Microvolt T-wave alternans during exercise and pacing are not comparable

AIMS

The absence of microvolt T-wave alternans (MTWA) identifies a group of patients who are at low risk for ventricular arrhythmia or sudden cardiac death. However, in exercised assessed MTWA, 20-40% of all test results are indeterminate. We hypothesised that MTWA during pacing would yield less indeterminate results.

METHODS AND RESULTS

Thirty patients with ischaemic cardiomyopathy and prior dual chamber implantable cardioverter defibrillator implantation were enrolled. All patients underwent sequential MTWA testing using an exercise (E), atrial-paced (A), and atrioventricular-paced (AV) protocol. The number of indeterminate tests was lower during pacing (A: 17%; AV: 3%) compared with exercise (37%) (E vs. A: P = 0.015, E vs. AV: P = <0.001). When positive and indeterminate test results were grouped as non-negative, the concordance rates between E and A, E and AV, and A and AV were 60% (kappa = 0.17), 57% (kappa = 0.058), and 70% (kappa = 0.348), respectively. If indeterminate results were excluded, agreements were 60% (kappa = 0.19), 50% (kappa = 0.129) and 67% (kappa = 0.33), respectively.

CONCLUSION

Indeterminate test results are less common during pacing. However, there is a low concordance rate between test results using different protocols. This necessitates further study to determine the predictive value of each method in high risk patients with ischaemic cardiomyopathy.

Challenging pacemaker implantation: persistent left superior vena cava with absent right superior vena cava

A persistent left superior vena cava (PLSVC) in combination with an absent right superior vena cava (RSVC) is a rare congenital cardiovascular abnormality which is usually found by chance during pacemaker (PM) implantation. In this case we describe a PM implantation using right cephalic approach through PLSVC and coronary sinus (CS), with lead fixation in right atrium and a posterolateral branch of the CS.

Acute success and short-term follow-up of catheter ablation of isthmus-dependent atrial flutter; a comparison of 8 mm tip radiofrequency and cryothermy catheters

Objectives

To compare the acute success and short-term follow-up of ablation of atrial flutter using 8 mm tip radiofrequency (RF) and cryocatheters.

Methods

Sixty-two patients with atrial flutter were randomized to RF or cryocatheter (cryo) ablation. Right atrial angiography was performed to assess the isthmus. End point was bidirectional isthmus block on multiple criteria. A pain score was used and the analgesics were recorded. Patients were followed for at least 3 months.

Results

The acute success rate for RF was 83% vs 69% for cryo (NS). Procedure times were similar (mean 144 ± 48 min for RF, vs 158 ± 49 min for cryo). More applications were given with RF than with cryo (26 ± 17 vs. 18 ± 10, p < 0.05). Fluoroscopy time was longer with RF (29 ± 15 vs. 19 ± 12 min, p < 0.02). Peak CK, CK-MB and CK-MB mass were higher, also after 24 h in the cryo group. Troponin T did not differ. Repeated transient block during application (usually with cryoablation) seemed to predict failure. Cryothermy required significantly less analgesia (p < 0.01), and no use of long sheaths (p < 0.005).

The isthmus tended to be longer in the failed procedures (p = 0.117). This was similar for both groups, as was the distribution of anatomic variations. Recurrences and complaints in the successful patients were similar for both groups, with a very low recurrence of atrial flutter after initial success.

Conclusions

In this randomized study there was no statistical difference but a trend to less favorable outcome with 8 mm tip cryocatheters compared to RF catheters for atrial flutter ablation. Cryoablation was associated with less discomfort, fewer applications, shorter fluoroscopy times and similar procedure times. The recurrence rate was very low. Cryotherapy can be considered for atrial flutter ablation under certain circumstances especially when it has been used previously in the same patient, such as in an AF ablation.

Outcome in patients with an ICD incorporating cardiac resynchronisation therapy: Differences between primary and secondary prophylaxis

BACKGROUND

The incidence of ventricular tachyarrhythmias in ICD patients with cardiac resynchronisation therapy (CRT-D) is not well studied.

