Electrocardiogram abnormalities in older individuals by race and ethnicity.

BACKGROUND: Aging is associated with many ECG changes. ECG abnormalities are known to be more prevalent with age and differ across race and ethnicity, yet there are limited studies categorizing the ECG changes in the older population and the differences seen among racial groups. We sought to determine ECG differences associated with race and ethnicity in this ethnically diverse, elderly population. METHODS: The ECG parameters of subjects between the ages of 75 and 99 years from a large and diverse inner-city patient population were analyzed. Subjects were grouped into one of four categories: Hispanic, Black, Non-Hispanic White, or Other for analysis. Rhythm, axis, voltage, and conduction parameters were determined according to the 12 SL algorithm and interpretation statements (GE Healthcare, Wauwatosa, Wisconsin) that were confirmed by an overreading cardiologist. RESULTS: 38,238 subjects were included. Of all groups, Non-Hispanic Whites exhibited more conduction abnormalities such as bundle branch block compared to the other groups, as well as the highest incidence of atrial fibrillation (AF) (12.6%, p < 0.05). Hispanics had the highest proportion of normal sinus rhythm. Blacks exhibited the least amount of AF (6.3%), as well as the highest incidence of LVH (25.5%), RAD (13.5%), and the largest percentage of abnormal ECGs (72.8%). CONCLUSION: Significant differences among the elderly of different race and ethnicity were noted with most parameters.

Sinus node recovery after 25 years of atrial flutter.

This case report demonstrates that the sinus node can recover relatively quickly even after being suppressed by atrial flutter for 25 years, and that a permanent pacemaker may not always be necessary in all patients with sinus arrest after a successful atrial flutter ablation.

Case report: is this SVT or VT? An exception to the rule.

This case illustrates the difficulties sometimes encountered by clinicians when using algorithms in diagnosing a wide-complex tachycardia based on a 12-lead EKG.

Histopathological correlation of ablation lesions guided by noncontact mapping in a patient with peripartum cardiomyopathy and ventricular tachycardia.

A patient with peripartum cardiomyopathy developed a nearly incessant nonsustained VT. Guided by a noncontact mapping system, the tachycardia was mapped to the mid-septum of the right ventricle and ablated. Despite transient success, the tachycardia recurred and the patient subsequently died of multiorgan failure. Histopathological correlation of the ablation site revealed a nontransmural lesion that may have contributed to the failure of the ablation.

Internal transcardiac pericardiocentesis for acute tamponade.

If the catheter is still in the pericardium when tamponade is recognized during catheterization or electrophysiologic procedures, it can be used for definitive aspiration and relief of tamponade. This is physiologically beneficial to the patient, and psychologically beneficial to both patient and medical staff.

Abnormal signal-averaged electrocardiogram (SAECG) in obesity.

OBJECTIVE: The occurrence of small high-frequency electrocardiogram (ECG) potentials (1 to 20 microV) seen at the end of the QRS complex and into the ST segment have been correlated with increased risk for ventricular arrhythmias and sudden cardiac death. Computer-assisted analysis of these "late potentials" by signal-averaged electrocardiography (SAECG) has been studied and utilized to predict the likelihood of ventricular arrhythmias in various clinical states. Obesity is associated with significant cardiovascular morbidity and sudden death. Ventricular arrhythmias are postulated causes. We studied the occurrence of late potentials in a randomly selected group of obese patients and healthy volunteers. RESEARCH METHODS AND PROCEDURES: We performed SAECG on 105 subjects. Of these, 62 were obese ambulatory patients with body mass index (BMI) of >30 kg/m2, whereas 43 were healthy asymptomatic volunteers with a BMI of <30 kg/m2. Patients with a history of clinical heart disease and pulmonary disease, electrolyte abnormalities, recent hospitalizations, or abnormal screening ECG or taking medications known to alter the QRS interval were excluded. At least 250 beats were analyzed with a noise level of <0.50 microV. Criteria of a late potential include QRS duration >114 ms, high-frequency low amplitude >38 ms, and root-mean-square voltage <20 microV. Patients were divided into four subgroups based on BMI values. The prevalence of SAECG abnormalities in each BMI subgroup was studied. We utilized multiple logistic regression analysis to study the effect of obesity, hypertension, and diabetes mellitus on abnormal SAECG results. RESULTS: Compared to age- and sex-matched healthy volunteers with BMI of <30 kg/m2, obese patients with BMI of >30 kg/m2 had significantly more abnormalities on SAECG (4.6% vs. 55%). In the obese group, the prevalence and number of abnormalities increased with increase in BMI (35% in the BMI 31 to 40 kg/m2 subgroup, 86% in the BMI 41 to 50 kg/m2 subgroup, and 100% in patients with BMI of >50 kg/m2). Multiple logistic regression analysis shows that BMI is an independent predictor variable of abnormal SAECG results in obese patients (n = 62) with BMI of >30 kg/m2 as well as in all study subjects (n = 105). BMI also predicts abnormality of each abnormal SAECG criterion in both obese and all subjects. Hypertension was found to influence the QRS duration alone in obese and all subjects. DISCUSSION: Obesity is associated with increased occurrence of abnormal SAECG results. These abnormalities are found both in obese patients with and without hypertension and/or diabetes. Obesity is an independent predictor variable of abnormal SAECG results. A history of hypertension predicts abnormality of QRS duration only.

