The surface electrocardiogram predicts risk of heart block during right heart catheterization in patients with preexisting left bundle branch block: implications for the definition of complete left bundle branch block.
BACKGROUND
Patients with left bundle branch block (LBBB) undergoing right heart catheterization can develop complete heart block (CHB) or right bundle branch block (RBBB) in response to right bundle branch (RBB) trauma. We hypothesized that LBBB patients with an initial r wave (>or=1 mm) in lead V1 have intact left to right ventricular septal (VS) activation suggesting persistent conduction over the left bundle branch. Trauma to the RBB should result in RBBB pattern rather than CHB in such patients.


METHODS
Between January 2002 and February 2007, we prospectively evaluated 27 consecutive patients with LBBB developing either CHB or RBBB during right heart catheterization. The prevalence of an r wave >or=1 mm in lead V1 was determined using 118 serial LBBB electrocardiographs (ECGs) from our hospital database.


RESULTS
Catheter trauma to the RBB resulted in CHB in 18 patients and RBBB in 9 patients. All 6 patients with >or=1 mm r wave in V1 developed RBBB. Among these 6 patients q wave in lead I, V5, or V6 were present in 3. Four patients (3 in CHB group and 1 in RBBB group) developed spontaneous CHB during a median follow-up of 61 months. V1 q wave >or=1 mm was present in 28% of hospitalized complete LBBB patients.


CONCLUSIONS
An initial r wave of >or=1 mm in lead V1 suggests intact left to right VS activation and identifies LBBB patients at low risk of CHB during right heart catheterization. These preliminary findings indicate that an initial r wave of >or=1 mm in lead V1, present in approximately 28% of ECGs with classically defined LBBB, may constitute a new exclusion criterion when defining complete LBBB.
The Care Group, LLC, Indianapolis, Indiana, USA. bpadanil@thecaregroup.com
Benzy J
BJ
Padanilam
Kent E
KE
Morris
Jeff A
JA
Olson
Janet S
JS
Rippy
Mary Norine
MN
Walsh
Natrajan
N
Subramanian
Alex
A
Vidal
Eric N
EN
Prystowsky
Leonard A
LA
Steinberg
D000368:Aged; D000369:Aged, 80 and over; D002036:Bundle of His / Q000293:injuries* / Q000503:physiopathology; D002037:Bundle-Branch Block / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D006328:Cardiac Catheterization / Q000009:adverse effects*; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006327:Heart Block / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D007196:Indiana; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors