• Phase analysis
• gated SPECT
• myocardial perfusion imaging
• cardiac resynchronisation therapy
• heart failure
• pacemakers
• nuclear cardiology
• risk stratification
• coronary artery disease (CAD)

In their paper published in this issue of Heart, Pazhenkottil et al1 demonstrate for the first time that left ventricular (LV) dyssynchrony, as determined by phase analysis of gated myocardial perfusion SPECT (GMPS), is a strong predictor of major adverse cardiac events independent of other known predictors such as regional myocardial perfusion defects or decreased LV ejection fraction (LVEF) (see page 33). The current investigation agrees with previous investigations in patients with heart failure and LV dyssynchrony2–5 but extends it now to an unselected patient population with suspected or known coronary artery disease. Similar observations were also reported more recently by Aljaroudi et al6 in 144 patients with end-stage renal disease. In their specific study population with end-stage renal disease, the proof of LV dyssynchrony by phase analysis with GMPS was associated with increased all-cause mortality during a mean follow-up of 41±28 months. The reasons for LV dyssynchrony in these two populations studied1 6 remain uncertain but could be related to volume overload of the left ventricle, pulmonary hypertension with right ventricular dilatation associated with septal wall flattening, leading to abnormal contraction, left bundle branch block, LV hypertrophy, myocardial interstitial fibrosis in the process of LV remodelling and other, but not yet determined, factors. Independent of …