Cardiac memory after radiofrequency ablation of accessory pathways: the post-ablation T wave does not forget the pre-excited QRS.

INTRODUCTION: Normalization of the pre-excited QRS following ablation is accompanied by repolarization changes but their directional relationship to changes in ventricular activation has not been well characterized. METHODS: Accordingly, we measured QRS and T wave vectors and QRS-T angles from 12 lead ECG recordings immediately before and after accessory pathway (AP) radiofrequency ablation in 100 consecutive patients. Patients with bundle branch block, intraventricular conduction defect or intermittent pre-excitation were excluded, leaving a study group of 45 patients: 35 with pre-excitation and 10 with concealed APs. RESULTS: With AP ablation, changes occurred in the QRS and T wave vectors and QRS-T angles that were essentially equal and opposite, so that the newly normalized QRS complex and QRS vector were accompanied by a T wave whose vector approximated that of the pre-ablation QRS vector. This tended to maintain a large QRS-T angle: 72 degrees +/- 50 degrees before, and 54 degrees +/- 34 degrees after QRS normalization (p = NS). A QRS-T angle >40 degrees was found before and after ablation in 22/35 patients (63%) with baseline pre-excitation; but never in patients with a concealed AP (p = 0.001). The angle between the pre-excited QRS and the post-ablation T wave was 35 degrees +/- 37 degrees, and

Symptomatic improvement after AV nodal ablation and pacemaker implantation for refractory atrial fibrillation and atrial flutter.

Symptomatic Improvement was evaluated in 64 patients with drug-refractory atrial fibrillation or atrial flutter who underwent atrioventricular (AV) nodal ablation and permanent pacemaker implantation. The arrhythmias were chronic in 40 patients and paroxysmal in 24 patients. All were refractory to multiple drugs (3.7 +/- 1.5) and had severe symptoms: palpitations (58 patients), dyspnea (n=58), dizziness (n=38), asthenia (n=37), and chest pain (n=20). All underwent AV nodal ablation and single- (n=39) or dual-chamber (n=25) pacemaker implantation. During follow-up of 20.4 +/- 17.8 months, palpitations improved in 100% of 58 patients who had palpitations before the ablation, dyspnea improved in 75% of 58 patients, chest pain in 95% of 20 patients, asthenia in 75% of 37 patients, and dizziness in 93% of 38 patients. Moderate to significant improvement in these symptoms was reported in 83% of patients and mild improvement in 5%. Before ablation, 77% of patients were in New York Heart Association functional class III or IV. After ablation, 19% of patients were in the same functional classes (P < 0.05). Thus, AV nodal ablation and pacemaker implantation in patients with drug-refractory atrial fibrillation or flutter was associated with significant improvement in presenting symptoms and functional capacity. A randomized, controlled study is needed to compare this form of therapy with other therapeutic modalities.

Efficacy and safety of sotalol in patients with refractory atrial fibrillation or flutter.

Sotalol's usefulness in treatment of atrial fibrillation and atrial flutter is unproven. This study evaluated (1) the efficacy of sotalol in preventing recurrences of paroxysmal atrial fibrillation or atrial flutter and controlling ventricular rate (in chronic atrial fibrillation or relapse of paroxysmal atrial arrhythmias), (2) the safety of sotalol, and (3) predictors of sotalol efficacy. Thirty-three patients, 28 with paroxysmal and five with chronic atrial fibrillation or atrial flutter, received an average dose of 265 +/- 119 mg of oral sotalol per day. During a 10 +/- 12 month follow-up, recurrence rate for paroxysmal arrhythmia was 64%, with a 50% recurrence at 4.6 months. For patients with chronic atrial fibrillation, ventricular rates were well controlled with sotalol administration (136 +/- 33 beats/min versus 88 +/- 23 beats/min; p = 0.04). No patient with chronic atrial fibrillation converted to sinus rhythm during the study. Side effects necessitated sotalol discontinuation in three patients. By multivariate analysis, younger age, higher ejection fraction, and absence of hypertension independently predicted sotalol efficacy.

Ultrarapid train stimulation versus conventional programmed electrical stimulation for induction of ventricular arrhythmias in patients with coronary artery disease.

