Recommended given in conjunction with a beta blocker or nondihydropyridine calcium channel antagonist. AF indicates atrial fibrillation; AV, atrioventricular; BID, twice daily; BP, blood pressure; CrCl, creatinine clearance; ECG, electrocardiogram/electrocardiographic; HF, heart failure; INR, international normalized ratio; LV, left ventricular; QD, once daily; QID, 4 times a day; QTc, corrected QT interval; SA, sinoatrial; SVT, supraventricular tachycardia; TID, 3 times a day; and WPW, Wolff-Parkinson-White. Table 7. Continued Drug Initial Daily Dose(s) Maximum Total Daily Maintenance Dose Potential Adverse Effects Precautions (Exclude or Use With Caution) and Interactions Recommendations for Ongoing Management of Multifocal Atrial Tachycardia COR LOE Recommendations IIa B-NR 1. Oral verapamil (Level of Evidence: B-NR) or diltiazem (Level of Evidence: C-LD) is reasonable for ongoing management in patients with recurrent symptomatic MAT.227,230 C-LD See Online Data Supplement 8. Long-term management of MAT frequently involves slowing of the ventricular response because arrhythmia termination is often not achievable. Verapamil has the advantage of not exacerbating pulmonary disease. Although it would be expected for diltiazem to have a similar effect, data on its use in patients with MAT are lacking. These drugs should not be used in patients with severe conduction abnormalities or sinus node dysfunction because those conditions can be exacerbated with these agents. Recommendations for Acute Treatment of Multifocal Atrial Tachycardia COR LOE Recommendation IIa C-LD 1. Intravenous metoprolol229 can be useful for acute treatment in patients with MAT. See Online Data Supplement 7. The mechanism of MAT can involve triggered activity, and treatment with intravenous verapamil can terminate the arrhythmia with moderate success. In 1 small study, intravenous verapamil converted MAT in 8 of 16 patients treated.233 Alternatively, intravenous verapamil may acutely slow the ventricular response to MAT. 