Daniel R. Frisch

16-year trends in the infection burden for pacemakers and implantable cardioverter-defibrillators in the United States 1993 to 2008.

OBJECTIVES We analyzed the infection burden associated with the implantation of cardiac implantable electrophysiological devices (CIEDs) in the United States for the years 1993 to 2008. BACKGROUND Recent data suggest that the rate of infection following CIED implantation may be increasing. METHODS The Nationwide Inpatient Sample (NIS) discharge records were queried between 1993 and 2008 using the 9th Revision of the International Classification of Diseases (ICD-9-CM). CIED infection was defined as either: 1) ICD-9 code for device-related infection (996.61) and any CIED procedure or removal code; or 2) CIED procedure code along with systemic infection. Patient health profile was evaluated by coding for renal failure, heart failure, respiratory failure, and diabetes mellitus. The infection burden and patient health profile were calculated for each year, and linear regression was used to test for changes over time. RESULTS During the study period (1993 to 2008), the incidence of CIED infection was 1.61%. The annual rate of infections remained constant until 2004, when a marked increase was observed, which coincided with an increase in the incidence of major comorbidities. This was associated with a marked increase in mortality and in-hospital financial charges. CONCLUSIONS The infection burden associated with CIED implantation is increasing over time and is associated with prolonged hospital stays and high financial costs.

Clinical significance of atrial fibrillation detected by cardiac implantable electronic devices

The detection of atrial fibrillation (AF) by a cardiac implantable electronic device (CIED) in patients without a prior history of AF is increasing. This trend is the result of the increased number of CIEDs being implanted in a population whose multiple medical comorbidities are known to predispose to AF. Cardiac implantable electronic device-detected atrial fibrillation (CDAF) is independently associated with the development of ischemic stroke, and the annual risk may depend on both total AF burden and individual risk factors. No data evaluating the benefit of oral anticoagulation in this population are available, which makes the decision to initiate anticoagulation challenging. This review analyzes the available data on CDAF and the associated risk of ischemic stroke, and it presents a rationale for the use of long-term oral anticoagulation in this population.

Electrophysiological features differentiating the atypical atrioventricular node-dependent long RP supraventricular tachycardias.

Background—Diagnosing atypical atrioventricular node-dependent long RP supraventricular tachycardias (SVTs) can be challenging. Methods and Results—Nineteen patients with 20 SVTs (atypical atrioventricular nodal reentrant tachycardia without [n=11]/with [n=3] a bystander nodofascicular [NF] accessory pathway, orthodromic reciprocating tachycardia [ORT] using a decremental atrioventricular [permanent form of junctional reciprocating tachycardia; n=4] or NF [NF reentrant tachycardia; n=2]) accessory pathway underwent electrophysiological study. Postpacing interval (PPI)–tachycardia cycle length (TCL), corrected PPI, [INCREMENT]VA (ventriculoatrial), [INCREMENT]HA (His-atrial), [INCREMENT]AH (atrio-His) values, and responses to His-refractory ventricular premature depolarizations were studied. Compared with atrioventricular nodal reentrant tachycardia, ORT patients were younger (42±13 years versus 54±19 years; P=0.036) and were women (5/6 [83%] versus 3/14 [21%]; P=0.036); TCLs were similar (435 ms versus 429 ms; 95% confidence interval, −47.5 to 35.5). PPI–TCL was shorter for ORT (118 ms versus 176 ms; 95% confidence interval, 26.3–89.7) but only 50% had PPI–TCL <115 ms, whereas 5 of 6 (83%) had PPI–TCL <125 ms (sensitivity, 83%; specificity, 100%). Corrected PPI <110 ms, [INCREMENT]VA <85 ms, and [INCREMENT]HA <0 ms had equivalent sensitivity (67%) and 100% specificity for ORT. Compared with permanent form of junctional reciprocating tachycardia, NF reentrant tachycardia/atrioventricular nodal reentrant tachycardia had longer [INCREMENT]AH (29 ms versus 10 ms; 95% confidence interval, 3.03–35.0) or AH(SVT)<AH(NSR) (normal sinus rhythm) His-refractory ventricular premature depolarizations advanced (4/8 [50%]), delayed (4/8 [50%]), or terminated (5/8 [63%]) SVT in all accessory pathway patients. Conclusions—This unusual SVT requires separate maneuvers to delineate its upper and lower circuit. Standard entrainment criteria are modestly sensitive but highly specific for ORT; and PPI–TCL of 125 ms seems better than 115 ms. The [INCREMENT]AH criteria, or paradoxically AH(SVT)<AH(NSR), differentiates NF reentrant tachycardia/atrioventricular nodal reentrant tachycardia from permanent form of junctional reciprocating tachycardia. Bystander accessory pathways were only identified by His-refractory ventricular premature depolarizations.