Conventional programmed electrical stimulation (PES) of the ventricle is useful for establishing inducibility or noninducibility of clinical ventricular arrhythmias (VA) but is complex and time consuming. The present study was designed to compare a standard PES protocol with an alternative method using ultrarapid train stimulation in patients with VA and coronary artery disease (CAD). A prospective, randomized, crossover design was used. During each session in the electrophysiology laboratory, patients were studied using both the trains and PES protocols in randomized order. In 82 matched pairs of comparisons in 50 patients, results were concordant in 85% (p < 0.0001). There were no differences related to type of clinical arrhythmia or to the presence of antiarrhythmic drugs. There were no significant differences in the induction of nonclinical arrhythmias with the two methods (p < 0.0001 for concordance). There were no significant differences related to the cycle length of the trains (10, 20, or 30 ms, equivalent to 100, 50, or 33 Hz). The number of drive-extrastimuli sequences and the time required to complete the trains protocol was significantly shorter (p < 0.0001) using trains versus PES. Ultrarapid train stimulation provides results in CAD patients that are comparable with those of conventional PES protocols. There is a significant savings in time, adding practical value to intrinsic electrophysiologic interest. Trains may be useful when multiple inductions are desirable, for example, in the setting of antitachycardia pacing parameters in an implantable defibrillator (ICD), during ICD implantation, or in other circumstances where the main question is inducibility of ventricular arrhythmias.

Comparison of long-term outcomes of patients treated with nonthoracotomy and thoracotomy implantable defibrillators.

In 193 consecutive patients treated with implantable defibrillators at our institution, thoracotomy approaches were used in 87 patients and nonthoracotomy approaches in 106 patients. Long-term outcomes of the 2 groups were compared by the intention-to-treat analysis. Surgical mortality (30-day mortality) rates were 5.7% in the thoracotomy group and 0% in the nonthoracotomy group. Six of 106 patients who underwent nonthoracotomy implantation had a high defibrillation threshold and did not receive nonthoracotomy defibrillators. The duration of follow-up was 52 +/- 31 months in the thoracotomy group, and 23 +/- 15 months in nonthoracotomy group. Actuarial survival rates at 6 and 24 months were, respectively, 90% and 81% in nonthoracotomy patients and 89% and 80% in thoracotomy patients (p = NS). In patients with left ventricular ejection fraction <30%, surgical mortality was 0% by the nonthoracotomy and 10% by the thoracotomy approach. Despite the 10% difference in 30-day mortality, survival rates at 6 months were 85% in nonthoracotomy patients and 81% in thoracotomy patients. At 24 months they were 73% in nonthoracotomy patients and 74% in thoracotomy patients. Thus, this nonrandomized study suggests that while short-term survival is better in nonthoracotomy patients than thoracotomy patients, the difference in survival diminishes quickly during the first few months and disappears by 6 months. The results were similar in patients with severe ventricular dysfunction. Several important implantable-cardioverter defibrillator (ICD) trials initially utilized thoracotomy ICDs. Although questions may be raised with regard to applicability of such a trial in the era of nonthoracotomy ICDs, this study suggests that the results of such ICD trials will be largely applicable to patients treated with nonthoracotomy ICDs.

Comparison of burst pacing, autodecremental (ramp) pacing, and universal pacing for termination of ventricular tachycardia.

This study was designed to test the comparative efficacy of burst pacing, autodecremental (ramp) pacing, and universal (steep ramp) pacing for termination of ventricular tachycardia. A prospective, randomized sequence cross-over design was used to achieve comparisons of the pacing modalities that were matched for patient, day, and ventricular tachycardia characteristics. Thirty eight patients were enrolled, whose ventricular tachycardia was well-enough tolerated to be reinduced, and tested with 3 pacing modalities. There were 27 series 1 patients in which the pacing modalities were nonsynchronized burst pacing, synchronized burst pacing, and ramp pacing. The 11 patients in series 2 were tested with synchronized burst pacing, ramp pacing, and universal pacing. All pacing methods proved to be comparable in their ability to terminate ventricular tachycardia (p = NS). The 2 burst methods required the fewest number of attempts (significant vs ramp pacing). Universal pacing required the fewest number of stimuli. The mean paced cycle length was similar will all methods. The shortest paced cycle lengths were found with the autodecremental and universal methods because of their ramp patterns. It is concluded that burst, ramp, and universal pacing are of similar efficacy, although ramps were least efficient. Choice of a modality depends on operator preference, and individual patient response.

Evaluation of end points of serial drug testing in patients with sustained ventricular tachycardia after healing of acute myocardial infarction.

