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redicting Left Ventricularnd-Diastolic Pressure bychocardiography

We read with great interest the re-ent report by Su et al,1 who sought toredict left ventricular end-diastolicressure in patients with heart failure onhe basis of the Doppler echocardio-raphic measurement of certain electro-echanical parameters. We do have

oncerns about the definition and anal-sis of some of these parameters, par-icularly the measurement of isovolu-ic contraction time (IVCT) before the-wave inscription.Simultaneous electrocardiographic,

arotid arterial pulse tracing, and pho-ocardiographic recordings by Weisslert al2 showed that the preejection periodPEP) was derived by subtracting theeft ventricular ejection time from the-S2 duration (the onset of the Q waven the electrocardiogram to the onset of2 on the phonocardiogram). IVCT was

hen calculated by subtracting left ven-ricular ejection time from the S1-S2 du-ation (the onset of S1 to the onset of S2n the phonocardiogram). The intervaletween the onset of ventricular depo-arization, the Q wave, and the onset of1 on the phonocardiogram (Q-I) was

herefore representative of the electro-echanical interval (Figure 1). In sim-

ler terms, the PEP encompassed thelectromechanical interval and theVCT (PEP � Q-I � IVCT).

However, Su et al1 described andictorially depicted the PEP as part ofhe IVCT. Furthermore, the time inter-al measured by the investigators from

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he end of the diastolic mitral annularelocity pattern to the onset of the QRSthe AQ interval) should not includeither the PEP or the IVCT, becausehese intervals are determined after thenset of the QRS. We wonder, howuch impact did the inclusion of theEP or IVCT as part of the AQ intervalave on their finding that the AQ inter-al is a novel predictor of left ventric-lar end-diastolic pressure?

The more important issue here is theack of the consistent application ofedical terminology in publications.he interpretation of original scientificoncepts in newer technologic terms isot always unambiguous. Precise ad-erence to earlier descriptions is crucialnd can limit the errors that may arise as

igure 1. Depiction by Weissler et al2 of the elechonocardiography (top), carotid arterial pulse recCT � isovolumic contraction time; LVET � left-I � period from the onset of QRS to the onse

nterval between the onset of S1 and the onset of

ore of the older scientific principles

nc. All rights reserved.

re rediscovered. A better communica-ion of ideas between successive scien-ific generations will be a key step innsuring that we all speak the samejargon.”

Himanshu Tandon, MD

Anthony F. LaSala, MD

Hartford, Connecticut5 February 2007

. Su HM, Lin TH, Voon WC, Lee KT, Chu CS,Cheng KH, Yen HW, Lai WT, Sheu SH. Use-fulness of time interval between end of dia-stolic mitral annular velocity pattern and onsetof QRS for predicting left ventricular end-diastolic pressure. Am J Cardiol 2007;99:119–123.

. Weissler AM, Harris WS, Schoenfeld CD.Systolic time intervals in heart failure in man.Circulation 1968;37:149–159.

echanical changes during cardiac systole usinging (middle), and electrocardiography (bottom).tricular ejection time; PEP � preejection period;S1 (the electromechanical delay); S1S2 � time

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doi:10.1016/j.amjcard.2007.02.005

www.AJConline.org