Monitoring and Medicines for Heart Failure

Topic Overview

Heart failure is most often a lifelong illness that will require frequent changes in your medicine schedule and regular follow-up with your doctor. Over the years, many things will affect the course of your disease, including other illnesses that you develop, your age, your diet, your ability to tolerate and comply with your treatment, and hopefully the development of new drugs to treat heart failure.

Several important aspects of monitoring the course of your illness will help you to optimize your treatment:

1. Regular follow-up with your doctor. How often you need to see your doctor will vary depending on the severity of your symptoms at any given time. It is possible that you will be able to get on a stable medical regimen for years and may only need to see your cardiologist 2 or 3 times a year. At other times you may need to see the doctor as frequently as once a week. A good example of this would be when you start to take beta-blockers. These medicines can initially make heart failure symptoms worse and can cause low blood pressure and a slow heart rate, so you will need to be seen frequently to make sure the process of taking medicine goes smoothly.
2. Keeping track of your exercise tolerance and your symptoms. This is an important way for you and your doctor to monitor the severity of your heart failure. You can help keep track of this by keeping a record of how much exercise you can do and what types of activities you can do without symptoms. An accurate assessment of your exercise tolerance will help you and your doctor decide whether changes need to be made in your medical regimen.
3. Monitoring your electrolytes. Several of the medicines for heart failure can affect important electrolytes or minerals in the blood. Most importantly, diuretics can lower the amount of potassium and magnesium in the blood and can also decrease sodium and calcium. Low potassium, magnesium, or calcium can all raise your risk of having a dangerous ventricular arrhythmia. Angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), and spironolactone, on the other hand, can increase the level of potassium in your blood. If you are taking these medicines, it will be important for you to periodically have these electrolytes measured using a blood test. They should also be measured shortly after you start taking any new medicine.
4. Watching for side effects of your medicines. All medicines have side effects. Ask your doctor or pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine. If you develop any of these expected side effects or any new symptoms that you think can be attributed to one of the medicines that you are taking, it is important that you discuss the problem with your doctor immediately.
5. Monitoring your blood pressure and heart rate. Your blood pressure and heart rate are extremely important parameters that affect how well your heart can function and reflect how well your medicines are working. If you take your blood pressure and heart rate at home, keep a record to share with your doctor at your regular visits. Your doctor can give you a range of blood pressure and heart rates that are acceptable for you and instructions on what to do if your measurements are outside these ranges.
6. Monitoring your weight. Your weight is a direct indication of how much fluid you have in your body. With heart failure, you will always have a tendency to retain salt and water. You should record your weight daily. Call your doctor if you notice a sudden weight gain. Your doctor may tell you how much weight to watch for. But in general, call your doctor if you gain more than 2 lb (0.9 kg) to 3 lb (1.4 kg) in a day or 5 lb (2.3 kg) in a week. The medicine that most directly affects the amount of fluid in your body is your diuretic. If your weight drifts up quickly, you may need to take more diuretic; if your weight drifts down quickly, you may need to take less.

What type of monitoring do I need?

Heart failure drug or class of drugs	Necessary monitoring
ACE inhibitors	Blood pressure Potassium level Kidney function
Beta-blockers	Blood pressure Heart rate Severity of heart failure symptoms Weight gain
Diuretics	Weight Potassium level Magnesium level Calcium level Kidney function
Digoxin	Heart rate Digoxin level Potassium level
Angiotensin II receptor blockers (ARBs)	Blood pressure Potassium level Kidney function
Vasodilators (hydralazine and nitrates)	Blood pressure