Implantable Cardioverter-Defibrillator of Korean Patients in a Single Center Registry

Distinct Substrates of Idiopathic Ventricular Fibrillation Revealed by Arrhythmia Characteristics on Implantable Cardioverter-Defibrillator

BACKGROUND

Idiopathic ventricular fibrillation (IVF) can be associated with undetected distinct conditions such as microstructural cardiomyopathic alterations (MiCM) or Purkinje (Purk) activities with structurally normal hearts.

OBJECTIVE

This study sought to evaluate the characteristics of recurrent VF recorded on implantable defibrillator electrograms, associated with these substrates.

METHODS

This was a multicenter collaboration study. At 32 centers, we selected patients with an initial diagnosis of IVF and recurrent arrhythmia at follow-up without antiarrhythmic drugs, in whom mapping demonstrated Purk or MiCM substrate. We analyzed variables related to previous ectopy, sinus rate preceding VF, trigger, and initial VF cycle lengths. Logistic regression with cross validation was used to evaluate the performance of criteria to discriminate Purk or MiCM substrates.

RESULTS

Among 95 patients (35 women, age 35 ± 11 years) meeting the inclusion criteria, IVF was associated with MiCM in 41 and Purk in 54 patients. A total of 117 arrhythmia recurrences including 91% VF were recorded on defibrillator. Three variables were mostly discriminant. Sinus tachycardia (≤570 ms) was more frequent in MiCM (35.9% vs 13.4%, P = 0.014) whereas short-coupled (<350 ms) triggers were most frequent in Purk-related VF (95.5% vs 23.1%, P = 0.001), which also had shorter VFCLs (182 ± 15 ms vs 215 ± 24 ms, P < 0.001).The multivariable combination provided the highest prediction (accuracy = 0.93 ± 0.05, range 0.833-1.000), discriminating 81% of IVF substrates with a high probability (>80%). Ectopy were inconsistently present before VF.

CONCLUSIONS

Characteristics of arrhythmia recurrences on implantable cardioverter- defibrillator provide phenotypic markers of the distinct and hidden substrates underlying IVF. These findings have significant clinical and genetic implications.

Cognitive Function of Recipients of Primary or Secondary Defibrillator Therapy: A Comparative Study Involving Nondefibrillator Patients With Systolic Heart Failure

BACKGROUND

The extent to which cognitive function differs between patients who receive implantable cardioverter-defibrillator (ICD) therapy and patients with heart failure (HF) who do not receive ICD therapy remains to be elucidated.

OBJECTIVES

The aim of this study was to compare the cognitive function between patients with primary or secondary ICDs and patients with HF without an ICD.

METHODS

This descriptive, comparative study included 116 patients who received ICDs and 74 patients with HF who did not receive ICDs. Patients underwent neuropsychological assessment for general cognition, memory, and executive function.

RESULTS

Immediate recall memory loss (18.9%) occurred more often in patients with HF without an ICD than in patients with primary (3.1%) and secondary (7.1%) ICDs (P = .018). After adjusting for age and education, delayed recall memory of patients with HF without ICDs was significantly worse than that of patients with primary ICDs (4.0 vs 6.5; P < .001), whereas delayed recall memory of patients with primary ICDs was better than that of patients with secondary ICDs (6.0 vs 6.5; P = .006). Executive function of patients with HF without ICDs was significantly worse than that of patients with primary (35 vs 58 seconds; P < .001) and secondary (28 vs 58 seconds; P = .0012) ICDs.

CONCLUSIONS

Patients with ICDs, regardless of primary or secondary indication, had less impairment of memory and executive function than patients with HF without ICDs, implying that ICD therapy did not interfere with cognitive performance. Cognitive screening as a part of routine care could be helpful for identifying impairment and implementing early cognitive training, especially in patients with HF.

Effect of physical and psychocognitive function and perceived health status on 12-month adverse cardiac events among implantable cardioverter-defibrillator recipients

BACKGROUND

Post-implant recovery in patients with implantable cardioverter-defibrillators (ICDs) is often compromised because of reduced physical and psycho-cognitive function and poor health perception, leading to short event-free survival.

OBJECTIVES

To examine the effects of psychocognitive function, health perception, and ICD-related factors on 12-month cardiac events among ICD patients.

METHODS

Using a prospective study design, ICD patients underwent baseline assessment and were followed for 12 months to assess cardiac events.

RESULTS

Cardiac events occurred in 14 patients (18.9%) (N = 74: age, 58 years; primary ICDs, 45.9%). Time after ICD implant (odds ratio [OR] = 1.002; p = .028) and executive function (OR = 1.021; p = .027) were significant predictors of 12-month cardiac events, while other physical and psychological indices were not.

CONCLUSIONS

Reduced executive function and longer time after implant predicted the events. Healthcare professionals need to assess executive function and provide treatment and support to improve executive function.