Atrial fibrillation (AF) and Heart failure (HF) often co-exist and since they worsen each other prognosis, it is very important to understand the importance of managing both the conditions simultaneously in an effective manner.  Unfortunately, there are still a large subset of people under treated for co-existing AF and HF. AF and worsening HF constitute a classic ‘vicious cycle’ of deterioration in HF, and a combined approach is needed in managing both the conditions to break the cycle, and prevent the increase in mortality.

Patients with HF classically fall under two major groups, those with left ventricular systolic dysfunction LVSD-HF (Ejection fraction < 45%) with poor pumping of blood, and other group with preserved LV systolic function PSF-HF (Ejection fraction >45%) with adequate pumping of blood by heart.  Recommended drugs for AF and LVSD- HF are combination of beta blockers (BB), angiotensin- converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) and oral anticoagulants (OAC), according to European Society of Cardiology and American College of Cardiology/ American Heart Association 2001 guidelines. The following are the possible contraindications for the use of this recommended therapy: ventricular rate < 50 beats /min, renal failure, chronic obstructive pulmonary disease (COPD), sick sinus syndrome, systolic blood pressure < 85mm Hg and atrio-ventricular block grade 2 to 3. Major bleeding and malignancy are the contraindications for the use of OAC.  There is less evidence of the efficacy of these drugs in PSF-HF.

A recent European heart survey led by Dr. Robby Nieuwlaat (Atrial Fibrillation and  Heart Failure in Cardiology Practise: Reciprocal Impact and Combined Management From the Perspective of Atrial Fibrillation”,Journal of American College of Cardiology  Vol.53 No.18 : 1690-8), threw light on association between AF and HF. A total of 5,333 AF patients were enrolled in 182 centers across 35 European Society of Cardiology member countries in 2003 and 2004. A follow up was performed to assess mortality and incidence of major adverse events during the 1st year. Patients enrolled were > 18 yrs old, and had EKG or Holter recording showing AF during admission/consultation or in preceding 12 months.

AF patients with HF were older and had more co-morbidities than AF patients without HF.  Among those who had co-existing AF and HF, those with LVSD- HF were relatively young age, with h/o of CAD, mainly myocardial infarction and with a large left atrium. Patients with PSF- HF were mostly women with underlying mitral stenosis or valve surgery and hypertension.

The recommended drugs for managing both AF and HF, according to the guidelines mentioned above, were more commonly used in patients who were first detected with AF, with other co-morbid conditions like CAD, hyperlipidemia, and diabetes as compared with those who had permanent or persistent AF, with other medical conditions like COPD, high blood pressure. Similarly the prescribed full package of drugs was used more commonly among who had LVSD- HF than PSF- HF.

AF patients with HF have worst outcome compared to those who don’t have HF, with increase in both cardiovascular mortality and all- cause mortality. Particularly old age patients with HF and prior major bleeding episodes, stroke or TIA, and low systolic blood pressure are significantly associated with higher all-cause mortality. Patients who were at sinus rhythm at discharge after an episode of AF, female sex, and the usage of ACEI/ARB are associated with low mortality. There are no specific mortality differences in the two groups of HF patients. Also AF is more likely to progress in patients with HF.

AF patients with heart failure also have increased risk of developing stroke, which can be prevented by the use of OAC. But still large groups of people in this subset are under treated. Creating awareness about this potential preventable risk with regular use of OAC can bring down the incidence of stroke in this group of patients.

In HF, both ACEIs and ARBs reduce morbidity and mortality and therefore are strongly recommended. They also have the potential to decrease atrial pressure, reduce atrial fibrosis and AF recurrence. Among beta-blockers, only Carvedilol has proven protective effect in this group of people, although a large randomized trial is needed to asses the mortality benefits of Carvedilol and other beta-blockers in patients with AF and HF.

AF and HF can also cause substantial left atrial and left ventricular remodeling compared to those without HF. As mentioned above, they tend to have more advanced forms of AF, with increased progression to persistent and permanent AF and are less likely to undergo cardioversion. This reinforces the notion that AF and HF are a part of vicious cycle of deterioration but also suggests that this complex disease combination may instill a sense of therapeutic futility and nihilism among clinicians. Only 32% of patients without contraindication are being treated with OAC, beta-blockers,ACEIs and ARBs, suggesting a large shortfall in quality of care.

REFERENCES

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