Acute loss of capture due to flecainide acetate

Antiarrhythmic drugs increase pacing threshold, but this is rarely of clinical significance. Administration of flecainide acetate in a 75-year-old woman with an implanted AAIR pacemaker because of sick sinus syndrome caused an abrupt rise of pacing threshold and failure of pacing. Pacing threshold returned to the normal value a few days after flecainide treatment was stopped.

Recurrence of symptomatic ventricular arrhythmias in patients with implantable cardioverter defibrillator after the first device therapy: implications for antiarrhythmic therapy and driving restrictions. CARE Group

OBJECTIVES

The purpose of this study was to investigate whether clinical or electrophysiologic characteristics could predict initial and subsequent implantable cardioverter defibrillator (ICD) therapy.

BACKGROUND

Identification of markers to predict subsequent ICD therapy and symptoms after the first event could affect patient management.

METHODS

We analyzed baseline and follow-up data on 125 ICD patients followed for 408+/-321 days. Medications and ICD programming were not changed after first ICD therapy.

RESULTS

Implantable cardioverter defibrillator therapy occurred in 58 patients (46%). Clinical features were as follows: mean left ventricular ejection fraction (LVEF) 29%+/-15%; coronary artery disease 84%; presenting arrhythmia with sustained monomorphic ventricular tachycardia (SMVT) in 68%. In a multivariate analysis the relative risk for ICD therapy in patients presenting with SMVT versus cardiac arrest (CA) was 2.57 (range, 1.32 to 5.01), and for patients with LVEF < or =25%, 1.95 (1.11 to 3.45), respectively (p < 0.05). Implantable cardioverter defibrillator therapy was not predicted by any other variable. Forty-six patients had second ICD therapy. Mean time to second ICD therapy was only 66+/-93 days compared with 138+/-168 days for first ICD therapy (p < 0.05). No predictor for second ICD therapy was found. Regarding symptoms, impaired consciousness during initial ICD therapy was predicted only by SMVT cycle length <250 ms at electrophysiologic testing. In contrast, symptoms were similar between first and second ICD therapy (p = 0.0001). Of note, ventricular tachycardia cycle length preceding first and second ICD therapy was similar (r = 0.76, p = 0.001).

CONCLUSIONS

First ICD therapy tends to occur in patients presenting with SMVT and LVEF < or =25%. Subsequent therapy occurs sooner and is unpredictable, suggesting that antiarrhythmic drug therapy should be considered after the first symptomatic ICD therapy. Symptoms during first ICD therapy predict subsequent symptoms, and patients presenting with SMVT and asymptomatic first ICD therapy are at very low risk for future syncopal ICD therapy.

Lead insertion by supraclavicular approach of the subclavian vein puncture

Total occlusion of the left subclavian vein was diagnosed in a 76-year-old patient, 6 years after implantation of an ICD with VVI pacing backup. Replacement of the ICD included upgrading of the ICD system because of the presence of pacemaker syndrome when the patient was VVI paced. Insertion of an atrial lead through the ipsilateral vein system was made possible by using the supraclavicular approach of the subclavian, enabling puncturing of the left subclavian vein medially to the obstruction.

Failure of left-sided implantable cardioverter defibrillator implantation due to absence of left brachiocephalic vein

Implantation of an implantable cardioverter defibrillator by the transvenous approach was impossible from the left side in a patient with on absence of the left brachiocephalic vein; the left subclavian vein was connected by a large left superior intercostal vein to the accessory hemiazygos vein that joined the azygos vein; then the blood flowed into the superior vena cava. Implantation was successfully attempted using the right-sided venous access.

[Propafenone dose for emergency room conversion of paroxysmal atrial fibrillation]

Paroxysmal atrial fibrillation (AF), a frequent cause of repeated hospitalization, is effectively treated with propafenone. The time to conversion to sinus rhythm is a consideration when managing AF in the emergency room. We investigated the conversion rates of paroxysmal AF by 3 different oral propafenone (P) regimens, in terms of time to conversion. 188 patients with onset of AF within 48 hours were treated with propafenone (P): 48 received 600 mg as a first oral dose followed after 8 hrs by 150 mg (Group A); 82 received 300 mg as a first dose, followed by the same dose 3 and again 8 hrs later (B); 58 received 150 mg every 3 hrs, up to a total dose of 600 mg (C). P was stopped when sinus rhythm was achieved. Rates of conversion to sinus rhythm after 3 hrs in the 3 groups were: 46%, 41% and 26% respectively; after 8 hrs: 77%, 78% and 70%; and after 12 hrs: 81%, 84% and 76%. Treatment was discontinued in 8. There was excessive QRS widening (> 25% of the basal value) in 1 in group A, 1 in group B and 2 in group C; wide-QRS tachycardia occurred in 4 in group B. In Group A there was a higher rate of early successful conversion, with a lower incidence of side-effects than with the other regimens.

