Twenty seven patients with dilated cardiomyopathy (DCM) were studied by phonocardiography and mechanocardiography. The diagnosis was made in each case by history, laboratory, echocardiogram, hemodynamic study and coronary arteriography. Patients with left complete bundle branch block were excluded. As controls we studied 24 subjects with comparable age an sex. The phonomecanocardiographic records were performed with a Siemens-Elema machine (Mingograph-34) with direct ink recording with electrocardiogram in lead DII, phonocardiogram in mitral focus, and carotid pulse or apexcardiogram (ACG) simultaneously. The following data were assessed: heart rate (HR) electromechanical interval (Q-S2), preejection period of left ventricular contraction (PEP), left ventricular ejection time (LVET), relative ejection period (REP), ratio PEP/LVET (IW), "a" wave of the ACG ("a" wave), rising period of the apex-cardiogram (RPACG), isovolumic relaxation time (IRT), first heart sound intensity (S1I), third and fourth heart sound presence (S3 and S4) respectively. The average values (mean) and their standard deviation for the groups (N) and DCM respectively were: HR (b/m): 67.08 +/- 7.67 and 88.84 +/- 15.31; Q - S2 (msec.): 554.23 +/- 28.37 and 561.35 +/- 30.99; PEP (msec.): 145.13 +/- 17.64 and 194.11 +/- 22.09; LVET (msec): 409.38 +/- 27.68 and 375.54 +/- 28.21; REP (%): 102 +/- 9.27 and 84.78 +/- 8.61; IW: 0.395 +/- 0.078 and 0.72 +/- 0.11; "a" wave (%): 7.37 +/- 2.15 and 19.47 +/- 6.76; RPACG (sec.): 0.093 +/- 0.0015 and 0.143 +/- 0.067; IRT (sec.): 0.094 +/- 0.0012 and 0.105 +/- 0.018.(ABSTRACT TRUNCATED AT 250 WORDS)