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Pacemaker infections are one of the most distressing and morbid complications for patients and can present a challenging management problem for physicians. Pacemaker leads, especially those that dwell in the venous system and inside the cardiac chambers, are prone to becoming colonized with bacteria owing to their sizeable surface area, the nature of their external exposed materials (usually silicone or polyurethane) that are prone to biofilm formation, and their close association with the skin surface at the level of the pacemaker pocket.1 Leads that cross the tricuspid valve (TV) may be at additional risk for lead-associated endocarditis owing to contact with infected valvular structures, and the local environment of turbulent, high-velocity jets. Leadless pacemakers, on the other hand, have features that may reduce their risk of becoming infected, including a smaller surface area, a metal-only exposed surface, no interaction with the TV, and no component that has proximity to the skin surface. Micra (Medtronic, Minneapolis, MN) is a battery-operated leadless intracardiac pacemaker that was designed to stay anchored inside the right ventricle, thus reducing the infection risk of conventional pacemakers. The cylindrical device is 26 mm long, about the size of a large pill (a volume of 1 cm3), occupying clinically insignificant space within the right ventricular chamber. The Micra leadless pacemaker is placed with a transvenous implantation catheter via the right femoral vein, so no thoracotomy is required for this procedure.2 We present a case where a Micra leadless pacemaker was used to manage a challenging patient with a history of TV endocarditis, complete heart block, and multiple pacemaker system infections. Key Teaching Points • Standard pacemaker leads are prone to bacterial adherence and chronic colonization in the setting of bacteremia and endocarditis. Full extraction of the pacing system is needed as part of curative treatment when lead-associated endocarditis is present. • Multiple episodes of endocarditis over time can mandate sequential removal of transvenous hardware (including pacemaker leads) in order to achieve definitive control of these infections. The need for multiple lead extractions does not preclude the possibility of long-term cure from relapsing endocarditis. • The Micra (Medtronic, Minneapolis, MN) leadless pacemaker has a lower risk of bacterial colonization than standard transvenous pacemaker leads for several reasons, and may be an appropriate choice for chronic pacing in patients at high risk for bacterial endocarditis.

Background Innominate vein stenosis and venous tortuosity are common findings during cardiac implantable electronic device upgrades or replacements and present a challenge to the implanting physician. Various techniques have been described to facilitate lead placement, including serial dilation, balloon venoplasty, and percutaneous access medial to the stenosis, each with its own benefits and risks. Objective The purpose of this study was to assess the feasibility, safety, and efficacy of the wire countertraction ("body flossing") technique to facilitate sheath placement through tortuous and stenotic vessels. Methods Patients undergoing cardiac implantable electronic device procedures requiring the body flossing technique due to inability to place vascular sheaths over the wire through stenoses or tortuosity were retrospectively analyzed. Clinical characteristics, procedural equipment, and outcomes were analyzed. Results Simultaneous countertraction was successful in all attempted cases, including 8 patients with stenoses and 2 with tortuosity. In 2 of the stenosis cases, venoplasty had previously failed. No complications occurred. Conclusion Simultaneous countertraction (body flossing) is an effective tool to overcome venous stenosis and tortuosity that are amenable to wire advancement but not to vascular sheaths. It seems to be a safe and effective alternative to other techniques used in these scenarios.

Transseptal puncture is a critical procedural step in pursuing left-sided catheter ablations. Most centers use either fluoroscopic and/or intracardiac echocardiographic (ICE) guidance.1, 2 However, not uncommonly, these routinely used approaches may not be sufficient to repeatedly obtain transseptal access in a safe manner.3 We present a recently described novel approach to transseptal puncture using a concomitant ablation catheter in the left atrium (LA) in 2 challenging cases.

Background— Intracardiac echocardiography (ICE) has played a limited role in defining the substrate for ventricular tachycardia (VT). The purpose of this study was to assess whether ICE could identify abnormal epicardial substrate in patients with nonischemic cardiomyopathy (NICM) and VT. Methods and Results— We studied 18 patients with NICM and recurrent VT who had abnormal echogenicity identified on ICE imaging. Detailed left ventricular (LV) endocardial and epicardial electroanatomic mapping was performed in all patients. Low-voltage areas (2 ; minimum-maximum, 2.1–31.7 cm 2 ) in 9 patients (5 posterolateral LV, 4 perivalvular LV). Detailed epicardial mapping revealed areas of low voltage (39 cm 2 ; minimum-maximum, 18.5–96.3 cm 2 ) and abnormal, fractionated electrograms in all 18 patients (15 posterolateral LV, 3 lateral LV). In all patients, the epicardial scar identified by electroanatomic mapping correlated with the echogenic area identified on ICE imaging. ICE imaging identified no areas of increased echogenicity in the control group. Conclusions— ICE imaging identified increased echogenicity in the lateral wall of the LV that correlated to abnormal epicardial substrate. These findings suggest that ICE imaging may be useful to identify epicardial substrate in NICM.

ObjectivesThe aim of the study was to define the epicardial substrate and ablation outcome in patients with left ventricular nonischemic cardiomyopathy (NICM) and suspected epicardial ventricular tachycardia (VT).BackgroundVentricular tachycardia in NICM often originates from the epicardium.MethodsTwenty-two patients with NICM underwent detailed endocardial and epicardial bipolar voltage maps and VT ablation for suspected epicardial VT. Eight patients with normal hearts and idiopathic VT served to define normal epicardial electrograms. Low-voltage regions were also assessed for wide (>80 ms), split, or late electrograms.ResultsNormal epicardial bipolar voltage was identified as >1.0 mV on the basis of the reference population. Confluent low-voltage areas were present in 18 epicardial (82%) and 12 endocardial (54%) maps and were typically over basal lateral LV. In the 18 patients with epicardial VT on the basis of activation/pacemapping, the mean epicardial area was greater than the endocardial low-voltage area (55.3 ± 33.5 cm2vs. 22.9 ± 32.4 cm2, p < 0.01). Epicardial low-voltage areas showed 49.7% wide (>80 ms), split, and/or late electrograms rarely seen in the reference patients (2.3%). During follow-up of 18 ± 7 months, ablation resulted in VT elimination in 15 of 21 patients (71%) including 14 of 18 patients (78%) with epicardial VT.ConclusionsIn patients with NICM and VT of epicardial origin, the substrate is characterized by areas of basal LV epicardial > endocardial bipolar low voltage. The electrograms in these areas are not only small (80 ms), split, and/or late, and help identify the substrate targeted for successful ablation.