The role of trigger factors in the occurrence of appropriate ICD shocks and their clinical and prognostic implications.

BACKGROUND: The role of triggers in the occurrence of appropriate implantable cardioverter-defibrillator (ICD) shocks due to ventricular tachyarrhythmias is not well known. The aim of the study was to assess the prevalence of trigger factors in appropriate ICD shocks and to analyze their prognostic impact on clinical outcome. METHODS: A total of 710 consecutive patients of a prospective single-center ICD-registry who received a first appropriate ICD shock between 2000 and 9/2021 were analyzed. RESULTS: In 35% of ICD patients with first ICD shock, at least one of the following triggers was found: Ischemia (22%), Compliance (9%), Decompensation (38%), Stress (12%), Technical (5%), Electrolyte/endocrinological disorder (22%) and Medication side effects (4%). The trigger factors can be summarized under the acronym ICD-STEMi. The prospective application of the ICD-STEMi scheme increased the rate of identified triggers from 32% to 56% (p < .001). Patients with triggered first ICD shock had an increased 5-year mortality rate (50% vs. 38%, p < .001). Patients with triggers did not show different mortality outcomes or recurrent ICD shocks whether they received arrhythmia therapy or not. CONCLUSIONS: The evaluation of trigger factors after the occurrence of ICD shocks is mandatory and can be systematically evaluated using the acronym ICD-STEMi. Systematic evaluation of triggers using the ICD-STEMi scheme can identify triggers in about half of ICD patients with first appropriate ICD shock. Patients with triggered ICD shock have a 12% higher 5-year mortality rate.

Prognostic relevance of new onset arrhythmia and ICD shocks in primary prophylactic ICD patients.

BACKGROUND: The prognostic relevance of new onset arrhythmias compared to ICD shocks in ICD patients is not well known. OBJECTIVES: Aim of the study was to evaluate the prognostic relevance of new onset atrial fibrillation (AF) or ventricular arrhythmias (VT/VF) compared to ICD shocks in primary prophylactic ICD-patients. METHODS: A total of 622 of 1955 (32%) patients of the prospective single-centre ICD-registry Ludwigshafen with primary prophylactic ICD indication and sinus rhythm (SR) at baseline without history of AF were analyzed. All patients underwent an ICD implantation between 1992 and 2012. RESULTS: During the median follow-up time of 6 years, 200 (32%) ICD patients developed new AF and 249 (40%) patients new VT/VF. There was an approximately 10% increase of 5-year mortality rate depending on the type of new onset arrhythmia (no arrhythmia 19%, new AF 28%, new VT 36% and new VF 55% 5-year mortality). In a multivariate analysis, new onset of AF or VT/VF was an independent predictor for increased mortality whereas VT shocks and inappropriate ICD shocks were not. CONCLUSION: More than half of primary prophylactic ICD patients with SR at baseline develop new AF or VT/VF after 6 years. New onset arrhythmias of AF and VT/VF are independent prognostic factors for increased mortality in primary prophylactic ICD patients. ICD shocks itself, inappropriate or appropriate, are not additionally associated with a worse outcome. These results support the hypothesis that in clinical practice rather the arrhythmia than the ICD shock itself is responsible for a deteriorated prognosis.

Long-term performance and lead failure analysis of the Durata defibrillation lead compared to its previous model, the recalled Riata defibrillation lead.

INTRODUCTION: Data on long-term durability of St Jude Medical Durata defibrillation leads compared to its previous model, the St Jude Medical Riata leads in clinical practice are missing. Aim of the study was to analyze the long-term performance of the Durata defibrillation leads compared to the Riata leads in clinical practice. METHODS AND RESULTS: A total of 1407 consecutive patients of a prospective single-centre implantable cardioverter defibrillator (ICD)-registry were analyzed who underwent ICD implantation with a Durata (n = 913) or Riata (n = 494) ICD lead between 2002 and 2017. Most of the leads were implanted via a subclavian vein access. The estimated lead defect rates after 5 and 10 years were not different between the Durata (11% and 36%) and Riata leads (13% and 38%). Among Durata leads single coil and DF-4 connector ICD leads had a lower incidence of lead failure. Major causes of lead failure were compression of the lead in the clavicular region, generator to lead friction and distal fatigue fracture whereas lead defect due to externalization was a rare cause of lead defect in Riata leads (3%). CONCLUSION: Among ICD leads implanted via the subclavian vein access the lead defect rate of Durata leads after 10 years is similar to that of Riata leads. Single coil and DF-4 ICD leads are associated with a lower lead failure rate. Mechanical stress represents a major cause of lead failure mechanism whereas externalization might only play a minor role in clinical practice.

