Hospital utilisation and the costs associated with complications of ICD implantation in a contemporary primary prevention cohort.

INTRODUCTION: Implantation of an implantable cardioverter defibrillator (ICD) is standard care for primary prevention of sudden cardiac death. However, ICD-related complications are increasing as the population of ICD recipients grows. METHODS: ICD-related complications in a national DO-IT Registry cohort of 1442 primary prevention ICD patients were assessed in terms of additional use of hospital care resources and costs. RESULTS: During a median follow-up of 28.7 months (IQR 25.2-33.7) one or more complications occurred in 13.5% of patients. A complication resulted in a surgical intervention in 53% of cases and required on average 3.65 additional hospital days. The additional hospital costs were €6,876 per complication or €8,110 per patient, to which clinical re-interventions and additional hospital days contributed most. Per category of complications, infections required most hospital utilisation and were most expensive at an average of €22,892. The mean costs were €5,800 for lead-related complications, €2,291 for pocket-related complications and €5,619 for complications due to other causes. We estimate that the total yearly incidence-based costs in the Netherlands for hospital management of ICD-related complications following ICD implantation for primary prevention are €2.7 million. CONCLUSION: Complications following ICD implantation are related to a substantial additional need for hospital resources. When performing cost-effectiveness analyses of ICD implantation, including the costs associated with complications, one should be aware that real-world complication rates may deviate from trial data. Considering the economic implications, strategies to reduce the incidence of complications are encouraged.

High incidence of (ultra)low oesophageal temperatures during cryoballoon pulmonary vein isolation for atrial fibrillation.

BACKGROUND: Low oesophageal temperatures (OTs) during cryoballoon pulmonary vein isolation (PVI) have been associated with complications. This study assessed the incidence of low OT in clinical practice during cryoballoon PVI and verified possible predictive values for low OT. METHODS: Consecutive patients who underwent PVI using the second-generation cryoballoon were retrospectively included. The distance from the oesophagus to the different pulmonary veins (PVs) (OP distance), body mass index (BMI), sex, age, balloon temperature and application time were studied as potential predictors of low OTs. Computed tomography was performed before the procedure to determine the OP distance. OT was measured using an oesophageal temperature probe. Applications were ended prematurely if the OT reached <16 °C. Low and ultralow OT were defined as OT <20 and <16 °C respectively. RESULTS: Two hundred and four patients were included. Low OT was observed in 54 patients (26%) and 27 patients (13%) reached ultralow OTs. OP distance was the only predictor of low OTs after multivariate analysis. A cut-off value of 19 mm showed 96.2% sensitivity and 37.8% specificity in predicting low OTs. No clinically relevant relation was found between low OTs and BMI, age, sex, balloon temperature or application duration. CONCLUSIONS: The incidence of low OT was 26% for cryoballoon PVI. OP distance was the only predictor of low OTs. Since an OP distance <19 mm was present in all patients in at least one PV, we recommend routine OT measurement during PVI cryoballoon therapy to prevent oesophagus-related complications.

Comparison of complications and shocks in paediatric and young transvenous and subcutaneous implantable cardioverter-defibrillator patients.