AIM

To analyse event free survival in CRT-D patients with a primary or a secondary prophylactic ICD indication.

METHODS

Prospective, single centre. Eighty-six patients, 44% with a primary prophylactic indication. Actuarial event-free rates for mortality and arrhythmias were calculated.

RESULTS

Baseline clinical characteristics were not significantly different between primary and secondary prophylaxis. Primary prophylaxis patients were more likely to be in NYHA class III. Over 21 months, 724 ventricular events with therapy occurred in 36 patients (42%). The actuarial event-free rates, at 1 and 3 years, from appropriate ICD therapy were higher (P<0.001) for primary (79.0% and 67.8%) than for secondary prophylaxis (45.6% and 27.0%). Appropriate ICD therapy occurred more in NYHA class II compared to class III (P=0.016). Underlying disease (ischemic versus non-ischemic) and functional class did not play a role in multivariate analysis.

CONCLUSION

Important arrhythmic events in patients with heart failure, and CRT-D occur at a very high rate when the indication is secondary prophylaxis. Patients with primary prophylaxis have an annual event rate of 10%, even though they tend to have a worse heart failure class.

One-year follow-up in a prospective, randomized study comparing radiofrequency and cryoablation of arrhythmias in Koch's triangle: clinical symptoms and event recording

AIMS

To rely solely on clinical symptoms of recurrent palpitations to evaluate the success of interventional procedures can be misleading. This study was designed to assess the efficacy of event recording in evaluating long-term success in patients treated for atrioventricular nodal reentrant tachycardia (AVNRT) or right posteroseptally located accessory pathways (RPS) either by radiofrequency (RF) or by cryoablation (CA).

METHODS AND RESULTS

Sixty-three patients with AVNRT and eight with RPS were randomized. Patients were encouraged to activate an event recorder in the case of recurrent palpitations for the first 3 months. One year after the procedure, patients were asked specific arrhythmia related questions. Thirty-six patients underwent RF and 35 CA. Acute success was finally achieved in 34 (94%) patients in the RF and 33 (94%) in the CA groups. Assessment of long-term success demonstrated a similar proportion of palpitations in the RF and CA groups: 11 (31%) vs. 17 (49%). Only 12 patients activated the event recorder, four patients in RF, including one patient with chest pain, and eight in the CA group. Analysis of recordings revealed recurrent AVNRT or circus movement tachycardia in four patients (one RF and three CA), atrial fibrillation in one RF patient, and sinus tachycardia in six (one RF and five with CA). In addition, a complete 12 lead ECG of a recurrent arrhythmia was made in three RF and two CA patients (in-hospital or after the event recording). A total of seven patients underwent a second procedure (four RF and three CA). Without the event recorder, seven patients would have been misclassified as having recurrent arrhythmia.

CONCLUSION

Event recording enhances the sensitivity of detecting arrhythmia recurrences in evaluating therapy efficacy and should be considered in every interventional follow-up study. Analysis of recordings showed that CA is as effective as RF in the treatment of AVNRT and RPS at long-term follow-up.

Imaging of a coronary artery bypass graft during coronary sinus venography

Retrograde coronary sinus perfusion to maintain viability during cardiac surgery means that a connection via the capillary system to the coronary arteries, and potentially bypass grafts, may be possible. Coronary sinus (CS) venography prior to resynchronisation therapy in this patient with previous bypass grafting was associated with visualisation of these grafts.

Magnetic navigation in AV nodal re-entrant tachycardia study: early results of ablation with one- and three-magnet catheters

AIMS

Steering soft, flexible catheters using an external magnetic field could have advantages for heart catheterization, especially for therapy of tachyarrhythmias. Our aims were to assess the feasibility of magnetic navigation to Koch's triangle and reliable ablation of atrioventricular nodal re-entry tachycardia (AVNRT) with a magnetic catheter.

