Table 4.

PV loop assessment of LV function in animals exposed IH or IA with or without β-adrenergic blockade

	IA (n = 13)	IH (n = 15)	IA + Propranolol (n = 9)	IH + Propranolol (n = 9)
Heart rate, beats/min	543±14	564±15	461±11c	466±16e
Parallel conductance, μl	34.9±1.0	35.2±1.1	31.8±1.1	32.5±1.1d
Maximal pressure, mmHg	90.7±2.5	97.6±2.3	80.4±3.1	88.8±3.6
dP/dtmax, mmHg/s	6,951±524	8,698±484a	4,843±285b	6,072±448e
dP/dt@LVP40, mmHg/s	6,556±579	8,398±627	4,600±223	5,772±430e
dP/dtmin, mmHg/s	−7,825±519	−9,152±533	−5,158±350c	−6,093±412e
End-diastolic pressure, mmHg	4.35±0.45	5.74±0.90	3.34±0.17	4.78±0.99
EDV, μl	22.7±1.3	19.8±1.6	31.2±4.0	25.3±2.5
ESV, μl	13.0±1.2	8.8±1.3	18.2±2.9	13.3±1.5
Stroke volume, μl	11.6±0.5	12.7±0.6	15.3±1.5	13.6±1.7
Cardiac output, μl/min	6,294±213	7,169±384	7,107±771	6,246±687
Stroke work, mmHg·μl	829±48	951±54	982±74	985±122
Arterial elastance, mmHg/μl	7.63±0.34	7.56±0.43	6.12±0.74	7.21±1.0
Ejection fraction, %	50.5±2.6	63.4±3.5a	48.5±2.2	51.2±3.6d
Preload-adjusted maximal power, mW/μl2	136±16	228±29a	68.6±8.9	135±37
τ, ms	6.79±0.32	6.32±0.28	8.59±0.39c	8.43±0.47e

Values are means ± SE; n, number of animals exposed to IH or IA for 4 wk. PV, pressure-volume; dP/dt, 1st derivative of LV pressure (LVP) with respect to time; τ, time constant.

^aP < 0.05 vs. IA.

^bP < 0.05 and

^cP < 0.015 vs. IA.

^dP < 0.05 and

^eP < 0.015 vs. IH.