Although QRS duration (QRSd) is an important determinant of cardiac resynchronization therapy (CRT) response, non-responder rates remain high. QRS fragmentation can also reflect electrical ...dyssynchrony. We hypothesized that quantification of abnormal QRS peaks (QRSp) would predict CRT response.
Forty-seven CRT patients (left ventricular ejection fraction = 23±7%) were prospectively studied. Digital 12-lead ECGs were recorded during native rhythm at baseline and 6 months post-CRT. For each precordial lead, QRSp was defined as the total number of peaks detected on the unfiltered QRS minus those detected on a smoothed moving average template QRS. CRT response was defined as >5% increase in left ventricular ejection fraction post-CRT.
Sixty-percent of patients responded to CRT. Baseline QRSd was similar in CRT responders and non-responders, and did not change post-CRT regardless of response. Baseline QRSp was greater in responders than non-responders (9.1±3.5 vs. 5.9±2.2, p = 0.001) and decreased in responders (9.2±3.6 vs. 7.9±2.8, p = 0.03) but increased in non-responders (5.5±2.3 vs. 7.5±2.8, p = 0.049) post-CRT. In multivariable analysis, QRSp was the only independent predictor of CRT response (Odds Ratio 95% Confidence Interval: 1.5 1.1-2.1, p = 0.01). ROC analysis revealed QRSp (area under curve = 0.80) to better discriminate response than QRSd (area under curve = 0.67). Compared to QRSd ≥150ms, QRSp ≥7 identified response with similar sensitivity but greater specificity (74 vs. 32%, p<0.05). Amongst patients with QRSd <150ms, more patients with QRSp ≥7 responded than those with QRSp <7 (75 vs. 0%, p<0.05).
Our novel automated QRSp metric independently predicts CRT response and decreases in responders. Electrical dyssynchrony assessed by QRSp may improve CRT selection and track structural remodeling, especially in those with QRSd <150ms.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background It is believed that most sudden cardiac arrests ( SCA s) in young people occur in previously healthy people with rare risk factors for sudden death. Few studies have investigated large ...populations with complete ascertainment. Our objective was to use multisource records to identify and classify all out-of-hospital cardiac arrests in the Greater Toronto Area (population 6.6 million) in people aged 2 to 45 years from 2009 to 2012. Methods and Results Expert reviewers employed a systematic process, with emergency medical services, in-hospital and coroner records, to adjudicate the cause of death as SCA from cardiac or noncardiac causes. We report the adjudicated etiologies, circumstances, triggers, and characteristics of the SCA cohort. Of 2937 eligible out-of-hospital cardiac arrest cases, 608 (20.7%) SCA s had an adjudicated etiology of cardiac cause (120 survivors and 488 nonsurvivors). Two thirds of these SCA patients had a history of cardiovascular disease, and over 50% had been diagnosed with ≥1 cardiovascular disease risk factor. Moreover, 20.1% of SCA s were diagnosed with psychiatric disease and 30% had central nervous system drugs prescribed. Over 30% of SCA patients had central nervous system active drugs, including drugs of abuse detected postmortem, with opioids and ethanol being detected most frequently. Potentially heritable structural cardiac diseases accounted for only 6.9% of SCA events, with acquired cardiac diseases comprising the rest. Conclusions The underlying causes of SCA , in people aged 2 to 45 years, often occur in those with previously diagnosed cardiovascular diseases, and are associated with contributory factors including prescribed medications, recreational drugs, and a concomitant psychiatric history.
