Radiofrequency ablation for post infarction ventricular tachycardia. Report of a single centre experience of 112 cases

OBJECTIVES

This report presents the largest consecutive series to date of radiofrequency ablation in the treatment of post infarction ventricular tachycardia.

METHODS

One hundred and twelve consecutive patients were studied, with an average of 12 documented episodes of ventricular tachycardia in the month preceding the radiofrequency ablation. Seventy-four percent of the subjects had an ejection fraction of less than 35%; 84% had more than one morphology of ventricular tachycardia and 30% had haemodynamically unstable ventricular tachycardia. The mean follow-up period was 61 months.

RESULTS

Complete success defined as no inducible sustained monomorphic ventricular tachycardia was achieved in 38%. Modified result, defined as ventricular tachycardia only inducible by two stimuli more aggressive than at baseline was achieved in 34%. During follow-up, ventricular tachycardia recurred in 25 patients: 22 after a failed procedure, two following a modified result and one following a complete success. Twenty-five patients died: 13 of progressive cardiac failure and four of presumed arrhythmic causes, three after a failed procedure and one following a modified result. There were no procedure-related deaths. Procedural complications occurred in seven patients.

CONCLUSIONS

In this report, radiofrequency ablation of post infarction ventricular tachycardia is a successful procedure with a low complication rate. Acute procedural success accurately predicts long-term freedom from recurrent ventricular tachycardia.

Reduction of symptoms from LVOT tachycardia following inadvertent fast pathway ablation

VT was mapped to above the aortic valve in a young patient with troublesome palpitations. A single 15-second RF application was inadvertently delivered to a reference His catheter producing permanent first-degree heart block. The patient has been completely asymptomatic since.

Effects of surgery for postinfarction ventricular tachycardia on parameters of left ventricular function

Heart failure is the leading cause of death in patients after surgery for ventricular tachycardia. This study examines the effects of antiarrhythmic surgery on 4 parameters of left ventricular (LV) function. Global ejection fraction, segmental wall motion score, homogeneity of contraction, and diastolic function were measured in 32 patients by technetium-99m radionuclide ventriculography. Ejection fraction was measured from the left anterior oblique image. Wall motion score was assessed semiquantitatively for 11 LV segments from 3 projections. Homogeneity of contraction was expressed as the SD of the LV phase analysis curve during systole from the left anterior oblique image. Diastolic function was expressed in terms of peak and mean first time derivative of the action potential (dV/dt) of the LV function curve. Subgroup analyses were performed to distinguish the effects of aneurysmectomy, coronary artery bypass grafting, and changes in angiotensin converting enzyme inhibitor therapy. Mean systolic function improved after surgery (ejection fraction 22% vs 32%, p <0001; wall motion score 20 vs 13, p <0.0001; phase analysis 18 vs 12, p <0.03). Mean diastolic function also improved (peak dV/dt 0.83 +/- 0.32 vs 1.49 +/- 0.39, p = 0.006; mean dV/dt 0.41 +/- 0.15 vs 0.76 +/- 0.27, p = 0.006). Improvements were not confined to those who had aneurysmectomy or coronary bypass grafting and were not explained by changes in vasodilator therapy. Thus, antiarrhythmic surgery does not inherently damage LV function. Significant improvements were observed in most patients. Failure to improve indicated a poor longer term prognosis.

Thoracoscopic mapping and cryoablation of right ventricular tachycardia

A 14-year-old girl with right ventricular dysplasia and recurrent drug refractory ventricular tachycardia underwent thoracoscopic mapping cryoablation. Good access to the right ventricular free wall was obtained. We suggest this technique may have an important role in the management of patients with right ventricular tachycardia.

Surgery for postinfarction ventricular tachycardia in the pre-implantable cardioverter defibrillator era: early and long term outcomes in 100 consecutive patients

OBJECTIVE

To report outcome following surgery for postinfarction ventricular tachycardia undertaken in patients before the use of implantable defibrillators.

DESIGN

A retrospective review, with uniform patient selection criteria and surgical and mapping strategy throughout. Complete follow up. Long term death notification by OPCS (Office of Population Censuses and Statistics) registration.

