Insight into specific pro-arrhythmic triggers in Brugada and early repolarization syndromes: results of long-term follow-up.

The pro-arrhythmic triggers in Brugada and early repolarization syndromes (BrS, ERS) have not been analyzed systematically except for case reports. We clinically investigated the circumstances which precede/predispose to arrhythmic events in these syndromes during long-term follow-up. A detailed history from the patients/witnesses was taken to investigate the antecedent events in the last few hours that preceded syncope/ventricular fibrillation (VF); medical records, ECG and blood test from the emergency room (ER) were reviewed. 19 patients that fulfilled the investigation criteria were followed up for 71 ± 49 months (34-190 months). Prior to the event (syncope/VF), the patients were partaking different activities in the following decreasing order; drinking alcoholic beverage, having meal, and getting up from sleep, exercise. 3 patients reported mental/physical stress prior to the event and 2 patients developed VF several days after starting oral steroid for treatment of bronchial asthma. In the ER, elevated J-wave amplitude (0.27 ± 0.15 mV) was found with 58 % of the patients having hypokalemia. After electrolyte correction and cessation of steroids, the following day plasma K+ (4.2 ± 0.3 mEq/L, P < 0.001) was significantly increased and J-wave amplitude (0.13 ± 0.1 mV, P < 0.001) was remarkably reduced. Three patients were kept on oral spironolactone/potassium supplements. During follow-up for 71 ± 49 (34-190) months, among 4 patients with VF recurrence, one patient developed VF after taking oral steroid. In ERS and BrS, hypokalemia and corticosteroid therapy add substantial pro-arrhythmic effects, but potentially treatable. Stopping steroid therapy and avoiding hypokalemia had excellent long-term outcome.

Inhaled nitric oxide modifies left ventricular diastolic stress in the presence of vasoactive agents in heart failure.

Nitric oxide (NO) inhalation therapy has been widely used in several diseases with pulmonary hypertension. However, application of NO inhalation therapy remains controversial in heart failure. Cardiovascular effects of inhaled NO (iNO) were evaluated in dogs before and after induction of heart failure with and without infusion of vasoactive agents. iNO did not affect the baseline left ventricular (LV) function or the response to isoproterenol in control conditions or heart failure induced by procainamide. Pulmonary vascular resistance was significantly decreased by iNO in heart failure with infusion of vasoactive agents. Unexpectedly, LV end-diastolic pressure was significantly elevated by iNO in heart failure in the presence of infusion of vasoactive agents independent of their types; either the vasodilating agents of acetylcholine and nitroglycerin or the vasoconstricting agents of norepinephrine and angiotensin-II. The end-diastolic LV dimension and wall stress were also significantly increased by iNO, however, those at end systole were not affected. These results suggested that NO inhalation therapy reduced pulmonary vascular resistance, whereas in the presence of additional stress of vasoactive agents, it increased LV preload and end-diastolic wall stress in heart failure.