Table 3.

Coronary sinus Ca²⁺, Na⁺, and K⁺ Levels After Pacing

	Controls			HFpEF
	125 bpm	(n=9) 0 to 15 s	15 to 60 s	125 bpm	Patients With HFpEF (n=8) 0 to 15 s	15 to 60 s
		After Pacing			After Pacing
Ca, mg/dL	8.84±0.45	8.86±0.42	8.80±0.48	8.75±0.30	8.83±0.36	8.89±0.34*
Na, mg/dL	141.1±2.3	141.9±1.9	142.0±1.9	141.0±1.7	140.6±1.3	140.6±1.7
K, mg/dL	4.24±0.23	4.22±0.23	4.11±0.26	4.50±0.61	4.44±0.57	4.40±0.48

Pacing at 125 beats per minute (bpm) versus sinus rhythm after 125 bpm pacing. HFpEF indicates heart failure with preserved ejection fraction.

^* P=0.03.