As we have seen throughout this book, women are at significant risk for cardiovascular disease. Women are undertreated and underserved and often do not receive the same therapy as their male counterparts. Sudden cardiac death (SCD) is an unfortunate but frequent complication associated with coronary artery disease (CAD). It is estimated by the American Heart Association (AHA) in their 2014 report that nearly 425,000 people die suddenly from SCD in the US alone annually.¹ In fact, the AHA estimates that nearly 1,000 people suffer non-traumatic cardiac arrests outside of hospitals every single day — the survival rate is only around 5–10%. Only 60% of these arrests are treated by the emergency medical system ( EMS) and, of these, nearly 25% were found to have a rhythm such as ventricular fibrillation (VF) or ventricular tachycardia (VT). Either of these rhythms would be easily treated with a shock from an implantable cardioverter-defibrillator (ICD) or an automatic external defibrillator (AED). When bystander CPR is initiated survival rates significantly increase, and if an AED is present the rates may exceed 70%.

ICDs have been used in humans since 1980 when the first human implant was performed.2 A short time later in 1985, the FDA approved the device for routine implantation and expanded access of the device to patients all over the country. The device consists of a lead (or wire) that is placed inside the heart via a blood vessel, as well as an ICD generator which is implanted inside the chest. The generator is an advanced computer that monitors heart rate and rhythm and can react to abnormalities in heart rhythm with either pacing or a life-saving shock. Over the last 30 years, there have been numerous improvements in functionality and performance. ICDs have become widely accepted as life-saving therapy for patients with heart disease that have lowered ejection fractions (less than 35%) and are listed by the American College of Cardiology as class-I indications in many cases. When compared to other at-risk patients without ICD therapy, risk of death is lowered by nearly 30%.

It is clear that ICDs save lives — in both primary and secondary prevention of SCD. Evidence from numerous clinical trials including the Multicenter Automatic Defibrillator Implantation Trial (MADIT)-I, MADIT-II and the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) make it quite clear — in patients who meet particular criteria and are at risk for SCD who are implanted with ICDs, survival is improved.3^–5 In patients who have survived an out-of-hospital cardiac arrest, data from the Antiarrhythmics versus Automatic Implantable Defibrillator Trial (AVID), suggests that ICD therapy should be considered first-line therapy in the secondary prevention of SCD.⁶ In addition, ICDs have been proven to be effective and incredibly cost-effective — in secondary prevention the number of patients that need to be treated to save one life was determined to be 12 patients over two years. The average cost of treatment therefore becomes just 66,000 dollars for each life saved.⁷

The implantation of an ICD once included a thoracotomy where the leads were placed directly on the epicardial surface of the heart. Patients were often hospitalized for days after the procedure. Today, most devices can be implanted under conscious sedation utilizing a very small incision in the chest and the leads are implanted in the heart via a percutaneous, trans-venous approach. In fact, most patients are able to go home after a one-night observation stay in the hospital. Over the last 20 years, indications for ICD implantation have expanded and hundreds of thousands of patients have benefited from device therapy. While the pool of ICD-eligible patients continues to increase, it has become clear that women are not implanted at the same rates as men with similar risk profiles. Data from numerous clinical trials show that women are under-represented in ICD registries and are much less likely to receive appropriate therapy.

In spite of an enormous body of evidence supporting the use of ICDs in the prevention of sudden cardiac death, women are not treated as aggressively as men. In a landmark trial published in Journal of the American Medical Association in 2007, a Medicare database was analyzed in order to determine if there were any gender-based differences in the utilization of ICD therapy for both primary and secondary prevention. In the study, it was found that women were much less likely to be referred for implantation of ICD devices even when they met the exact same criteria as men.8 When men were compared with women who met criteria for primary prevention ICD implantation and secondary prevention ICD implantation, men were 3.2 and 2.4 times, respectively, more likely to receive a ICD therapy.

Why do women suffer from disparities in ICD utilization?

There are numerous theories as to why women are less likely to be implanted with an ICD even though they meet the same criteria as men. As we have discussed earlier in the book, women often present later with more significant and more widespread disease. Women often have more co-morbidities and are more likely to suffer in hospital complications. The prevalence of diabetes, hypertension and peripheral vascular disease seems to be higher in women as compared to men undergoing the same procedures. In a paper by MacFadden et al. from the Annals of Internal Medicine, researchers attempted to identify factors that may influence ICD implantation in women.9 After analysis of nearly 6,021 patients (half of whom were male), it was determined that women were more likely to suffer procedure-related complications as well as receive more inappropriate shocks from their device. In this registry, women were 1.7 times more likely to suffer complications at 45 days and nearly 31% less likely to receive appropriate ICD shock therapy.⁹ As we have mentioned previously, women are more likely to suffer complications with other invasive cardiovascular procedures such as coronary artery bypass grafting and percutaneous revascularization procedures.¹⁰ In order to balance risk with benefit, many physicians may be less likely to offer women invasive procedures in order to avoid complications. Peterson et al. found that women undergoing ICD implantation in the particular population of study were 31% more likely to suffer any adverse event as compared to men. More concerning is the fact that women were 71% more likely to suffer a major adverse event. Other studies have substantiated the higher complication rates with ICD implantation in women.¹¹ The reasons for the increased rate of complications, particularly with ICD, may very well have to do with anatomic considerations — smaller body size, smaller blood vessels and thinner right ventricular myocardium are likely to contribute to the higher rates of vascular damage and cardiac perforation seen in female patients undergoing implantation.

