You have not indicated age of your dog? Excessive panting in dogs can be due to fever, anemia, poisoning, heartworms, conditions of fear and excitement, and hypothyroidism.
Excessive panting in dogs during nights can be due to congestive heart failure. This can be due to heartworms, cardiomyopathy, problems of heart valve, arrhythmia, and disease of pericardium. Diagnosis is by general and physical exam, echocardiogram, ECG, Blood pressure measurement, chest x-ray etc. Treatment depends upon underlying cause. So, take your dog to vet for differential diagnosis and treatment.
Excessive panting in dogs during nights can be due to congestive heart failure. This can be due to heartworms, cardiomyopathy, problems of heart valve, arrhythmia, and disease of pericardium. Diagnosis is by general and physical exam, echocardiogram, ECG, Blood pressure measurement, chest x-ray etc. Treatment depends upon underlying cause. So, take your dog to vet for differential diagnosis and treatment.