Rare cases of serious cardiovascular adverse events, including electrocardiographic QT / QT c interval prolongation, cardiac arrest, torsades de pointes, and other ventricular arrhythmias, have been observed . ( See CONTRAINDICATIONS . ) In addition, deaths have been reported rarely with concomitant administration of terfenadine and erythromycin.
32.
By 1963, Dr . William Bruce, aware of the tendency of people with coronary artery disease to experience angina ( cardiac chest discomfort ) during exercise, developed the first standardized method of " stressing " the heart, where serial measurements of changes in blood pressure, heart rate and electrocardiographic ( ECG / EKG ) changes could be measured under " stress-stress " conditions.
33.
Target complications were defined as cardiac arrest ( defined as chaotic cardiac rhythm requiring initiation of basic or advanced life support ) or MI ( defined as e " 1 of the following : documented electrocardiographic findings of MI, ST elevation of e " 1 mm in > 1 contiguous leads, new left bundle-branch block, new Q-wave in e " 2 contiguous leads, or troponin > 3 times normal in setting of suspected ischemia ).
34.
Myocardial infarction ( MI ) is often difficult to detect when LBBB is present on ECG . A large clinical trial of thrombolytic therapy for MI ( GUSTO-1 ) evaluated the electrocardiographic diagnosis of evolving MI in the presence of LBBB . Among 26, 003 North American patients who had a myocardial infarction confirmed by enzyme studies, 131 ( 0.5 % ) had LBBB . A scoring system, now commonly called Sgarbossa criteria, was developed from the coefficients assigned by a logistic model for each independent criterion, on a scale of 0 to 5.