BACKGROUND: Young implantable cardioverter-defibrillator (ICD) patients are prone to complications and inappropriate shocks (IAS). The subcutaneous ICD (S-ICD) may avoid lead-related complications. This study aims to describe the incidence and nature of device-related complications in young transvenous ICD (TV-ICD) and S­ICD patients. METHODS: Single-chamber TV-ICD and S­ICD patients up to and including the age of 25 years implanted between 2002 and 2015 were retrospectively analysed. Complications were defined as device-related complications requiring surgical intervention. IAS were defined as shocks for anything other than ventricular tachycardia or ventricular fibrillation. Follow-up data were collected 5 years post-implantation. Kaplan-Meier estimates for complications at 5­year follow-up were calculated with a corresponding 95% confidence interval. RESULTS: Eighty-one patients (46 TV-ICD, 35 S-ICD) were included (median age 19.0 (IQR 16.0-23.0) and 16.5 (IQR 13.0-20.2) years respectively). Median follow-up was 60 and 40 months respectively. All-cause complication rate was 34% in the TV-ICD group and 25% in the S­ICD group (p = 0.64). TV-ICD patients had more lead complications: 23% (10-36%) versus 0% (p = 0.02). The rate of infections did not differ between TV-ICD and S­ICD: 2% (0-6%) versus 10% (0-21%) (p = 0.15). No systemic infections occurred in the S­ICD patients. The rates of IAS were similar, TV-ICD 22% (9-35%) versus S­ICD 14% (0-30%) (p = 0.40), as were those for appropriate shocks: 25% (11-39%) versus 27% (6-48%) (p = 0.92). CONCLUSION: The rates of all-cause complications in this cohort were equal, though the nature of the complications differed. S­ICD patients did not suffer lead failures or systemic infections. An era effect is present between the two groups.

Prognostic value of microvolt T-wave alternans in a real-world ICD population. Twente ICD Cohort Studie (TICS).

INTRODUCTION: Survival benefit from ICD implantation is relatively low in primary prevention patients. Better patient selection is important to maintain maximum survival benefit while reducing the number of unnecessary implants. Microvolt T-wave alternans (MTWA) is a promising risk marker. In this study, we aimed to evaluate the predictive value of MTWA in ICD patients. METHODS AND RESULTS: This study was a substudy of the Twente ICD Cohort Study (TICS). Patients with ischaemic or non-ischaemic left ventricular dysfunction who received an ICD following current ESC guidelines were eligible for inclusion. Exercise-MTWA was performed and classified as non-negative or negative. The primary endpoint was the composite of mortality and appropriate shock therapy. Analysis was performed in 134 patients (81 % male, mean age 62 years, mean ejection fraction 26.5 %). MTWA was non-negative in 64 %. There was no relation between non-negative MTWA testing and mortality and/or appropriate shock therapy (all p-values >0.15). Due to clinical conditions, 24 % were ineligible for testing. These patients experienced the highest risk for mortality (p < 0.01). CONCLUSION: Non-negative MTWA testing did not predict mortality and/or appropriate shock therapy. Furthermore, MTWA testing is not feasible in a large percentage of patients. These ineligible patients experience the highest risk for mortality.

Towards a better risk stratification for sudden cardiac death in patients with structural heart disease.

With the introduction of the implantable cardioverter defibrillator (ICD), patients can be protected against sudden cardiac death (SCD) due to ventricular arrhythmia (VA). Guidelines have been drawn up for selecting patients for primary and secondary prophylaxis. However, most ICD recipients today who receive an ICD for primary prevention will not experience a life-threatening VA requiring antitachypacing or shock therapy. Better risk stratification is desirable with efficacy, costs and complication rate in mind. An overview is presented of widely accepted and potentially valuable risk markers and the role they may play in better identifying candidates for ICD therapy. (Neth Heart J 2009;17:101-6.).

Exercise capacity after His bundle ablation and rate response ventricular pacing for drug refractory chronic atrial fibrillation.

OBJECTIVE: To evaluate exercise capacity of patients with chronic atrial fibrillation in whom His bundle ablation followed by ventricular rate response pacing (VVIR) was carried out because of drug refractoriness. DESIGN: Prospective study. PATIENTS: 25 consecutive patients, all with chronic symptomatic drug refractory atrial fibrillation, underwent His bundle ablation. Before this intervention all patients were on antiarrhythmic drugs to attain acceptable heart rate control and to relief symptoms. MAIN OUTCOME MEASURES: Exercise capacity, including measurements of VO2, was examined before and after a mean interval of seven months following His bundle ablation. RESULTS: Exercise capacity after His bundle ablation increased from a mean of 109 (SD 49) W to 118 (46) W (P < 0.002), but VO2 at peak exercise did not change significantly. Maximum exercise capacity was achieved with a significantly lower maximum driven heart rate than the spontaneous heart rate before ablation. CONCLUSIONS: Exercise capacity of patients who underwent His bundle ablation followed by VVIR pacing remained unchanged or improved during a mean follow up of seven months. Larger patient populations with longer follow up are necessary to examine determinants of improved exercise capacity.

