Transient out-of-range impedance in "hybrid" implantable cardioverter-defibrilator system: A case series.

A retrospective analysis of 60 patients with hybrid implantable cardioverter-defibrilator (ICD) systems: Boston Scientific device paired with non-Boston leads. In 10 (17%) patients transient, out-of-range peaks of ventricular pace impedance trend were observed. Probable cause is header-lead interaction incompatibility. This matter is known mainly for pacemakers systems but not for ICDs. Investigation this issue is crucial because consequences in ICD systems are unpredictable and risk might be higher than in pacing systems.

Left ventricular global longitudinal strain in predicting CRT response: one more J-shaped curve in medicine.

The aim of the study was: (1) to verify the hypothesis that left ventricular global longitudinal strain (LVGLS) may be of additive prognostic value in prediction CRT response and (2) to obtain such a LVGLS value that in the best optimal way enables to characterize potential CRT responders. Forty-nine HF patients (age 66.5 ± 10 years, LVEF 24.9 ± 6.4%, LBBB 71.4%, 57.1% ischemic aetiology of HF) underwent CRT implantation. Transthoracic echocardiography was performed prior to and 15 ± 7 months after CRT implantation. Speckle-tracking echocardiography was performed to assess longitudinal left ventricular function as LVGLS. The response to CRT was defined as a ≥ 15% reduction in the left ventricular end-systolic volume (∆LVESV). Thirty-six (73.5%) patients responded to CRT. There was no linear correlation between baseline LVGLS and ∆LVESV (r = 0.09; p = 0.56). The patients were divided according to the percentile of baseline LVGLS: above 80th percentile; between 80 and 40th percentile; below 40th percentile. Two peripheral groups (above 80th and below 40th percentile) formed "peripheral LVGLS" and the middle group was called "mid-range LVGLS". The absolute LVGLS cutoff values were - 6.07% (40th percentile) and - 8.67% (80th percentile). For the group of 20 (40.8%) "mid-range LVGLS" patients mean ΔLVESV was 33.3 ± 16.9% while for "peripheral LVGLS" ΔLVESV was 16.2 ± 18.8% (p < 0.001). Among non-ischemic HF etiology, all "mid-range LVGLS" patients (100%) responded positively to CRT (in "peripheral LVGLS"-55% responders; p = 0.015). Baseline LVGLS may have a potential prognostic value in prediction CRT response with relationship of inverted J-shaped pattern. "Mid-range LVGLS" values should help to select CRT responders, especially in non-ischemic HF etiology patients.

Regional Strain Pattern Index-A Novel Technique to Predict CRT Response.

BACKGROUND: Cardiac resynchronization therapy (CRT) improves outcome in patients with heart failure (HF) however approximately 30% of patients still remain non-responsive. We propose a novel index-Regional Strain Pattern Index (RSPI)-to prospectively evaluate response to CRT. METHODS: Echocardiography was performed in 49 patients with HF (66.5 ± 10 years, LVEF 24.9 ± 6.4%, QRS width 173.1 ± 19.1 ms) two times: before CRT implantation and 15 ± 7 months after. At baseline, dyssynchrony was assessed including RSPI and strain pattern. RSPI was calculated from all three apical views across 12 segments as the sum of dyssynchronous components. From every apical view, presence of four components were assessed: (1) contraction of the early-activated wall; (2) prestretching of the late activated wall; (3) contraction of the early-activated wall in the first 70% of the systolic ejection phase; (4) peak contraction of the late-activated wall after aortic valve closure. Each component scored 1 point, thus the maximum was 12 points. RESULTS: Responders reached higher mean RSPI values than non-responders (5.86 ± 2.9 vs. 4.08 ± 2.4; p = 0.044). In logistic regression analysis value of RSPI ≥ 7 points was a predictor of favorable CRT effect (OR: 12; 95% CI = 1.33-108.17; p = 0.004). CONCLUSIONS: RSPI could be a valuable predictor of positive outcome in HF patients treated with CRT.

Risk factors and prognostic role of an electrical storm in patients after myocardial infarction with an implanted ICD for secondary prevention.

INTRODUCTION: The aim of our study was to determine the risk factors for electrical storm (ES) and to assess the impact of ES on the long-term prognosis in patients after myocardial infarction (MI) with an implantable cardioverter-defibrillator (ICD) for secondary prevention of sudden cardiac death (SCD). MATERIAL AND METHODS: We retrospectively analyzed 416 patients with coronary artery disease after MI who had an implanted ICD for secondary prevention of SCD. Fifty (12%) patients had one or more incidents of an electrical storm - the ES (+) group. We matched the reference group of 47 patients from 366 ES (-) patients. RESULTS: We analyzed 3,408 episodes of ventricular arrhythmias: 3,148 ventricular tachyarrhythmic episodes in the ES (+) group (including 187 episodes of ES) and 260 in the ES (-) group. Multivariate logistic regression showed that inferior wall MI (RR = 3.98, 95% CI: 1.52-10.41) and the absence of coronary revascularization (RR = 2.92, 95% CI: 1.18-7.21) were independent predictors of ES (p = 0.0014). During 6-year observation of 97 patients, there were 39 (40%) deaths: 25 (50%) subjects in the ES (+) group and 14 (30%) in the ES (-) group (p = 0.036). Independent predictors of death were: the occurrence of ES (HR = 1.93), older age (HR = 1.06), and lower left ventricular ejection fraction (HR = 0.95) (for all p < 0.001). CONCLUSIONS: Electrical storm in patients after MI with ICD for secondary prevention is a relatively common phenomenon and has a negative prognostic significance. Myocardial infarction of the inferior wall and the absence of coronary revascularization are predisposing factors for the occurrence of an ES.