Contemporary benefit-harm profile over two decades in primary prophylactic ICD-therapy.

BACKGROUND: Implantable cardioverter defibrillator (ICD) was implemented into clinical routine more than 20 years ago. Since then, ICD therapy became standard therapy for primary and secondary prevention of sudden cardiac death in clinical practice. OBJECTIVES: Aim of the study was to evaluate the benefit-harm profile of contemporary primary prophylactic ICD therapy. METHODS: A total of 1222 consecutive patients of a prospective single-center ICD-registry were analyzed who underwent primary prophylactic ICD implantation between 2000 and 2017. Patients were divided into two groups according to the implantation year: 2010-2017 (group 1, n = 579) and 2000-2009 (group 2, n = 643). RESULTS: The rate of estimated appropriate ICD therapy after 8 years was 51% in the 2000s and 42% in the 2010s (P < .001). The complication rate changed slightly from 53% to 47% (P = .005). This decline was mainly driven by the reduction of inappropriate ICD shocks (30% vs 14%, P < .001) whereas the rate of ICD shock lead malfunction and device/ lead infection remained unchanged over time. Nonischemic cardiomyopathy was an independent predictor for ICD complications without benefit of ICD therapy (HR 1.37, 95% CI 1.07-1.77). CONCLUSION: The ICD therapy rate for ventricular arrhythmias in patients with primary prophylactic ICD implantation is decreasing over the last two decades. Complication rate remains high due to an unchanged rate of ICD shock malfunctions and device infections. Nonischemic cardiomyopathy is an independent predictor for ICD complications without benefit of ICD therapy in primary prophylactic ICD-therapy.

Clinical course and prognostic relevance of antitachycardia pacing-terminated ventricular tachyarrhythmias in implantable cardioverter-defibrillator patients.

AIMS: In patients with an implantable cardioverter-defibrillator (ICD), ICD shocks due to ventricular tachycardia (VT) or ventricular fibrillation (VF) have been associated with an increased mortality. It is not known whether patients with antitachycardia pacing (ATP)-terminated VT/VF episodes have a similar worse outcome. The aim of this study was to evaluate the clinical course and prognostic impact of ATP-terminated episodes on mortality in ICD patients. METHODS AND RESULTS: A total of 1398 consecutive patients of the prospective single-centre ICD-registry Ludwigshafen who underwent an ICD implantation between 1992 and 2008 for primary or secondary prevention of sudden cardiac death were analysed. Patients treated with ATP were compared with patients with appropriate ICD shocks or patients without any appropriate ATP or ICD shock. During the median follow-up time of 6 years, 749 (54%) patients experienced 17 827 episodes of VT or VF which were terminated by ATP in 74% and by shock in 26% of patients. In approximately half (n = 321/749) of those patients with VT/VF, the first episode was terminated by ATP. In a multivariate analysis adjusted for different baseline confounding parameters, the occurrence of first ATP therapy was associated with a higher mortality rate [hazard ratio (HR) 2.60, 95% confidence interval (CI) 2.02-3.35]. When excluding all patients with appropriate ICD shocks first ATP therapy remained associated with a worse prognosis (HR 1.92, 95% CI 1.38-2.67). CONCLUSIONS: In ICD patients, about three-fourths of ventricular arrhythmias are terminated by ATP. The occurrence of ATP-terminated episode is associated with an increased mortality rate.

A patient with severely reduced LV function and electrical storm saved by wearable cardioverter-defibrillator: a case report.

The wearable cardioverter-defibrillator (WCD) is indicated in patients who are considered to be at temporarily high risk for sudden cardiac death (SCD), when an implantable defibrillator is not yet clearly indicated. We report the case of a 41-year-old patient with a newly diagnosed severely reduced left ventricular (LV) function for suspected myocarditis and repeated nonsustained ventricular tachycardia (VT). This patient was supplied with a WCD who came back to the hospital 4 weeks after discharge with an electrical storm and adequate discharge of the WCD. After application of amiodarone, no further arrhythmias were detected during intrahospital course. For further risk stratification, we performed a magnetic field imaging (MFI), that was reported to be useful in risk assessment of SCD in patients with ischemic cardiomyopathy. This measurement showed a normal result, but we decided to give an implantable cardioverter-defibrillator (ICD) to the patient. During a follow-up of 1 year, no further arrhythmias occurred. With this case, we report the efficacy of a WCD, which is a novel tool in patients at temporarily high risk of SCD and we report a novel method of risk stratification in patients with a high risk of SCD.

