Cardiac Implantable Electronic Device-Related Infections

*Måns Almqvist, Gustav Mattsson, Robin Razmi and Peter Magnusson* 

## **Abstract**

 The use of cardiac devices, that is, pacemakers and implantable cardioverter defibrillators, has increased, and the incidence will likely continue to increase due to an aging population with associated risk factors. Unfortunately, this implies an increasing number of complications, including infections. Cardiac device-related infection is a dreaded complication causing both increased morbidity and mortality, and considerable costs. Because of the presence of a foreign body in subcutaneous tissue, vasculature, and the heart, patients with cardiac device systems are at increased risk of endocarditis due to microbial agents. In general, an infected device system should be removed in its entirety. The timing of reimplantation varies due to indication and severity of the infection. Furthermore, the explant procedure may be complicated and should be performed by an experienced team including facilities to handle life-threatening complications. The subcutaneous implantable cardioverter defibrillator or leadless pacemaker can serve as an option in selected cases. This chapter will describe clinical aspects of cardiac device-related infections.

**Keywords:** cardiac device, endocarditis, infection, implantable cardioverter defibrillator, pacemaker

#### **1. Introduction**

 Infective endocarditis (IE) is a potentially lethal disease. First described by Osler more than a century ago, it remains associated with a considerable burden of complications and death [1–3]. In fact, the incidence has increased over the years—in part reflecting a growing number of comorbidities in an aging population. Improvements in cardiovascular health care have not only contributed to increased life expectancy but also to a growing number of patients living with underlying cardiovascular pathologies that constitute risk factors for IE. Thus, endocarditis can be described as an adverse consequence of medical advances. This is certainly valid in the case of endocarditis affecting cardiac implantable electronic devices (CIEDs). Since the introduction of the pacemaker as a routine treatment for bradyarrhythmias in the 1960s, a rapid evolution of technology has resulted in several new implantable devices. CIEDs also include implantable cardioverter defibrillators (ICD) and cardiac resynchronization therapy (CRT). Today, device therapy is an essential therapeutic modality of cardiovascular care. It has extended the life span of patients and also improved health-related quality of life. Nowadays, approximately 1.2 million CIEDs are implanted each year worldwide [4].

This highly conventional and routine device treatment is however clouded by its potentially devastating complications. CIED infection is a severe complication associated with high mortality [5, 6]. The implantation rate is increasing globally and US data indicate that this is coupled with increased implantation in older patients with more co-morbidities. An increased use of more complex device systems also implies higher risks. All of this contributes to an end result of more CIED infections. As the disease panorama and indications are similar in large parts of the world, a similar increase outside the US seems inevitable.

A CIED infection can be challenging to diagnose and treat. It may involve the generator pocket, the leads, the endocardial structures, or a combination thereof. Involvement of endocardial structures including valves implies higher mortality. Diagnostic difficulties can be even greater than in IE because echocardiography is less accurate, blood cultures are less sensitive, and the diagnosis is sometimes not considered because of unspecific symptoms. Attempts to salvage infected devices are often unsuccessful. In this chapter, we present an outline of current recommendations regarding prevention, diagnostics, and management of CIED infections.