METHODS AND RESULTS

Consecutive patients with AVNRT were mapped and ablated with a magnetically enabled catheter (Helios I or II), with, respectively, one and three magnets at the tip. The catheter was remotely advanced with the Cardiodrive system and orientated with the Navigant control system. After initial positioning with the external magnets, adjustment was made in 5 degrees steps. Success rates, procedure, and fluoroscopy times were analysed, and compared with a local contemporary series of conventional AVNRT ablations. Magnetic navigation was feasible in all 20 patients. Targets were easily reached. Catheters remained stable in position during accelerated junctional rhythms. Ablation was successful in 18/20 procedures (90%). No significant complications occurred. Median patient fluoroscopy time was 12 min, median physician fluoroscopy time was 4 min. Fluoroscopy times tended to be shorter than that in the conventionally treated group. Procedure duration decreased significantly over time, median procedure time was similar to that in the conventional group.

CONCLUSION

AVNRT can be successfully mapped and ablated using magnetic navigation. A learning curve was evident, unrelated to catheter type, but to increasing operator experience. Physician radiation times were one-third of patient times. No complications occurred. Procedure time is comparable with that of conventional ablation.

Left Ventricular Lead Placement Within a Coronary Sinus Side Branch Using Remote Magnetic Navigation of a Guidewire: A Feasibility Study

BACKGROUND

A novel magnetic navigation system (MNS) allowing remote guidance of catheters and guidewires might assist in implantation of left ventricular (LV) pacing leads.

OBJECTIVE

To assess the feasibility of deploying a LV pacing lead into a coronary sinus (CS) side branch using a magnetically guided wire and of performing the procedure without a CS guiding sheath.

METHODS

Twenty-one patients were included in this study. Nine underwent CRT device implantation using a MNS to steer the guidewire (MNS group) while 12 patients were conventionally implanted (control group). In 6 patients in the MNS group, the procedure was performed using a CS guiding sheath. In 3 others, the decision was to perform the procedure without a CS sheath. In these patients the wire was advanced manually, while the external magnets oriented it toward the CS os. In the CS, "vector based" navigation was used to guide the wire to the desired side branch.

RESULTS

In all 9 patients in the MNS group, the target vessel could be successfully engaged by the magnetically guided wire. In 7, the LV lead was lodged in the target vessel. In 2 patients, the LV lead was repositioned in an anterolateral side branch due to instability or inability to engage the vessel with it. Mean total procedure time was 164 +/- 58 minutes (without sheath 229 +/- 52 vs with sheath 132 +/- 26 minutes; P = 0.007). Mean fluoroscopy time was 28 +/- 9 minutes. For control patients, the procedure and fluoroscopy time were similar (144 +/- 41 minutes and 26 +/- 12 minutes, respectively). No major complications occurred.

CONCLUSION

LV lead implantation can be performed using a remote magnetically steered guidewire. Though the lead could be implanted without a CS guiding sheath, longer procedure times were required.

Intracardiac echocardiography during interventional procedures

BACKGROUND

As non-surgical percutaneous interventions are increasingly considered for many cardiac conditions, high quality near field continuous imaging is warranted, in order to optimize the results, and to prevent and detect complications. Transesophageal echocardiography is the standard imaging technique, however general anesthesia and endotracheal intubation is required during prolonged monitoring of percutaneous interventions. Intracardiac echocardiography is a novel emerging tool that allows a view within the cardiac chambers and the large vessels and can be employed by the interventional cardiologist.

METHOD

In our department, a phased array, multi-frequency, four-way steerable catheter (AcuNaV - Siemens) was used for anatomic and haemodynamic cardiac assessment and for guidance and monitoring during non-coronary percutaneous interventions. In total 135 patients underwent intracardiac echocardiographic investigation, 4 during diagnostic heart catheterization, 6 during percutaneous coronary intervention with the use of a new left ventricular assist device, the Impella Recover LP 2.5 system, 26 during percutaneous transluminal septal myocardial ablation (10 patients were reevaluated with intracardiac echocardiography at 6 months), 50 during interatrial communication closure, 4 during percutaneous left atrial appendage transcatheter occlusion, 7 during percutaneous balloon valvuloplasty, 1 during percutaneous aortic valve replacement and 27 during pulmonary vein ablation. All patients tolerated the procedure very well with no catheter related complications. However, there were two complications, which were due to the guidewire and the sheath, an inferior vena cava dissection and a femoral vein dissection, respectively.