Certainly, the implantation of a medical device such as an ICD can have an impact on body image. For women, this impact may be greater than that experienced by men. Studies have shown that women who are considering ICD implantation may not be willing to proceed due to misconceptions about the appearance of the device in the chest and how others may perceive them. Data from the University of North Carolina indicates that women are more concerned with the appearance of the surgical scar and how it may affect the way clothes fit and their ability to wear a swimsuit.12 In another study, Sowell et al. find that it is essential for healthcare providers to discuss alternative ICD implant techniques (such as sub-pectoral implants, axillary implants, etc.) with female patients and allow them more time to make informed decisions concerning the procedure.13 Alternative implantation techniques have been shown to be reliable and effective in long-term follow-up and provide the same risk reduction as standard implantation techniques and sites.¹⁴ It is essential to provide both pre-operative and postoperative counseling and support for women undergoing ICD implantation in order to avoid any negative body image repercussions. In addition, providing information on the size and shape of the device and offering the possibility of plastic surgery input has been shown to be quite effective in helping women adapt well to ICD implantation.¹⁵ As physicians and healthcare providers for women, it is essential that we are sensitive to the psychological issues surrounding the implantation of an ICD. Through engagement and sharing of information, we can ease patient worry and increase implantation rates for women.

More research is needed!

Ultimately, as healthcare providers, we must look for answers and derive ways to make ICD implantation safer for women. We know that ICDs save lives and that women are not referred for implantation at the same rate as men. It is essential that we carefully analyze the reasons behind increased complication rates and create new technology and interventions to improve safety. While many of the early trials in ICD therapy included a pre-dominance of male subjects, we must design trials composed of female patients and explore gender-specific interventions to improve outcomes, reduce complications and improve care. In order to better treat female patients with arrhythmias we must reach a better understanding of the specific ways in which interventions such as ICDs impact women as compared to men. It is clear that biologic differences can make an enormous impact on the effectiveness and safety of particular therapies. As medicine moves into the next decade, personalized medicine and patient-specific therapies will be the norm — it is my hope that these types of interventions will foster the equal treatment of individuals, irrespective of gender, race or socioeconomic status.

1 AHA (2014). Statistical Update Heart Disease and Stroke Statistics — 2014 Update. A Report from the American Heart Association Circulation. Volume 129, e28–e292.

² Mirowski, M., Reid, P. R., Mower, M. M. et al. (1980). Termination of malignant ventricular arrhythmias with an implanted automatic defibrillator in human beings. N Engl J Med, Volume 303, 322–324.

³ Moss, A. J., Hall, W. J., Cannom, D. S. et al. (1996). Multicenter Automatic Defibrillator Implantation Trial Investigators. Improved survival with an implanted defibrillator in patients with coronary disease at high risk for ventricular arrhythmia. N Engl J Med, Volume 335(26), 1933–1940.

⁴ Moss, A. J., Zareba, W., Hall, W. J. et al. (2002). Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med, Volume 346(12), 877–883.

⁵ Bardy, G. H., Lee, K. L., Mark, D. B. et al. (2005). Amiodarone or an implantable cardioverter-defibrillator for congestive heart failure. N Engl J Med, Volume 352(3), 225–237.

⁶ Antiarrhythmics versus Implantable Defibrillators (AVID) Investigators (1997). A comparison of antiarrhythmic- drug therapy with implantable defibrillators in patients resuscitated from near-fatal ventricular arrhythmias. N Engl J Med, Volume 337(22), 1576–1583.

⁷ Larsen, G., Hallstrom, A., McAnulty, J. et al. (2002). Cost-effectiveness of the implantable cardioverter-defibrillator versus antiarrhythmic drugs in survivors of serious ventricular tachyarrhythmias: Results of the Antiarrhythmics versus Implantable Defibrillators (AVID) economic analysis substudy. Circulation, Volume 105, 2049–2057.

⁸ Curtis, L. H., al-Khatid, S. M., Shea, A. M. et al. (2007). Sex differences in the use of implantable cardioverter-defibrillators for primary and secondary prevention of sudden cardiac death. JAMA, Volume 298(13), 1517–1524.

⁹ MacFadden, D. R., Crystal, E., Krahn, A. D. et al. (2012). Sex Differences in implantable cardioverter-defibrillator outcomes: findings from a prospective defibrillator database. Ann Intern Med, Volume 156, 195–203.

¹⁰ Jacobs, A. K. (2003). Coronary revascularization in women in 2003: sex revisited. Circulation, Volume 107, 375–377.

¹¹ Peterson, P. N., Daugherty, S. L., Wang, Y. et al. (2009). National cardiovascular data registry. Gender differences in procedure-related adverse events in patients receiving implantable cardioverter-defibrillator therapy. Circulation, Volume 119, 1078–1084.

¹² Davis, L. L., Vitale, K. A., Irmiere, C. A. (2004). Body image changes associated with dual-chamber pacemaker insertion in women. Heart and Lung, The Journal of Acute and Critical Care, Volume 33(5), 273–280.

¹³ Sowell, L. V., Kuhl, E. A., Sears, S. F. (2006). Device implant technique and consideration of body image: specific procedures for implantable cardioverter defibrillators in female patients. J Womens Health, Volume 15(7), 830–835.

¹⁴ Obeyesekere, M. N., Kamberi, S., Youngs, N. et al. (2010). Long-term performance of submammary defibrillator system. Europace, Volume 12(9), 1239–1244.

¹⁵ Walkerm, R. L., Campbell, K. A., Sears, S. F. et al. (2004). Women and the Implantable Cardioverter Defibrillator: A lifespan perspective on key psychosocial issues. Clin Cardiol, Volume 27, 543–546.