SETTING

Tertiary referral centre for arrhythmia management.

PATIENTS

100 consecutive postinfarction patients who underwent map guided endocardial resection at this hospital in the period 1981-91 for drug refractory ventricular tachyarrhythmias.

RESULTS

Emergency surgery was required for intractable arrhythmias in 28 patients, and 32 had surgery within eight weeks of infarction ("early"). Surgery comprised endocardial resections in all, aneurysmectomy in 57, cryoablations in 26, and antiarrhythmic ventriculotomies in 11. Twenty five patients died < 30 days after surgery, 21 of cardiac failure. This high mortality reflects the type of patients included in the series. Only 12 received antiarrhythmic drugs after surgery. Perioperative mortality was related to preoperative left ventricular function and the context of surgery. Mortality rates for elective surgery more than eight weeks after infarction, early surgery, emergency surgery, and early emergency surgery were 18%, 31%, 46%, and 50%, respectively. Actuarial survival rates at one, three, five, and 10 years after surgery were 66%, 62%, 57%, and 35%.

CONCLUSIONS

Surgery offers arrhythmia abolition at a risk proportional to the patient's preoperative risk of death from ventricular arrhythmias. The long term follow up results suggest a continuing role for surgery in selected patients even in the era of catheter ablation and implantable defibrillators.

Identifying patients at low risk of death from cardiac failure after operation for postinfarct ventricular tachycardia

BACKGROUND

In unselected patients, cardiac failure accounted for most deaths after antiarrhythmic operation (ER) for postinfarction ventricular tachycardia (VT). This study aimed to determine whether patients at low risk of this outcome could be predicted from a retrospective analysis of variables from 100 consecutive ER patients.

METHODS

Thirteen variables suggested by other researchers as predictive of outcome were analyzed. At the time of study, ER was the only therapy available for drug refractory VT.

RESULTS

Only emergency ER, wall motion score less than 3 and Killip classification were significantly related to death from cardiac failure. The lack of correlation between emergency ER and variables of ER timing, VT less than 24 hours of ER or VT type implies that the need for emergency ER is also related to ventricular dysfunction. Multivariate analysis identified a group at particularly low risk of death with a specificity of 95%.

CONCLUSIONS

Patients at low risk of death after ER can be identified prospectively. In the implantable cardioverter defibrillator era, elective ER is best reserved for such patients. Emergency ER may still be justified in younger patients without comorbidity who will die of VT without it.

Right ventricular disarticulation procedures: the role of late potentials in the genesis of postoperative ventricular arrhythmias

Arrhythmogenic right ventricular disease may be associated with life-threatening and drug refractory ventricular arrhythmias. Right ventricular disarticulation procedures are effective antiarrhythmic surgical approaches in selected patients. This study examined the role of late potentials in the postoperative development of new ventricular arrhythmias, and showed that right ventricular isolation is effective, probably because it destroys the tissue giving rise to late potentials. Total disarticulation is associated with fewer postoperative arrhythmias than partial isolation procedures. Total disarticulation may be the surgical approach of choice in such patients.

Electrocardiographic features of septal location of right ventricular outflow tract tachycardia

A consistent 12-lead electrocardiogram (ECG) morphology and characteristic frontal plane axis shift from sinus rhythm to ventricular tachycardia (VT) was demonstrated in 10 consecutive patients with idiopathic right ventricular outflow tract (RVOT) VT. All arrhythmias were successfully ablated on the septal side of the RVOT.

Rescue thrombolysis: alteplase as adjuvant treatment after streptokinase in acute myocardial infarction

BACKGROUND

In acute myocardial infarction patients who do not reperfuse their infarct arteries shortly after thrombolytic treatment have a high morbidity and mortality. Management of this high risk group remains problematic, especially in centres without access to interventional cardiology. Additional thrombolytic treatment may result in reperfusion and improved left ventricular function.

