Radiofrequency catheter ablation in 246 children with supraventricular tachyarrhythmia.

INTRODUCTION: Radiofrequency catheter ablation (RFA) is the treatment of choice for a variety of cardiac arrhythmias in adults. RFA is considered effective and is associated with few complications. We aimed to review the characteristics and outcomes of invasive electrophysiological study (EPS) and RFA in children with supraventricular tachyarrhythmia. METHODS: Consecutive patients younger than 16 years of age undergoing EPS and possible RFA from January 2009 to September 2018 at Aarhus University Hospital (uptake three million people) were reviewed retrospectively. Procedural and outcome data were collected from patient charts and from the Danish Ablation Database. Numbers (%) or median (range) are reported. RESULTS: A total of 304 patients (148 girls) underwent EPS (352 procedures). RFA was performed in 246 patients (279 procedures), aged 13 (1-15) years and weighing 46 (6-99) kg. Treatment success was achieved in 195 (79%) of the initial procedures. Using more than one procedure, 227 (92%) patients were free from arrhythmia after 89 (26-143) months of follow-up. The procedure time was 60 (22-222) min. and ablation time 2 (1-23) min. Major complications occurred in two cases. One patient developed transient superior vena cava syndrome and one patient developed an atrioventricular block requiring pacemaker implantation. CONCLUSIONS: RFA may be performed in children with a high success rate and a low but not negligible risk of complications. FUNDING: none. TRIAL REGISTRATION: Approval was obtained from the Danish Data Protection Agency (1-16-02-430-13).

Infected cardiac-implantable electronic devices: prevention, diagnosis, and treatment.

Cardiac implantable electronic device (CIED) infection, according to current trends, appears to be an increasing problem. It can be indolent and its diagnosis challenging. Cardiac implantable electronic device infections are potentially lethal, and timely diagnosis and early initiation of correct treatment are of highest importance for patient prognosis. For reducing CIED infections, careful patient selection, preventative measures, and appropriate choice of device are key. The current review presents available data and consensus opinion within the field of CIED infection and identifies important current practice points and aspects for future development. Strategies for reducing CIED infection should be tested in sufficiently powered and well-designed multicentre randomized controlled trials.

[Radiofrequency ablation therapy of intractable ventricular tachycardia present with a left ventricular assist device]. / Radiofrekvensablation af ventrikulær takykardi hos en patient med kunstig hjertepumpe.

Ventricular tachycardia (VT) occurs in up to 59% of patients with left ventricular assist devices (LVAD). In some of these patients, the VT cannot be managed medically or by implantable cardioverter-defibrillator. In this case, a 66-year-old male was successfully treated with radiofrequency ablation of intractable VT that developed months after implantation of an LVAD (Heartware). The LVAD provided haemodynamical support during mapping and did not interfere with the ablation.

Ablation for idiopathic ventricular arrhythmia - with and without arrhythmia-induced cardiomyopathy.

OBJECTIVES: We conducted a study to assess the procedural success and long-term freedom from arrhythmia in patients treated with radiofrequency ablation (RFA) for idiopathic ventricular arrhythmia (VA) with and without arrhythmia-induced cardiomyopathy (AIC). DESIGN: We identified 131 patients treated with RFA for idiopathic VA in our institution; 16 of whom had AIC. Data were obtained from patient files. A questionnaire was used to assess the improvement in subjective symptoms late after RFA. RESULTS: At the initial RFA, any VA was abolished in 93 patients (71%), non-targeted VA still was observed in 5 patients (4%), and the targeted VA remained present in 29 (22%). In 4 patients (3%) procedural success was undeterminable. During a median follow-up time of 8 months after latest RFA, 100 patients (76%) stayed free from recurrence. We observed no difference in procedural or long-term success between patients with and without AIC. When excluding patients with fascicular ventricular tachycardia (VT), a significantly higher proportion of patients with AIC had VA originating from the left ventricle (p = 0.027). Patients with AIC had a significant improvement of ejection fraction after RFA (p < 0.001). Totally 89 of 99 patients (90%) who returned the questionnaire reported symptomatic benefit a median of 64 months after their latest procedure. CONCLUSIONS: RFA is effective for treating idiopathic VA with and without AIC, with high rates of long-term freedom from VA and symptomatic relief. We found more patients with AIC had left ventricle VA.

His or para-His pacing preserves left ventricular function in atrioventricular block: a double-blind, randomized, crossover study.

