Send to

Choose Destination
Ann Intern Med. 2005 Jun 21;142(12 Pt 1):968-73.

An electrocardiogram-based algorithm to detect loss of left ventricular capture during cardiac resynchronization therapy.

Author information

University Hospital, Basel, Switzerland.



Loss of left ventricular capture in patients with cardiac resynchronization devices may account for worsening heart failure and can be difficult to diagnose without a programmer.


To determine whether distinct morphologic changes on the surface electrocardiogram indicate loss of left ventricular capture.


After analysis of the R-S spike ratio in the 12-lead electrocardiogram during right ventricular and biventricular pacing in 10 patients, an algorithm to detect loss of left ventricular capture was developed.


University hospital.


54 patients with a cardiac resynchronization device and underlying left bundle-branch block.


Leads V1 and I of a 12-lead electrocardiogram were assessed after biventricular pacing was confirmed and after the device was programmed to right ventricular pacing only (simulating loss of left ventricular capture).


The sensitivity of the algorithm to correctly identify loss of left ventricular capture was 94% (95% CI, 88.2% to 97.7%), and the specificity was 93% (CI, 86.3% to 95.8%). The likelihood ratio of a positive test result was 12.8 (CI, 6.443 to 23.310), and the likelihood ratio of a negative test result was 0.06 (CI, 0.024 to 0.137).


The algorithm was tested in patients in whom the right ventricular electrode was placed in the apex of the right ventricle only.


Presence of biventricular capture--the prerequisite for successful cardiac resynchronization therapy--and loss of left ventricular capture can be accurately detected by an algorithm based on analysis of the R-S ratio on leads V1 and I of the surface electrocardiogram.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Silverchair Information Systems
Loading ...
Support Center