Electrophysiologic Features Differentiating the Atypical AV Node-Dependent Long RP Supraventricular Tachycardias

Background—Diagnosing atypical atrioventricular node-dependent long RP supraventricular tachycardias (SVTs) can be challenging. Methods and Results—Nineteen patients with 20 SVTs (atypical atrioventricular nodal reentrant tachycardia without [n=11]/with [n=3] a bystander nodofascicular [NF] accessory pathway, orthodromic reciprocating tachycardia [ORT] using a decremental atrioventricular [permanent form of junctional reciprocating tachycardia; n=4] or NF [NF reentrant tachycardia; n=2]) accessory pathway underwent electrophysiological study. Postpacing interval (PPI)–tachycardia cycle length (TCL), corrected PPI, [INCREMENT]VA (ventriculoatrial), [INCREMENT]HA (His-atrial), [INCREMENT]AH (atrio-His) values, and responses to His-refractory ventricular premature depolarizations were studied. Compared with atrioventricular nodal reentrant tachycardia, ORT patients were younger (42±13 years versus 54±19 years; P=0.036) and were women (5/6 [83%] versus 3/14 [21%]; P=0.036); TCLs were similar (435 ms versus 429 ms; 95% confidence interval, −47.5 to 35.5). PPI–TCL was shorter for ORT (118 ms versus 176 ms; 95% confidence interval, 26.3–89.7) but only 50% had PPI–TCL <115 ms, whereas 5 of 6 (83%) had PPI–TCL <125 ms (sensitivity, 83%; specificity, 100%). Corrected PPI <110 ms, [INCREMENT]VA <85 ms, and [INCREMENT]HA <0 ms had equivalent sensitivity (67%) and 100% specificity for ORT. Compared with permanent form of junctional reciprocating tachycardia, NF reentrant tachycardia/atrioventricular nodal reentrant tachycardia had longer [INCREMENT]AH (29 ms versus 10 ms; 95% confidence interval, 3.03–35.0) or AH(SVT)<AH(NSR) (normal sinus rhythm) His-refractory ventricular premature depolarizations advanced (4/8 [50%]), delayed (4/8 [50%]), or terminated (5/8 [63%]) SVT in all accessory pathway patients. Conclusions—This unusual SVT requires separate maneuvers to delineate its upper and lower circuit. Standard entrainment criteria are modestly sensitive but highly specific for ORT; and PPI–TCL of 125 ms seems better than 115 ms. The [INCREMENT]AH criteria, or paradoxically AH(SVT)<AH(NSR), differentiates NF reentrant tachycardia/atrioventricular nodal reentrant tachycardia from permanent form of junctional reciprocating tachycardia. Bystander accessory pathways were only identified by His-refractory ventricular premature depolarizations.

Time for contrast material to traverse the epicardial artery and the myocardium in ST-Segment elevation acute myocardial infarction versus unstable angina pectoris/non–ST-elevation acute myocardial infarction☆

Although the time for contrast material to fill the epicardial artery in the setting of acute coronary syndromes has been studied extensively, the time for contrast material to fill the myocardium has not been evaluated. We compared differences in myocardial contrast material transit among patients with unstable angina pectoris/non-ST-elevation acute myocardial infarction (UAP/NSTEAMI) with patients with ST-elevation acute myocardial infarction (STEAMI). The time it took for contrast material to first appear and to arrive at peak intensity in the myocardium was compared in 224 patients with STEAMI enrolled in the LIMIT-AMI study versus 430 patients with UAP/NSTEAMI enrolled in the TACTICS-TIMI 18 trial. In patients with STEAMI, there was a delay in both the time for contrast material to first enter the myocardium (5,619 +/- 1,789 vs 4,663 +/- 1,626 ms, p <0.0001) and the time from entrance to peak blush intensity (2,387 +/- 1,359 vs 1,959 +/- 1,244 ms, p = 0.003) compared with patients with UAP/NSTEAMI. STEAMI remained significantly associated with impaired entrance of contrast material into the myocardium (p <0.0001) in a multivariate model controlling for known correlates of impaired epicardial flow (presence of thrombus, percent diameter stenosis, left anterior descending artery location, and contrast material inflow in the epicardial artery [corrected TIMI frame count]). The time for contrast material to enter the myocardium is impaired to a greater degree in STEAMI compared with UAP/NSTEAMI, even after adjusting for other variables known to delay flow in the epicardial artery. These data provide insight into potential mechanistic differences between these 2 clinical syndromes.