METHODS

Failure of reperfusion was assessed non-invasively as less than 25% reduction of ST elevation in the electrocardiographic lead with maximum ST shift on a pretreatment electrocardiogram. 37 patients with acute myocardial infarction who showed electrocardiographic evidence of failed reperfusion 30 minutes after 1.5 MU streptokinase over 60 minutes were randomly allocated to receive either alteplase (tissue type plasminogen activator (rt-PA) 100 mg over three hours) (19 patients) or placebo (18 patients). 43 patients with electrocardiographic evidence of reperfusion after streptokinase acted as controls. Outcome was assessed from the Selvester Q wave score of a predischarge electrocardiogram and a nuclear gated scan for left ventricular ejection fraction 4-6 weeks after discharge.

RESULTS

Among patients in whom ST segment elevation was not reduced after streptokinase, alteplase treatment resulted in a significantly smaller electrocardiographic infarct size (14% (8%) v 20% (9%), P = 0.03) and improved left ventricular ejection fraction (44 (10%) v 34% (16%), P = 0.04) compared with placebo. This benefit was confined to patients who failed fibrinogenolysis after streptokinase (fibrinogen > 1 g/l). In patients in whom ST segment elevation was reduced after streptokinase, infarct size and left ventricular ejection fraction were not significantly different from those in patients treated with additional alteplase.

CONCLUSION

Patients without electrocardiographic evidence of reperfusion after streptokinase may benefit from further thrombolysis with alteplase.

Coil embolization of a coronary fistula in a post-transplant patient

A 23-year-old man 6 months after post-orthotopic heart transplant was troubled by fatigue and breathlessness and noted to have a continuous murmur. Coronary angiography revealed five fistulae from the left anterior descending artery draining into the right ventricle. The left-to-right shunt was obliterated by coil embolization and this was associated with improvement in the patient's symptoms and a reduction in the murmur.

QT dispersion and components of the QT interval in ischaemia and infarction

OBJECTIVE

To evaluate changes in QT dispersion and components of the QT interval in patients admitted with unstable angina and acute myocardial infarction and to study the dynamics of these changes in patients with infarction.

METHODS

Prospective study recording electrocardiograms at 50 mm/s in patients admitted with typical cardiac chest pain. Subsequent confirmation of acute myocardial infarction according to standard criteria. Single blind analysis for QT dispersion and QT components using a digitiser and simple computer program. Results are expressed as native QT dispersion, QTc dispersion, and the QT dispersion ratio defined as QT dispersion divided by cycle length and expressed as a percentage.

RESULTS

QT dispersion, QTc dispersion, and QT dispersion ratio were all higher in patients with acute myocardial infarction than in those with unstable angina (mean (SD) 66 (18) ms, 75 (26) ms1/2, and 8.1 (2.4)% compared with 38 (13) ms, 39 (13) ms1/2, and 4.5 (1.7) % respectively). Dynamic changes in QTc dispersion were seen after acute infarction with significant differences in the QT components occurring between the different patient groups. Levels of QT dispersion (87 (15) ms), QTc dispersion (105 (17) ms1/2), and QT dispersion ratio (11.7 (0.8)%) in the four patients with ventricular fibrillation were significantly higher. Use of QT dispersion ratio gave a narrower confidence interval.

CONCLUSION

QT dispersion is increased after myocardial infarction and levels are higher in patients with ventricular fibrillation. The changes in QT dispersion are dynamic and may reflect the changing pattern of underlying ventricular recovery of ventricular excitability, which is profoundly disturbed in the earliest phase of acute infarction. Expressing QT dispersion as a percentage of cycle length (QT dispersion ratio) rather than using standard rate correction may be superior in identifying patients who develop ventricular fibrillation.

Is ventricular ectopy a legitimate target for ablation?

Radiofrequency ablation has an established role in the treatment of non-ischaemic ventricular tachycardia. A few patients present with symptomatic but benign ventricular ectopy that can be mapped to the right ventricular outflow tract. The successful use of radiofrequency ablation in a patient with drug resistant, symptomatic ventricular ectopy is reported. Radiofrequency ablation may have a useful role in more benign arrhythmias.