[Implantable cardioverter-defibrillator in the treatment of two patients with an increased risk of sudden cardiac death]. / Implanteerbare cardioverterende defibrillator bij de behandeling van 2 patiënten met een verhoogde kans op plotse hartdood.

A 23-year-old female with familial long-QT syndrome and a 48-year-old male with familial dilated cardiomyopathy were given an implantable cardioverter-defibrillator (ICD) as prophylaxis. About half a year after the implantation, there was an appropriate and successful ICD-discharge in both patients in connection with ventricular tachycardia. Treatment with an ICD can be life-saving in patients with cardiac rhythm disorders. The most common indication is ventricular tachycardia or fibrillation due to ischaemic heart disease, but an ICD may also be indicated in patients with cardiomyopathy, congenital heart disease, hereditary arrhythmia or a planned heart transplantation.

[Radiofrequency catheter ablation in patients with atrioventricular nodal reentry tachycardia is as effective as rhythm surgery, but less stressful]. / Radiofrequentiekatheterablatie bij patiënten met tachycardieën vanuit de atrioventriculaire knoop even goed als ritmechirurgie, maar minder belastend.

OBJECTIVE: To compare the long-term results of surgical modification and of radiofrequency (RF) catheter modification of the atrioventricular node (AV node), to combat recurrent atrioventricular nodal re-entrant tachycardia (AVNRT). DESIGN: Retrospective descriptive. SETTING: St. Antonius Hospital, Nieuwegein, the Netherlands. METHOD: In the period 1988-1992, 26 patients underwent surgical modification and in 1991-1996, 120 patients were subjected to RF catheter modification of the AV node for recurrent AVNRT. The follow-up amounted to at least one year. RESULTS: Surgery was immediately successful in 96%, and RF catheter ablation in 92%. A recurrence AVNRT was seen in 12 and 17% respectively, the ultimate success rates (after retreatment) were 100 and 98%. Three patients (3%) in the RF catheter ablation group developed a second or third-degree AV block necessitating pacemaker implantation. No third-degree AV block was seen in the surgical group. Mean follow-up was 53 months in the surgical group and 28 months in the RF catheter ablation group. Both procedures were accompanied by other supraventricular tachycardias, viz. in 27% of the surgical and in 11% of the RF catheterization ablation group. CONCLUSION: RF catheter ablation for the treatment of AVNRT had early and long-term results comparable with those of rhythm surgery. Since catheter treatment is far less taxing to the patient than rhythm surgery, RF catheter ablation now constitutes the most appropriate method for treatment of this arrhythmia.

Health care utilisation after defibrillator implantation for primary prevention according to the guidelines in 2 Dutch academic medical centres.

BACKGROUND: The benefit of implantable defibrillators (ICDs) for primary prevention remains debated. We analysed the implications of prophylactic ICD implantation according to the guidelines in 2 tertiary hospitals, and made a healthcare utilisation inventory. METHODS: The cohort consisted of all consecutive patients with coronary artery disease (CAD) or dilated cardiomyopathy (DCM) receiving a primary prophylactic ICD in a contemporary setting (2004-2008). Follow-up was obtained from hospital databases, and mortality checked at the civil registry. Additional data came from questionnaires sent to general practitioners. RESULTS: There were no demographic differences between the 2 centres; one had proportionally more CAD patients and more resynchronisation therapy (CRT-D). The 587 patients were followed over a median of 28 months, and 50 (8.5%) patients died. Appropriate ICD intervention occurred in 123 patients (21%). There was a small difference in intervention-free survival between the 2 centres. The questionnaires revealed 338 hospital admissions in 52% of the responders. Device-related admissions happened on 68 occasions, in 49/276 responders. The most frequently reported ICD-related admission was due to shocks (20/49 patients); for other cardiac problems it was mainly heart failure (52/99). Additional outpatient visits occurred in 19%. CONCLUSION: Over a median follow-up of 2 years, one fifth of prophylactic ICD patients receive appropriate interventions. A substantial group undergoes readmission and additional visits. The high number of admissions points to a very ill population. Overall mortality was 8.5%. The 2 centres employed a similar procedure with respect to patient selection. One centre used more CRT-D, and observed more appropriate ICD interventions.

