The goal of this study was to determine the distribution of left ventricular (LV) systolic and diastolic dysfunctions and their prognostic value in canine parvovirus-infected dogs suffering from severe sepsis and septic shock (SS/SS). Twenty dogs with SS/SS (experimental group) and 18 healthy dogs (control group) were used in the study. Systolic and diastolic dysfunction was present in three (15%) and 14 (70%) diseased dogs, respectively, with both types of dysfunction present in two (10%) of the patients. These dogs were split into two groups: survivors (Sv, n = 14) and non-survivors (non-Sv, n = 6). The pulsed wave tissue Doppler (PW-TDI) septal mitral annulus systolic velocity (LVS’), an index of systolic dysfunction, had a high sensitivity and specificity to differentiate Sv and non-Sv animals, with values of 83.3% (95% CI: 41.6–98.4) and 83.3% (95% CI: 59.8–94.8), respectively, at an optimum cut-off point of ≥ 9.90. The PW-TDI septal early mitral annulus early-diastolic peak velocity (E’), an index of diastolic dysfunction, had the best sensitivity and specificity to differentiate Sv and non-Sv dogs, with values of 100% (95% CI: 55.2–100) and 100% (95% CI: 78.9–100), respectively, at an optimum cut-off point of ≤ 6.50. Therefore, diastolic dysfunction determined by E’ is a good independent outcome predictor.