The efficiency of intervention for patients with panic disorder and comorbid non-cardiac chest pain could be enhanced by focusing on heart-related fear and attention.

Non-cardiac chest pain (NCCP) is usually benign but may affect the quality of life of the people suffering from it. Medical consultations for NCCP cost between 8 and 13 billion dollars yearly in the United States. Majority of the undesirable outcomes associated with NCCP arises due to its comorbidity with Panic Disorder (PD) which is known to be 11 times more predominant in patients with NCCP. There are numerous potential elucidations for the robust association between PD and NCCP. The first explanation can be the occurrence of NCCP during a panic attack. Although first-line treatment for PD is efficacious in patients with comorbid NCCP, the effect of such treatment approaches on chest pain seems inadequate. This means that the intensity of NCCP may not be decreased by only reducing the symptoms of PD. Also, many biopsychosocial models propose that the association between NCCP and PD is probably due to the standard mechanisms and susceptibility factors between both conditions. Anxiety sensitivity (AS), fear, attention, and avoidance of cardiac sensations are the possible psychological mechanisms. Studies have shown that patients with raised AS have a lesser threshold for pain and a powerful fear of pain, both of which naturally leads to adverse experiences of pain. Heart-focused fear signifies catastrophic readings of cardiac symptoms, which are linked with functioning turbulences in NCCP patients and with the maintenance of PD. Therefore, heart-focused attention is possibly the reason for development and maintenance of NCCP. A chief factor in the maintenance of PD and NCCP is avoidance due to its influence on fear of symptoms. It may directly affect pain by stimulating physical deconditioning through physical activity avoidance. Deconditioning tends to worsen painful physical symptoms, thereby supporting fear and attention, which in turn fortifies avoidance.

Rationale behind the research:

Till date, no study has specifically tried to identify the relationships between AS, as well as fear, attention, and avoidance of cardiac sensations in patients with comorbid PD and NCCP. A more precise understanding of these associations is vital to increase the efficiency of interventions for patients with both conditions.

Objective:

• To assess the relationships between AS, heart-focused fear, attention, and avoidance, as well as panic symptoms, and chest pain level in patients with comorbid PD and NCCP
• To document the relationships between changes in AS, heart-focused fear, attention, and avoidance, as well as panic symptoms, and reduction in perceived chest pain intensity following evidence-based intervention for PD or usual care
  

Note: There were 2 groups of patients. Group 1 included the entire sample (cross-sectional sample) and Group 2 included patients with post-intervention data (prospective sample).

Study outcomes:

• The Anxiety Disorders Interview Schedule for Diagnostic and Statistical Manual of Mental Disorders (ADIS-IV): This instrument was used to diagnose PD. The diagnosis reliability of the ADIS-IV for PD was 92 % in a randomly selected sample including 30% of the interviews.
• The Panic and Agoraphobia Scale (PAS): This 13-item instrument assesses the severity and frequency of PD and agoraphobia symptoms over the past week
• The Anxiety Sensitivity Index (ASI): This 16- item questionnaire measures the tendency to attribute negative consequences to anxiety symptoms (anxiety sensitivity)
• The Short-form McGill Pain Questionnaire, chest pain version (SF-MPQ-CP): This 15-item questionnaire measures subjective chest pain intensity
• The Cardiac Anxiety Questionnaire (CAQ): This 18-item questionnaire measures heart-focused anxiety. Its three subscales assess heart-focused fear, heart focused attention, and avoidance of cardiac sensations

Time Points: Baseline and after 3 months

Study outcomes

Baseline characteristics: There was no significant difference in the baseline characteristics between the two groups.

• Relationship between CAQ subscales, AS, panic symptoms, age and pain: Only the CAQ heart-focused attention subscale (r=0.465; p<0.01) and heart-focused fear subscale (r= 0.270; p<0.05) scores were significantly correlated with SFMPQ-CP score. Together, these two variables explained 19.5 % of the variance in SF-MPQ-CP score (F (2, 63) = 8.857; p<0.001). Sex did not significantly contribute to the model.

* p<0.05; ** p<0.01; CAQ Cardiac Anxiety Questionnaire, PAS Panic and Agoraphobia Scale, ASI Anxiety Sensitivity Index, SF-MPQ-CP Short-form McGill Pain Questionnaire, chest pain version

Table 1 Correlation matrix for CAQ subscales, ASI, PAS, SF-MPQ-CP and age (n = 66)

• Relationships between changes in CAQ subscales, AS, panic symptoms, age and changes in pain at postintervention: Change in all parameters were significantly linked with a reduction in SF-MPQ-CP scores except the PAS. The multivariate model explained 20.3 % of the variance in change in SF-MPQ-CP scores, F(4,48) = 4.315; p< 0.01. However, the only change in the CAQ heart-focused fear subscale contributed significantly to the model (p=0.038).
  

In this study, heart-focused fear and attention for cardiac sensations (heart focused attention) were found to be linked with NCCP intensity; together, they explained 19.5 % of the variance in pain scores. However, only the effect of attention was statistically significant. The prospective analysis unveiled that change in AS, as well as in fear, attention, and avoidance of cardiac sensations was linked with changes in NCCP over a period of 14 weeks of evidence-based intervention for PD or usual care. But, the only difference in fear contributed significantly to change in chest pain intensity, independently of other factors, explaining 20.3 % of its variance. Based on the results of this study, NCCP is a condition independent on PD rather a symptom of this anxiety disorder. A most likely explanation for the relatively weak effect of the intervention for PD on NCCP severity was also provided by this study. Though PD intervention reduces AS and fear of symptoms, it appears that directly focusing fear of cardiac symptoms is vital for alleviating NCCP intensity. This is not astonishing as chest pain is the defining symptom of NCCP.  But, none of the exposure exercises used in cognitive-behavioral therapy certainly aggravate chest pain. Also, alteration of interpretation of symptoms mostly addresses the link between symptoms and anxiety, which may not be sufficient to influence fear of cardiac symptoms. In this case, the addition of a model that mainly targets heart-focused fear and heart-focused attention may enhance the efficiency of PD intervention to alleviate comorbid NCCP.