Noninvasive detection of epicardial and endocardial activity of the heart.

Determining electrical activation of the heart in a noninvasive way is one of the challenges in cardiac electrophysiology. The ECG provides some, but limited information about the electrical status of the heart. This article describes a method to determine both endocardial and epicardial activation of the heart of an individual patient from 64 electrograms recorded from the body surface. Information obtained in this way might be helpful for the treatment of arrhythmias, to assess the effect of drugs on conduction in the heart and to assess electrical stability of the heart.

Peak longitudinal strain delay is superior to TDI in the selection of patients for resynchronisation therapy.

BACKGROUND: Mechanical dyssynchrony has proven to be superior to QRS duration in predicting response to cardiac resynchronisation therapy (CRT). Whether time to peak longitudinal strain delay between the mid-septum and mid-lateral left ventricular wall better predicts CRT response than tissue Doppler imaging (TDI) is unclear. This study compares the value of the two methods for the assessment of mechanical dyssynchrony and prediction of CRT responders. METHODS: 66 clinical responders and 17 nonresponders to CRT with severe systolic heart failure (LVEF <35%), New York Heart Association classification III or IV and a wide QRS >130 ms with left bundle branch block were evaluated by peak longitudinal strain and TDI. Doppler echocardiograms and electromechanical time delay (EMD) intervals were acquired before and after pacemaker implantation. RESULTS: In all responders EMD measured by peak longitudinal strain was >60 ms before implantation, compared with 76% of the patients measured by TDI. Nonresponders had EMD <60 ms measured by both techniques. Only peak longitudinal strain delay showed shortened values in every responder postimplantation and demonstrated the most significant reduction and could predict responders to CRT. However, EMD measured by TDI did not diminish in 30% of the positive clinical responders. Nonresponders showed worsening of the EMD with peak longitudinal strain, but not with TDI. CONCLUSIONS: Responders to CRT can be excellently predicted if EMD before implantation determined by peak longitudinal strain delay is >60 ms. Peak longitudinal strain delay appears to be superior to TDI to predict the response to CRT. (Neth Heart J 2010;18:574-82.).

Ten year follow-up after radiofrequency catheter ablation for atrioventricular nodal reentrant tachycardia in the early days forever cured, or a source for new arrhythmias?

BACKGROUND: Radiofrequency (RF) catheter ablation is highly effective with a low complication rate. However, lesions created by RF energy are irreversible, inhomogeneous, and therefore potentially proarrhythmic. OBJECTIVES: The aim of this study was to examine the magnitude and importance of long-term proarrhythmic effects of RF energy. METHODS AND RESULTS: Between 1991 and 1995, 120 patients underwent RF ablation for atrioventricular nodal reentrant tachycardia (AVNRT). Patient data were collected by contacting patients and/or filling out a questionnaire, and medical files were screened for recurrent, documented arrhythmias, pharmacological treatment, and repeated EP study. Referring cardiologists were asked about recurrences of tachyarrhythmias. Fourteen patients (11%) were lost to follow-up. During a mean follow-up of 10 years, six patients died. Recurrences of AVNRT were not any more observed after 3 years after ablation. A total of 29 patients (24%) suffered from new arrhythmias, 6 from type 1 atrial flutter, 6 from atrial tachycardia, 9 from atrial fibrillation, and finally 16 from symptomatic premature atrial contractions (PACs), needing medical treatment or a combination of these arrhythmias. Nine patients underwent pacemaker implantation, 4 after developing procedural atrioventricular (AV) conduction disturbances, 2 after His ablation for permanent atrial fibrillation, 1 patient for sick sinus syndrome, and another 2 patients after developing late AV block, respectively, 7 and 9 years after ablation. CONCLUSION: During long-term follow-up after RF ablation for AVNRT, no AVNRT recurrences were observed, but 29 patients (24%) suffered from new arrhythmias or late AV block. This potential proarrhythmic effect of RF energy promotes the application of alternative energy sources for ablative therapies for cardiac arrhythmias.