Serial electrophysiologic drug testing was used to guide antiarrhythmic therapy in a consecutive series of 150 patients with clinical sustained ventricular tachycardia (VT) or cardiac arrest and inducible monomorphic VT. All patients had coronary artery disease and a history of myocardial infarction. For patients with clinical sustained VT, drug responders and partial drug responders (VT slowed by drug to rate < 150 beats/min, with systolic blood pressure > or = 90 mm Hg) had similar total mortality rates (2-year actuarial survival 100% and 94%, p = NS), which were statistically different from that of patients with drug inefficacy (2-year survival 67%). Partial drug responders had high arrhythmia recurrence rates, similar to those of patients with drug inefficacy. For cardiac arrest survivors, the results of electrophysiologically guided drug testing did not predict prognosis. Patients with a change in mode of VT induction during antiarrhythmic therapy had a favorable prognosis (no deaths during follow-up).

Reproducibility of electrophysiological testing during antiarrhythmic therapy for ventricular arrhythmias unrelated to coronary artery disease.

Although electrophysiological studies are commonly used in the management of patients with ventricular tachycardia (VT), the reproducibility of these studies during therapy has not been established in patients in whom VT is associated with conditions other than coronary artery disease. Therefore, we performed confirmation studies during drug therapy in 60 patients (mean age 48 +/- 18 years; 41 male) with sustained ventricular arrhythmias induced during initial study to assess the reproducibility of drug effect. The stimulation protocol used included the serial introduction of up to three premature ventricular stimuli during sinus rhythm and with ventricular pacing at two pacing rates. Rapid ventricular pacing techniques were also used. Antiarrhythmic drug efficacy was confirmed in 78% of patients. Sustained VT was induced at repeat electrophysiological study in 18% of patients during antiarrhythmic therapy that had been felt to be effective on the basis of a single drug study. We conclude that electrophysiological study results during antiarrhythmic therapy exhibit significant day-to-day variability. Sustained VT can be induced during antiarrhythmic therapy previously determined to be effective by electrophysiological techniques in many patients.

Long-term outcomes and modes of death of patients treated with nonthoracotomy implantable defibrillators.

Long-term outcomes of all patients who underwent nonthoracotomy implantable cardioverter-defibrillator (ICD) implantation at our institution from April 1991 to October 1994 were studied using the intention-to-treat analysis. Of 94 consecutive patients, 81 underwent nonthoracotomy ICD implantation and 13 underwent thoracotomy (for concomitant surgery in 11 and unavailability of nonthoracotomy leads in 2). Six of 81 patients had a high defibrillation threshold, 4 subsequently underwent thoracotomy, and 2 were treated with amiodarone. Surgical mortality was 0%. The duration of follow-up was 20 +/- 13 months, and was > 12 months in 74% of 67 living patients. Actuarial survival rates at 1 and 2 years were, respectively, 98% and 94% for sudden death and 91% and 83% for total mortality. Deaths during long-term follow-up were mostly due to nonsudden cardiac or noncardiac deaths. Two-year mortality rates were 12% and 25% in patients with ejection fraction > or = 30% and < 30%, respectively. Thus, instances of sudden death and surgical mortality are very few in patients with nonthoracotomy ICDs. Deaths during long-term follow-up are mostly due to nonsudden cardiac and noncardiac deaths. Therefore, ICD therapy may have greater impact on survival in patients with lower risks of nonsudden cardiac and cardiac death (e.g., younger patients with minimal heart disease) than in patients with severe cardiac or noncardiac disease. Prospective studies are needed to address this question.

Prediction of electrophysiologic study results in patients treated with amiodarone.

To identify whether electrophysiologic study results during early-phase amiodarone therapy can be predicted by previous electrophysiologic study, we reviewed the electrophysiologic data of 50 patients with inducible sustained ventricular arrhythmias who underwent 4.3 +/- 1.3 drug trials before being given amiodarone. Study results during testing with agents of the modified Vaughan Williams Ia classification were compared with data obtained after 2 weeks of amiodarone therapy. Partial response by electrophysiologic study was defined as well-tolerated ventricular tachycardia < 150 beats/min associated with a blood pressure > or = 90 mm Hg. Significant slowing in the rate of induced ventricular tachycardia was seen during therapy with both Ia agents and amiodarone, although there was a trend toward greater slowing during amiodarone treatment (180 +/- 45 beats/min vs 164 +/- 65 beats/min; p = 0.09). Two of three patients with noninducible ventricular tachycardia during amiodarone showed profound ventricular tachycardia slowing during Ia therapy. Thirty-eight of 50 patients demonstrated concordance of electrophysiologic study results with regard to achieving partial response criteria. Twenty patients died during a mean follow-up period of 37 +/- 29 months; 7 of the 10 sudden deaths occurred in patients who did not meet partial response criteria. We conclude that patients with inducible sustained ventricular arrhythmias failing serial drug testing with Ia agents only rarely have their ventricular tachycardia suppressed during amiodarone therapy. Partial response criteria are often concordant between testing on agents of the Ia classification and amiodarone, and there was no significant difference in survival in patients based on their partial response status.