AIMS: To compare left ventricular function after a long-term His or para-His pacing (HP) and right ventricular septal pacing (RVSP) in patients with atrioventricular block (AVB). METHODS AND RESULTS: We included consecutive patients with AVB, a narrow QRS < 120 ms, and a preserved left ventricular ejection fraction (LVEF) >0.40, in a prospective, randomized, double-blinded, crossover design. All patients were treated with 12 months HP and 12 months RVSP. A total of 38 patients [mean age, 67 ± 10 years; 30 (79%) men] were included. The primary endpoint was LVEF, which was significantly lower after a 12 months RVSP (0.50 ± 0.11) than after 12 months of HP (0.55 ± 0.10), P = 0.005. We measured the difference in time-to-peak systolic velocity between opposite basal segments in the apical views by using tissue Doppler imaging. In the four-chamber view, the difference was 58 (±7) ms after RVSP and 49 (±7) ms after HP, P = 0.27; in the two-chamber view, the difference was 45 (±5) ms after RVSP and 31 ±(4) ms after HP, P = 0.02, and in the apical long-axis view, the difference was 63 (±6) after RVSP and 44 (±7) after HP, P = 0.03. There was no difference in New York Heart Association class, 6-min hall walk test, quality-of-life assessments, or device-related complications. The mean threshold was significantly higher in HP leads than in RVSP leads. CONCLUSION: His or para-His pacing preserves LVEF and mechanical synchrony as compared with RVSP after 12 months pacing in patients with AVB, narrow QRS, and LVEF > 0.40.

Catheter ablation for ventricular tachycardia in ischaemic heart disease; acute success and long-term outcome.

OBJECTIVES: We conducted a study to assess the acute procedural success and the long-term effect of radiofrequency ablation (RFA) for ventricular tachycardia (VT) in patients with ischaemic heart disease. DESIGN: We included 90 patients with ischaemic heart disease treated with RFA for VT in our institution. Data were obtained from patient files, and implantable cardioverter-defibrillator (ICD) discharges were recorded from in-house and remote follow-up data. Recurrence of VT during follow-up was noted as date of first ICD therapy for VT or first recurrence of symptomatic VT. RESULTS: After the initial RFA procedure no VT was inducible in 42 patients (47%), non-clinical VT was inducible in 21 patients (23%), and the clinical VT was still inducible in 14 patients (16%). The procedural success was indefinable in 13 patients (14%). After a median follow-up of 33 months after the latest RFA, 38 patients (42%) stayed free from recurrent VT. The number of ICD shocks/year was significantly reduced from median 1.1 (interquartile range: 0.3-2.8) to 0 (0-0.4) (p < 0.0001). CONCLUSIONS: Procedural success rate as well as long-term freedom from recurrent VT is modest after RFA for VT in ischaemic heart disease. However, ICD discharges are significantly reduced after RFA, and a considerable proportion of patients remain free from recurrent VT during the long-term follow-up.

Long-term outcome of ablative therapy of post-operative atrial tachyarrhythmias in patients with tetralogy of Fallot: a European multi-centre study.

AIM: Post-operative atrial tachyarrhythmias (AT) in patients with tetralogy of Fallot (ToF) are associated with congestive heart failure, stroke, and cardiac death. Effective treatment is therefore essential. The aim of the study is to evaluate long-term outcome of ablative therapy of AT in ToF patients and to study characteristics of AT recurrences. METHODS AND RESULTS: Tetralogy of Fallot patients (N = 38, age 43 ± 12 years) referred for ablation of post-operative AT, appearing 26 ± 10 years after complete repair, were studied. Electro-anatomical/entrainment mapping was performed prior to ablation. Successful ablation was defined as (i) achievement of bi-directional conduction block for isthmus-dependent atrial flutter (IDAF), (ii) termination during ablation for intra-atrial reentrant tachycardia (IART) and focal atrial tachycardia (FAT). Fifty-two AT were ablated, including 37 IDAF [cycle length (CL) 294 ± 70 ms], 11 IART (CL 295 ± 46 ms), and 4 FAT (CL 371 ± 93 ms). Ablation was successful in 98%. Fifty-one of 52 AT involved the cavo-tricuspid isthmus and/or the area between scar tissue related to prior atriotomy incisions and the inferior caval vein. Multiple AT developed in 11 patients, with different mechanisms in 9. After 45 ± 24 months, 32 patients were in sinus rhythm; 5 used anti-arrhythmic drugs. CONCLUSION: Ablative therapy of AT in ToF patients is an effective curative treatment modality with a high procedural success rate. Sinus rhythm during long-term follow-up was obtained in the majority of patients. Fifty-one of 52 AT originated from sites related to surgical incisions created at complete repair, suggesting that extending the atriotomy incision towards the inferior caval vein during cardiac surgery combined with surgical ablation of the cavo-tricuspid isthmus will be effective in preventing development of AT.