Radiofrequency catheter ablation of accessory pathways associated with a coronary sinus diverticulum.

In two patients with a symptomatic posteroseptally localized accessory atrioventricular pathway, but with distinct electrocardiographic patterns, a coronary sinus diverticulum appeared to be the site of this connection. Radiofrequency catheter ablation in the diverticulum was implemented to interrupt the pathway in both cases. This study demonstrates the necessity to perform coronary sinus angiography when ablation attempts in the posteroseptal region are not immediately successful, or optimal signals are not detected.

Unsatisfying results in long-term atrial pacing with a bipolar active fixation atrial lead.

A high dislodgment rate during long-term atrial pacing using the unipolar sickle-shaped active fixation lead was recently reported; therefore, the long-term results of atrial pacing in 118 consecutive patients with the bipolar sickle-shaped active fixation lead (Biotronik FH60-BP) were evaluated. Between January 1989 and September 1993, 87 leads (74%) were inserted for dual chamber pacing and 31 leads (26%) for atrial pacing only. At the time of implantation, the bipolar atrial electrogram had a mean voltage of 4.4 +/- 1.6 mV, whereas the acute atrial threshold was 0.72 +/- 0.38 V and 1.46 +/- 0.67 mA at 0.5-msec pulse duration and mean resistance 506 +/- 79 omega. Early lead dislodgment (< 1 month after implantation) occurred in 9 patients (7.6%). During a mean follow-up of 21.8 months (median 20.9 months), late dislodgment (> 1 month after implantation) occurred in 6 patients (5.1%) after a mean interval of 7.9 months (range 3-14 months). Due to the unacceptably high late dislodgment rate, which to date remains unexplained, new implants of this lead are not recommended.

Temporary pacing after His bundle ablation for drug-refractory atrial fibrillation: a risky enterprise?

AIM: In patients with and without a permanent pacemaker His bundle ablation was performed for symptomatic drug-refractory atrial fibrillation. This study was performed to examine the complications of temporary pacing in patients without an already implanted pacemaker. METHODS AND RESULTS: Between January 1996 and December 1998, 152 consecutive patients, both referred and our own (non-referred), underwent His bundle ablation for drug-refractory atrial fibrillation. Primary end-point complications were temporary lead dislodgement requiring immediate repositioning (1), severe arrhythmia (2), death (3) and persistent damage to an already implanted pacing system (4). Secondary end-points were malsensing and malpacing of the temporary lead, and blood vessel problems. Lead dislodgement of the temporary pacemaker occurred in three patients (2.9%), all of whom were in the referred group. Severe arrhythmia and death did not occur. Persistent damage of the already implanted pacing system was not observed. Secondary end-points occurred in 15.8%) of the patients and were successfully managed by a conservative approach. CONCLUSION: Permanent pacemaker implantation is recommended prior to His bundle ablation in order to avoid haemodynamic deterioration due to dislocation of the temporary pacemaker lead. RF current used for His bundle ablation caused no permanent damage to permanent pacing systems.

Successful surgical ablation of sustained ventricular tachycardia associated with mitral valve prolapse guided by a multielectrode basket catheter.