Frequency of chronic obstructive airways disease and pulmonary hypertension in patients with acute inferior myocardial infarction with or without right ventricular infarction

OBJECTIVE

Factors influencing the incidence of right ventricular infarction among patients with acute inferior myocardial infarction have not yet been fully established. Chronic obstructive airways disease and right ventricular hypertrophy were suggested as possible predisposing factors but no definite evidence was shown. This study analyses the frequency of chronic obstructive airway disease and of Doppler assessed pulmonary hypertension among patients with acute inferior myocardial infarction with or without right ventricular infarction.

DESIGN AND PATIENTS

Sixty consecutive patients with acute inferior myocardial infarction were prospectively enrolled into the study.

MEASUREMENTS

Standard 12-lead ECG with right precordial leads (V3-6R) were recorded on admission to the Coronary Care Unit and on days 2 and 3. Doppler echocardiography was performed within 48 h after the onset of myocardial infarction and repeated 6 weeks later together with a pulmonary function test. Routine biochemical and clinical data were collected.

RESULTS

Right ventricular infarction occurred in 35% of patients with acute inferior myocardial infarction. No differences in respiratory indices of chronic obstructive airways disease or in Doppler echocardiography parameters of pulmonary hypertension were revealed among patients with and without right ventricular infarction. Peak total creatine kinase level and creatine kinase myocardial isoenzyme levels were higher in patients with right ventricular infarction than in those without (2925 +/- 1321 vs. 1682 +/- 1216 U/l; P < 0.001 and 207 +/- 108 vs. 127 +/- 102 U/l; P < 0.05, respectively).

CONCLUSIONS

In the course of acute inferior myocardial infarction, the frequencies of chronic obstructive airways disease and/or pulmonary hypertension were not higher among patients with right ventricular infarction than among those without right ventricular infarction. Thus, history of chronic obstructive airways disease and/or pulmonary hypertension do not necessitate specific precautions in respect of right ventricular infarction.

Errors in manual measurement of QT intervals

OBJECTIVE

To quantify the errors associated with manual measurement of QT intervals and to determine the source of the errors.

DESIGN

A randomised study of QT measurement by four cardiologists of electrocardiograms plotted on paper in presentations with different noise levels, paper speeds, amplifier gains, and with and without a second QRST complex to indicate the RR interval.

SUBJECTS

Four electrocardiograph leads (I, aVR, V1, V5) recorded in eight healthy people relaxing in a semirecumbent position.

MAIN OUTCOME MEASURES

Manual measurement of QT interval in 512 electrocardiograms (eight subjects x four leads x eight presentations x two repeats) by each of four cardiologists.

RESULTS

QT intervals measured were significantly longer with greater amplifier gain: by 8 ms for a doubling of gain (p < 0.005), equivalent to a doubling of T wave height. QT intervals measured were significantly longer at slower paper speeds: by 11 ms when paper speed was reduced from 100 to 50 mm/s (p < 0.001) and by 16 ms when speed was further reduced from 50 to 25 mm/s (p < 0.001). Neither the presence of noise nor the presence of a second QRST complex altered the mean QT measurements. There were consistent differences in the measurements between cardiologists, amounting to a maximum mean difference of 20 ms.

CONCLUSIONS

Manual measurement of QT interval is significantly affected by the paper speed used to plot the electrocardiogram and by electrocardiogram gain, and hence also T wave amplitude. Manual QT measurement also differed consistently with different cardiologists.

Practical considerations in the use of sotalol for ventricular tachycardia and ventricular fibrillation

Sotalol is a unique antiarrhythmic drug that combines beta-blocking effects with actions to prolong action potential duration. The net effect is a drug that is efficacious in the management of ventricular tachyarrhythmias. Although sotalol has effects on both heart rate and QT interval, these effects do not help predict the antiarrhythmic efficacy of the agent. Changes in QT dispersion may, however, prove to be relevant to both the antiarrhythmic effects and the arrhythmogenic effects of sotalol. Thus, although sotalol may occasionally cause torsades de pointes, this complication may be predictable and clinically controllable. Sotalol is well tolerated, and it may be used, with caution, in some patients with impaired myocardial contractile performance, despite its beta-blocking action. Sotalol has an important indication for the management of ventricular tachyarrhythmias.

