Surface ECG criteria can discriminate post-septal pacing cardiac memory from ischemic T wave inversions.

Cardiac memory (CM) refers to transient T wave changes that appear after cessation of a period of abnormal ventricular activation, such as right ventricular (RV) pacing. ECG criteria for differentiating post-pacing CM from ischemia-induced T wave changes were previously published only for apical, but not for septal RV pacing. AIM: To find ECG criteria for discriminating post-septal pacing CM from ischemic T wave inversions. METHODS: ECGs were analyzed in 2 groups: CM (n = 23) and ischemia (n = 26). CM was induced by 2 weeks of DDD pacing with a short AV delay. Ischemic patients were grouped by culprit vessel: left anterior descending (LAD), circumflex (Cx), right coronary artery (RCA). RESULTS: CM was visible on the ECG after 1 week of ventricular pacing, started to disappear in <1 week after pacing cessation and was completely reversible within 4 weeks of pacing cessation. T wave axis differed between CM (75.8 ±â€¯18.5°) and Cx (-25.2 ±â€¯25.5°, p < 0.01) and RCA (-18.3 ±â€¯18.9°, p < 0.01) groups, but not compared to LAD group (96.4 ±â€¯65.0°, p = 0.17). The combination of (1) positive T wave in aVF; and (2) (i) T wave amplitude in aVF ≥ the absolute value of the most negative precordial T wave, or (ii) positive T wave in V5 and positive or isoelectric T wave in lead I identified CM from all ischemia with a sensitivity of 91% and a specificity of 92%. CONCLUSION: ECG criteria can discriminate post-septal RV pacing CM from ischemic changes with high sensitivity and specificity.

Do left atrial strain and strain rate reflect intrinsic atrial function, or are they determined by left ventricular function?

BACKGROUND: Left atrial (LA) strain (S) and strain rate (SR) are reported as measures of intrinsic function. AIM: Since the LA and left ventricle (LV) are connected through the mitral annulus, we investigated: (1) if deformation indices in the LA are mostly predicted by deformation of the LV; (2) if timings of S and SR events are similar in both the LA and LV; and (3) if alteration of S and SR in patients with primarily LV dysfunction would be similar in the LA and LV. METHODS: We retrospectively assessed 50 asymptomatic women (Group 1) and 20 patients with recent (< 96 h) acute pulmonary oedema (10 women) (Group 2). Using speckle tracking, the amplitude and timings of S and SR were averaged from three apical views, for one cardiac cycle, starting from the P-wave. RESULTS: In Group 1, all deformation indices were higher in the LA compared with the LV (p < 0.001 for all). In Group 2, S and SR during LA contraction were higher in the LA vs. LV (p < 0.05 for both), but all other deformation indices were not different in the LA vs. LV. All timings of S and SR occurred simultaneously in LA and LV in both groups, except S during LA contraction in Group 1, which occurred slightly earlier in LA than in LV. By multiple regression analysis, the most important predictors of LA deformation indices were the corresponding LV deformation indices, especially in patients with LV dysfunction (Group 1: r = 0.35-0.52; Group 2: r = 0.76-0.85; p < 0.05 by Fisher r-to-z transform). CONCLUSIONS: LA deformation strongly reflects LV deformation both in asymptomatic subjects and in patients with LV dysfunction. With the possible exception of LA contraction in asymptomatic individuals, discriminating intrinsic LA function from LV influence is difficult using deformation analysis.

Right ventricular electrical and mechanical synchronization by properly timed septal pacing in a patient with right bundle branch block and first degree AV block--a case report.

We present a case of near-normalization of the QRS by septal pacing in a patient with dual-chamber pacemaker and underlying complete right bundle branch block and first degree atrioventricular block. The right ventricular mechanical synchronization suggested by the ECG was validated as such by strain echo. To the best of our knowledge, this is the first time it has been shown that the narrowing of the QRS corresponds to mechanical synchronization in a case of this seldom-recognized phenomenon.

Left ventricular strain analysis reveals better synchrony and diastolic function for septal versus apical right ventricular permanent pacing.

OBJECTIVES: Left ventricular function and synchrony may be altered by right ventricular (RV) apical pacing. Septal pacing might be a better alternative. We compared effects on cardiac synchrony and function, between the 2 pacing sites, in chronically implanted patients. MATERIAL AND METHODS: 40 pacing-dependent patients (74±9 years, 21 men), 20 paced at the apex, were studied 11±4 months after implantation (baseline); 32 of them were re-examined after 1 year. Systolic function was assessed from ejection fraction (EF), cardiac index (CI), mean longitudinal systolic strain (MLSS), and strain rate (MLSR); diastolic function from E/A, E/E', and E/Vp ratios. Intraventricular dyssynchrony from standard deviation (SSD) and maximal difference (MAXS) of the 12 LV myocardial systolic timings, and sum of all times from the aortic valve closure to peak strain (SUMTAVC) for those segments with post-systolic shortening; interventricular synchrony from the aorto-pulmonary delay (APD). OUTCOMES: Four patients died, all of them from the apical group. NYHA functional class was not different. Cardiac synchrony was not significantly different between the two pacing sites at baseline, and after 1 year follow-up. Although at baseline there was a greater dyssynchrony for the septal site, this did not progress at follow-up, whereas this increased for the apical site. Meanwhile, there was a higher LV filling pressure (E/E' ratio) for the apical site at 1 year (13±6 vs.18±6; p=0.04). CONCLUSIONS: Both septal and apical pacing sites affect negatively LV mechanical activation timings and synchrony. Apical, but not septal site, affects LV synchrony at 1 year, associated with increased filling pressure.

Inaccuracy of radiological and ECG criteria for right ventricular outflow tract implantation of pacemaker leads.

We present three cases of active fixation pacemaker lead implantation, where the leads were believed to be inserted in the right ventricular outflow tract (RVOT) septal position, using established radiological criteria. However, when the exact location of the leads was documented by three-dimensional echocardiography, true septal RVOT position was achieved in only one patient. In the other two patients, the leads were, in fact, implanted into the RVOT anterior free wall. The electrocardiogram criteria were not able to identify the septal position from the anterior RVOT free wall position.

Successful slow pathway ablation in a patient with persistent left superior vena cava.

Persistent left superior vena cava (PLSVC) is a rare vascular variant which can add difficulties to slow pathway (SP) ablation procedures because of the disturbed anatomy of the triangle of Koch. We describe a case of a successful SP ablation using an anatomical approach in a patient with PLSVC.