In presence of a right heart failure, which pattern would likely be observable on an ECG?

The S1Q3T3 pattern is specifically associated with conditions that lead to right heart strain or right heart failure, such as pulmonary embolism. In this ECG pattern, the S wave is prominent in the lead I, there is a Q wave in lead III, and the T wave in lead III is inverted. This triad of findings indicates that the right ventricle is experiencing increased workload due to dysfunction or obstruction, which is characteristic of right heart failure.

In cases of right heart failure, the right atrium and ventricle may struggle to cope with higher pressures or volume, leading to specific changes observed on an ECG. The S1Q3T3 pattern reflects these changes and is a useful diagnostic clue.

The other options, while indicative of different cardiac conditions, do not specifically relate to right heart failure in the same way. QRS widening tends to suggest intraventricular conduction delays, ST segment elevation is often indicative of myocardial infarction, and inverted T waves can signify various conditions, including ischemia, but aren't specific to right heart failure. Thus, the S1Q3T3 pattern stands out as the correct choice for identifying right heart failure on an ECG.