His and para-His pacing in AV block: feasibility and electrocardiographic findings.

PURPOSE: Right ventricular apical pacing induces a dyssynchronous activation of the left ventricle and is associated with adverse clinical outcome. We aimed to establish permanent His-bundle pacing or para-His pacing in patients with high-grade atrioventricular (AV) block. METHOD: We included patients with pacemaker indication due to second- or third-degree AV block, left ventricular ejection fraction >0.40, QRS duration <120 ms, and sinus rhythm. All patients received a pacemaker with one atrial lead, one right ventricular mid-septal lead, and one lead in the His bundle or in the para-His position. Pacing from apex was performed temporarily. Patients were followed for 12 months. RESULTS: Thirty-eight patients were included (mean age, 67 ± 10 years; 30 (79%) male). Mean implantation time was 85 ± 31 min, mean fluoroscopy time was 23 ± 13 min, and mean position attempts of the His bundle lead was 8 ± 5. In four patients, we established direct His-bundle pacing with a mean QRS of 100 ± 19 ms, and in 28 patients, para-His pacing was achieved with a mean QRS of 112 ± 18 ms, and in six patients, neither direct His-bundle pacing or para-His pacing could be achieved. The mean QRS duration was 153 ± 12 ms with mid-septal pacing and 161 ± 15 ms with apical pacing. CONCLUSION: Stable direct His-bundle pacing or para-His pacing is feasible in 85% of patients with narrow QRS and high-grade AV block and leads to a normal or near-normal ventricular activation pattern.

Diastolic dysfunction after an acute myocardial infarction in patients with antecedent hypertension.

OBJECTIVE: We sought to assess changes in the left ventricular systolic and diastolic function in patients with antecedent hypertension and an acute myocardial infarction. METHODS: A group of 38 patients with antecedent hypertension and acute myocardial infarction were compared with an age-matched nonhypertensive control group. There was a 30-day follow-up. Outcome measures were left ventricular volumes and ejection fraction, systolic velocities, and strain. Diastolic function was assessed by mitral inflow combined with tissue velocities of the mitral ring. RESULTS: Patients with antecedent hypertension did not experience any regression in the E/E' ratio (16.5 +/- 7.5 vs 17.1 +/- 9.0, P = not significant) or increase in the E'/A' ratio (0.76 +/- 0.5 vs 0.84 +/- 0.6, P = not significant) compared with significant improvements in E/E' ratio (18.9 +/- 8.7 vs 12.8 +/- 7.4, P < .01) and E'/A' ratio (0.76 +/- 0.5 vs 1.1 +/- 0.7, P < .01) in the control group. This was found despite similar changes ejection fraction, volumes, and systolic strain. CONCLUSIONS: Patients with antecedent hypertension have incomplete improvement of the diastolic function compared with control subjects despite comparable left ventricular volumes and ejection fraction after an acute myocardial infarction.

No beneficial effects of coronary thrombectomy on left ventricular systolic and diastolic function in patients with acute S-T elevation myocardial infarction: a randomized clinical trial.

OBJECTIVE: We sought to evaluate the effect of acute coronary thrombectomy, as adjunctive treatment to primary percutaneous coronary intervention, on the systolic and diastolic left ventricular function, in patients with acute S-T elevation myocardial infarction. METHODS: In a prospective randomized study, patients with acute S-T elevation myocardial infarction were randomized to treatment with primary percutaneous coronary intervention with or without thrombectomy. Outcome measures were left ventricular volumes and ejection fraction in addition to systolic long-axis function, estimated from the tissue Doppler systolic velocities of the mitral ring. Diastolic function was assessed by mitral inflow and diastolic velocities of the mitral ring movement. RESULTS: Of the 215 patients included, 172 patients (80%) had a 30-day follow-up. There were no significant differences in ejection fraction between groups during follow-up (thrombectomy at baseline 47 +/- 14% vs 47 +/- 14% at follow-up, control group at baseline 48 +/- 11% vs 51 +/- 12% at follow-up, P = not significant). Systolic velocities were significantly higher in the control group at follow-up (thrombectomy, at baseline, 6.5 +/- 1.9 vs 6.3 +/- 1.8 cm/s at follow-up; control group, at baseline, 6.5 +/- 1.9 vs 7.0 +/- 1.9 cm/s at follow-up; P < .05). There were no significant differences in diastolic function between the two groups. CONCLUSION: Thrombectomy had no beneficial effect on the left ventricular function in patients with acute S-T elevation myocardial infarction.

