Atypical electrocardiographic features of cavotricuspid isthmus-dependent atrial flutter occurring during left atrial fibrillation ablation.

BACKGROUND: Patients who have undergone percutaneous catheter ablation for atrial fibrillation (AF) may develop cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL), which can occur either spontaneously during left atrial (LA) ablation for AF or by induction from sinus rhythm during the procedure. The electrocardiographic (ECG) characteristics of CTI-dependent AFL occurring during LA ablation have not been described. The purpose of this study was to describe the ECG features of CTI-dependent AFL occurring during percutaneous LA catheter ablation for AF. METHODS AND RESULTS: Of 223 patients presenting for first AF ablation at our institution between May 2004 and February 2008, 20 patients (9%) developed CTI-dependent AFL during LA ablation for AF. CTI-dependent AFL developed spontaneously in 4 patients (20%) and was induced in 16 patients (80%). Among these 20 patients, 3 (15%) had typical ECG patterns and 17 (85%) had atypical ECG patterns. Flutter waves in the inferior leads were biphasic in 10 patients (50%), downward in 3 patients (15%), positive in 3 patients (15%), and not fitting the above classifications in 4 patients (20%). There was no statistically significant association between AFL pattern and LA size, left ventricular ejection fraction, total ablation time, duration of prior AF, or type of prior AF. CONCLUSION: A majority of patients with CTI-dependent AFL occurring during LA ablation have atypical ECG patterns. Biphasic flutter waves in the inferior leads are common ECG features, occurring in one-half of patients. Right atrial CTI-dependent AFL should be suspected even if the ECG appearance is atypical.

Effects of hormone replacement therapy on ambulatory blood pressure and vascular responses in normotensive women.

The effects of chronic oestrogen replacement therapy (ERT) (conjugated equine oestrogen 0.625 mg/day) and combined oestrogen and progestogen replacement therapy (HRT) (ERT plus continuous medroxyprogesterone acetate 5 mg/day) on 24-h ambulatory blood pressure recordings, forearm vascular resistance (FVR) and FVR responses to noradrenaline, angiotensin II, acetylcholine and nitroprusside were studied in 17 normotensive postmenopausal women in a 3-month randomized, double-blind, placebo-controlled crossover trial with 1 month of therapy in each treatment arm. During the last few days of each 1-month treatment period, the subjects underwent 24-h ambulatory blood pressure recordings and measurements of FVR responses. ERT and HRT reduced mean 24-h diastolic blood pressure by 4 and 5 mmHg, systolic blood pressure by 6 and 9 mmHg and mean 24-h heart rate by 5 and 3 beats/min, respectively for ERT and HRT (p < 0.05). Basal FVR was reduced by approximately 18% by ERT and HRT, but FVR responses to noradrenaline, angiotensin II, acetylcholine and nitroprusside were unaffected. ERT and HRT therapy for 1 month lowers blood pressure and basal FVR, but does not appear to influence FVR responses to acetylcholine, nitroprusside, noradrenaline and angiotensin II.