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. 2013 Jan 30;304(10):C954–C965. doi: 10.1152/ajpcell.00383.2012

Fig. 4.

Fig. 4.

Disruption of the cardiomyocyte molecular clock stretch-induced arrhythmias in the isolated heart. Stretch-induced conduction block was tested by increasing preload from 10 mmHg to 12.5, 15, and 20 mmHg in iCSΔBmal1+/+ or iCSΔBmal1−/− hearts paced from the right atrium at 8 Hz. A delay in QRS is due to a delay/block of conduction. A: representative sequence of left ventricular pressure (LVP) and the corresponding ventricular depolarizations (QRS) from an isolated iCSΔBmal1+/+ heart. No conduction block was observed at preloads from 10 to 15 mmHg and only 2 out of 7 hearts showed atrioventricular block at a 20 mmHg preload. B: example of block followed by three wide QRS complexes generated from an ectopic foci (note the inversion of the QRS complex). The three wide QRS complexes following the supraventricular conduction block appeared to be generated from a similar source other than the supraventricular stimulus. The iCSΔBmal1−/− mouse hearts showed conduction block at 12.5 mmHg and became more frequent at 15 mmHg preload (3 out of 6) and 20 mmHg (5 out of 6).