J. ELECTROCARDIOLOGY 17 (2), 1984, 157-160

Left Ventricular Hypertrophy inLeft Bundle Branch Block

By LARRY M. NOBLE, M.D.*, STEVEN B. HUMPHREyt AND GAYLE B. MONAGHAN**

SUMMARYThe detection of left ventricular hypertrophy (LVH) in the presence of left bundle

branch block (LBBB) remains a difficult clinical problem. Its prevalence and significancehave not previously been studied in a group of living patients.

M-mode echocardiography was utilized to determine the prevalence of anatomic LVHin 28 patients with LBBB. Various ECG and chest x-ray criteria as predictors of LVHwere assessed. Anatomic LVH was present in 89% by echocardiography. A left atrial ab­normality on ECG and a cardio-thoracic ratio greater than .50 were the best predictors ofLVH.

Hypertension and/or ischemic heart disease was present in 78.5% of the patients whileonly one patient was free of any evidence of cardiovascular disease.

The prevalence of left ventricular hypertrophy(LVH) in patients with complete left bundlebranch block (LBBB), and the usefulness of theelectrocardiogram (ECG) and chest X-ray in mak­ing this diagnosis have not been systematicallystudied in a group of living patients. Echocar­diography, an accurate method to assess left ven­tricular mass in the human subject", was used inthis study to determine the frequency of LVH ina population of hospital patients with completeLBBB.

MATERIALS AND METHODSPatient selection.

Of 3,662 patients who had ECGs done at our institu­tion between January 1981 and January 1982,39 wereidentified as having complete LBBB. Two patients ex­pired and seven could not be contacted, leaving 30 pa­tients in the study group.Electrocardiography.

All of the following criteria were required for thediagnosis of complete LBBB: 1) documented atrioven-

From the Division of Cardiology, Department of Medicine,University of Nevada School of Medicine, 1000 LocustStreet, Reno, Nevada 89520"'Assistant Professor of Medicine.[Associate Professor of Medicine."""Chief Echocardiographic Technician.The costs of publication of this article weredefrayed in partby the payment ofpage charges. This articlemust thereforebehereby marked "advertisement" in accordance with 18U.S.C.§ 1734 solely to indicate this fact.Reprint requests to: Larry M. Noble, M.D., Division of Car­diology, University of Nevada School of Medicine, 1000Locust Street, Reno. Nevada 89520.

157

tricular conduction; 2) absence of the Wolff-Parkinson­White syndrome; 3) QRS duration in the limb leads of.12 seconds or greater; 4) intrinsicoid deflection greaterthan 50 msec in the left heart leads; 5) deformity of theR wave in the left heart leads consisting of slurred,notched, flat, or bifid R wave; 6) major fraction of theQRS duration in the left heart leads occupied by the Rwave; 7) absence of Q waves in any left heart lead; and8) ST segment depression and/or T wave inversion inthe left heart leads.

All ECGs were coded by one investigator who had noknowledge of the echocardiographic results. Thefollowing ECG information was recorded: 1) height(mV) of R waves in leads I, II, III, aVL, a VF, VI-V6 aswell as S wave depth in the same leads; 2) maximumQRS width (msec) from any lead; 3) the mean frontalplane QRS axis; and 4) presence or absence of a leftatrial abnormality-",Echocardiography.

M-mode echocardiograms were obtained using acommercially available Varian 3000 interfaced with aHoneywell model 1856 fiber optic recorder", Long andtransverse sweeps of the left ventricle were recorded.The echocardiograms were, without knowledge of theECG or chest X-ray results, interpreted independentlyby two investigators. There were no major differencesin interpretation between the two observers. Left ven­tricular echograms were measured at or just below thetips of the mitral leaflets, in areas of the recording thatshowed the largest left ventricular internal dimension(LVID). LVID, diastolic posterior wall thickness(PWT), and interventricular septal thickness (ST)wereidentified using the "Penn measurement convention",(Fig. 1)1. Echocardiographic LV mass (echo LVM) wasdetermined with a regression corrected "cubeformula'":

Echo LVM = 1.04[(LVID + PWT + ST)3. LVID3] -14 grams

158 NOBLE ET AL

Fig. 1. Penn convention measurements(right) compared to conventionalmeasurements (left). In the Penn Con­vention, endocardial echoes are excludedfrom the interventricular septalthickness (SThP) and posterior wallthickness (PWThP), but are included inthe left ventricular internal diastolicdimension (LVIDP).

PW Th(P)

-- .

PWTh~=

LVH was considered to exist if LV mass as determin­ed by this formula, was 215 grams or greater", Allchest x-rays reviewed by the investigators, withoutknowledge of the ECG or echocardiographic results,were assessed for cardiomegaly as defined by a car­diothoracic ratio (CT ratio) greater than .50. Chartswere reviewed to determine the presence, if any, ofclinically apparent cardiovascular conditions.Analytical Methods.