Prognostic value of electromagnetic QRS fragmentation in survivors of sustained ventricular tachycardia or ventricular fibrillation compared with healthy controls.

BACKGROUND: Magnet field imaging (MFI) is a noninvasive method to determine cardiac electromagnetic activity. AIM OF THE STUDY: This study aims to compare the electromagnetic QRS fragmentation index (eQFI) in survivors of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) to healthy individuals. METHODS: Twenty-five consecutive patients with documented sustained VT or VF who underwent a MFI investigation between December 2009 and October 2011 were compared with 25 age- and sex-matched healthy individuals. RESULTS: Patients with documented VT or VF showed a trend to higher eQFI values compared with the control group (p = 0.06). This increase was mainly driven by VT/VF patients with ischemic cardiomyopathy (CMP) which was markedly elevated compared with the healthy controls (1.48 vs. 1.07; p = 0.01). In patients with nonischemic CMP or acute coronary syndrome, eQFI was not different from the healthy group. CONCLUSIONS: Electromagnetic QRS fragmentation is increased in VT/VF patients with ischemic CMP but not in patients with ventricular arrhythmias of other origin. Further investigations in prospective cohorts should evaluate the prognostic value of electromagnetic QRS fragmentation in patients with ischemic heart disease to predict the occurrence of VT/VF and to guide therapy.

Characteristics and clinical outcome of 458 patients with acute myocardial infarction requiring mechanical ventilation. Results of the BEAT registry of the ALKK-study group.

BACKGROUND: Information about the clinical course of patients with acute myocardial infarction requiring mechanical ventilation is scarce. We sought to evaluate the clinical outcome of a large cohort of such patients in clinical practice. METHODS: The German BEAT registry prospectively enrolled consecutive patients requiring mechanical ventilation who were admitted to an internal intensive care unit (ICU) of 45 participating German hospitals between September 2001 and June 2002. For this analysis, we created a subgroup of patients with acute ST-segment-elevation or non-ST-segment-elevation myocardial infarction. RESULTS: During the 9-month study period, 458 consecutive patients fulfilled our inclusion criteria. The mean age was 68 ± 8 years and 71% were men. 40% of the patients were already intubated in the prehospital phase. The initial reason for intubation was in 48% of the cases ventricular fibrillation/tachycardia or sudden cardiac death, in 39% congestive heart failure and in 13% of the cases non-cardiac. The median time of ventilation was 2 days (1-5) among survivors and 1 day (0-5) among non-survivors. Of the 458 patients, 256 (56%) had already or developed cardiogenic shock, 86 (19%) acute renal failure, 76 (17%) coma or brain damage, 64 (14%) severe infection, 46 (10%) sepsis and 28 (6%) multiorgan distress syndrome; 11% were treated with fibrinolysis, 39% with PCI and 6% with coronary artery bypass grafting. The overall hospital mortality rate was 48%. In patients with cardiogenic shock, mortality was even higher with 69%. CONCLUSIONS: Patients requiring mechanical ventilation during an acute myocardial infarction constitute a high risk group with a mortality of about 50%. Further research is necessary to improve the outcome of these patients.

Clinical, angiographic and cardiovascular magnetic resonance findings in consecutive patients with Takotsubo cardiomyopathy.

BACKGROUND: The aim was to assess clinical, angiographic and cardiovascular magnetic resonance (CMR) findings in patients with Takotsubo cardiomyopathy. METHODS: Between 2003 and 2007, 20 consecutive patients admitted to our hospital with suspected acute myocardial infarction and presenting with apical ballooning in the left ventricular (LV) angiogram in the absence of a significant coronary artery disease, were included in the study. Echocardiography and CMR was performed in all patients. RESULTS: The mean age of patients with Takotsubo cardiomyopathy was 62 +/- 8 years (range 43-78 years). Eighteen (90%) were female. Clinical presentations included chest pain (95%) and cardiogenic shock (5%). The mean angiographic LV ejection fraction on admission was 45% +/- 9% (range 26%-60%) and resolved rapidly in all cases. Mean time delay between presentation CMR was 2 +/- 1 days (range 1-6 days). Mean ejection fraction was 51% +/- 15% (range 25%-81%). While 19 (95%) patients showed no evidence of late enhancement or signs of myocarditis in the CMR, 1 (5%) patient who was resuscitated showed hyperenhancement confined to the apex. CONCLUSION: In patients showing the clinical picture of an acute myocardial syndrome and angiographic picture of a TakoTsubo cardiomyopathy, CMR might be helpful in confirming the diagnosis through the exclusion of other causes for the acute LV dysfunction.