Aims
The aim of this study is to provide guidance for the clinical interpretation of electrocardiograms (ECGs) in prone position and to establish the electroanatomic explanations for the possible differences to supine position ECGs that may be observed. Additionally, to determine if prone back ECG can be used as an alternative to standard ECG in patients who may benefit from prone position.
Methods and results
The ECG in supine (standard ECG), prone back (precordial leads placed on the patient’s back), and prone anterior position (precordial leads placed in the standard position with the subjects in prone position) were prospectively examined on 85 subjects. Comparisons of ECG parameters between these positions were performed. Computed tomography (CT) scans were performed in both positions to determine possible electroanatomic aetiologies for prone-associated ECG changes. There were significant differences in QRS amplitude in Leads V1–V5 between supine and prone positions. Q waves were more frequently observed in prone back position vs. supine position (V1: 74.1 vs. 10.6%, P < 0.0001; V2: 23.5 vs. 0%, P < 0.0001, respectively). Flat and inverted T waves were more common in prone back leads (V1: 98 vs. 66%, P < 0.0001; V2: 96 vs. 8%, P < 0.0001; V3: 45 vs. 7%, P < 0.0001). The 3D-CT reconstructions measurements corroborated the significant inverse correlation between QRS amplitude and the distance from the centre of the heart to the estimated lead positions.
Conclusion
In prone back position ECG, low QRS amplitude should not be misinterpreted as low voltage conditions, neither should Q waves and abnormal T waves are considered anteroseptal myocardial infarction. These changes can be explained by an increased impedance (due to interposing lung tissue) and by the increased distance between the electrodes to the centre of the heart.
Introduction: Capsulectomy is recommended in patients with
cardiac implantable electronic device (CIED) infection after transvenous
lead extraction (TLE) but is time-consuming and requires extensive
tissue debridement. In this study, we describe the outcomes of
chlorhexidine gluconate (CHG) scrubbing in lieu of capsulectomy for the
treatment of CIED infections. Methods: This retrospective
observational study included patients who underwent TLE for CIED-related
infections. In the capsulectomy group, complete capsulectomy was
performed after hardware removal. In the CHG group, thorough scrubbing
of the generator pocket with 20 cc of 2% CHG followed by irrigation
with approximately 500 cc of sterile normal saline (SNS) was performed.
The primary outcomes included reinfection and hematoma formation in the
generator pocket. Secondary outcomes included any adverse reaction to
chlorhexidine, the need for reintervention, infection-related mortality,
and total procedural time. Results: A total of 102 patients
(mean age 67.2±13 years, 32.4% female) underwent CIED extraction with
either total capsulectomy (n=54) or CHG (n=48) scrubbing. Hematoma
formation was significantly higher in the capsulectomy group vs. the CHG
group (13% vs. 0%, p=0.014), with no significant differences in the
reinfection rate. Capsulectomy was associated with longer procedural
time (133.7±78.5vs. 89.9±51.8 minutes, p=0.002). No adverse reactions to
CHG were found. Four patients (4.3%) died from worsening sepsis: 3 in
the capsulectomy group and 1 in the CHG group (p=0.346).
Conclusions: In patients with CIED infections, the use of CHG
without capsulectomy resulted in a lower risk of hematoma formation and
shorter procedural times without an increased risk of reinfection or
adverse events associated with CHG use.
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