Time dependent changes in the level of anxiety
Time-dependent changes in the level of anxiety and proportion of patients with anxiety after ICD growth hormone secretagogue are unclear. Among patients treated with ICD for the secondary prevention of sudden cardiac death, Kamphuis et al. suggested that the proportion of patients with anxiety did not change from implantation to 12 months after discharge . However, the level of anxiety may decrease with time after implantation, especially in ICD patients who do not experience shock .
Some studies have evaluated the role of emotional stress in the occurrence of ventricular arrhythmias in ICD patients [15,37–39]. Lampert et al. reported that anxiety was not significantly associated with ventricular arrhythmia requiring shock therapy but that anger was an independent predictor . A study by van den Broek et al. showed that the combination of anxiety and type D personality, but not anxiety alone, predicted the occurrence of ventricular arrhythmia requiring ICD therapies in the first year after implantation . The biological mechanisms underlying this finding are not understood; however, it appears that intensive emotional stress may increase the sympathetic tone, leading to the occurrence of arrhythmia.
Posttraumatic stress disorder Life-threatening cardiovascular disease is recognized as a cause of acute distress and posttraumatic stress disorder (PTSD). PTSD occurs in people who have been exposed to an extreme stressor or a traumatic life-threatening event and experience fear, helplessness, or horror. Three distinct types of symptoms, namely, re-experiencing of the event, avoiding reminders of the event, and hyperarousal, must be present for ≥1 month for a diagnosis of PTSD . The prevalence of PTSD in the general population is estimated to be 7.8% , whereas it is 30% and 15% in patients who have survived cardiac arrest [42,43] and those who have myocardial infarction, respectively [44,45]. Recently, trauma-induced reactions such as PTSD have received attention in ICD patients because shock therapy may have a traumatic impact on patients and may act as a continuous reminder of the presence of a potentially fatal disease [46–49]. The prevalence of PTSD in ICD patients has been reported to be approximately 20%, although neither the definition of PTSD nor the clinical characteristics of patients were uniform across the studies [50–54]. A recent study by Rahmawati et al. reported the prevalence (23.5%) of a PTSD score of ≥20 using the Impact of Event Scale-Revised (IES-R) in Japanese patients with an ICD; this result is comparable to previously reported results . Kapa et al. found that 21% of 223 ICD patients met the criteria for PTSD with an IES-R score ≥24 at initial assessment (within 2 months after implantation), which decreased significantly to 12% after 6 months. The prevalence remained relatively stable at 13% at 1 year after implantation . However, von Känel documented an increase in IES-R score from baseline to follow-up and found that nearly one-fifth of patients had newly developed PTSD 2–5.5 years after implantation in a cohort of 107 consecutive patients with an ICD . The mechanism underlying the development of PTSD and the effect of PTSD on clinical outcomes in ICD patients are not well documented. It is not clear whether cardiac status such as life-threatening arrhythmia provokes PTSD or whether ICD shocks can trigger and maintain PTSD. Habibović et al. suggested that ICD shocks themselves were not significantly associated with PTSD. For the 30 (7.6%) of 395 ICD patients in their study who met PTSD criteria, type D personality and baseline anxiety were significant predictors of posttraumatic stress at 18 months after implantation, independent of shocks and other clinical or demographic covariates . However, Kapa et al. revealed that although no significant differences were observed in IES-R among the patients who experienced ICD shocks, 5 patients who experienced electrical storms had significantly higher baseline PTSD scores . von Känel et al. also showed that experiencing ≥5 ICD shocks was a predictor of PTSD . Moreover, Ladwig et al. reported that the relative mortality risk was 3.45 (adjusted for age, sex, diabetes, left ventricular ejection fraction, beta-blocker use, depression, and anxiety) in ICD patients with PTSD (high IES-R score) compared with those without PTSD . To date, personality traits such as type D, comorbidities (e.g., underlying cardiac disease, life-threatening arrhythmia, and anxiety), and frequent ICD shocks or electrical storms have been found to be key contributors to PTSD. In addition, persistent PTSD may be a predictor of prognosis in ICD patients.