Cardiac Electrophysiology · Conduction System Pacing

Acute and Subacute LBBAP Lead Dislodgement and Breaststroke Swimming in Elderly Patients

What is the incidence of acute and subacute LBBAP lead dislodgement in elderly patients who perform the repetitive shoulder adduction, thoracic compression, and undulating body motions characteristic of breaststroke swimming?

Why no specific figure exists

The question presupposes a quantifiable incidence for a very narrow intersection — elderly conduction-system-pacing recipients who swim breaststroke — and that figure has never been generated. No registry or cohort has stratified LBBAP lead outcomes by swim stroke, or operationalized breaststroke kinematics as a measured exposure variable. Any percentage attached to “breaststroke-induced LBBAP dislodgement in the elderly” would therefore be invented rather than derived. The honest approach is to use the general acute and subacute dislodgement rate as the only defensible denominator.

The relevant proxy: registry incidence data

The multicentre European MELOS study (2,533 patients, mean follow-up 6.4 months) reported LBBAP lead dislodgement in 38 cases — about 1.5% — while other contemporary series placed it lower, in the 0.3–0.9% range. Threshold rise beyond 2 V was seen in under 1% over that window. Notably, MELOS folded macro-dislodgement into a broader transseptal-route complication category of 8.3%, most of which reflects acute or delayed septal perforation rather than frank displacement, and no further complications occurred after repositioning.

More mature real-world cohorts are lower still. The C-SING Italian network reported LBBAP lead dislodgement of just 0.2% during follow-up — below the rate observed for atrial and conventional right ventricular myocardial leads in the same population.

Macro- versus micro-dislodgement

The distinction matters more than the headline number. Macro-dislodgement is frank displacement of the lead and generally produces complete loss of capture, unless intermittent contact with the right ventricular myocardium persists. Micro-dislodgement is the LBBAP-specific failure mode: the lead tip retracts back within the interventricular septum, yielding loss of conduction-system capture while right ventricular septal myocardial capture often continues. This change is invisible on the rate channel and is detectable only on follow-up paced ECG morphology — which is why serial 12-lead paced ECGs at short-term follow-up are essential. Contemporary lumenless-lead implants show lower rates than the 4.7–7% micro-dislodgement figures seen in early experience, and lower than stylet-driven leads.

Do breaststroke kinematics load the failure mechanism?

The anatomy works against the premise. The dominant determinants of acute LBBAP failure are intrinsic to the septal fixation: improper helix fixation from a “drill” effect, micro-perforation, and inadequate lead slack. The distal helix is anchored deep in the contracting septum, mechanically decoupled from the pectoral and shoulder-girdle motion that drives conventional lead complications.

The proposed motions — repetitive shoulder adduction, thoracic compression, and undulating trunk movement — act on the extrathoracic lead segment, the venous entry, and the device pocket. That is precisely where conventional transvenous leads fail (subclavian crush, pocket-level traction), but it is not where the 3830 distal helix is at risk. The breaststroke-specific elements with any theoretical traction are the repetitive bilateral isometric thoracic compression during the glide and the Valsalva-like intrathoracic pressure swings, which transiently alter venous return and septal geometry — but there is no evidence these produce cumulative fixation failure.

The real lever: lead slack

The one pathway that could transmit upper-body loading to the septal helix is lead slack. Too little slack converts respiratory and trunk excursion into axial tension at the fixation point. This is plausible, but it is a function of implant technique rather than stroke selection, and it would apply equally to freestyle swimming, rowing, vigorous coughing, or other repetitive trunk activity. The very-late dislodgement case literature attributes displacement to fibrotic remodeling and slack dynamics over years — not to a definable activity exposure such as a particular swim stroke.

What is actually measurable

For an individual patient, the tractable signal is not an epidemiologic incidence but serial device interrogation. The parameters that track LBBAP integrity include unipolar tip impedance trend, R-wave amplitude, paced QRS morphology (V6 R-wave peak time and the selective-to-non-selective transition), and any drift toward isolated right ventricular septal capture. Comparing these before and after sustained swimming activity is far more informative for a given patient than any population figure.

Bottom line

Acute and subacute macro-dislodgement runs roughly 0.2–1.7% across general LBBAP populations regardless of physical activity, with micro-dislodgement somewhat higher in early-experience cohorts and lower in mature lumenless-lead practice. There is no measured increment attributable to breaststroke swimming, and the mechanistic case for one is weak because the septal fixation is decoupled from shoulder-girdle motion. The actionable variable is lead slack at implant, and the actionable surveillance tool is serial interrogation — not a stroke-specific incidence figure that does not exist.