Reginald T. Ho

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.

EEG and ECG in Sudden Unexplained Death in Epilepsy

Summary:  Purpose: Sudden unexpected death in epilepsy (SUDEP) is a major cause of mortality for patients with epilepsy. Cardiac factors may be involved and were evaluated in this study.

Lead-associated endocarditis: the important role of methicillin-resistant Staphylococcus aureus.

Background: Infection is a potentially life‐threatening complication of cardiac device implantation. Lead‐associated endocarditis (LAE) may be the most serious complication since it is associated with a high mortality.

Differentiating atrioventricular nodal reentrant tachycardia from atrioventricular reentrant tachycardia by ΔHA values during entrainment from the ventricle

BACKGROUND Differentiating atrioventricular nodal reentrant tachycardia (AVNRT) from orthodromic atrioventricular reentrant tachycardia (AVRT) can be difficult. The His bundle and atria are activated sequentially over the AV node during entrainment of AVNRT from the ventricle but simultaneously during supraventricular tachycardia (SVT). They are activated in parallel during entrainment of AVRT but sequentially during SVT. OBJECTIVE The purpose of this study was to test the hypothesis that a DeltaHA (HA((entrainment)) - HA((SVT))) cutoff value of 0 reliably differentiates AVNRT from AVRT. METHODS AND RESULTS Of 61 patients undergoing electrophysiologic evaluation for paroxysmal SVT, retrograde His-bundle potentials were recorded in 57 (93%) and entrainment performed in 49 (34 AVNRT, 15 AVRT). DeltaHA values during entrainment from the ventricle were significantly longer during AVNRT than AVRT (31 +/- 24 ms vs -38 +/- 31 ms, P <.001). All DeltaHA values were positive (minimum: 3 ms) for AVNRT and negative (maximum: -2 ms) for AVRT. DeltaHA of 0 had sensitivity, specificity. and positive predictive value of 100% for correct diagnosis. CONCLUSION The DeltaHA criterion during entrainment of tachycardia from the ventricle reliably differentiates AVNRT (positive values) from AVRT (negative values).

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.

Long-term cardiac rhythm and repolarization abnormalities in refractory focal and generalized epilepsy

This prospective study evaluated 19 individuals with refractory focal or generalized epilepsy utilizing an implantable cardiac loop recorder. Recording averaged 15 months (range 12–19 months) in 18 patients and 1.5 months in one patient. A median of 37 seizures per patient (range 3–657) occurred, with 1,477 seizures total. Cardiac arrhythmias and repolarization abnormalities occurred frequently (in 42% of patients) in refractory epilepsy, particularly during generalized tonic–clonic and tonic seizures. Patients with Lennox‐Gastaut syndrome may be at high risk for cardiac abnormalities.

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.

Simultaneous Use of Neurostimulators in Patients With a Preexisting Cardiovascular Implantable Electronic Device

Object:  Neurostimulation is widely accepted for the treatment of refractory Parkinsons disease, essential tremor, and chronic pain. The presence of a cardiovascular implantable electronic device (CIED) might be considered a contraindication for neurostimulators due to the possible interaction between the two devices. The purpose of this study is to report the feasibility and safety of concomitant use of neurostimulators and CIED, and to review surgical and clinical precautions needed to avoid possible interference between the two systems.

Entrainment versus resetting of a long RP tachycardia: what is the diagnosis?

t c s a p b c d t t d i t P s Case presentation A 71-year-old man with a history of chronic obstructive pulmonary disease presented for electrophysiological study because of recurrent hospitalizations due to a long-RPinterval narrow complex tachycardia refractory to verapamil therapy. His 12-lead electrocardiogram and echocardiogram were normal. Baseline atrio-His and His-ventricular intervals measured 56 ms and 41 ms, respectively. During programmed atrial extrastimulation, dual atrioventricular (AV) node physiology was not observed. Retrograde conduction was midline (earliest at the anteroseptum) and confirmed to be over the fast pathway (FP) of the AV node by paraHisian pacing at multiple cycle lengths. Tachycardia was easily and reproducibly induced from both the ventricle and the atrium (Figure 1). The response of tachycardia to entrainment from the ventricle and diastolic ventricular premature depolarizations (VPDs) are shown in Figures 2 and 3, espectively. Based on these observations, what is the mechnism of tachycardia?

Permanent pacing from a left ventricular vein in a patient with persistent left superior vena cava and absent right superior vena cava: use of an over-the-wire system.

In patients with a persistent left superior vena cava, placement of a permanent transvenous pacing lead for ventricular pacing via the left subclavian vein can be technically challenging. Permanent pacing was achieved in a patient with a persistent left superior vena cava and absent right superior vena cava using a left ventricular vein. Use of an over-the-wire lead system greatly facilitated this procedure.