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.

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.

Incidence and predictors of phantom shocks in implantable cardioverter defibrillator recipients.

BACKGROUND: Implantable cardioverter defibrillators (ICDs) are designed to deliver shocks or antitachycardia pacing (ATP) in the event of ventricular arrhythmias. During follow-up, some ICD recipients experience the sensation of ICD discharge in the absence of an actual discharge (phantom shock). The aim of this study was to evaluate the incidence and predictors of phantom shocks in ICD recipients. METHODS: Medical records of 629 consecutive patients with ischaemic or dilated cardiomyopathy and prior ICD implantation were studied. RESULTS: With a median follow-up of 35 months, phantom shocks were reported by 5.1 % of ICD recipients (5.7 % in the primary prevention group and 3.7 % for the secondary prevention group; p=NS). In the combined group of primary and secondary prevention, there were no significant predictors of the occurrence of phantom shocks. However, in the primary prevention group, phantom shocks were related to a history of atrial fibrillation (p=0.03) and NYHA class

Infarct tissue characteristics of patients with versus without early revascularization for acute myocardial infarction: a contrast-enhancement cardiovascular magnetic resonance imaging study.

Histopathological studies have suggested that early revascularization for acute myocardial infarction (MI) limits the size, transmural extent, and homogeneity of myocardial necrosis. However, the long-term effect of early revascularization on infarct tissue characteristics is largely unknown. Cardiovascular magnetic resonance (CMR) imaging with contrast enhancement (CE) allows non-invasive examination of infarct tissue characteristics and left ventricular (LV) dimensions and function in one examination. A total of 69 patients, referred for cardiac evaluation for various clinical reasons, were examined with CE-CMR >1 month (median 6, range 1-213) post-acute MI. We compared patients with (n = 33) versus without (n = 36) successful early revascularization for acute MI. Cine-CMR measurements included the LV end-diastolic and end-systolic volumes (ESV), LV ejection fraction (LVEF, %), and wall motion score index (WMSI). CE images were analyzed for core, peri, and total infarct size (%), and for the number of transmural segments. In our population, patients with successful early revascularization had better LVEFs (46 ± 16 vs. 34 ± 14%; P < 0.01), superior WMSIs (0.53, range 0.00-2.29 vs. 1.42, range 0.00-2.59; P < 0.01), and smaller ESVs (121 ± 70 vs. 166 ± 82; P = 0.02). However, there was no difference in core (9 ± 6 vs. 11 ± 6%), peri (9 ± 4 vs. 10 ± 4%), and total infarct size (18 ± 9 vs. 21 ± 9%; P > 0.05 for all comparisons); only transmural extent (P = 0.07) and infarct age (P = 0.06) tended to be larger in patients without early revascularization. CMR wall motion abnormalities are significantly better after revascularization; these differences are particularly marked later after infarction. The difference in scar size is more subtle and does not reach significance in this study.

Is T-wave alternans testing feasible in candidates for prophylactic implantable defibrillators?

AIMS: Previous studies have demonstrated that microvolt T-wave alternans (TWA) screening in patients with ischaemic and dilated cardiomyopathy is effective in identifying patients at high or low risk of sudden cardiac death. It remains unclear which percentage of potential recipients of an implantable cardioverter defibrillator (ICD) are able to perform TWA testing using an exercise protocol which is, at this moment, the golden standard. In this study, we evaluated the feasibility of TWA in the risk stratification of potential ICD recipients with ischaemic or dilated cardiomyopathy. METHODS AND RESULTS: Medical charts of 165 primary prevention ICD recipients were reviewed to decide if patients were able to perform a TWA exercise test or not. Reasons to waiver a test were: atrial fibrillation or flutter, pacemaker dependency, recent (cardiovascular) surgery (<1 month) and inability to exercise. Of the potential ICD recipients 35% had one or more of these contraindications and were therefore not suitable for testing. CONCLUSION: In several studies, TWA is a promising risk stratifier for predicting sudden cardiac death; however, in our population, 35% of the potential ICD candidates could not be tested. In order to fulfil its promise as a predictor for SCD, an alternative means to measure TWA needs to be evaluated.

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.).

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.