Breathing problem. To seek your advice?

Dear Doctor, I would like to seek your advice regarding my 80-year-old father. In 2025, he was admitted to the same hospital with heavy breathing and discomfort in his lower chest and upper abdomen. He was diagnosed with acute gastritis, and we were told that his breathing difficulty could be related to the gastric problem. In 2026, he was admitted again with almost identical symptoms, including heavy breathing and chest discomfort, but without pain or cramps in his chest, jaw or arm. This time, he was diagnosed with acute left ventricular failure (LVF). We are confused as to why similar symptoms led to different diagnoses on these two occasions. He continues to experience these episodes, particularly after lunch and his afternoon sleep. Could you please advise whether these recurring symptoms could be related to gastritis or acid reflux, or a cardiac condition ?