Does postsystolic motion or shortening predict recovery of myocardial function after primary percutanous coronary intervention?

OBJECTIVE: The purpose of the study was to evaluate whether presence of postsystolic motion or shortening defined by Doppler tissue imaging may predict recovery of regional myocardial function in patients with ST-elevation myocardial infarction. METHODS: Echocardiography was performed a few hours after primary percutanous coronary intervention and at a 3-month follow-up visit in 83 patients with ST-elevation myocardial infarction. Based on visual assessment of wall thickening in a 16-segment model, segments were classified into those with: dyskinesia/akinesia (type A, n = 63) or hypokinesia (type B, n = 141) in the acute phase and no recovery of function at follow-up; dyskinesia/akinesia in the acute phase and partial recovery of function at follow-up (type C, n = 86); dyskinesia/akinesia/hypokinesia in the acute phase and complete recovery of function at follow-up (type D, n = 243); and normal myocardial function in the acute phase (type E, n = 759). RESULTS: There were no differences among type A, B, C, and D segments with regard to the proportion presenting postsystolic tissue velocity equal to or greater than 1.0 cm/s (0.52, 0.54, 0.60, and 0.47, respectively, P = .20) or with respect to postsystolic negative increase in strain (median -2.9, -1.9, -1.8, and -1.5%, respectively, P = .13) in the acute phase. However, type E segments less often presented postsystolic tissue velocity greater than 1.0 cm/s and presented lower postsystolic increase in strain (0.39 and -1.0%, respectively, P < .001 as compared with type A-D segments). In initially dysfunctional segments, presence of postsystolic contraction was not associated with improvement in strain or wall-motion score at follow-up. CONCLUSION: In patients with ST-elevation myocardial infarction postsystolic motion or shortening appears more frequently in the acute phase in myocardial segments with impaired systolic function compared with normally functioning segments. However, presence of postsystolic contraction is not associated with improvement in strain or wall-motion score at follow-up, and does not seem to be a marker of viability.

Potential significance of spontaneous and interventional ST-changes in patients transferred for primary percutaneous coronary intervention: observations from the ST-MONitoring in Acute Myocardial Infarction study (The MONAMI study).

AIMS: In patients with ST-elevation myocardial infarction (STEMI) scheduled for primary percutaneous coronary intervention (primary PCI), acute risk-assessment may be valuable for tailoring of adjunctive therapy at the time of coronary intervention. The present study was designed to quantify pre-, per-, and post-interventional ST-changes, to evaluate whether a pre-specified continuous ST-monitoring classification provides potential prognostic information in the pre- and per-interventional phase, and to compare post-interventional ST-resolution parameters derived from continuous ST-monitoring and snapshot ECGs, respectively. METHODS AND RESULTS: In 92 STEMI patients, continuous ST-monitoring was initiated in the pre-hospital phase and continued during and 90 min following PCI. Patients were divided into three groups: (A) patients achieving spontaneous ST-resolution before PCI; (B) patients with preserved ST-elevation immediately before PCI and with no increase in ST-elevation during PCI; and (C) patients with preserved ST-elevation immediately before PCI and with increase in ST-elevation during PCI. Groups A (n=22), B (n=43), and C (n=27) differed in peak level of troponin-T (1.4, 4.7, and 7.2 microg/L, P<0.001), creatinine kinase MB isoenzyme (35, 150, and 325 microg/L, P<0.001), and N-terminal pro-brain natriuretic peptide (Nt-pro-BNP) (183, 175, and 269 pmol/L, P=0.084) during admission, and left ventricular ejection fraction evaluated within 2 h of PCI (0.53, 0.48, and 0.45, P=0.047) and after 3 months (0.58, 0.54, and 0.45, P<0.001). Groups B and C also differed in time from first balloon inflation to > or =70% resolution of ST-elevation (14 vs. 42 min, P=0.002), whereas no differences were observed in traditional 90 min ST-resolution analysis or angiographically assessed parameters. CONCLUSION: STEMI patients transferred for primary PCI are heterogeneous with respect to pre- and per-interventional ST-changes, and a pre-specified ST-monitoring classification seems useful for stratification of patients at time of PCI into groups with low, intermediate, and high risk profile. Furthermore, post-interventional ST-monitoring indicates that traditional 90 min ST-resolution analysis may have limited value in the era of primary PCI.