Ventricular tachycardia occurs frequently in patients with mitral valve prolapse. If antiarrhythmic drug therapy fails or mitral valve surgery is indicated, concomitant arrhythmia surgery may be considered. This report describes the first clinical use of an atrial transseptally inserted multielectrode basket catheter, placed across the mitral valve, to guide intraoperative mapping and ablation of monomorphic sustained ventricular tachycardia in association with mitral valve prolapse. Endocardial covering and signal quality of this percutaneous mapping catheter were of good quality, allowing an accurate localization of the site of origin of the tachycardia.

Relation between body surface mapping and endocardial spread of ventricular activation in postinfarction heart.

INTRODUCTION: Body surface mapping (BSM) can be used to identify the site of earliest endocardial activation of ventricular tachycardias (VTs). The multielectrode QRS morphology during VT is determined by both the site of earliest activation and the subsequent spread of electrical activation through the ventricles. This study investigated the relationship between the site of earliest endocardial activation, endocardial spread of activation, and the morphology of the multielectrode surface map in patients with remote myocardial infarction. METHODS AND RESULTS: In 14 patients with VT late (8.2+/-5.2 years) after myocardial infarction, BSM and simultaneous left ventricular 64-site basket endocardial mapping was performed during a total of 17 monomorphic VTs. In addition, multisite pacing by sequential use of the 64 basket electrodes was performed in 9 patients. BSM and basket mapping revealed the same endocardial breakthrough sites in 8 (47%) of 17 VTs and 189 (59%) of 322 pacing sites; adjacent sites were found in 2 (12%) of 17 VTs and 36 (11%) of 322 pacing sites. Large zones of conduction block explained the mismatch in localization in 2 (12%) of 17 VTs and 52 (16%) of 322 pacing sites. Regional differences in endocardial electrogram amplitudes were found as a cause for dissimilarity in 3 (18%) of 17 VTs and 73 (23%) of 322 pacing sites. Multiple endocardial breakthrough sites were found in 1 (6%) of 17 VTs and 8 (2%) of 322 pacing sites Finally, an epicardial exit site was suggested in 3 (18%) of 17 VTs as an explanation for mismatch, as no early endocardial activity could be recorded. CONCLUSION: Zones of conduction block, regional differences in signal amplitude, and multiple endocardial breakthrough sites are frequent causes for mismatch between BSM and basket catheter activation mapping.

Pace mapping of postinfarction scar to detect ventricular tachycardia exit sites and zones of slow conduction.

INTRODUCTION: The exit site and central common pathway of slow conduction are preferred sites to guide radiofrequency ablation of postinfarction ventricular tachycardia (VT). Both require inducibility of VT. In addition, their low amplitude hampers direct recording of potentials generated by activation in pathways of slow conduction. We hypothesized that pace mapping during sinus rhythm would help to detect the VT exit site and potentials generated by activation in pathways of slow activation. METHODS AND RESULTS: In 13 patients suffering from VT late after anterior (n = 10) or inferior (n = 3) myocardial infarction, stimulation was performed in scarred endocardium at 23.5 (range 13 to 36) sites per patient during arrhythmia surgery. Multielectrode recordings (64 sites) during stimulation at a fixed cycle length of 500 msec were obtained. Endocardial breakthrough sites distant (>2 cm) from the pacing site were found at 4.3 (range 3 to 19) pacing sites per patient. Low-amplitude discrete potentials (LADPs) could be detected between the pacing site and the breakthrough site in 2.3 (range 0 to 13) of 4.3 stimulation sequences. In these patients, 19 VTs were induced and the exit site determined. In 6 patients, the distant pacing breakthrough site was identical to the VT exit site; in 7 patients, no similar exit sites were found. LADPs during VT were found at a median 2.0 (range 0 to 14) sites per patient. CONCLUSION: Pace mapping of the postinfarction endocardial scar during sinus rhythm revealed 50% of the endocardial exit sites of VT and the same number of LADPs observed during VT.