CONCLUSION

Phased array intracardiac imaging is a safe technology, which facilitates non-surgical interventions by providing high quality images. It eliminates the need for general anesthesia and thus increases the patient comfort.

Contrast echocardiography for perfusion in right ventricular cardiomyopathy

Right ventricular (RV) cardiomyopathy is a familiar myocardial disease of RV characterized by extensive fatty replacement of the myocardium. Conventional echocardiography is able to show abnormalities in myocardial contractility, but fat on the images appears to be similar to the surrounding tissue or fluid. The present case suggests the clinical role of contrast echocardiography showing perfusion abnormalities in patients with RV cardiomyopathy in the region of the fat depositions.

Targets and endpoints in ablation therapy for atrial fibrillation in the light of pathophysiological mechanisms

Atrial fibrillation (AF), an important public health problem is a complex and multifactorial arrhythmia. Non-pharmacological treatment for symptomatic patients is of increasing importance. The different catheter ablation techniques in AF treatment developed during recent years, all based on different pathophysiological insights, are discussed. The non-standardized use of different follow-up methods after ablation make interpretation and comparison of results difficult.

Pulmonary vein antrum isolation guided by phased-array intracardiac echocardiography: A third way to do PV ablation

BACKGROUND

Pulmonary vein isolation (PVI) has emerged as an important strategy in the treatment of patients with atrial fibrillation (AF). The two most frequently used techniques are segmental PVI and left atrial circumferential ablation.

AIM

To describe and discuss pulmonary vein antrum isolation guided by phased-array intracardiac echocardiography (ICE) as an alternative approach, and to present initial results.

METHODS

Patients with symptomatic AF were included. The antra (the larger circumferential area around the PVs) were isolated guided by ICE. ICE was also used to titrate the ablation energy.

RESULTS

38 patients (3 with persistent AF) were included. Of the 35 patients with paroxysmal AF, 24 are without recurrences, and in six the incidence of paroxysms was significantly reduced after one procedure and a mean follow-up of 201 days. No major complications occurred.

CONCLUSION

Pulmonary vein antrum isolation guided by ICE is a promising technique in AF ablation and has the potential to avoid severe complications.

Anticoagulation in atrial fibrillation and flutter

Atrial fibrillation and atrial flutter are important risk factors for stroke. Based on a literature search, pathogenesis of thromboembolism, risk assessment in patients, efficacy of anticoagulation therapy and its alternatives are discussed. Special emphasis is put on issues like paroxysmal atrial fibrillation, atrial flutter and anticoagulation surrounding catheter ablation and cardioversion. A strategy for anticoagulation around the time of pulmonary vein ablation is suggested.

Combined transesophageal echocardiography and transesophageal cardioversion probe: technical aspects

A probe assembly for simultaneous transesophageal echocardiography and transesophageal cardioversion has been developed. This probe allows cardioversion with the delivery of much lower energy than the standard external approach. Details of the probe construction and its use are described, as is the prospect for future practice. The use of a combined probe may be the technique of choice for patients who require both cardioversion and transesophageal echocardiography.

Sixteen multidetector row computed tomography of pulmonary veins: 3-months' follow-up after treatment of paroxysmal atrial fibrillation with cryothermal ablation

The aim of the study was to assess pulmonary veins (PVs) for the presence of stenosis 3 months after cryothermal ablation (CA) with a new method of electrical isolation of PVs using contrast-enhanced 16 multidetector row computed tomography (MDCT). Twenty four patients with symptomatic atrial fibrillation underwent CA in 46 PVs. MDCT of PVs was performed before the treatment and after 3-months' follow-up. Following cryoablation, 13/24 (54%) patients showed clinical improvement and had reduced attacks of atrial fibrillation. The dimensions of the treated PVs remained unchanged: the coronal ostial diameter was 19.1+/-2.4 preprocedural versus 18.6+/-2.4 mm at follow-up, p>0.05; the ratio of the coronal and axial diameters at the ostium was 1.2+/-0.2 versus 1.2+/-0.1, p>0.05, respectively, and the coronal diameter of the proximal 10 mm was 17.1+/-2.5 mm versus 16.5+/-2.2 mm, p>0.05, respectively. CA is a promising technique for electrical isolation of PVs that has not been associated with stenosis at the orifice and the proximal 10 mm of the PVs after 3-months' follow-up. MDCT is a noninvasive, fast and comfortable method for assessment of PVs in a three-dimensional manner prior to ablative treatment and during the follow-up.

