ECG as a risk stratification tool in patients with wearable cardioverter-defibrillator.

BACKGROUND: The wearable cardioverter defibrillator (WCD) is increasingly used in patients at elevated risk for ventricular arrhythmias but not fulfilling the indications for an implantable cardioverter defibrillator (ICD). Currently, there is an insufficient risk prediction of fatal arrhythmias in patients at risk. In this study, we assessed the prognostic role of baseline electrocardiogram (ECG) in WCD patients. METHODS: WCD patients from diverse clinical institutions in Germany (n = 227) were retrospectively enrolled and investigated for the incidences of death or ventricular arrhythmias during WCD wearing. In addition, the widely accepted ECG predictors of adverse outcome were analyzed in patients with arrhythmic events. RESULTS: Life-threatening arrhythmias occurred in 22 (9.7 %) patients, mostly in subjects with ischemic heart disease (15 of 22). There was no difference in baseline left ventricular ejection fraction (LVEF) in subjects with and without arrhythmic events (31.3 ±â€¯7.9 % vs. 32.6 ±â€¯8.3 %; p = 0,24). Patients with arrhythmia exhibited significantly longer QRS duration (109.5 ±â€¯23.1 ms vs. 100.6 ±â€¯22.3 ms, p = 0,04), Tpeak-Tend (Tp-e) (103.1 ±â€¯15.6 ms vs. 93.2 ±â€¯19.2 ms, p = 0,01) and QTc (475.0 ±â€¯60.0 ms vs. 429.6 ±â€¯59.4 ms, p < 0,001) intervals. In contrast, no significant differences were found for incidences of fragmented QRS (27.3 % vs. 24 %, p = 0.79) and inverted/biphasic T-waves (16.6 % vs. 22.7 %, p = 0,55). In multivariate regression analysis both Tp-e (HR 1.03; 95 % CI 1.001-1.057; p = 0.02) and QTc (HR 1.02; 95 % CI 1.006-1.026; p < 0.001) were identified as independent predictors of ventricular arrhythmias. After WCD use, the prophylactic ICD was indicated in 76 patients (33 %) with uneventful clinical course but persistent LVEF ≤35 %. The ECG analysis in these subjects did not reveal any relevant changes in arrhythmogenesis markers. CONCLUSIONS: ECG repolarization markers Tp-e and QTc are associated with malignant arrhythmias in WCD patients and may be used - in addition to other established risk markers - to identify appropriate patients for ICD implantation.

Device fracture as a potential complication of a left ventricular microaxial pump catheter: a case report.

Background: The use of an Impella pump catheter has advanced substantially in the last few years due to the simple insertion procedure and smaller device size. However, its use is still associated with some risks and complications. Here, we report a device fracture as a rare complication that occurred during the device extraction a few days after the initial insertion. Case summary: A 74-year-old man with cardiogenic shock due to acute non-ST-segment elevation myocardial infarction presented to our hospital, and he was transferred to the cath lab for emergency percutaneous coronary intervention (PCI). An Impella CP pump was inserted without any complication prior to PCI. After successful PCI, the patient was transferred to the intensive care unit with device left for continued haemodynamic support. After 3 days, as the patient's condition remarkably improved, we tried to remove the device. However, a persistent mechanical resistance hindered the further catheter retraction; therefore, a decision was made to remove the catheter under fluoroscopy. Indeed, the fluoroscopy revealed a broken distal part of the pump at the level of the ascending aorta. The retained catheter tip was eventually snared with a snare catheter and removed without any complication. Discussion: An Impella microaxial pump may improve the overall outcome by providing haemodynamic support in critically ill patients. However, its application is not without complications. Intravascular device tip fracture, as demonstrated in this case report, is a rarely reported complication. The use of a snare catheter can be an option in retrieving a broken pump.