Diagnosis of right ventricular involvement in chronic inferior myocardial infarction by means of body surface QRS changes

The opposite polarity of the PQ segment compared to the P wave isointegral maps

The aim of our work was to study the opposite polarity of the PQ segment to the P wave body surface potential maps in different groups of patients. We constructed isointegral maps (IIM) in 26 healthy controls (C), 16 hypertensives (HT), 26 patients with arterial hypertension and left ventricular hypertrophy (LVH) and 15 patients with myocardial infarction (MI). We analyzed values and positions of map extrema and compared the polarity of maps using the correlation coefficient. The IIM P maxima appeared mainly over the precordium, the minima mainly in the right subclavicular area. The highest maxima were in the MI group, being significantly higher than in the HT and LVH groups. No differences concerning any values of other extrema were significant. The IIM PQ maxima were distributed over the upper half of the chest; the minima mainly over the middle sternum. A statistically significant opposite polarity between the IIM P and IIM PQ was found in 80 % of cases. The opposite polarity of the P wave and the PQ segment was proved in isointegral body surface maps. The extrema occurred in areas not examined by the standard chest leads. This has to be considered for diagnostic purposes.

QRST isointegral departure mapping after exercise in patients with congenital long QT syndrome

Congenital long QT syndrome (LQTS) is known to be a critical syndrome associated with a bizarre T wave, prolonged QT interval, and ventricular arrhythmias and is followed by syncope and/or sudden death. Body surface mapping, especially QRST isointegral departure mapping, was used after exercise to assess exercise-induced repolarization changes in patients with this syndrome. This study included 12 patients with the Romano-Ward syndrome (LQTS group, 9 women, 30 +/- 19 years) and 19 healthy adults (control group, 5 women, 24 +/- 5 years). In the LQTS group, there was a significant increase in the number of local extrema and abnormal points after exercise in the departure maps. In the LQTS group, QRST isointegral departure mapping presented more marked abnormalities of repolarization after an exercise stress test. In mild cases that revealed abnormalities only after the exercise stress, such testing may be helpful for LQTS diagnosis.

Thoracic location of the lead with maximal ST-segment deviation during posterior and right ventricular ischemia: comparison of 18-lead ECG with 192 estimated body surface leads

By using our database of continuous 18-lead electrocardiographic (ECG) recordings (standard + V3-5R + V7-9) during coronary angioplasty, we selected 68 patients with left circumflex balloon occlusions (posterior ischemia model) or proximal right coronary artery balloon occlusions (right ventricular IRV] ischemia model). ST-segment amplitudes (J + 60 ms) at preangioplasty baseline were subtracted from maximal ST amplitudes during balloon inflation to create a positive or negative change score (deltaST) for each of the 18 leads. DeltaST elevation was used to describe a change in the ST level in the positive direction from baseline, whether or not actual ST elevation from the isoelectric line was present. DeltaST depression was used to describe a change in the ST level in the negative direction from baseline, whether or not actual ST depression from the isoelectric line was present. ST amplitudes from 8 of the 12 standard leads were then used to estimate ST amplitudes at 192 body surface sites spanning the entire anterior and posterior thorax using the transformation technique of Lux. Thoracic distributions of the DeltaST values were displayed on a torso figure, including locations of the 18 lead locations and points of maximal ST elevation and depression. The 192 estimated body surface unipolar leads were compared with 18-lead ECGs (bipolar and unipolar). During 53 left circumflex occlusions, the maximal deltaST elevation was always located in the 18-lead ECG, with the most frequent locations at leads III, II (41%), V7-8 (34%), and V5-6 (25%). The maximal deltaST depression was located outside the 18-lead ECG (89%), with the most frequent locations above standard lead V2 (67%) and V3 (14%). During 16 proximal right coronary artery occlusions, the maximal deltaST elevation was always located in the 18-lead ECG, with the most frequent locations at leads III (81%) and V2-3R (13%). The maximal deltaST depression was located outside the 18-lead ECG (93%), with the most frequent locations above standard lead V2 (50%), V3 (14%), and V4 (14%). We conclude that maximal deltaST elevation is always located in the 18-lead ECG and maximal deltaST depression is frequently located outside of 18-lead ECG during left circumflex and proximal right coronary artery occlusions. Future studies are required to determine the bipolar leads for the 192 estimated body surface potential mapping leads.

Influence of right ventricular ischemia on septal Q waves determined by coronary angioplasty

The aim of this study is to evaluate the influence of right ventricular ischemia on the amplitude of septal Q waves. Twenty-two patients without previous myocardial infarction who underwent isolated right coronary artery angioplasty were studied. The criterion for right ventricular ischemia was defined as ST elevation of 0.1 mV or more in lead V4R during angioplasty. The patients were divided into two groups: those with (group A, n = 12) and those without (group B, n = 10) right ventricular ischemia. There was no significant difference in the amplitude of septal Q waves in any lead before angioplasty between the two groups. During angioplasty, group A showed a reduction in the amplitude of septal Q waves in leads V5 and V6 but no change in the amplitude of septal Q waves in leads I and aVL. Group B had no significant reduction in the amplitude of septal Q waves in any lead. During angioplasty group A had a higher incidence of reduction of at least 0.05 mV of the septal Q wave amplitude in any lead (58% vs 10%). These results indicate that the amplitude of septal Q waves is occasionally reduced by right coronary occlusion and most such cases are accompanied by right ventricular ischemia. Therefore reduction of the amplitude of septal Q waves during right coronary occlusion appears to be caused by reduction of the electrical force derived from the right ventricular myocardium.

Electrocardiographic findings in a patient with pure septal infarction

The electrocardiogram in a 65 year old man in whom pure septal infarction had been produced by occlusion of the septal branch during percutaneous transluminal coronary angioplasty showed that this had led to the disappearance of septal Q waves and reciprocal ST segment depression in the inferior leads.