A 44-year-old man presented with a 6-month history of progressive dyspnoea (NYHA class III). The electrocardiogram showed sinus rhythm with continuous short runs of atrial tachycardia resulting in a heart rate of 200 beats/min (Fig. 1a). An echocardiogram demonstrated left ventricular dilatation and a reduced ejection fraction of 15–25%. During runs of atrial tachycardia, the mitral valve faile...

Steele SL, Lo KH, Li VW, Cheng SH, Ekker M, Perry SF. Loss of M2 muscarinic receptor function inhibits development of hypoxic bradycardia and alters cardiac -adrenergic sensitivity in larval zebrafish (Danio rerio). Am J Physiol Regul Integr Comp Physiol 297: R412–R420, 2009. First published June 10, 2009; doi:10.1152/ajpregu.00036.2009.—Fish exposed to hypoxia develop decreased heart rate, or ...

BACKGROUND Evidence suggests that increased ambient air pollution concentrations are associated with health effects, although relatively few studies have specifically examined infants. OBJECTIVE We examined associations of daily ambient air pollution concentrations with central apnea (prolonged pauses in breathing) and bradycardia (low heart rate) events among infants prescribed home cardiore...