Table 2

ECG analysis

ECG parameters
Heart rate (bpm)593±11630±12*665±10†,§536±12*,||539±12*,||
QRS duration (ms)17.4±1.132.8±1.4†33.1±1.1†33.5±1.2†28.2±0.9*,§,¶
QTc interval (ms)32.2±1.351.3±1.4†59.5±1.6‡46.4±3.2†,§45.7±2.4†,§
QTSTV (ms)178±34362±31†454±45†285±33‡,§149±55||,¶
Heart rate variability
LF (ms2)0.052±0.0050.012±0.009†0.009±0.004†0.028±0.005†,§0.041±0.004*,||,¶
HF (ms2)0.032±0.0050.028±0.0090.025±0.0060.032±0.0050.033±0.009
LF to HF1.62±0.110.43±0.12†0.36±0.28†0.87±0.27*,§1.24±0.19*,||,¶
SDNN (ms)14.9±2.49.1±1.4*5.8±1.3†13.5±2.1§18.1±2.1||,¶
RMSSD (ms)5.7±0.93.18±0.8*3.54±1.1*3.7±1.0*3.6±1.1*
Number of VA21.3±4.244.7±3.1†56.2±2.7†28.3±4.2§16.6±2.4||,¶
SVT (%)
 During treatment850†66‡,§0||8||
 After treatment058†58†33§8||,¶
  • BB+BNP improved heart rate variability and were more efficient than metoprolol alone to prevent variability of ventricular repolarisation and VA. Parameters estimated from 12 h nocturnal ECG: heart rate, QRS duration, corrected QT interval (QTc) and short term variability of QT (QTSTV). Heart rate variability analysis in the frequency- and time-domain with low frequencies (LF), high frequencies (HF) spectral power, LF to HF ratio, SD of all normal R-R intervals (SDNN) and square root of the mean square successive differences between successive normal R-R intervals (RMSSD). Number of spontaneous ventricular extrasystoles (VA) developed over 12 h ECG recording. Percentage of mice developing SVT following injection of isoproterenol (2.5 mg/kg intraperitoneal) during and assessed 4 weeks after treatment. *,†,‡ p<0.05, p<0.01, p<0.001 versus Sham; §,|| p<0.05, p<0.01 versus PMI; ¶ p<0.05 versus BB-PMI; n=15/group.

  • BB, β1-adrenergic blocker; BNP, B-type natriuretic peptide; PMI, postmyocardial infarction; SVT, sustained ventricular tachycardia; VA, ventricular arrhythmia.