Predicting Irreversible Left Ventricular Dysfunction After Acute Myocardial Infarction

Patients with reduced left ventricular ejection fractions (LVEFs) and previous myocardial infarctions or heart failure are at increased mortality risk. Implantable cardioverter-defibrillators may mitigate this risk. The aim of this study was to identify patient characteristics at the time of presentation with ST elevation myocardial infarction (STEMI) that predict irreversible left ventricular dysfunction. From January 2003 to December 2005, patients presenting with STEMIs and an LVEFs after percutaneous coronary intervention <or=0.4 were included (n = 118). Clinical, angiographic, and electrocardiographic characteristics at the time of STEMI were evaluated to predict LVEF at >or=90 days. Multivariate analysis identified post-percutaneous coronary intervention LVEF <or=0.3 (odds ratio 5.4, 95% confidence interval 2.1 to 14.1, p = 0.001), presentation with Killip class >I (odds ratio 4.4, 95% confidence interval 1.5 to 12.6, p = 0.006), and Q waves on postrevascularization electrocardiography (odds ratio 6.3, 95% confidence interval 1.5 to 26.5, p = 0.011) to be significantly more common in the group with LVEFs <or=0.3 at >or=90 days. The presence of all 3 factors, present in 14 patients (12%), had a positive predictive value of 100% that LVEF would be <or=0.3 at >or=90 days. In conclusion, in patients with STEMIs referred for catheterization, a post-percutaneous coronary intervention LVEF <or=0.3, presentation with Killip class >I, and pathologic Q waves after revascularization each predicted that the LVEF measured at >or=90 days would remain <or=0.3. The presence of all 3 features had a positive predictive value of 100%. These findings may identify a high-risk group of patients who might benefit from early aggressive therapy such as an implantable cardioverter-defibrillator.

Atrioventricular Nodal Reentrant Tachycardia in Two Siblings with Wolfram Syndrome

This is a case of two siblings with the autosomal recessive Wolfram syndrome who both have documented atrioventricular nodal reentrant tachycardia (AVNRT). This is the first report to our knowledge that links AVNRT to a syndrome in which the putative gene has been identified.

Recurrent orthostatic syncope due to left atrial and left ventricular collapse after a continuous-flow left ventricular assist device implantation

Left ventricular assist devices (LVADs) have become an established treatment for patients with advanced heart failure as a bridge to transplantation or for permanent support as an alternative to heart transplantation. Continuous-flow LVADs have been shown to improve outcomes, including survival, and reduce device failure compared with pulsatile devices. Although LVADs have been shown to be a good option for patients with end-stage heart failure, unanticipated complications may occur. We describe dynamic left atrial and left ventricular chamber collapse related to postural changes in a patient with a recent continuous-flow LVAD implantation.

Clinical and electrophysiological characteristics of patients with paroxysmal intra-His block with narrow QRS complexes

BACKGROUND Atrioventricular (AV) block is usually due to infranodal disease and associated with a wide QRS complex; such patients often progress to complete AV block and pacemaker dependency. Uncommonly, infranodal AV block can occur within the His bundle with a narrow QRS complex. OBJECTIVES The aims of this study were to define clinical/echocardiographic characteristics of patients with AV block within the His bundle and report progression to pacemaker dependency. METHODS We retrospectively identified patients with narrow QRS complexes and documented intra-His delay or block at electrophysiology study (group A) or with electrocardiogram-documented Mobitz II AV block/paroxysmal AV block (group B). Clinical, electrophysiological, and echocardiographic variables at presentation and pacemaker parameters at the last follow-up visit were evaluated. RESULTS Twenty-seven patients (19 women) were identified (mean age 64 ± 13 years; range, 38-85 years). Four patients who had <1 month of follow-up were excluded. There were 12 patients in group A and 11 in group B; 21 of 23 presented with syncope/presyncope. All patients received pacemakers: 8 single chamber and 15 dual chamber. After a median follow-up of 6.4 years, the median percentage of ventricular pacing was 1% (interquartile range 0%-4.66%). One patient developed true pacemaker dependency. Aortic and/or mitral annular calcification was present in 13 of 22 patients with available echocardiograms. CONCLUSION Patients who present with syncope and narrow QRS complexes with intra-His delay or Mobitz II paroxysmal AV block with narrow QRS complexes rarely progress to pacemaker dependency and require infrequent pacing. This entity is more common in women, with a higher prevalence of aortic and/or mitral annular calcification. If confirmed by additional studies, single-chamber pacemaker may be sufficient.

Idiopathic Ventricular Fibrillation Ablation Facilitated by PENTARAY Mapping of the Moderator Band

A 44-year-man presented with an out-of-hospital ventricular fibrillation (VF) arrest and subsequently experienced more than 50 external defibrillator shocks despite intravenous lidocaine and amiodarone. Twelve-lead electrocardiography did not show early repolarization. Results of coronary