CRAVT: a prospective, randomized study comparing transvenous cryothermal and radiofrequency ablation in atrioventricular nodal re-entrant tachycardia

BACKGROUND

Transvenous catheter ablation of atrioventricular nodal re-entrant tachycardia (AVNRT) with radiofrequency (RF) is effective and safe, but carries a 1-3% incidence of early and potentially late heart block. Cryothermy can create transient effects, and identify potentially successful ablation sites and decrease the risk for permanent heart block.

METHODS

In this prospective, randomized trial 102 patients with recurrent narrow QRS-complex tachycardia suggestive of AVNRT were randomized to either RF or cryoablation before a diagnostic study.

RESULTS

In 63 patients with AVNRT, 33 were randomized to RF and 30 to cryoablation. Procedural success was achieved, respectively, in 30 (91%) patients in the RF and 28 (93%) in the cryoablation group. The median number of cryothermal applications was significantly lower than the number of RF applications (2 versus 7, p<0.005). No accelerated junctional rhythm was seen with cryothermy, while it was present in 31/33 RF patients. Both fluoroscopy and procedural times were comparable. The radiological position of the successful site in relation to anatomical landmarks was slightly different (p<0.05). No cryothermy related complications were observed, and no permanent AV conduction disturbances occurred. During a mean follow up of 13+/-7 months long-term clinical success was seen in one additional patient in each group. In the same period, 3 patients in both groups experienced recurrent AVNRT.

CONCLUSION

Cryoablation is as effective and safe as RF for AVNRT. Significantly fewer applications are necessary, with comparable procedure times. This makes cryothermy useful for the treatment of tachyarrhythmias near the compact AV node.

Usefulness of transesophageal echocardiography using a combined probe when converting atrial fibrillation to sinus rhythm

We studied the feasibility and efficacy of transesophageal echocardiography (TEE) combined with transesophageal cardioversion (TEC). Secondary aims were to study left atrial flow velocities before and 1 and 5 minutes after TEC, biochemical markers of myocardial damage, and patient tolerability. TEC after a short period of anticoagulation and exclusion of a clot with TEE was safe. TEC was well tolerated and efficacious. The use of a combined probe for TEE and TEC therefore can save time and be more effective. A custom-made probe for combined TEE plus TEC was used. TEC was performed with a step-up protocol (20 J to between 30 and 50 J) and with biphasic shocks. Presence of spontaneous echo contrast was scored. Cumulative energy needed to achieve sinus rhythm was calculated. Discomfort was scored on a scale of 0 to 10. Twenty-six patients underwent combined TEE/TEC. Sinus rhythm was achieved in 24 of 26 patients (92%) with a mean cumulative energy of 42.3 J. Sixteen of 26 patients were cardioverted with a 20-J shock, and 6 of these patients had early recurrence of atrial fibrillation. All biochemical markers were unaffected, and TEE/TEC was well tolerated. Left atrial appendage velocity decreased significantly after TEC. Thus, the use of a TEE/TEC probe offers effective cardioversion with low energy levels, is well tolerated, and hemodynamics during and immediately after cardioversion can be monitored. Early cardioversion after exclusion of a clot with this combined probe is time saving and cost effective.

Twiddler's Syndrome Detected by Home Monitoring Device

Lead fracture due to twiddler's syndrome, was detected in a 68-year-old patient 1 month after implantation of an ICD by means of the incorporated home monitoring system. The patient was admitted and the lead replaced. This case illustrates the clinical benefit of the home monitoring system.