Post-infarction communication between a left ventricular aneurysm and the right atrium

A 70-year-old patient presented with ventricular tachycardia and left ventricular failure. He was found to have a communication between a posterior left ventricular aneurysm and the right atrium. The causal myocardial infarction had been silent. This defect was satisfactorily closed at operation from which he made an uneventful recovery. This is the first report of a left ventricular-right atrial communication developing in association with ischaemic heart disease and highlights the role of transoesophageal echocardiography in the diagnosis and surgical management of such a condition.

The management and outcome of late post-infarct ventricular tachycardia presenting to a district general hospital

A review was undertaken of late post-infarct ventricular tachycardia in a district hospital cardiac care unit in order to study the clinical course of a total population of such patients from initial presentation to ultimate outcome. Thirty-six patients with this diagnosis were identified over a 3 1/2-yr period. Twelve were treated by empirically chosen antiarrhythmic drugs. Twenty-four were referred for electrophysiologically guided treatment, of whom 16 were treated by antiarrhythmic drugs, 3 by anti-ischaemic measures alone, and 5 by non-pharmacological antiarrhythmic treatments (antiarrhythmic surgery, percutaneous ablation, defibrillator implantation, cardiac transplantation). Of those treated empirically, 4 died in hospital of their arrhythmia, 1 died suddenly at home, and 2 suffered non-fatal arrhythmia recurrences during mean follow-up of 20 months. There were no arrhythmic deaths in those whose treatment was guided by serial electrophysiology studies, although 4 patients died of cardiac failure or reinfarction, and 3 were hospitalised with a recurrence of ventricular tachycardia during mean follow-up of 16 months. Age, concomitant medical problems and the apparent response to initial antiarrhythmic therapy were the main factors influencing management decisions. The apparent superiority of more intensive management strategies based on electrophysiology studies must be interpreted in the context of the selection processes applied to the total population initially presenting.

Surgery for ventricular tachycardia associated with right ventricular dysplasia: disarticulation of right ventricle in 9 of 10 cases

Ten patients (nine men, one woman; mean age 39 years) with arrhythmogenic right ventricular dysplasia underwent surgery to control life-threatening drug refractory ventricular arrhythmias. All had ventricular tachycardia causing syncope and six had a history of cardiac arrest. In all a minimum of three antiarrhythmic drugs (mean five) had been ineffective. At operation, the right ventricle was grossly diseased in all patients. Ventricular tachycardias were induced and mapped intraoperatively in all patients. The surgical plan was to ablate the arrhythmogenic focus if it was less than 4 cm2; one patient was so managed. Of the remaining nine, four underwent partial (approximately 40% of the right ventricular free wall) and five underwent total right ventricular disarticulation. All survived the operation and are alive at a mean follow-up interval of 24 months (range 5 to 67). Two patients developed new sustained ventricular tachycardias. These were well tolerated and, unlike the original arrhythmias, were easily controlled by drug treatment. All patients who underwent right ventricular disarticulation manifested signs of right heart failure in the early postoperative period, but these lessened progressively with the development of systolic septal movement into the right ventricular cavity. All 10 patients are in New York Heart Association class I or II at last review. In selected patients with arrhythmogenic right ventricular dysplasia, surgery offers a curative treatment for ventricular tachycardia and should be considered for patients whose arrhythmias are life-threatening and refractory to drug treatment.

Acute and chronic hemodynamic impact of total right ventricular disarticulation

Right ventricular disarticulation is a radical operation to control ventricular arrhythmias in patients with arrhythmogenic right ventricular dysplasia. This report describes the acute and chronic hemodynamic impact of the procedure based on our experience of five patients with life-threatening arrhythmias unresponsive to medical therapy who have undergone total disarticulation of the right ventricle. Although all patients suffered acute postoperative hemodynamic problems, all survived and returned to an excellent functional class. Right ventricular disarticulation should be considered in patients with drug refractory ventricular tachycardias due to arrhythmogenic right ventricular dysplasia when the arrhythmia either poses a life threat or results in chronic morbidity.