Reduction of treatment delay in patients with ST-elevation myocardial infarction: impact of pre-hospital diagnosis and direct referral to primary percutanous coronary intervention.

AIMS: The majority of patients with ST-elevation myocardial infarction (STEMI) are admitted to local hospitals without primary percutaneous coronary intervention (primary PCI) facilities. Acute transferral to an interventional centre is necessary to treat these patients with primary PCI. The present study assessed the reduction in treatment delay achieved by pre-hospital diagnosis and referral directly to an interventional centre. METHODS AND RESULTS: Two local hospitals without primary PCI facilities were serving the study region. Pre-hospital diagnoses were established with the use of telemedicine, by ambulance physicians, or by general practitioners. Primary PCI was accepted as the preferred reperfusion therapy in patients with STEMI. From 31 October 2002 to 31 January 2004 all patients transported by ambulance and transferred for primary PCI were registered. Patients with STEMI were divided into three groups: (A) patients diagnosed at a local hospital (n = 55), (B) patients diagnosed pre-hospitally and admitted to a local hospital (n = 85), and (C) patients diagnosed pre-hospitally and referred directly to the interventional centre (n = 21). When comparing group A with group B and C, no difference was found in age, sex, infarct location, or distance from the scene of event to the interventional centre, whereas the median time from ambulance call to first balloon inflation was 41 min shorter in group B compared with group A (P<0.001) and 81 min shorter in group C compared with group A (P<0.001). CONCLUSION: In a cohort of patients scheduled for admission to a local hospital and subsequent transferral to an interventional centre for primary PCI, those diagnosed pre-hospitally had shorter treatment delay compared with those diagnosed in hospital, both in the setting of initial admission to a local hospital, and to an even larger extent in the setting of referral directly to the interventional centre.

Mortality rates in patients with ST-elevation vs. non-ST-elevation acute myocardial infarction: observations from an unselected cohort.

AIMS: Acute myocardial infarction (AMI) is categorized, according to the presenting electrocardiogram, into non-ST-elevation myocardial infarction (non-STEMI), ST-elevation myocardial infarction (STEMI), or bundle branch block myocardial infarction (BBBMI). Data on the prognostic significance of these categories mainly originate from voluntary based registries or large-scale clinical trials and may be hampered by selection and information bias. The aim of this historical cohort study was to evaluate the prognostic significance of different categories of AMI in an unselected cohort. METHODS AND RESULTS: From 1 November 1999 to 31 October 2001, patient records were reviewed from all admissions to hospitals serving a study region with 139,000 inhabitants. An Endpoint Committee determined whether patients fulfilled the European Society of Cardiology criteria of AMI. A total of 654 patients with AMI were identified. The proportion having non-STEMI, STEMI, and BBBMI was 54, 39 and 6%, and the associated 1 year mortality was 31, 21, and 55%, respectively (log rank 54, P<0.001). The more favourable outcome observed in patients with STEMI remained significant according to multivariable analysis (P=0.044). CONCLUSION: In an unselected cohort of patients admitted with AMI, the mortality was considerably higher than expected from voluntary-based registries and large-scale clinical trials. The most favourable outcome is observed in patients with STEMI.

Toxoplasma gondii inhibits MHC class II expression in neural antigen-presenting cells by down-regulating the class II transactivator CIITA.

Major histocompatibility complex (MHC) class II expression by microglia and astrocytes is critical for CD4+-mediated immune responses within the central nervous system. Here, we demonstrate that the obligate intracellular parasite, Toxoplasma gondii, down-regulates activation-induced MHC class II expression in human-derived glioblastoma cells as well as in primary astrocytes and microglia from cortices of rat fetuses. Down-regulation of MHC class II proteins was predominantly observed in parasite-positive, but not parasite-negative, host cells of T. gondii-infected cell cultures. MHC class II transcript levels induced by IFN-gamma alone or in combination with TNF-alpha were also clearly diminished after parasitic infection. Furthermore, T. gondii dose-dependently down-regulated the transcript levels of the class II transactivator CIITA. These results suggest that T. gondii partially evade CD4+-mediated intracerebral immune responses, a mechanism which may contribute to long-term persistence of the parasite within the CNS.