Dynamicity of early and late phases of repolarization in patients with remote anterior myocardial infarction: the interlead differences.

BACKGROUND: Repolarization dynamicity (QT/RR) is supposed to be a prognostic marker in post-MI patients. However, data on the relationships between early and late phases of QT and RR intervals (QT peak/RR and T peak-T end/RR) are insufficient, and which ECG lead should be used for the analysis is unclear. We analyzed repolarization dynamicity in patients after anterior MI with and without VT/VF history using two leads of Holter recordings- modified V(5) and V(3) . The daytime and nighttime periods were also analyzed. METHODS: Cohort of 88 patients after anterior MI (>6 months) consisted of 43 patients without VT/VF (33 males; 59 ± 12 years; LVEF: 41 ± 7%; NoVT/VF), and 45 patients with VT/VF history- ICD implanted as secondary prevention (40 males; 64 ± 10 years; LVEF: 32 ± 8%; VT/VF). QT/RR, QT peak/RR and T peak-T end/RR were calculated from 24-hour ECG for the entire recording, daytime and nighttime periods, from V(5) and V(3) leads, respectively. RESULTS: VT/VF patients had lower LVEF (P = 0.001). There were no differences in age and gender. VT/VF group had steeper QT/RR, QT peak/RR, and T peak-T end/RR in V(5) : 0.233 ± 0.04 versus 0.150 ± 0.05, P = 0.0001, 0.181 ± 0.04 versus 0.120 ± 0.04, P = 0.0001, 0.052 ± 0.02 versus 0.030 ± 0.02, P = 0.0001, and in V(3) : 0.201 ± 0.04 versus 0.149 ± 0.05, P = 0.0001, 0.159 ± 0.03 versus 0.118 ± 0.04, P = 0.0001, and 0.042 ± 0.02 versus 0.031 ± 0.02, P = 0.004; respectively. VT/VF patients had higher indices in V(5) than in V(3) lead (P = 0.001). QT/RR and QT peak/RR were steeper at daytime period in both leads. It was not found for T peak-T end/RR. CONCLUSIONS: Patients with VT/VF history are characterized by steeper relationships between repolarization duration and RR intervals. These findings are more evident in modified V(5) lead.

Heart rate turbulence in postinfarction patients with history of malignant ventricular arrhythmias.

UNLABELLED: In the study, there has been retrospectively analyzed heart rate turbulence in postinfarction patients. The cohort of 158 patients consisted of 94 patients with documented ventricular tachycardia and/or ventricular fibrillation (VT/VF) and 64 patients without history of VT/VF. Turbulence onset and slope were calculated from Holter recordings, and left ventricle ejection fraction (LVEF) ≤35% was regarded as severe left ventricle dysfunction. Study groups were similar in age and sex. Left ventricle ejection fraction was lower in the VT/VF group (P < .005). Patients with VT/VF had higher turbulence onset (-0.22% ± 1% vs -0.8% ± 2%; P = .005) and lower turbulence slope (2.6 ± 1.9 vs 4.1 ± 3.5 milliseconds per RR interval; P = .01). These trends were observed in patients with LVEF >35% but not in subjects with LVEF ≤35%. Diabetes mellitus, previous coronary artery bypass graft, and amiodarone therapy have diminished the intergroup differences significantly. CONCLUSIONS: Heart rate turbulence is diminished in postinfarction patients with a history of malignant ventricular arrhythmias. It seems to separate subjects at arrhythmic risk among patients with relatively preserved left ventricle function, but it is diminished in patients with previous coronary artery bypass graft, diabetes, and amiodarone therapy.

Impact of left ventricular remodeling on ventricular repolarization and heart rate variability in patients after myocardial infarction treated with primary PCI: prospective 6 months follow-up.

