Micra implantation in a patient with transposition of great arteries.

We describe a 56-year-old male with transposition of the great arteries and Mustard repair, superior vena cava obstruction, atrial fibrillation, and progressive deterioration of his epicardial lead performance. We were successful in deploying of Micra (Medtronic, Minneapolis, MN, USA) at the septo-apical area of his nonsystemic ventricle in a stable position with satisfactory pacing and sensing thresholds.

Pacemaker-mediated arrhythmias.

Pacemakers can be directly involved in initiating or sustaining different forms of arrhythmia. These can cause symptoms such as dyspnea, palpitations, and decompensated heart failure. Early detection of these arrhythmias and optimal pacemaker programming is pivotal. The aim of this review article is to summarize the different types of pacemaker-mediated arrhythmias, their predisposing factors, and mechanisms of prevention or termination.

Long-term pacemaker dependency and impact of pacing on mortality following transcatheter aortic valve replacement with the LOTUS valve.

OBJECTIVES: To determine permanent pacemaker (PPM) dependency following transcatheter aortic valve replacement (TAVR) with the Lotus™ valve system (Boston Scientific), and the impact of PPM implantation on long-term morbidity and mortality. BACKGROUND: Conduction abnormalities are among the most common complications following TAVR. Limited studies have assessed pacing dependency following TAVR. METHODS: Consecutive patients (n = 166) with severe aortic stenosis who underwent TAVR with the Lotus valve system were prospectively recruited from a single-center. PPMs were implanted according to standard clinical criteria. Patients were followed in-hospital and at 1, 3, 6, and 12 months to determine pacemaker dependency and clinical outcomes. RESULTS: Fourteen patients with a pre-existing PPM (8%) were excluded with the remaining 152 patients aged 83.6 ± 5.6 years and 46% male. PPMs were implanted 3.8 ± 4 days post-TAVR in 38/152 patients (25%). Indication for PPM was complete heart block in 29 (76%) of patients. At 30-day and one-year follow up, 57% and 38% of patients were pacemaker dependent, respectively. The mean ventricular pacing percentage decreased in the first three months after PPM implantation and remained relatively stable after that. CONCLUSION: Only 38% of Lotus recipients who require a PPM following TAVR with the Lotus valve remain pacing dependent at one year.

Pacing and implantable cardioverter defibrillator lead perforation as assessed by multiplanar reformatted ECG-gated cardiac computed tomography and clinical correlates.

INTRODUCTION: We aimed to assess the utility of cardiac computed tomography (CT) in the evaluation of right atrial (RA) and right ventricular (RV) pacemaker and implantable cardiac defibrillator lead perforation. METHODS: Images from a 320-slice electrocardiogram-gated cardiac CT scanner were retrospectively independently analyzed by two reviewers for lead position, pericardial effusion, and perforation.Perforation results were correlated with pacing sensing, impedance, and threshold measurements. RESULTS: A total of 52 patients had RV leads and 35 had RA leads. Five of 17 RV apical, one of 35 RV nonapical, and none of the 35 RA leads perforated through the myocardium on CT imaging criteria. Two "clinically" perforated leads (that had protruded 5 mm and 15 mm from the outer edge of the myocardium)had pericardial effusions and changes in pacing parameters, and required RV lead repositioning. In contrast,there were four apparent "radiologic" perforations (that had protruded only an average 1.5±0.5 mm from the outer edge of the myocardium) that did not require repositioning. These had the radiologic appearance of perforation on cardiac CT; however, they were not associated with pericardial effusions or significant changes in RV pacing lead sensing, impedance, and threshold measurements. CONCLUSIONS: Cardiac CT scanning with multiplanar reformatting is useful for documenting lead position and assessing for possible cardiac perforation. The clinical significance and natural history of leads with only the appearance of perforation on cardiac CT is uncertain.

Validation of conventional fluoroscopic and ECG criteria for right ventricular pacemaker lead position using cardiac computed tomography.

INTRODUCTION: It is hypothesized that pacing the right ventricular (RV) septum is associated with less deleterious outcomes than RV apical pacing. Our aim was to validate fluoroscopic and electrocardiography (ECG) criteria for describing pacemaker and implantable cardioverter defibrillator RV "septal" lead position against the proposed gold standard: cardiac computed tomography (CT). METHODS: Using the conventional fluoroscopic criteria, we intended to place RV nonapical leads on the interventricular septum. Lead positions were later retrospectively analyzed with CT and correlated with ECGs and fluoroscopic projections: posterior-anterior, 40° left anterior oblique (LAO), 40° right anterior oblique (RAO), and left lateral. RESULTS: Only 21% (nine of 35) of presumed "septal" RV nonapical leads using the conventional fluoroscopic criteria were on the true septum. A schema developed to define septal position in the RAO fluoroscopic view had high agreement with CT images. ECG criteria had only fair to moderate agreement with CT. The paced QRS duration was significantly longer (P < 0.001) with RV apical pacing (176 ± 10.7 ms), compared to RV nonapical pacing (144.5 ± 14.3 ms). CONCLUSION: Using the conventional fluoroscopic criteria, only a minority of RV leads were implanted on the true RV septum. Instead, aiming for the middle of the cardiac silhouette in the RAO fluoroscopic view, confirming rightward orientation in the LAO view, and having a paced QRS duration <140 ms may allow the implanting cardiologist a simple, more accurate method to achieve true RV septal lead positioning.

Proximity of pacemaker and implantable cardioverter-defibrillator leads to coronary arteries as assessed by cardiac computed tomography.

INTRODUCTION: There have been rare case reports of damage to adjacent coronary arteries by screw-in pacemaker and implantable cardioverter-defibrillator (ICD) leads. Our aim was to assess the proximity of pacemaker and ICD leads to the major coronary anatomy using cardiac computed tomography (CT). METHODS: Cardiac CT images were retrospectively analyzed to assess the spatial relationship of device lead tips to the major coronary anatomy. RESULTS: Fifty-two right ventricular (RV) leads (17 apical, 35 nonapical) and 35 right atrial (RA) leads were assessed. Leads on the RV antero-septal junction (20 of 52) were close (median 4.7 mm) to, and orientated toward, the left anterior descending (LAD) coronary artery. RA leads in the anterior (26 of 35) and lateral (seven of 35) walls of the RA appendage were not close to (16.9 ± 7.7 mm and 18.9 ± 12.4 mm, respectively) and directed away from the right coronary artery. However, an RA lead adjacent to the superior border of the tricuspid valve was 4.3 mm from the right coronary artery and an RA lead on the medial wall of the RA appendage was 1.6 mm away from the aorta. An RV pacemaker lead in the lateral wall of the RV inlet was 3.4 mm from the right coronary artery. CONCLUSIONS: In our cohort, a majority of RV leads were on the antero-septal junction and close to the overlying LAD coronary artery. RA leads adjacent to the tricuspid valve or on the medial RA appendage were in close proximity to the right coronary artery and aorta, respectively.

Cardiac re-synchronization therapy in a child with severe anthracycline-induced congestive heart failure and normal QRS duration.

We report the case of a 9-year-old girl who developed acute anthracycline-induced cardiotoxicity with severe, refractory congestive heart failure. Rescue treatment with cardiac re-synchronization therapy was initiated, resulting in rapid improvement in left ventricular function and clinical status.