Insulation lead failure: is it a matter of insulation coating, venous approach, or both?

Lead insulation material and implant route have a major impact on lead reliability and durability. We compare the incidence of lead insulation failure resulting from both the venous approach and insulation type. Two hundred ninety consecutive leads were followed for a mean period of 57 +/- 30 months; leads with < 1 year follow-up were excluded. There were 116 Silicone Rubber insulated leads and 174 with polyurethane (151 Pellethane 80A and 23 Pellethane 55D) insulation; 279 leads were bipolar and 11 unipolar; 274 leads were implanted in the ventricle and 66 in the atrium. The venous route was the subclavian vein for 170 leads (58%) and the cephalic vein for 120 leads (42%). Insulation failure was diagnosed when a single sign of oversensing, undersensing, failure to capture, early pulse battery depletion, and lead impedance < 250 omega was present. Measurement of lead impedance was performed intraoperatively at implantation and during lead revision or pulse generator replacement. Lead failure caused by conductor coil fracture was not considered. There were 13 lead insulation failures, all among leads with polyurethane insulation (12 Pellethane 80A and 1 Pellethane 55D). Eleven failures (10%) occurred when the subclavian vein and 2 (3%) when the cephalic vein approach was used. The cumulative survival rate of polyurethane and silicone rubber insulated leads was 88.7% and 100%, respectively (P = 0.02); the cumulative survival rate of polyurethane insulated leads was 83.2% when the subclavian vein and 95.1% when the cephalic vein were used (P = 0.03). The mean time to polyurethane lead failure when the subclavian vein approach was used was 54 +/- 17 months and when the cephalic route was 73 +/- 4 months (P < 0.02). By multivariate analysis, the route of entry was found to be a significant variable related to polyurethane insulated lead failure (P < 0.05). At lead revision failure to capture was present in 7, oversensing in 4, and undersensing in 2 instances; impedance was < 250 omega in all cases. Pellethane 80A insulated leads are prone to insulation failure, but more when the subclavian vein is used, rather than the cephalic vein.

The outcome of patients with acute myocardial infarction ineligible for thrombolytic therapy. Israeli Thrombolytic Survey Group

PURPOSE

The aim of this study was to determine the proportion of patients with acute myocardial infarction (AMI) excluded from thrombolytic therapy on a national basis and to evaluate the prognosis of these patients by reasons of ineligibility and according to the alternative therapies that they received during hospitalization.

PATIENTS AND METHODS

During a national survey, 1,014 consecutive patients with AMI were hospitalized in all the 25 coronary care units operating in Israel.

RESULTS

Three hundred and eighty-three patients (38%) were treated with a thrombolytic agent and included in the GUSTO study. Ineligible patients for GUSTO were treated: (1) without any reperfusion therapy (n = 449), (2) by mechanical revascularization (n = 97), or (3) given 1.5 million units of streptokinase (n = 85) outside of the GUSTO protocol. The inhospital and 1-year post-discharge mortality rates were 6% and 2% in patients included in the GUSTO study; 6% and 5% in those mechanically reperfused; 15% and 10% in those treated with thromoblysis despite ineligibility for the GUSTO trial, and 15% and 13% among patients not treated with any reperfusion therapy.

CONCLUSIONS

Ineligibility for thrombolysis among patients with AMI remains high. Patients ineligible for thrombolysis according to the GUSTO criteria, but nevertheless treated with a thrombolytic agent were exposed to an increased risk.

Transiliac vein approach to a rate responsive permanent pacemaker implantation

A 60-year-old patient was admitted for elective replacement of a depleted pulse generator. The pacemaker was implanted 5 years before because of sick sinus syndrome and it was connected to an epicardial lead due to total occlusion of the superior vena cava. The pacing threshold of the epicardial electrode was unacceptably high, so an endocardial lead was inserted through the iliac vein. The lead was connected to a VVIR pacemaker, which was located in the abdomen just lateral to the umbilicus. During a 1-year follow-up period, the patient felt well and pacemaker performance was satisfactory.

A Soviet nuclear pacemaker

A Soviet nuclear pacemaker is described. It is a large VOO bipolar pacemaker, probably nonprogrammable. It has unique electrode connectors. No isotope leak or excessive radiation hazard was detected. Because we had no knowledge of its end-of-life markers and because of the impossibility of assuming long-term safety, the device was removed.