Background Action potential alternans can induce ventricular tachyarrhythmias and manifest on the surface ECG as T-wave alternans (TWA) and QRS alternans (QRSA). We sought to evaluate microvolt QRSA ...in cardiomyopathy patients in relation to TWA and ventricular tachyarrhythmia outcomes. Methods and Results Prospectively enrolled cardiomyopathy patients (n=100) with prophylactic defibrillators had 12-lead ECGs recorded during ventricular pacing from 100 to 120 beats/min. QRSA and TWA were quantified in moving 128-beat segments using the spectral method. Segments were categorized as QRSA positive (QRSA+) and/or TWA positive (TWA+) based on ≥2 precordial leads having alternans magnitude >0 and signal:noise >3. Patients were similarly categorized based on having ≥3 consecutive segments with alternans. TWA+ and QRSA+ occurred together in 31% of patients and alone in 18% and 14% of patients, respectively. Although TWA magnitude (1.4±0.4 versus 4.7±1.0 µV,
<0.01) and proportion of TWA+ studies (16% versus 46%,
<0.01) increased with rate, QRSA did not change. QRS duration was longer in QRSA+ than QRSA-negative patients (138±23 versus 113±26 ms,
<0.01). At 3.5 years follow-up, appropriate defibrillator therapy or sustained ventricular tachyarrhythmia was greater in QRSA+ than QRSA-negative patients (30% versus 8%,
=0.02) but similar in TWA+ and TWA-negative patients. Among QRSA+ patients, the event rate was greater in those without TWA (62% versus 21%,
=0.02). Multivariable Cox analysis revealed QRSA+ (hazard ratio HR, 4.6; 95% CI, 1.5-14;
=0.009) and QRS duration >120 ms (HR, 4.1; 95% CI, 1.3-12;
=0.014) to predict events. Conclusions Microvolt QRSA is novel phenomenon in cardiomyopathy patients that can exist without TWA and is associated with QRS prolongation. QRSA increases the risk of ventricular tachyarrhythmia 4-fold, which merits further study as a risk stratifier.
Abstract Background T wave variability (Tvar) is a proposed method to predict sudden cardiac death (SCD). The purpose of this trial was to evaluate the reproducibility of Tvar measurements over time ...and demonstrate a difference in Tvar between patient populations at risk for ventricular arrhythmias and healthy subjects. Methods Sixty subjects were enrolled in into 3 groups: healthy subjects (Population I), patients at high risk of SCD (Population II), and patients with a recent ventricular tachyarrhythmia event (Population III). Recording and analysis of T wave amplitude variance (TAV) as a measure of Tvar was performed at baseline and 3 months. Results TAV could not be interpreted in 12 of 43 patients in Populations II and III due to PVCs or noise. No subject had a TAV value suggestive of high risk of SCD as per a previously defined cutoff of > 59 μV. Median (range) values of TAV in μV at baseline for Populations I, II and III were 26 (15–39), 21 (13–43), and 24 (18–41), respectively (p = 0.39). TAV was reproducible within population's from baseline to 3 months (p = 0.27, 0.53, 0.17 for Populations I, II and III, respectively). There was no significant difference between TAV values of high risk patients and healthy subjects. Conclusion Tvar was reproducible primarily in patients with left ventricular dysfunction. However, the role of Tvar as a risk stratifying tool remains inconclusive.
Implantable cardioverter defibrillator (ICD) generator advisories present management dilemmas for physicians regarding competing risks of ICD failure and replacement-related complications. There is ...currently a paucity of long-term data concerning the complications associated with advisory ICD replacement.
In a large multicenter advisory ICD generator replacement cohort followed for 12 months, we aimed to assess replacement-related complications by performing a case-control determination of complication risk factors to identify characteristics that could assist with advisory ICD replacement decision making.
Twelve large ICD implanting centers reviewed the 1-year follow-up outcome of advisory ICDs replaced between October 2004 and October 2005. The complication cohort was characterized and compared in a nested case-control analysis with age- and gender-matched controls without complications from the same replacement population.
At the 12 participating institutions, 451 of 2635 advisory ICD devices were replaced (17.1%). Over 355 +/- 204 days of follow-up, there were 41 (9.1%) complications; 27 (5.9%) required reoperation and included two deaths. There were 14 minor complications (3.1%). Multivariate analysis demonstrated that the number of previous pocket procedures was associated with an increase in complications and that combined consultant and fellow operators was associated with a decrease in complications compared with a single operator alone.
Complications from advisory ICD generator replacement are frequent and include infection and, rarely, death. The risk of replacement is increased in patients with multiple previous pocket procedures.
