Inverted U wave in ergonovine‐induced vasospastic angina

Abstract

Summary:The relationship between inverted U wave in leads V5 and I1 and the location of myocardial ischemia was studied in 52 positive patients and in 50 negative patients with ergonovine provocation test, Development of a biphasic or negative U wave, or increased negativity of U wave (inverted U wave) was observed in 15 of 17 patients with spasm in only the right coronary artery (RCA), in 6 of 8 with spasm in only the left anterior descending artery (LAD), in 2 of 8 with spasm in only the left circumflex artery (LCx), and in 23 of 24 with spasm in two or more vessels. Of 52 positive patients in the ergonovine provocation test, 46 (88.5%) had inverted U wave. Of these, 17 (32.7%) had inverted U wave without discernible ST deviation. Of 50 negative patients, 2 had inverted U wave. Inverted U wave in lead Vs was frequently seen in patients with spasm of LAD, but this finding was not uncommon in spasm of RCA or LCx. On the other hand, inverted U wave in lead I1 was frequently seen in spasm of RCA and LCx, but not in spasm of LAD. These findings suggest that inverted U wave in lead V5 is not specific for myocardial ischemia due to spasm of LAD and that inverted U wave in lead I1 is specific for spasm of RCA and LCx.

The negative U wave: A pathogenetic enigma but a useful, often overlooked bedside diagnostic and prognostic clue in ischemic heart disease

“…The following findings reported in the literature are new and useful elements for bedside diagnosis. An nU may be the only sign of ischemia; 8,10,17,19,23,50,51,57 it precedes the typical ST-T changes 19,21 and increases the sensitivity of the stress test, 9,18,22,25,52,54 It appears when a vast myocardial territory is involved, 7,19,24,25,26,54 helps locate the culprit vessel 15,19,23,25,53 --the possible site of myocardial involvement 6,15,27,[54][55][56][57] --and is the expression of extensive ischemia or stunning. 55,56 It indicates the presence of viable myocardium in patients with a previous anterior infarction and the presence of collateral circulation when appearing during spontaneous or stress-provoked ischemia.…”

“…It returns to normal within minutes when the cause is ischemia. [19][20][21]36 In 130 hypertensive patients in whom the U wave changed polarity within a year, 107 were receiving drug therapy and 23 had undergone surgery. Among the latter it changed polarity within a week after renal transplant in nine and after prosthetic valve implantation in six patients; it changed polarity within a month in eight patients after coronary artery bypass graft (CABG).…”

“…9,13,16,27 The transitory inducibility of the nU by acute supply ischemia during PTCA offers an experimental model in humans that may help explain its pathogenesis. 18,19,21 During the ischemic cascade, the mechanical response precedes typical ST-T changes; similarly, during PTCA-induced ischemia, the nU precedes ST-T changes. 19,21 This similar temporal sequence of events suggests the U-wave changes to represent the mechanical effect of ischemia, namely stretch, and therefore supports the mechanoelectrical hypothesis of U-wave changes.…”

“…18,19,21 During the ischemic cascade, the mechanical response precedes typical ST-T changes; similarly, during PTCA-induced ischemia, the nU precedes ST-T changes. 19,21 This similar temporal sequence of events suggests the U-wave changes to represent the mechanical effect of ischemia, namely stretch, and therefore supports the mechanoelectrical hypothesis of U-wave changes. 5,[31][32][33][39][40][41] This hypothesis is also backed by the appearance of the nU during rapid filling when stretch occurs.…”

“…With rare exceptions, a negative U wave (nU) is considered a pathologic sign, mostly of cardiac origin. 5,9,10 An nU has been reported in aortic and mitral regurgitation, myocardial hypertrophy, hypertension, [9][10][11][12][13] dilated cardiomyopathy, 14 myocardial ischemia during exercise 9,15-17 and pharmacologic tests, 5,9,18 vasospastic angina, 8,19,20 during percutaneous transluminal coronary angioplasty (PTCA), 6,7,21 with anterior descending pathology 9, 22-25 when a vast myocardial territory is involved by ischemia regardless of the culprit vessel, 7,19,26 and in previous anterior myocardial infarctions. 27,28 In 488 patients with an nU, the primary diagnosis was hypertension in 39.5%, coronary disease in 33.7%, and valvular disease in 15.4%.Of these, 81.3% with isolated aortic valvular disease had regurgitation; no evident heart disease was found in only 7.2%.…”