Electrocardiographic variables and chest x-ray CTratios were compared to the echocardiographic

measurements of LV mass using the following for­mulas:

Sensitivity (% of patients True Positiveswith disease who = True Positives +have a positive test) False Negatives x

100%

Specificity (% ofpatients = True Negativeswithout disease who True Negatives +have a negative test) False Negatives x

100%

J. ELECTROCARDIOLOGY 17 (2) 1984

HYPERTROPHY IN BUNDLE BRANCH BLOCK 159

Table IUnderlying Cardiovascular Disease

Number ofCardiovascular Abnormality Patients

Hypertension 6Ischemic Heart Disease 9Hypertension and Ischemic Heart Disease 7Idiopathic Congestive Cardiomyopathy 3Aortic Stenosis 1Rheumatic Heart Disease 1No Detectable Cardiovascular Abnormality 1

RESULTSTechnically satisfactory echocardiograms were

obtained in 28 of the 30 patients. LV mass ex­ceeded 215 grams in 25 of 28 patients (89.3%).Mean LV mass was 348 grams (range 169-662).Clinical characteristics.

All patients were male and the mean age was 68

DISCUSSIONThis study demonstrates a high prevalence

(89.3%) of LVH in a general hospital patient

(range 47-89). Table I demonstrates the cardio­vascular disorders identified in the patientpopulation studied. Hypertensive andlorischemic heart disease was present in 22/28 pa­tients (78.5%). Only one patient had no evidenceof cardiac disease or hypertension.Electrocardiographic Diagnosis of LVH in LBBB.

Table II provides the sensitivity, specificity,and predictive accuracy for various ECG criteriaused in the diagnosis of L VH as compared to adiagnosis of LVH by echocardiography. Severalcriteria (R in aVL greater than lImY, RV5 or RVsgreater than 26mV, and left atrial abnormality)were associated with 100% specificity but suf­fered from lack of sensitivity and predictive ac­curacy. Of all ECG criteria examined, the pre­sence of a left atrial abnormality was the bestoverall predictor of LVH in the presence of LBBBwith a predictive accuracy of 64%.Chest x-ray diagnosis of LVH.

Table II also provides the sensitivity, specific­ity, and predictive accuracy data for chest x-rayas compared to echocardiography. A cardio­thoracic ratio greater than .50 resulted in apredictive accuracy of 75%.

True Positives +True NegativesTotal NumberStudied X 100%

Predictive Accuracy (% ofpatients with apositive test whohave disease)

Table II(ECG Criteria for LVH)

ECG LVH Criteria Sensitivity Specificity Accuracy

Limb Leads

a) RI + Sill> 25mV 0% 100% 14%b) R. VL > 11 mV 4% 100% 18%c) RI> 20mV 0% 100% 14%dl RI + Sill> 17mV 8% 75% 18%

Precordial Leads

e) SV1 + RV5 or V6 ~ 35mV 37% 50% 37%f) Deepest S + tallest R> 35mV 54% 50% 55%g) RV5 or RV6 >25mV 8% 100% 21%

Miscellaneous

h) LAD> -30 44% 66% 46%i) Left atrial abnormality 58% 100% 64%

Chest X-Ray Criteriaal CT Ratio> .50 79% 50% 75%

J. ELECTROCARDIOLOGY 17 (2) 1984

160 NOBLE ET AL

population with LBBB. This is in accord withseveral necropsy studiesv-", Zmyslinski and co­workers", reviewing the ECGs of 2,500 con­secutive individuals who came to necropsy, found43 (1.7%) to have complete LBBB, of whom 41(95%) had anatomic LVH. Havelda et a1. 7 describ­ed 70 individuals with LBBB who came to post­mortem. Seventy percent had LVH. In addition,the sensitivity, specificity, and predictive ac­curacy of various ECG criteria for LVH wereassessed. A number of criteria (Rr+Sm greaterthan 25mV, Rr+Sm greater than 17 mV, deepestS + tallest R in precordial leads greater than55mV, and RV5 or RV6 greater than 25mV) had100% specificity but suffered from low sensitivi­ty. These authors concluded that LVH was fre­quently present with LBBB, but was poorlydefined by the ECG.

Our study does not refute these observationsbut, through the use of echocardiography, cor­roborates them in a group of patients seen in ageneral hospital setting. The presence of a leftatrial abnormality as an electrocardiographicpredictor of LVH in the presence of LBBB hasnot previously been reported. Although limitedby its sensitivity, it is the single best ECGcriterion yet reported. Its usefulness, as well asthat of an increased cardiothoracic ratio on chestx-ray, most likely reflects the increased preva-

lence of left ventricular disease associated withLBBB in our population of patients.

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J. ELECTROCARDIOLOGY 17 (2) 1984