Study Group

Two hundred eleven patients who underwent permanent pacemaker implantation in the Kartal Kosuyolu Heart Education and Research Hospital between 1988 and 2005 were telephoned and invited to participate in this retrospective study. Detailed histories were obtained, and physical examinations were performed at the initial visit. Thirty-nine patients refused to participate in this study, 24 had received either antibiotic or anticoagulant drugs within the past 2 weeks at that time, 27 had active infections, 13 had histories of infective endocarditis or pulmonary embolism, and 33 had declined to undergo TEE examinations. These patients were excluded from this study, and information regarding nonparticipants had no effect with respect to our final analysis. The remaining 75 patients constituted the study population. The indications for pacemaker implantation, the types of leads, and the New York Heart Association functional classes of the patients during pacemaker implantation were recorded. Blood samples were obtained from the antecubital vein for microbiologic and biochemical studies. Each patient underwent transthoracic echocardiographic (TTE) imaging on the first visit day and TEE imaging ≤72 hours after TTE imaging. The study protocol was approved by the institutional ethics committee, and all participating patients gave written informed consent.

Follow-Up

Five years after initial enrollment, each patient or primary contact was called and asked about clinical events. Patients’ relatives were asked about the cause of mortality, and health records were investigated. Living patients were invited to the hospital, and echocardiographic screening was performed. All telephone calls were placed by two cardiologists.

Echocardiographic Examination

TTE and TEE examinations were performed using Vivid 3 Expert equipment (GE Vingmed Ultrasound AS, Horten, Norway) with a conventional 1.7-MHz phased-array TTE probe and a multiplane 5-MHz TEE probe. Left ventricular dimensions were measured using two-dimensional guided M-mode echocardiography; left ventricular ejection fraction was measured using the modified biplane Simpson method according to the guidelines of the American Society of Echocardiography. Right heart chambers, pulmonary artery, and pacemaker leads were evaluated from the parasternal long-axis and short-axis, apical four-chamber, and subcostal views according to the guidelines of the American Society of Echocardiography. Pulmonary artery systolic pressure was estimated using continuous-wave Doppler in the apical four-chamber view from tricuspid regurgitation jet velocity with the addition of right atrial pressure, assuming a right atrial pressure of 3 to 5 mm Hg.

TEE examinations were performed ≤72 hours after TTE examinations, under sedation and after a fasting period of ≥4 hours. Premedication consisted of lidocaine spray and intravenous sedation with midazolam. According to the criteria of the American Society of Echocardiography, a comprehensive evaluation of the right heart chambers and leads was performed using a set of upper, middle, and lower esophageal and transgastric cross-sectional views. Images were enlarged (in most cases 3 to 5 times) at the time of the study using conventional zoom features, recorded on VHS videotape, and reviewed later. All echocardiographic examinations were performed by two skilled echocardiologists.

Blood Samples

Three sets of blood samples, each from a separate vein, were obtained during the 24 hours before TTE procedures. Thirty milliliters of blood were sampled each time for two aerobic and one anaerobic blood culture, and the cultures were incubated in bloody agar, sheep bloody agar, and eosin methylene blue agar using the BacT/ALERT 30/60 device (bioMérieux, Inc., Durham, NC). The cultures were incubated for ≥5 days in the media. Patients with negative blood cultures during the 5-day period were labeled as culture negative.

Additional 10-cm ³ blood samples were obtained for hemogram, erythrocyte sedimentation rate, and high-sensitivity C-reactive protein (hs-CRP) measurements. For hs-CRP measurements, the blood samples were kept in citrated tubes and were evaluated using nephelometry (Beckman Coulter, Inc., Brea, CA). Values between 0 and 0.8 mg/dL were considered normal for hs-CRP. For hemogram analysis, samples were collected in tubes with ethylenediaminetetraacetic acid and analyzed automatically using a Sysmex-XT 2000I (Sysmex, Kobe, Japan) device. Values of 3,000 to 10,000 for leukocyte count, 36% to 50% for hematocrit, and 11 to 18 mg/dL for hemoglobin were accepted as the normal limits.

Definitions and Classifications of Lead Accretions

Fibrillary accretions on the pacemaker leads were evaluated as described by Freedberg et al. Three types of lead accretions were identified: (1) thin, mobile, filamentous projections 1 to 2 mm in width and a few millimeters in length that were attached to the pacemaker leads were defined as fibrillary accretions; (2) immobile, circular, echo-dense structures that caused localized thickening on the pacemaker leads were defined as sessile accretions; and (3) the existence of both kinds of accretions over a single pacemaker lead was defined as mixed-type accretions.

Accretion type, number, and localization in each patient were recorded. The distinction of lead accretions from Eustachian valve remnants or Chiari networks, which can be seen in the right atrium, was performed by monitoring the accretions using different TEE angles and visualizing a clear attachment of the accretion to the lead.

Statistical Analysis

Statistical analysis was performed using SPSS version 11.0 (SPSS, Inc., Chicago, IL). Data are expressed as mean ± SD. Continuous variables were compared using unpaired Student t tests. Chi-square statistics were used to compare proportions. Fisher exact tests were applied when the expected value of at least one cell was <5. Logistic regression analysis was used to identify independent predictors of mortality from the clinical and echocardiographic parameters. P values < .05 were considered statistically significant.