Visualization of a coronary sinus valve using intracardiac echocardiography

Cannulation of the coronary sinus (CS) is sometimes difficult due to the presence of anatomical anomalies. Fluoroscopy is of limited value in visualizing these variations. This case is the first to demonstrate how intracardiac echocardiography (ICE) allows visualization of a valve, which is one of the causes of problematic cannulation of the CS. Based on information obtained by ICE an appropriate catheter could be selected.

First Dutch experience with percutaneous left atrial appendage transcatheter occlusion

BACKGROUND

Patients with atrial fibrillation (AF) have an increased risk of thromboembolic stroke, dependent on clinical variables. Oral anticoagulation significantly decreases the risk of stroke or embolism, but sometimes this is difficult to manage and may be contraindicated. Approximately 90% of atrial thrombi in nonrheumatic AF are found in the left atrial appendage (LAA). A new device has been developed which allows percutaneous LAA occlusion (PLAATO) and might be an alternative to oral anticoagulation. Feasibility in dogs and humans was described previously.

METHODS AND RESULTS

As part of an international multicentre trial, three patients received a percutaneous transcatheter LAA occlusion device. Implantations were performed without general anaesthesia, guided by intracardiac and transoesophageal echocardiography and without major complications. The implantations were well tolerated by the patients, who entered a long-term follow-up to be compared with a historical control group.

CONCLUSION

Transseptal percutaneous LAA occlusion is feasible. Its role as an alternative to oral anticoagulation, however, needs to be further defined.

Electrical isolation of pulmonary veins using cryothermal energy: study design and initial results

In the September 2003 issue of the Netherlands Heart Journal, the wrong figures where inserted in this article. The article is reprinted here with the correct figures.

BACKGROUND

Atrial fibrillation (AF) is the most frequently encountered arrhythmia. Radiofrequency pulmonary vein (PV) ablation is promising for symptomatic paroxysmal AF, but is associated with a significant risk of PV stenosis.

OBJECTIVES

To assess the efficacy of cryothermal PV ablation and the incidence of PV stenosis.

METHODS

Highly symptomatic patients with paroxysmal or persistent AF were eligible for cryothermal ablation. Multislice spiral CT scans were performed before, and three months after ablation. AF burden was assessed using transtelephonic ECG recording and by telephone enquiry.

RESULTS

An attempt was made to isolate 27 PVs in 15 patients. In total, 20 PVs could be isolated (74% acute success). No significant difference in PV diameter was seen before and after ablation. Five out of 12 patients with paroxysmal AF were completely without AF after one ablation procedure. An additional two patients reported a significant reduction in symptoms. In the three patients with persistent AF no improvement was reported.

CONCLUSION

Cryothermal PV ablation was effective in isolation of the targeted PVs. It appears to be safe, as no PV stenosis was seen in this study three months after the ablation. Taking into account a learning curve, we consider the clinical results to be very promising.

Electrical isolation of pulmonary veins using cryothermal energy: study design and initial results

BACKGROUND

Atrial fibrillation (AF) is the most frequently encountered arrhythmia. Radiofrequency pulmonary vein (PV) ablation is promising for symptomatic paroxysmal AF, but is associated with a significant risk of PV stenosis.

OBJECTIVES

To assess the efficacy of cryothermal PV ablation and the incidence of PV stenosis.

METHODS

Highly symptomatic patients with paroxysmal or persistent AF were eligible for cryothermal ablation. Multislice spiral CT scans were performed before, and three months after ablation. AF burden was assessed using transtelephonic ECG recording and by telephonic enquiry.

RESULTS

An attempt was made to isolate 27 PVs in 15 patients. In total, 20 PVs could be isolated (74% acute success). No significant difference in PV diameter was seen before and after ablation. Five out of 12 patients with paroxysmal AF were completely without AF after one ablation procedure. An additional two patients reported a significant reduction in symptoms. In the three patients with persistent AF no improvement was reported.

CONCLUSION

Cryothermal PV ablation was effective in isolation of the targeted PVs. It appears to be safe, as no PV stenosis was seen in this study three months after the ablation. Taking into account a learning curve, we consider the clinical results to be very promising.