1. Chest tightness and palpitations: Sudden chest tightness and palpitations, especially after meals or before bed, could indicate myocardial ischemia. Seek urgent medical attention if accompanied by breathlessness and difficulty breathing at rest.

2. Dizziness: Dizziness is a common symptom of heart disease.

Patients may experience visual blackouts and loss of consciousness. Prompt medical attention is necessary. 

3. Shortness of breath: Sudden shortness of breath and chest tightness require heightened vigilance for a heart attack or heart failure. Urgent medical care is needed.

4. Chest pain: Chest pain is a major symptom of heart disease, particularly in cases like angina, myocarditis, and pericarditis.

Typically felt behind the sternum or in the precordial area, the pain worsens with physical activity and is described as a dull ache.