Aims:
Patients with reentrant supraventricular tachycardia (SVT) are often highly symptomatic and the mechanism of symptoms is not well understood. We hypothesized that variation in ventriculoatrial ...interval (QRS to P) modulates the left atrial pressure and symptoms during tachycardia.
Methods and Results:
Three hundred twenty‐six patients awaiting electrophysiological study completed a questionnaire regarding “neck pounding” or “shirt flapping” during tachycardia. Mean left atrial pressure was measured during simulated atrioventricular reentry tachycardia (AVRT) and atrioventricular nodal reentry tachycardia (AVNRT) in 18 patients. Pulmonary venous flow reversal was assessed using transesophageal echocardiography in 12 dogs when pacing at 220 bpm with different VA delays (0 to 250 ms). “Shirt flapping” is present more often during AVNRT than during AVRT (58.6% vs 43.8%, respectively, P < 0.05). Simulated AVNRT is associated with higher left atrial pressure compared with AVRT (19.4 ± 4.8 mmHg vs 13.7 ± 3.9 mmHg, respectively, P < 0.05). In dogs, pulmonary venous flow reversal during atrial systole was observed with significantly decreasing amplitude as VA delays increased: 668 ± 167% at 0 ms; 492 ± 138% at 100 ms; 278 ± 148% at 180/ms; and 134 ± 91% at 220 ms.
Conclusion:“Shirt flapping” and “neck pounding” frequently occur during AVNRT. LA contractions during AV valve closure increase left atrial pressure and may explain differences in certain symptoms between AVNRT and AVRT.
Complications of Variant Angina: A Case Report Bohm, Adam, MD, DSc; Kiss, Robert, MD, PhD; Dorian, Paul, MD, MSc ...
Canadian journal of cardiology,
03/2012, Letnik:
28, Številka:
2
Journal Article
Recenzirano
Abstract The case of a patient with Prinzmetal's angina causing syncope due to atrioventricular block, and later causing death, is presented. Electrocardiogram during the episodes demonstrate ...multiple coronary artery involvement. Detection and differential diagnosis of ST-segment elevation during paced rhythm is discussed.
The case of a patient with a unipolar VVIR, who developed a sensor-driven increased pacing rate at rest following pulse generator replacement, is presented. The cause was pectoral muscle stimulation, ...which triggered a sensor-driven rate response in the supine position. The possible causes and management are discussed.
Abstract Background Limited data suggest that optimal atrioventricular (AV) and interventricular (VV) delays are different at rest than during exercise in patients with heart failure. We assessed the ...feasibility and reproducibility of an electrogram-based method of optimization called QuickOpt at rest and during exercise. Methods Patients with a St Jude Medical cardiac resynchronization therapy implantable cardioverter-defibrillator were subjected to a graded treadmill test, and QuickOpt was repeatedly measured prior to, during, and after the exercise. Results Twenty-four patients (16 males, aged 67.4 ± 7.7 years) participated. At rest, delays (in ms) were 110.4 ± 20.1 for sensed AV delay and –70 (LV pacing first) to +20 (RV pacing first) for VV delay. The changes in QuickOpt-derived delays at rest were not significant despite change in body position. During exercise, QuickOpt-derived AV delays did not change in 11 patients, were shorter during peak exercise in 8 patients, and were longer in 3 patients (average value during peak exercise was 126.5 ± 15.8 ms, P = 0.04 compared to baseline). The QuickOpt-derived VV delay gradually shifted toward earlier right ventricular pacing during exercise in 19 patients, while no changes were seen in 3 patients, and a shift occurred toward earlier left ventricular pacing in 2 patients (average value during peak exercise was –30.7 ± 22.2; P = 0.001 compared to baseline). There was no correlation between changes in the QuickOpt-derived AV and VV delays and heart rate. Conclusions The application of electrogram-based algorithm is feasible both at rest and during exercise. The results are reproducible. QuickOpt-derived AV and VV delays individually change during exercise.
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