Value of echocardiographic determination of isovolumic relaxation time in the detection of heart transplant rejection

The reproducibility of the measurement of isovolumic relaxation time in heart transplant recipients was assessed in eight heart transplant recipients. The value of routine measurement of isovolumic relaxation time and fractional shortening by echocardiography in the diagnosis of rejection was assessed by comparison with endomyocardial biopsy results in 12 patients. Despite a large, unexplained variability that will limit the application of the test in the individual patient, there was a significant fall in isovolumic relaxation time with moderate to severe rejection.

Reduction in ST segment elevation after thrombolysis predicts either coronary reperfusion or preservation of left ventricular function

The usefulness of a reduction in ST segment elevation to predict coronary reperfusion in myocardial infarction remains uncertain. ST segment changes and angiographic findings were compared in 45 patients soon after thrombolysis. The percentage ST segment change 3 hours after treatment (in the lead showing the greatest initial ST elevation) was compared with the TIMI perfusion grade (thrombolysis in myocardial infarction trial) obtained between 90 minutes and 3 hours after treatment. Global ejection fraction and regional wall motion were assessed by cineventriculography (11 (5) days (mean (SD))) and by gated blood pool imaging (44 (11) days). Prediction of coronary patency by a reduction of greater than 25% in ST segment elevation 3 hours after thrombolytic treatment had a sensitivity of 97% but a specificity of only 43%. Where the ST segment elevation was reduced by greater than 25% the global ejection fraction was well maintained whether or not the infarct vessel was patent. In patients with a reduction of less than 25% in ST elevation, the ejection fraction was significantly lower and regional wall motion abnormality more severe. Reduction in ST elevation of greater than 25% within 3 hours of thrombolysis indicates either a patent infarct artery or preservation of left ventricular function. When the ST segment elevation does not fall by greater than 25% persistent coronary occlusion is likely (predictive accuracy 86%) and is associated with a lower ejection fraction. These patients may benefit from further treatment or additional interventions.

Systolic coronary occlusion due to myocardial bridging--a rare cause of ischaemia

Myocardial bridging causing systolic occlusion of the left anterior descending coronary artery was identified in a 47-year-old man with angina. A fixed anterolateral wall defect was demonstrated on thallium imaging and he underwent successful division of the bridge resulting in abolition of his symptoms and disappearance of the thallium defect.

Isometric exercise in the denervated heart: a Doppler echocardiographic study

The haemodynamic responses to isometric exercise of eight recipients of orthotopic heart transplants and eight healthy controls were studied. Each performed sustained exercise at 30% of maximal voluntary contraction for three minutes on a handgrip dynamometer. Cardiac output was measured by combined Doppler and cross sectional echocardiography before exercise and every 30 seconds during and after exercise. In the controls cardiac output and blood pressure increased significantly owing to an increase in heart rate with no change in stroke volume. In the transplant group cardiac output, heart rate, and stroke volume remained unchanged throughout exercise. In contrast with its response to dynamic exercise the denervated human heart is unable to increase cardiac output during isometric exercise. The pressor response that occurs is mediated via an increase in peripheral vascular resistance.

Coronary artery-right ventricular fistula after endomyocardial biopsy

A coronary artery-right ventricular fistula developed after endomyocardial biopsy in a recipient of an orthotopic cardiac transplant.

Fairground fever--a cautionary tale

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Effect of angiotensin converting-enzyme inhibition on potassium-mediated aldosterone secretion in essential hypertension

1. Eight patients with essential hypertension were challenged with an infusion of 32 mmol of potassium chloride in saline before and after control of their blood pressure by the angiotensin converting-enzyme (ACE) inhibitor enalapril. 2. The potassium infusion was associated with similar increases in plasma aldosterone before and during enalapril treatment, although absolute aldosterone levels were lower after enalapril treatment despite higher plasma potassium levels. 3. The handling of the potassium load was altered by ACE inhibition. The area under the curve of a plot of the increase in plasma potassium above baseline against time was greater during enalapril treatment than during treatment with placebo. 4. These observations contrast with data obtained in the dog and demonstrate that in patients with essential hypertension stimulation of aldosterone secretion by potassium is not abolished by chronic suppression of plasma angiotensin II; and although plasma aldosterone remains at a lower level, the homoeostasis of plasma potassium is only mildly impaired.