BACKGROUND: The relation between postinfarction left ventricle remodeling (LVR), autonomic nervous system and repolarization process is unclear. Purpose of the study was to assess the influence of LVR on the early (QTpeak) and late (TpeakTend) repolarization periods in patients after myocardial infarction (MI) treated with primary PCI. The day-to-night differences of repolarization parameters and the relation between QT and heart rate variability (HRV) indices, as well left ventricle function were also assessed. METHODS: The study cohort of 104 pts was examined 6 months after acute MI. HRV and QT indices (corrected to the heart rate) were obtained from the entire 24-hour Holter recording, daytime and nighttime periods. RESULTS: LVR was found in 33 patients (31.7%). The study groups (LVR+ vs LVR-) did not differ in age, the extent of coronary artery lesions and treatment. Left ventricle ejection fraction (LVEF) was lower (38%+/- 11% vs 55%+/- 11%, P < 0.001), both QTc (443 +/- 26 ms vs 420 +/- 20 ms, P < 0.001) and TpeakTendc (98 +/- 11 ms vs 84 +/- 12 ms, P < 0.005) were longer in LVR + patients, with no differences for QTpeakc. Trends toward lower values of time-domain (SDRR, rMSSD) HRV parameters were found in LVR+ pts. Day-to-night difference was observed only for SDRR, more marked in LVR-group. Remarkable relations between delta LVEF (6 months minus baseline), delta LVEDV and TpeakTendc were found, with no such relationships for QTpeakc. CONCLUSIONS: The patients with LVR have longer repolarization time, especially the late phase-TpeakTend, which represents transmural dispersion of repolarization. Its prolongation seems to be related to local attributes of myocardium and global function of the left ventricle but unrelated to the autonomic nervous influences. Remodeling with moderate LV systolic dysfunction is associated with insignificant decrease in HRV indices and preserved circadian variability.

QT/RR relationship in patients after remote anterior myocardial infarction with left ventricular dysfunction and different types of ventricular arrhythmias.

BACKGROUND: QT/RR relationship was found to be both rate-dependent and rate-independent, what suggests the influence of autonomic drive and other not-autonomic related factors on it. The steeper QT/RR slope in patients after acute myocardial infarction (MI) was described, but the relationship to ventricular arrhythmias is unknown. The purpose of this study was to calculate differences in QT/RR relationship in patients after remote anterior MI with left ventricular dysfunction and different types of ventricular arrhythmias. METHODS: The cohort of 95 patients (age: 63 +/- 11 years, LVEF: 35 +/- 9%) with previous anterior MI (mean 1.1 years) was divided into two well-matched groups-50 patients without episodes of ventricular tachycardia (VT) or ventricular fibrillation (VF) (NoVT/VF: 39 males, 64 +/- 12 years, LVEF 37 +/- 8%) and 45 patients with VT and/or VF (all with ICD implanted) (VT/VF: 35 males, 62 +/- 10 years, LVEF 34 +/- 10%). No true antiarrhythmics were used. QT/RR slope was calculated from 24-hour Holter ECG for the entire recording (E), daytime (D) and nighttime (N) periods. RESULTS: Groups did not differ in basic clinical data (age, LVEF, treatment). QT/RR slopes were steeper in VT/VF than in NoVT/VF group in all analyzed periods: E - 0.195 +/- 0.03 versus 0.15 +/- 0.03 (P < 0.001), N - 0.190 +/- 0.03 versus 0.138 +/- 0.03 (P < 0.001) and D - 0.200 +/- 0.04 versus 0.152 +/- 0.03 (P < 0.001). No significant day-to-night differences were found in both groups. CONCLUSIONS: Steeper QT/RR slope and complete lack of day-to-night differences in VT/VF patients show inappropriate QT adaptation to the heart rate changes. The prognostic significance of this parameter needs prospective studies.

Predictors of long-term outcome in patients with left ventricular dysfunction following coronary artery bypass grafting.

BACKGROUND: Prognostic significance of clinical and non-invasive risk markers in patients after surgical revascularisation remains unclear, especially in post-infarction patients with left ventricular (LV) dysfunction. AIM: The single-centre, prospective study was designed to assess survival and the predictive power of several clinical and non- -invasive risk markers of all-cause (ACM) and cardiovascular mortality (CVM) in post-CABG patients with LV dysfunction. METHODS: A cohort of 61 patients (age 59+/-9 years, 49 males, LVEF 33+/-6%) 6-12 months after CABG was prospectively followed for a median of 46 months. Demographics, clinical data, medication, LVEF, QRS>120 ms or late potentials (LP) presence, QT dispersion l80 ms, premature ventricular contractions (PVC) l10/h, non-sustained ventricular tachycardia (nsVT), and SDNN L70 ms in ambulatory ECG were analysed. The ACM and CVM were evaluated. The prognostic value of analysing parameters was determined. RESULTS: Fourteen patients died, 10 of them due to cardiovascular causes. Univariate Cox analysis showed that incomplete revascularisation, history of angina, heart failure, low LVEF, use of nitrates, digitalis or diuretics, and presence of LP or prolongation of QRS complex were predictors of poor outcome. Combination of angina and low LVEF was the best model in a multivariable Cox analysies for the prediction of both types of death. CONCLUSIONS: The present study showed that in post-CABG patients with LV dysfunction, angina class and low LVEF are the main predictors of ACM and CVM. Combination of LVEF <30% with the presence of QRS >120 ms or LP may also be helpful in the identification of high-risk subjects. Other common non-invasive risk markers, particularly arrhythmic and autonomic, seem to lose some of their predictive power in patients after CABG and receiving beta-blocking agents.