Modulation of ventricular repolarization in patients with transient left ventricular apical ballooning: a case control study.
OBJECTIVE
Even though diffuse T wave inversion and prolongation of the QT interval in the surface electrocardiogram (ECG) have been consistently reported in patients with transient stress-induced left ventricular apical ballooning (AB), ventricular repolarization has not yet been systematically investigated in this clinical entity.


BACKGROUND
AB, an emerging syndrome that mimics acute ST-segment elevation myocardial infarction (MI), is characterized by reversible left ventricular wall motion abnormalities in the absence of obstructive coronary heart disease and significant QT interval prolongation.


METHODS
We prospectively enrolled 22 consecutive patients (21 women, median age 65 years) with transient left ventricular AB. A total of 22 age-, gender-, body-mass-index-, and left-ventricular-function-matched patients with acute anterior ST-segment elevation MI undergoing successful direct percutaneous coronary intervention for a proximal occlusion of the LAD, as well as 22 healthy volunteers served as control groups. Beat-to-beat QT interval and QT interval dynamicity were determined from 24-hour Holter ECGs, recorded on the third day after hospital admission.


RESULTS
There were no significant differences in baseline clinical characteristics, except higher peak enzyme release in MI patients. Compared with MI patients, AB patients exhibited significantly prolonged mean QT intervals and rate-corrected QT intervals (QT: 418 +/- 37 vs 384 +/- 33 msec, P < 0.01; QTcBazett: 446 +/- 40 vs 424 +/- 35 msec, P < 0.05; QTcFridericia: 437 +/- 35 vs 412 +/- 31 msec, P < 0.05). Mean RR intervals tended to be higher in AB patients, without reaching statistical significance (877 +/- 96 vs 831 +/- 102 msec, P = NS). The linear regression slope of QT intervals plotted against RR intervals was significantly flatter in AB patients at both day- and nighttime (QT/RR slopeday: 0.18 +/- 0.04 vs 0.22 +/- 0.06, P < 0.01; QT/RR slopenight: 0.12 +/- 0.03 vs 0.17 +/- 0.05, P < 0.01).


CONCLUSIONS
The present study is the first to demonstrate significant differences of QT interval modulation in patients with transient left ventricular AB and acute ST-segment elevation MI. Even though transient AB is associated with a significant QT interval prolongation, rate adaptation of ventricular repolarization (i.e., QT dynamicity) is not significantly altered, suggesting a differential effect of autonomic nervous activity on the ventricular myocardium in transient AB and in acute MI.
Bonnemeier
Hendrik
H
From the Medizinische Klinik II, Universität zu Lübeck, Lübeck, Germany. Bonnemei@medinf.mu-luebeck.de
Ortak
Jasmin
J
Bode
Frank
F
Kurowski
Volkhard
V
Reppel
Michael
M
Weitz
Gunther
G
Barantke
Melanie
M
Schunkert
Heribert
H
Wiegand
Uwe K H
UK
D000368:Aged; D016022:Case-Control Studies; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000002:abnormalities*; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis*; D008297:Male; D009203:Myocardial Infarction / Q000175:diagnosis*; D013577:Syndrome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis*